Looking For More Punch From My 2245, 4345 Clone

[robertg]

I'm trying to get more punch or kick out of a 2245. The system that I had before my 4345 clones had dual 15" 2226 drivers. It had some serious kick.

My amp is a RAMSA WP9440 with 350 watts, I'm thinking I should try a bigger amp first? Maybe 6-700 watts?

Would a 2240 or 2242 be a direct replacement for the 2245 without changing the tuning? I'm not sure if I really need much below 50Hz, I just listen to 70s music, no home theatre.

[Mr. Widget]

I don’t think of the 2245 as a kicker... it is more about musicality and finesse. Where are you crossed over and to what?

If you crossed over at 250Hz to a 2202, I imagine you would have all the “kick” you could want.


Widget

[robertg]

I am crossed over to a 2123 at about 250 Hz right now. I've tried anywhere from 150 Hz to 300 Hz, I have an Xilica XP4080 active crossover. The red lights flash on my amp right now when I play it loud, that's why I'm thinking I might try a larger amp.

Basically it's winter here and I am bored and have too much time on my hands to think. I am thinking of buying a larger Crest amp, like a CA12, or a Crown Reverence 1 that is 760 watts.

[Robh3606]

I am crossed over to a 2123 at about 250 Hz right now. I've tried anywhere from 150 Hz to 300 Hz, I have an Xilica XP4080 active crossover. The red lights flash on my amp right now when I play it loud, that's why I'm thinking I might try a larger amp.

You have me scratching my head. If you don't have it now more power is not going to do it. You should have the "kick" at any power level. Even if you X4 your power it's all headroom and at 100db,which should be a cake walk for 2245's, it should be there.

Try placement.

Rob:)

[Earl K]

I'm trying to get more punch or kick out of a 2245. The system that I had before my 4345 clones had dual 15" 2226 drivers. It had some serious kick.

My amp is a RAMSA WP9440 with 350 watts, I'm thinking I should try a bigger amp first? Maybe 6-700 watts?

Would a 2240 or 2242 be a direct replacement for the 2245 without changing the tuning? I'm not sure if I really need much below 50Hz, I just listen to 70s music, no home theatre.


Hi Robert,

What are your 4345 clones currently tuned to?

I would first try moving the box tuning upwards ( after verifying what the current tuning is ).

FYI, boxes tuned too low ( sometimes done by accident ) can stress the woofer making it lose punch by wasting output/cone-movement on those frequencies that are barely heard.

Have you verified that your 2245H's have actual JBL cone kits installed ?



:)

BTW; I do have a few retired Crest CA12's here collecting dust ( they require a dedicated 20-30 amp circuit to work their magic ).

[Ian Mackenzie]

If it’s a clone you might follow Earl’s lead.

I have listened to 4343’s quite a bit with 2235 fifteen inch woofers.
The perception is they hit hard but in reality they don’t have the linearity of the 2245 bottom end.

The 4345 has a very immersive presentation which people tend to like.
It comes down to taste in the end. Think Stargate. It takes to somewhere else.

If you can get them six inches off the floor everything works better.

Getting the blend right between the 2245 and the 2123 is best done with a modified second order crossover. The low and high pass are not symmetrical. The passive bandpass filter used from the 4344mk11 behaves very differently in Biamp mode. Greg said you have to measure the voltage drives on the actual driver terminals. He knows. I went this route because it works beautifully with my 2420 drivers and dusted titanium diaphragms. The blend is inperceivable right across the spectrum.

Some claim good results with the 3155 network using 2123 with 2446 drivers on 2311 horns. Whatever floats your boat.

I use a Yamaha Power amp 800+800. 350 watts should do it.

It usually takes a little while to set these systems up to give their best.

[toddalin]

Something you may want to try, just for "shits and grins" is to let this run as a 3.5 way. IOW, don't the run high pass cap on the 2123 and let it roll of naturally at it's bottom end. You can just "jump" around the cap (but may need to disconnect the choke if present) for a trial. You won't hurt the 2123 in a home setting and may prefer the results.

This is what I ended up doing with the 2251J/2241H combination, and is the best they have sounded. Of course the 2251J has a very nice natural roll off at its bottom end that blends nicely with the 2241 (with 8 mH/95 mfd with a 100 mfd/1.2 ohm "Zobal").

Why would one want to ruin this beautiful rolloff by subjecting it to a cap?

https://lh3.googleusercontent.com/proxy/NoVbekwUQnvN41o7vx8b7L9dbdLmqMLY5bGbkvBESPk6LFqqDY lH6DuVjJKgcmI8KncfgJLh8WUmPNe34juRBt9LQ76EaVItpZYH-pW4ZSx3qOF_u0GuqqUjAnoDrEp3Hn-HLQp7chmQ937gpBFQ0KYGMw

[rusty jefferson]

I'd start troubleshooting at a pretty basic level. It looks like you're quad-amping? Confirm all your woofers are moving in the right direction with a battery charge applied to the binding posts. I've seen several systems with a simple connection reversed internally. Check your amps to speaker connections also. I've seen an instance where 1 end of a Speakon connector was accidentally wired backwards. You could put a 1kw amp on those woofers and get no bass if 1 is out of phase.

After confirming the above is all good and still no bass, you could try reversing polarity on just the 2245s with your crossover or at the binding posts and see if that helps.

Do you have measurement tools?

[BMWCCA]

Depending on your definition of "punch" it may have nothing to do with the 2245s.

"Kick", "snap", "punch" however you define them can occur at frequencies pretty much all over the map! :dont-know:

[robertg]

My first step was to reverse the wires to the woofers and take a measurement. My ears couldn't hear a major difference but using my REW program I came up with this. Now they are out of phase. Green is right, red is left, blue is both.

[robertg]

I will have to check my box tuning next. I followed the plans here closely, so I doubt if my tuning is wrong. I did change the opening to my ports by rounding them slightly. here is a picture of the front of the woofer. I was told they were OEM recones.

[Earl K]

Robert,

A couple of things;

(1) The blue trace; I would expect that both woofers playing together would add level/volume ( not subtract level, as is seen in your pic ).
- I think one of those 2245's is operating with flipped polarity to the other ( it could be your system electronics has a phase reversed cable ) .

(2) Unless the woofer cones are coated with aquaplas ( on the backside ) then the cone kits are aftermarket.

:)

[robertg]

Robert,

A couple of things;

(1) The blue trace; I would expect that both woofers playing together would add level/volume ( not subtract level, as is seen in your pic ).
- I think one of those 2245's is operating with flipped polarity to the other ( it could be your system electronics has a phase reversed cable ) .

(2) Unless the woofer cones are coated with aquaplas ( on the backside ) then the cone kits are aftermarket.

:)
That's with one of the woofer cables reversed. I was expecting a graph like that.

I'll have to pull one of the woofers and take a picture of the back side.

[Robh3606]

I will have to check my box tuning next.

Easy just do an impedance sweep and the lowest value between the 2 peaks is your box tuning. As long as your are in a Hz or two all should be fine.

Rob:)

[toddalin]

My first step was to reverse the wires to the woofers and take a measurement. My ears couldn't hear a major difference but using my REW program I came up with this. Now they are out of phase. Green is right, red is left, blue is both.


Maybe just one is out of phase? Got a compass???

I have a 2241 with a reversed polarity magnet and no matter which way I wired them (both being the same), they were always out of phase with no bass until I purposely wired one out of phase. ...So caca occurs..., and from what I understand, it is about 1 in 50.

[Robh3606]

Depending on your definition of "punch" it may have nothing to do with the 2245s.

"Kick", "snap", "punch" however you define them can occur at frequencies pretty much all over the map! :dont-know:

Good point I am taking it as sheer impact you know the visceral impact. A pair of 15's, especially depending on box tuning and placement can damn near beat you to death. Especially 100db 1 watt sensitive with kilowatt power handling. That's damn near a 4648 cinema box.

Rob:)

[robertg]

This is a sweep with everything hooked up correctly. I think it looks right, the blue is both speakers. I turned up the gain on the bottom amp so it is higher up to the first crossover point. I think it's 290 Hz now.

[robertg]

If it’s a clone you might follow Earl’s lead.

If you can get them six inches off the floor everything works better.



My 15" woofers did sit about six inches higher in the cabinets than these. I'm going to try to make a pair of stands to raise them.

As Mr Widget said, these definitely have more finesse than the dual 2226 drivers. When I hooked them up I did like them a lot better. Just playing some songs at insanely high levels the single 18" lost something that the dual 15" had.

[Mr. Widget]

Depending on your definition of "punch" it may have nothing to do with the 2245s.

"Kick", "snap", "punch" however you define them can occur at frequencies pretty much all over the map! :dont-know:Yes, that was my point. The 2202 is much punchier than the 2122 or 2123. Personally, I prefer the 10” woofers, but if my goal was punch, that is where I’d look.

Of course, as many here have pointed out, there are many factors to consider, properly operating drivers, proper tuning, room position, personal expectation...:blah:


Widget

[Mr. Widget]

Just playing some songs at insanely high levels the single 18" lost something that the dual 15" had.Now we’re getting somewhere.

Years ago I built a pair of 4355 clones. They really didn’t do it for me… they certainly kicked ass, but I prefer speakers with a more refined capability… that also can kick ass.

I don’t think the 2245 is letting you down, but I don’t think that the 10 inch mid bass driver is ever going to give you a bad ass rock concert in your house if that’s where you’re going. it will certainly get loud, but there’s something about it that doesn’t quite have the slam of a PA system driven hard. The 2202 will give you that. It would be interesting to get Audiohack’s opinion on this as well. He has been known to turn the system up loud occasionally.


Widget

[Ian Mackenzie]

My first step was to reverse the wires to the woofers and take a measurement. My ears couldn't hear a major difference but using my REW program I came up with this. Now they are out of phase. Green is right, red is left, blue is both.

Robert,

My suggestion is to use a process of elimination to finding the cause of your subjective issue.

I generally find if something sounds off that with some work I can isolate and fix the issue. Always trust your ears and assume nothing is ever perfect.

There is a bit to read through below. Use it as a check list in terms of what to look for and what to do about it.

Start by testing the box tuning frequency first. Also test for air leaks around the enclosure.

About box tuning. Check the Fb (box tuning frequency by sweeping a sine wave up and down from 20 - 35 hertz
and observe the point of minimal cone excursion. You can do this by gentle touch. The impedance curve is not
entirely accurate due the driver inductance according to Greg Timbers.
Greg said the tuning frequency should be around 28 hertz. A shade either side of that is permissible.
(that's the way he explained it to me when I built my clones in 2003).

Your enclosure should be lined with one inch fibre glass sheet insulation on five sides and around the Dog box.
If you are using another material that opens up unknown variables. ie the box volume might be smaller than
specified if you are using under felt or foam rubber or pillows.


Positioning. Try re-positioning of the enclosures if that is practical. A trolley board with 4 heavy duty casters works well.
Small incremental movement out from the rear wall can be helpful in obtaining the smoothest bass.
Try raising the enclosure if practical. The combination of horizontal and vertical movement from the wall/floor
boundaries can assist in moderating the worst of most bass response issues.

The bottom on the horn lens should be level with your ears for best imaging.

Measurements. Are you able to describe how you did these measurements?

Distance from the baffle?
Sine wave , Pink noise?

FWIW I have only ever obtained meaningful measurements on my driveway with the enclosures laying on the side (ground plane) using 5 db per division at 2 metres.

The phase cancellation which you might expect at the crossover point is unlikely to be visible if you take a measurement from the listening position inside your home. 10 db per division is not going to show much.

About the phase. Per the 3145 schematic and Giskard's equivalent schematic the mid range array drivers are wired out of phase
to the woofers after the L pads.
JBL specified 18 db slopes in the stock system. The 18 db active slope was chosen because it was the closest
standard filter to the custom 12 db passive filter slopes.

However you are using the 2123H and without knowing your bi amp crossover characteristic you can't
really predict or determine the effect of reversing the woofer electrical phase. The 2123 has a different low
frequency characteristic to the 2122 and requires different associated passive low pass filters to obtain a smooth
response.

So there are a few unknowns and you might advise how your passive crossovers are arranged for the 2123
drivers?

Active crossovers. The thing to appreciate is that most 3rd party active crossovers assume you are using text book drivers.
Unfortunately that is far from the case in this complex four way system where you have substituted out the stock
2122H mid range driver due to it being NLA with the 2123H. Like lots of things in audio everything matters and
the crossover is the heart if your loudspeaker. So its worth getting it right if you can. BTW the dog box should
only be lightly filled with fibre glasinsulation. Too much and it will sound over damped


You might try the 24 db LR filters and wire everything electrically in phase. Listen and see what the measurements look like.

The LR24 crossover is the most black and white crossover function as everything should in theory sum flat with
text book drivers wired electrically in phase. It kind of dumbs it down because the slopes are steep and its a good
compromise when you don't know what's going on in the diy space.
The 18 db filters are the son of a bastard in that they are neither here nor there.

As I hinted at previously I would use a 2nd order low pass filter and a 2nd order butter-worth high pass filter and
listen and measure if you are using the 4344mk11 mid range passive low pass filter.

If your digital active crossover allows custom filters then you can try adjusting the filters crossover point
"spread" until you get a measured null with the woofer electrically out of phase (LR24)(measured at 1 metre) or
electrically in phase (12 db) filters. The centre frequency should be 300 hertz

The subjective effect of acoustic anti phase driver is a thin sounding mid range generally.

I hope these points provide some clarity.

Ian

[Ian Mackenzie]

Now we’re getting somewhere.

Years ago I built a pair of 4355 clones. They really didn’t do it for me… they certainly kicked ass, but I prefer speakers with a more refined capability… that also can kick ass.

I don’t think the 2245 is letting you down, but I don’t think that the 10 inch mid bass driver is ever going to give you a bad ass rock concert in your house if that’s where you’re going. it will certainly get loud, but there’s something about it that doesn’t quite have the slam of a PA system driven hard. The 2202 will give you that. It would be interesting to get Audiohack’s opinion on this as well. He has been known to turn the system up loud occasionally.


Widget

I heard Elton John last week. Six arrays and wham. That was loud and punchy. They dial in the effects and bingo that crowd goes crazy. Its all very subjective and everyone has their own ear for what turns them on emotionally.

The thing is any SR based system is going to too slam and beat you up. If you like that cool. Bring on the wall of sound.
But are you really craving to get closer to the musicians. I think the slam and punch create that desire.

Turn it up at home. Are you craving for what's missing?

IMHO being front centre stage in a club in SF is more real. The pure tone, texture of the brass and strings, the snare and the growl of the Fender brings on a far more emotional engagement with the sensors.

Set up properly the 4345 ticks a lot of boxes without going financially off the deep end.

[robertg]

Robert,

My suggestion is to use a process of elimination to finding the cause of your subjective issue.

I generally find if something sounds off that with some work I can isolate and fix the issue. Always trust your ears and assume nothing is ever perfect.

There is a bit to read through below. Use it as a check list in terms of what to look for and what to do about it.

Start by testing the box tuning frequency first. Also test for air leaks around the enclosure.

About box tuning. Check the Fb (box tuning frequency by sweeping a sine wave up and down from 20 - 35 hertz
and observe the point of minimal cone excursion. You can do this by gentle touch. The impedance curve is not
entirely accurate due the driver inductance according to Greg Timbers.
Greg said the tuning frequency should be around 28 hertz. A shade either side of that is permissible.
(that's the way he explained it to me when I built my clones in 2003).

Your enclosure should be lined with one inch fibre glass sheet insulation on five sides and around the Dog box.
If you are using another material that opens up unknown variables. ie the box volume might be smaller than
specified if you are using under felt or foam rubber or pillows.


Positioning. Try re-positioning of the enclosures if that is practical. A trolley board with 4 heavy duty casters works well.
Small incremental movement out from the rear wall can be helpful in obtaining the smoothest bass.
Try raising the enclosure if practical. The combination of horizontal and vertical movement from the wall/floor
boundaries can assist in moderating the worst of most bass response issues.

The bottom on the horn lens should be level with your ears for best imaging.

Measurements. Are you able to describe how you did these measurements?

Distance from the baffle?
Sine wave , Pink noise?

FWIW I have only ever obtained meaningful measurements on my driveway with the enclosures laying on the side (ground plane) using 5 db per division at 2 metres.

The phase cancellation which you might expect at the crossover point is unlikely to be visible if you take a measurement from the listening position inside your home. 10 db per division is not going to show much.

About the phase. Per the 3145 schematic and Giskard's equivalent schematic the mid range array drivers are wired out of phase
to the woofers after the L pads.
JBL specified 18 db slopes in the stock system. The 18 db active slope was chosen because it was the closest
standard filter to the custom 12 db passive filter slopes.

However you are using the 2123H and without knowing your bi amp crossover characteristic you can't
really predict or determine the effect of reversing the woofer electrical phase. The 2123 has a different low
frequency characteristic to the 2122 and requires different associated passive low pass filters to obtain a smooth
response.

So there are a few unknowns and you might advise how your passive crossovers are arranged for the 2123
drivers?

Active crossovers. The thing to appreciate is that most 3rd party active crossovers assume you are using text book drivers.
Unfortunately that is far from the case in this complex four way system where you have substituted out the stock
2122H mid range driver due to it being NLA with the 2123H. Like lots of things in audio everything matters and
the crossover is the heart if your loudspeaker. So its worth getting it right if you can. BTW the dog box should
only be lightly filled with fibre glasinsulation. Too much and it will sound over damped


You might try the 24 db LR filters and wire everything electrically in phase. Listen and see what the measurements look like.

The LR24 crossover is the most black and white crossover function as everything should in theory sum flat with
text book drivers wired electrically in phase. It kind of dumbs it down because the slopes are steep and its a good
compromise when you don't know what's going on in the diy space.
The 18 db filters are the son of a bastard in that they are neither here nor there.

As I hinted at previously I would use a 2nd order low pass filter and a 2nd order butter-worth high pass filter and
listen and measure if you are using the 4344mk11 mid range passive low pass filter.

If your digital active crossover allows custom filters then you can try adjusting the filters crossover point
"spread" until you get a measured null with the woofer electrically out of phase (LR24)(measured at 1 metre) or
electrically in phase (12 db) filters. The centre frequency should be 300 hertz

The subjective effect of acoustic anti phase driver is a thin sounding mid range generally.

I hope these points provide some clarity.

Ian
Thanks, lots to work with here.

The measurements were taken about 13' from the speakers very close to my sitting position. I used REW and it is a sine wave sweep from what I know. I just used the default. I just started using REW and it is a lot over my head.

The room is 10'6"x21' and I sit at my desk about 15' from the speakers. There isn't really anywhere else to put the speakers, I just could move them away from the walls a bit. They are sitting against the short wall of the room. I could move them to another room that is larger, but I already have two other pairs of speakers in it.

I checked the tuning with my hand and it seemed like it was 28 Hz. I did this before you posted this. The cabinets dimensions match the plans posted here. They are lined with 1" fibreglass on five sides. The fibreglass is stiffer than home insulation, I believe it was made for insulating ducts. There is 1" insulation on five sides of the dog box also. There shouldn't be any leaks in the boxes, my carpentry skills are a lot better than my speaker tuning skills.

I am using an Xilica XP4080, so it has lots of choices for crossover slope, filters etc.

[toddalin]

The 2251Js (~9.75") have punch. I attribute it to the light cone and accordion edge working with the differential drive to create a fast transient response.

[robertg]

Hi Robert,

I understand.

My impression is your horns are around 8 feet apart or thereabouts.

Can l suggest you try sitting a bit closer to the system (10-11 ft) so you have less of the room indirect sound and more of the direct sound from the drivers. Try it with a spare chair. Toe in about 10 degrees might help.

I sit 3 meters (about 10 feet) from my system with the enclosures on the long wall ( horns 3 metres apart). It’s been that way for a while and l like it.
The horns are 6 ft apart. I have a couch in the room also, so moving closer to the speakers would be difficult I want to keep the couch as far from the speakers as possible. I still like the idea of lifting them.

[Ian Mackenzie]

Hi Robert,

I have been looking at some of your earlier threads and posts.

Getting back to your question a pair of 2226 a side is one very potent mid bass system with very sensitivity of over 100 dB. That might serve a number of applications in the SR industry.

The 4345 is not going to complete with that in the way you might be used to with the 2 pairs of 2226 drivers. If you are wedded to that presentation l recommend you look up Drew’s Clues in the Library on ideas to enhance what you like.

For example you might move this rig back into your larger room and end up with 2 x 18 inch 2245 (or 2242) subs per side 25-100 hertz , dual 2226 mid bass drivers 100-500 hertz , a single 2123 driver 500-1200 hertz, your 2440 driver 1200-8000 hertz, your slot 8000-20000.

This approach is building out and enhancing the dual 2226 approach by limiting the 2226 operating bandwidth to its optimal range and supplementing it above and below with other drivers.

That l think is what your really on about.

The idea of the 4345 is an accurate (1980 era) mastering monitor which it does well.
Replacing the 2245 with the 2242 is going to give you more of what the 2245 does.

You could also try the 2245 in your larger room at some point.

[toddalin]

2242's would be a mistake, as would 2240s. 2241H is the better way to go, especially if you have a big cabinet (10+ cu ft). But these will also work in a much smaller cabinet (down to 5+ cu ft). Run the WinISD simulations to convince yourself that there is no contest. :bash:

I use them in the Ethyl Mermans and they have a whole he-- of a lot more slam than the AlNiCo 2235s in the L300s.

[toddalin]

If you want a good track to assess "slam," listen to a high quality recording of the drum track at the opening of Billie Jean by MJ. With a bit of volume it should kick you in the chest and about knock you out of your chair. Don't expect it on the YouTube video over you computer.

https://youtu.be/Zi_XLOBDo_Y

[toddalin]

2241 makes a far better "subwoofer" than a 2242.

I use 8 mH/95 mfd with a 100 mfd/1.2 ohm Zobal on my 2241s. Run the simulation and you will see thats' subwoofer territory. 2242s would peak higher up. Again run the WinISD simulations and convince yourself.

BTW, 2242s are not true subwoofers even though they were marketed that way to theaters. Just look at their specs.

[toddalin]

A picture is worth 1,000 words. 2242 is a "subwoofer" in name only.

2241H in green and 2242H in red from WinISD:

http://www.audioheritage.org/photopost/data//500/ScreenHunter_231_Mar_03_18_48.jpg

[1audiohack]

Now we’re getting somewhere.... It would be interesting to get Audiohack’s opinion on this as well. He has been known to turn the system up loud occasionally.Widget.

I am working on it. I spent a couple of weekends knocking something up to see what all the fuss is about.

[Ian Mackenzie]

When you’ve built up a dual 2226 based system like Robert had and then compared both systems in a 10.5 x 21 ft room let us know....Lol

[1audiohack]

When you’ve built up a dual 2226 based system like Robert had and then compared both systems in a 10.5 x 21 ft room let us know....Lol

Haha I currently only have 12 dual 2226 boxes and used to have more so that ground is well trodden here.

This is my second 2245-2123 (tel:2245-2123) system and I pretty much know how this ends. Will they sound nice? You bet they will. They will play deep down low and full effortlessly, at low and moderate volume. They will have a lack of visceral impact that a cranked up proper dual 15 box will have and there is little that can be done about it. That is not the primary design goal for these here.

Barry.

[Ian Mackenzie]

A no compromise design by Drew Daniels.

http://www.audioheritage.org/html/perspectives/drews-clues/audiophile.htm

http://www.audioheritage.org/html/perspectives/drews-clues/8-sub-notes.html

[Dr.db]

From a sheer spl point of view, two 15"s should outdo a single 18". So maybe it´s not fair to compare those setups?
Changing the 2245 to a 2241 or 2242 wouldn´t change the shortage in cone area of those 18" woofers...

But the way those woofers sound is a different chapter.
I believe we should differentiate between spl and the way they sound.
Using two 2235 would give you more headroom compared to a single 2245. But they will still sound "softer" than the SR woofers...


As Ian and widget pointed out, when using the 2123 instead of a 2122 or 2202 you have to use a different crossover. Those 2123 have less bottom end and JBL used to cross them over higher.
2123 was used above 340hz, as 2122 or 2202 where used above 290hz.

[Dr.db]

Now we’re getting somewhere.

Years ago I built a pair of 4355 clones. They really didn’t do it for me… they certainly kicked ass, but I prefer speakers with a more refined capability… that also can kick ass.

I don’t think the 2245 is letting you down, but I don’t think that the 10 inch mid bass driver is ever going to give you a bad ass rock concert in your house if that’s where you’re going. it will certainly get loud, but there’s something about it that doesn’t quite have the slam of a PA system driven hard. The 2202 will give you that. It would be interesting to get Audiohack’s opinion on this as well. He has been known to turn the system up loud occasionally.


Widget

A very interesting comparison.
I own those 2123 myself, but no 2202 around...
My impression of the 2123 is they have a lot of slam, punch etc.... But they have no low end at all, they are pure midrange woofers.
The 2202 on the other hand looks more like a midbass woofer.
So I guess the 2202 simply puts out more spl down low than the 2123... They have more efficiency below 350hz than the 2123. JBL crossed over the 2202 lower than the 2123...
Maybe that fact yields to the impression of more punch?

It would be interesting if the 2202 would still sound more punchy when crossed over above 350hz like the 2123 :confused:

[Ian Mackenzie]

Its really quite simple.

The 2226 is a front of house sound reinforcement driver 97 dB, 30-2500 range, Fs 40 hertz, aluminium voice coil, mms 90 grams, 1.6 inch P - P excursion before damage. Used in pairs it’s 100 dB and 1200 watts into 4 ohms. It’s lethal but it’s not going to give you low bass.

On the spl of dual 2226 drivers it going to more dynamic than a single 2245.

The 2245H used in two pairs per size to match the sensitivity with dual 2226 per side would be a more appropriate comparison. In any direct comparison you are going to hear differences.

[robertg]

So I changed the crossovers to 24db LR and tried a different amp and they have a lot more punch. The amp is a Crest 7001 and has about 550w, the Ramsa had 350w. My next step is to raise them off the floor a bit.

[robertg]

If you want a good track to assess "slam," listen to a high quality recording of the drum track at the opening of Billie Jean by MJ. With a bit of volume it should kick you in the chest and about knock you out of your chair. Don't expect it on the YouTube video over you computer.

https://youtu.be/Zi_XLOBDo_Y
I bought this CD off eBay last week, but I don't have it yet. I remember a friend saying this song has good bass. I never thought I would ever buy a MJ CD, I never was a fan of that type of music.

[Ian Mackenzie]

Ditto

[Mike Caldwell]

Unless I missed it somewhere in your post are you high pass filtering the woofers?
Find you boxes tuned frequency, the tone sweep method mentioned works perfect.
Set a high pass frequency at of just slightly below the tuned frequency.

There is no sense in wasting power amplifying on what the system can't reproduce and at the
same time causing unnecessary woofer excursion that can take away from the "punch"

What are you using for a crossover?

[robertg]

Unless I missed it somewhere in your post are you high pass filtering the woofers?
Find you boxes tuned frequency, the tone sweep method mentioned works perfect.
Set a high pass frequency at of just slightly below the tuned frequency.

There is no sense in wasting power amplifying on what the system can't reproduce and at the
same time causing unnecessary woofer excursion that can take away from the "punch"

What are you using for a crossover?
I'm using an Xilica XP4080 crossover, the high pass is at 40 Hz and 6 db per octave.

[Mike Caldwell]

I'm using an Xilica XP4080 crossover, the high pass is at 40 Hz and 6 db per octave.

You got a real DSP!!

Have you tried a little steeper high pass cutoff, if your not all ready use a BW "butterworth" filter for the high pass, there flat out to the cutoff frequency.

Have you played with under lapping the crossover frequencies, look at the phase response as you open up the crossover overlap.

[robertg]

You got a real DSP!!

Have you tried a little steeper high pass cutoff, if your not all ready use a BW "butterworth" filter for the high pass, there flat out to the cutoff frequency.

Have you played with under lapping the crossover frequencies, look at the phase response as you open up the crossover overlap.
So underlapping crossover frequencies would mean kind of leaving a hole between frequencies? Instead of using 300 hz use 290 and 310?

[Ian Mackenzie]

Here are some guidelines for matching the crossover characteristics to jbl systems using your drivers in a 4 way monitor.

These characteristics are set for the driver locations on the baffle and the amplitude and phase characteristics of the drivers. The guidelines refer to the voltage drives not the amplitude response.

Use the Crossover Butter-worth filter characteristics
Woofer low pass
2nd Order Butter-worth 260 hertz


Mid 2123
Low pass 2nd order Butterworth 360 hertz
High pass 3rd order Butterworth 1,100 hertz
Wire the mid electrically out of phase.

What l suggest you do is install those values in the woofer and mid crossover and listen while adjusting the amplitude levels for a smooth tonal balance. See how that goes.

Edit : The above text book crossover parameters are an approximation of the customised voltage drives.

If you decide to use other filter characteristics your on your own.

You can try the 4th order LR characteristics @ 290 hertz and 1,100 hertz but it will take some experimentation to get the system optimised. As Mike said you may need to shift the crossover points around. Then listen and measure. Its quite tedious.

Edit
One point l will make is that most off the shelf active crossover networks use text book crossover characteristics whether they be Butter-worth, LR, Bessel or something else. These text book crossover characteristics rely on text book drivers to work properly. No driver is text book and they should be viewed as pass band transducers with varying amplitude and phase response.

This means the user needs to work with the transducer to come up with a crossover characteristic that is as close as possible to optimal. That means modifying the filter slope, Q factor and crossover points with a number of iterations while measuring, simulating, testing and listening. To be effective this requires a degree of skill, test equipment and a detailed understanding of network theory and design. This level of optimisation can be quite time consuming as you tinker with the various parameters. But people have fun doing this activity and it can be quite a journey as you try different approaches.

If you are of the persuasion that near enough is good enough that’s your call. But the system won’t deliver the potential it’s capable off or the subjective experience.

I find squeezing the most out of a system particularly rewarding in bring you ever closer to the music which is what its all about.

Once the crossover parameters have been set measure the system with REW using Greg Timbers method in 5 or 6 locations near your listening position. Use the PEQ to reduce the main room modes down by 1/2 the magnitude of the peak below 150 hertz. If you try removing the entire peak it might do more harm than good. Moderation is the key. There might be room resonance around 290 hertz. Use a PEQ dip filter with Q of 1.5 and - 1.5 dB.

The 2245 couples to the floor quite effectively so you need to compensate for that you want realistic bass from this system in your scenario with the enclosure close to walls and the corners of your room.

The idea is to apply a solution to specific issues that you can actually hear and measure.

[robertg]

Here are some guidelines for matching the crossover characteristics to jbl systems using your drivers in a 4 way monitor.

These characteristics are set for the driver locations on the baffle and the amplitude and phase characteristics of the drivers. The guidelines refer to the voltage drives not the amplitude response.

Use the Crossover Butter-worth filter characteristics
Woofer low pass
2nd Order Butter-worth 260 hertz


Mid 2123
Low pass 2nd order Butterworth 360 hertz
High pass 3rd order Butterworth 1,100 hertz
Wire the mid electrically out of phase.




I tried this and I like it so far. I had to turn down the 2245's amp slightly. I think I will have a bit of time in the next few weeks to play with this. I left the woofer high pass in there for now.

[Mike Caldwell]

So underlapping crossover frequencies would mean kind of leaving a hole between frequencies? Instead of using 300 hz use 290 and 310?


It doesn't leave a hole so to speak.

For example a standard 24 db per octave filter cutoff crossover at 300hz at 450hz the signal is attenuated 12db, at 600hz it is down 24db (one octave) at 1200hz it would be down 48db. The same attenuation scale work on both sides of the cutoff frequency.
There is area where both the low and the mid drivers are putting out an overlap of frequencies, using steeper cutoff rate filters will help minimize that, I use 48db on my sound systems.

Where it gets interesting is in what they call the acoustic crossover frequency that can be different from the electrical DSP crossover frequency.
In the case of crossing over from lows to mids or from any band pass to the next is when you run the band passes at different level as in more lows than mids raising the low output level increased the low drivers frequencies that are over lapping into the mid range area.

Excuse my crude drawing!

The middle vertical black line represents your intended crossover frequency.

The green line is your mid range crossover output level and cut off slope.

The red line to the left of the green line is the low frequency output level and cutoff slope.

Both at the same level the crossover frequency both electronic and acoustic is the same.
Now look at the upper red line that represents a higher low frequency output level and low pass cutoff frequency that is still set at the same high pass frequency as the mid range.

You can see that it moved the acoustic crossover frequency higher with more overlap between the lows and the mids.

The dashed blue line represents the same higher low frequency output level only with a
lower low pass frequency and the resulting acoustic crossover now matches what the intended electronic crossover frequency was to be.

You can listen by ear and play with the under lapping frequency, it is better to use a analyzer program so you can see the frequency response and phase response as you make adjustments.
With your DSP you can also correct for driver offset delay.

[robertg]

Mike I understand it by the way you explained it.

I did some measurements today with REW. I put the microphone in five different places. That program is a little too advanced for me, but I can understand the basics anyway.

Everything looks normal to me, I am using 1/6 smoothing.

I'm going to raise my speakers about six inches next. I'm still looking for a decent looking way to do it.

[Ian Mackenzie]

Get a trolly board with heavy duty casters.

[robertg]

That’s probably what I will do. I’m looking for a nice piece of butcher block to mount wheels to.

[JeffW]

Grizzly makes butcher block workbench tops in several sizes.

https://www.grizzly.com/search?q=(categoryid:360100)

[robertg]

Grizzly makes butcher block workbench tops in several sizes.

https://www.grizzly.com/search?q=(categoryid:360100)
I have no problem finding butcher block, I just want some for really cheap. Usually counter top manufacturers have some cut-offs, or maybe I can find a couple of used restaurant for a good price. If not I will make something myself. I just don't really want to go to a retail store these days and buy some lumber and wheels.

[robertg]

I made some changes to these lately. The mids are now 2450s, one has a 2451SL diaphragm and the other doesn't. I can't seem to find another 16 ohm SL diaphragm, and I can't hear the difference anyway. I bought a pair of 2403 tweeters and had some NOS diaphragms for them. I built a pair of stands with rollers, way easier to move around now. I also built a pair of crossovers, now I only run two amps. Running a four channel or 4 amps was a real pain.

I still want to buy a Bryston 10B crossover and a small Class A amp for the top end. I'm using a $100.00 Ramsa WP-9055 for now, but should really try something else. There doesn't seem to be much for sale right now.

Every change seems to make a little improvement in sound quality. Or at least I think it did.

[Earl K]

Looks great Rob.

86661

Nice Blue, plus I love the look of the painted port-internals.

Also the L94 lense is a nice touch .

:)

[grumpy]

Looks great!

[Ian Mackenzie]

Very nice!

[robertg]

Thanks, hopefully this will be the last pair of speakers that I build. I'll post again when I change the amp. I am looking to buy a small Bedini, or some other Class A. They are difficult to find in Canada.

[Mr. Widget]

I'm going to raise my speakers about six inches next. I'm still looking for a decent looking way to do it.Looks like you found a great way to do it. ;)

Nicely done all the way round. Good luck on the Bedini. If you find one, it should be serviced due to age, but they are out there and they are very nice amps.


Widget

[BMWCCA]

Thanks, hopefully this will be the last pair of speakers that I build. I'll post again when I change the amp. I am looking to buy a small Bedini, or some other Class A. They are difficult to find in Canada.
I seem to recall Greg suggesting a Crown D45 for this application at some point, if I remember correctly. Anyway, I started buying and stashing them some time ago. Cheap. Cute. Durable. :dont-know:

[robertg]

I seem to recall Greg suggesting a Crown D45 for this application at some point, if I remember correctly. Anyway, I started buying and stashing them some time ago. Cheap. Cute. Durable. :dont-know:
I bought quite a few D45s and D75s off eBay a couple of years ago. Every one had a big turn off thump that I didn't like. I remember they all had burnt resistors also. I ended up upgrading from my $60.00 Crown to $100.00 Ramsa WP-9055s. I have four of them now. I can't say anything bad about the Ramsa amps, I just want to upgrade a bit. Or maybe spend more money.

[BMWCCA]

I just want to upgrade a bit. Or maybe spend more money. :thmbsup:
I've only used the later versions without issue: The D75A and the later D45 with all-black face and after later ergonomic (not round) knobs (there is no D45A that I'm aware of).:dont-know:

[robertg]

I ended up buying a Krell KSA-50S. It's a 50w Class A amplifier. It sounds slightly better, or at least I think it does, than the Ramsa that's worth 1/10 the price. I don't exactly have golden ears either.

Some music sounds so good on these speakers and some is just mediocre. Female voices sound excellent, I find myself listening to some Joni Mitchell songs that I don't really care for, but it sounds so good.

[edgewound]

I ended up buying a Krell KSA-50S. It's a 50w Class A amplifier. It sounds slightly better, or at least I think it does, than the Ramsa that's worth 1/10 the price. I don't exactly have golden ears either.

Some music sounds so good on these speakers and some is just mediocre. Female voices sound excellent, I find myself listening to some Joni Mitchell songs that I don't really care for, but it sounds so good.

50 watts is pretty miniscule for 4345. 300-400 watts would be better.

As for the recordings, these speakers will reveal good recording vs. not so good recordings. Actually, most any decent speaker system will do that.

[robertg]

50 watts is pretty miniscule for 4345. 300-400 watts would be better.

This amp is just for 300Hz and up, below that for the 2245s I use a 550w Crest 7001. 50 watts seems like more than enough power.

[Mr. Widget]

This amp is just for 300Hz and up, below that for the 2245s I use a 550w Crest 7001. 50 watts seems like more than enough power. 50 wpc might be a little light, but should certainly do the job in an ideal world 100 would be best.


Widget

[Ian Mackenzie]

Turn up the Lpads up full and it will be fine for most listening situations.

That is like 98 db@ 1 watt sensitivity.

Technically with bi-amping at 300 hertz crossover point you get approximately 50%/50% split of the power between the woofer and the mid horn array. As result you get 6 db crest factor which works out to about 4 x the headroom of single power amp in full passive mode. So with the smaller amp rated at 50 watts thats like 200 watt amp in passive mode with 98 db@ 1 watt sensitivity out of each loudspeaker. You have stacks of headroom on the woofer.

They don't teach you that at Yale.

For most genres you'd be hard pressed to hit 20 watt peaks using the 50 watt amp with 98db@ 1 watt sensitivity.

Generally it will sound bigger rather than louder because you get quite a lift in linearity with the 2245H from 30 hertz up. The intermodulation distortion of these systems is also really low.

[robertg]

When I crank it up the clip/limit light on the 550w Crest 2445 amp are my limiting factor. When I was quad amping I used a 25w multi channel McIntosh amp on the top three. I could never make the power guard lights come on.

I was assuming a 25w amp would be fine? I guess you can't have too much power.

[Ian Mackenzie]

When I crank it up the clip/limit light on the 550w Crest 2445 amp are my limiting factor. When I was quad amping I used a 25w multi channel McIntosh amp on the top three. I could never make the power guard lights come on.

I was assuming a 25w amp would be fine? I guess you can't have too much power.

Up to a point that is true.

However, in domestic use the lust for power is sometimes about the notion more detail and clarity comes with loudness. Loudness certainly creates impact and a visceral soundscape.

Unfortunately turning it up louder is not the answer if the resolution of the power amplifier is not there in the first place. The desire to EQ a system can also be about the desire for clarity and resolution. Looking for what’s missing?

In my experience if you can’t hear what you want to hear at mid and high frequencies with 1 watt then start looking at a more transparent signal path.

[RMC]

Hi Robert,

RE "I was assuming a 25w amp would be fine?"

The following pic should give you some additional insight in figuring the power relations between the LF amp and HF amp in a biamped system, info is from Furman Sound electronic crossover Owner's manual I have. Other crossover manuals from gear i own (Rane and Ashly) don't mention this LF/HF amp power relations.

Does the Krell, or Mc Intosh multi-channel amp for that matter, have a highly regulated power supply, or is it able to provide some dynamic headroom that the other can't deliver? Music dynamic range also comes into play. Don't forget the difference between the Crest and Krell amps is a 10:1 power ratio. If other things were equal, and they probably aren't, that would represent a 10 db level difference.

On another matter, i noted you mentioned a while ago having some issues with Integrated Circuits, as i recall your tech mentioning counterfeit ones, poor China copies or some defective units? So by the same token i'm adding another pic from the same Furman Sound manual about what they have to say regarding IC reliability. Don't recall seeing this elsewhere in a manual either. Regards,

Richard

8672386724

[Horn Fanatic]

I'm trying to get more punch or kick out of a 2245. The system that I had before my 4345 clones had dual 15" 2226 drivers. It had some serious kick.

My amp is a RAMSA WP9440 with 350 watts, I'm thinking I should try a bigger amp first? Maybe 6-700 watts?

Would a 2240 or 2242 be a direct replacement for the 2245 without changing the tuning? I'm not sure if I really need much below 50Hz, I just listen to 70s music, no home theatre.

Greetings -

If more articulate, solid bass is what you're trying to achieve, I have had luck using larger than normal vent diameters. Up to six inches in some cases. Large vents will reduce the Mach number to zero. The down side, is that the larger the diameter, the longer the vent must be depending on the enclosure volume and tuning frequency. Vents are not required to be on the baffle. They can be placed anywhere on the enclosure as long as they are not obstructed. The frequency at which they allow the enclosure to resonate is omni-directional. Cutting a vent so as to be angled, or using PVC elbows may solve real estate problems that may occur. Keep in mind, a vent is considered a separate element in the acoustical circuit. In short, they take up physical volume, including the volume of the internal effective length. I am unsure if canned programs take that into consideration. You would be tuning a reduced volume enclosure to achieve the same frequency of resonance. I have found that tuning the enclosure to the resonance frequency of the driver increases articulation. I know some folks and manufacturers like to tune an enclosure a bit higher in frequency, some even a bit lower. Increasing amplifier power isn't always the solution to a simple problem.

On a side note; Your wrote that you don't need much response below 50Hz because you listen to 70's music. The E string on an electric bass guitar is approximately 40 Hz. So yes, you would want the response to reach at least 40Hz. You would have no problem achieving that frequency and below with the 2245. Better to have the capability, than not.

Good Luck,

H.F.

[1audiohack]

I built a 10 cubic foot 4345 sorta inspired system with a 2245, 2123, 2451J on a 4338 horn. This system is three way active. After all the measuring and tuning was done I sent a sine wave through the middle of the passband of each driver and measured the voltage to see what the real world power requirements were to select the MF and HF amps for the rack. This is something I always do as the results are sometimes surprising.

I planned on using a 350 watt per channel Crown K1 on the 2245. It turns out the voltage ratio is 3.2 to 1 to 1.

How is that possible you may ask? The 2123 needs a bit of a push on the bottom of it’s pass band to match the dynamics of the 2245 at 250-300 Hz. The 2451SL-4338 has an 18 dB SPL haystack hump in the middle that needs to be cut down to get to the Harman curve and even more if you want it flat.

The K1 is a 55 volt supply.
The 2123H wants a 28 volt supply. 100W into 8 Ohms
The 2451J wants a 28 volt supply. 50 into 16 Ohms

I listen to something with wide dynamic range while watching the voltage peaks on a scope.

So, if you want to preserve the live dynamics of well recorded music, you need a lot more than flea power.

For the record, I don’t like any more gain than necessary. It’s space, noise, heat and expense. But, if it doesen't jump with the music, I find no satisfaction in it. It has to have enough.

Your mileage may vary. It depends on what you prioritize.

Barry.

[Ian Mackenzie]

Hi Barry,

See section 1.3, 1.4 and 1.5 in this article.
https://sound-au.com/bi-amp.htm

[Ian Mackenzie]

Robert,

How long have you had the Xilica XP4080 active crossover?

What is your main source component?

[robertg]

Robert,

How long have you had the Xilica XP4080 active crossover?

What is your main source component?
I probably bought it around Christmas or so.

I have a Cambridge Audio DacMagic Plus DAC, Sonos Connect, Sony CDP-D12 CD player, Mcintosh C2200 tube preamp, Crest 7001 amp for the 2445s, and a Krell amp KSA-50S.

[Ian Mackenzie]

When I crank it up the clip/limit light on the 550w Crest 2445 amp are my limiting factor. When I was quad amping I used a 25w multi channel McIntosh amp on the top three. I could never make the power guard lights come on.

I was assuming a 25w amp would be fine? I guess you can't have too much power.


It’s depends on a number of factors? Like the genre of music, your preferred listening distance to the 4345’s and the level you find comfortable.

I personally have grown shall we say old of turning it up to a level neither l nor my neighbor can tolerate continuously. You have to ask yourself what is the point?

Then your have industrial deafness. A lot of musicians and people in the PA industry have that problem. They won’t admit to it but they have it.

Back to your plan l recommend you stay with the Krell as an
Upgrade End Point. I recommend you try an alternative source as a point of comparison.
If you are running an all digital signal stream your crossover may suffice. But l think saw a Mac Preamp?

If that is correct and you have an analogue signal into the pre amp and analogue signal out then there is potential for improvement with a high quality analogue crossover network.

[Mr. Widget]

I probably bought it around Christmas or so.

I have a Cambridge Audio DacMagic Plus DAC, Sonos Connect, Sony CDP-D12 CD player, Mcintosh C2200 tube preamp, Crest 7001 amp for the 2445s, and a Krell amp KSA-50S.Off topic but...

Anyone looking for a convenient moderately priced streaming device, the Bluesound Node2i is similar to the Sonos Connect in functionality and ease of use, but it sounds much better. It sounds better than the Sonos both when comparing their internal DACs or when using either with an external DAC.


Widget

[Ian Mackenzie]

Off topic but...

Anyone looking for a convenient moderately priced streaming device, the Bluesound Node2i is similar to the Sonos Connect in functionality and ease of use, but it sounds much better. It sounds better than the Sonos both when comparing their internal DACs or when using either with an external DAC.


Widget

Hi Widget,

No l think the context is useful. That clears that up.

I have a Blue Sound equiped Nad C658 preamp / streamer and its good on a Tidal MQA streaming.

Imho Bluesound is a great steaming system.

In relative terms l have a good analogue TT set up and its as good as the streamer. I have a really good TT setup and its way better.

I look forward to Robert’s future posts.

[robertg]

My next step is to buy a Bryston 10B crossover, hopefully I will find a reasonably priced one this summer.

A couple of days ago I played the same song at the same time on my Dac, CD, and Sonos. I couldn't tell a difference. I am going to buy a good turntable one day, I still have lots of vinyl.

Someone turned on the summer switch last week, so the audio hobby will be on hold for a little while.

[Mr. Widget]

A couple of days ago I played the same song at the same time on my Dac, CD, and Sonos. I couldn't tell a difference. I am going to buy a good turntable one day, I still have lots of vinyl.While based on my experience I find that hard to believe, a few years ago a fellow Forum member lent me some RCA interconnects he was certain would expand my listening horizons and I couldn’t hear the difference between my interconnects and the pair on loan.

FWIW: In my system with a Bryston BDA-1 and then with a BDA-2 DAC, Sonos was always distinctly inferior sounding (to me as well as to numerous visitors who I shared this comparison with over the years) when compared with a CD, a Mac Mini, or the Bluesound Node 2i all playing the same file. (Comparing the CD or a copy of the disc stored on my NAS.)

Comparing an analog version of a recording to a digital version they typically don’t sound the same, but I wouldn’t say either format is consistently superior.


Someone turned on the summer switch last week, so the audio hobby will be on hold for a little while.Excellent, enjoy it while it’s here!


Widget

[rusty jefferson]

While based on my experience I find that hard to believe, a few years ago a fellow Forum member lent me some RCA interconnects he was certain would expand my listening horizons and I couldn’t hear the difference between my interconnects and the pair on loan......
Widget
I can completely understand it, and for the same reason. When I experienced the demonstration of said cables with several members of this forum and "generic" cables, everyone present was astonished how poorly the system sounded with the genetic set. If at that moment we had inserted a poor quality source component, it's unlikely anyone would have thought it sounded much worse. :)

My feeling is that if robertg can't hear an obvious difference between those sources, he's got an issue to work out.

[Ian Mackenzie]

There are more transparent cables such as those with Transluminum conductors.

Transluminum is translucent aluminium.

The point is often this is about unknown unknowns.

You only know what you think you know?

Technically the input impedance of some preamps and power amps decreases with frequency and may change with the position of the volume control.

Depending on the output impedance of the source and the peak current capacity of the source the distortion levels and frequency response may be effected with changes in the signal level. The output impedance may also vary with frequency. This issue can also be effected by the inductance and capacitance of the inter connect cables. Typically valve equipment has higher impedances than solid state equipment but they are able to swing much higher voltages. This invites the possibility of random effects when different combinations of equipment are used with different cables.

So what’s the relationship between this and what you hear?

It’s generally agreed that the human ear is primarily sensitive to changes in amplitude or simply put tonal balance and harmonic distortion.

While it may look subtle on paper small variations in the frequency response of 0.5 dB are audible in the context of the overall frequency response otherwise heard as the tonal balance. One component might have a slightly tilt in the response in combination with certain cables and other components.

[1audiohack]

Hi Barry,

See section 1.3, 1.4 and 1.5 in this article.
https://sound-au.com/bi-amp.htm

Thank you Ian. Nice read.

It seems that Mr Elliot and I are in agreement.

Barry.

[Ian Mackenzie]

Continuing from my prior post....

Below is a simplified electrically model of a source component, a preamp and an interconnect cable.

The model is based on the following conditions.

The source has an output impedance of 100R and is typical of a consumer hifi CD player or preamp.

TypicalIy an opamp buffer has a 100R resister on the output to avoid oscillation when connected to the outside world.

In valve hifi components the output impedance is typically 300 - 1000 ohms. Seldom less than 300 ohms.

The output impedance may be much higher at high frequencies due to less negative feedback.

The ability of the buffer to deliver sufficient current at typical output levels of 1 to 2 volts into the cable is important. This varies according to the selection of the chip based opamp or discrete buffer. Typically a chip buffer will only deliver a fraction of a milli amp in class A mode while a discrete buffer may deliver 2-10 milliamps depending on the design. Don't expect to see a discrete buffer in preamp components under $3,500.00 these days. A source component like a CD player typically has chip buffer like an NE5532 or an OP275 unless it is a $2500 plus component. Reviewers often remark a source component sounds better with a preamp. Go figure.

The load impedance is 25K ohms. This is typical value in consumer audio components. In valve HiFi components this could be as high as 500K ohms.

The cable electrical properties are arbitrary. I used 10 nF of capacitance (0.01 uF) and cable shield inductance of 0.15 mH). ).The 0.01uf value is like a polystyrene bypass capacitors used in a passive crossover.

Depending on the cable construction including the shielding, the cable length and the terminations these properties can vary from low capacitance and inductance to the other extreme. In practice these properties would need to be measured.

The lower graph is a valve hifi components based model with a output impedance of 500R.

The output impedance was a key dependancy on the impact of the cable on the frequency response. The higher the output impedance the more sensitive the frequency response is to the impact of cable.

To the lay hifi buff this may seem technical but be aware of your python interconnect and how it may be interacting with your audiophile components. Some experimentation with different cables is recommended when purchasing a hifi component. The interconnect cable from your source components to the preamp is possibly more important than the interconnect cable from the preamp to the power amp. An alternative to buying an interconnect is to purchase a length of hi quality single core audio co axial cable like the Mogami brand, buy your favourite rca connectors and assemble the cable yourself. You will save have hundreds of dollars.

On the scale it is 0.3 dB per division.

The contemporary jbl systems have +- 0.3 dB trim controls for adjustment of the tonal balance. That is very audible. Under prolonged listening the impact of such variations can be more obvious as you listen to different genres of music.

Let your ears be the judge.

I have not discussed the actual terminations which can be gold plated nickel or exotic Cu alloys and cost up to $100 a pair or more. A good clean termination is important. But there is the law of diminishing returns.

On cables the essential thing is low noise, ideally low inductance and low capacitance.

The graphs may not necessarily be a specific indicator of your cable and your components.

I respect pride of ownership and people must let their ears be the judge. So l am not interested in the politics of one cable over another.

Copyright Ian Mackenzie

[Ian Mackenzie]

Thank you Ian. Nice read.

It seems that Mr Elliot and I are in agreement.

Barry.

I can’t remember what you said?

Btw in the system you described do you listening at 10 or 20 yards in the back paddock?

[1audiohack]

...Btw in the system you described do you listening at 10 or 20 yards in the back paddock?

Since this thread started about dynamics, I was talking about available voltage. I think you and Mr Elliot are focusing on power dissipation.

I’m a dynamics guy. Others focus on micro details. No ones wrong.

I am going to jump out. I don’t mean to be at odds with anyone and their focus on audio.

Barry.

[Ian Mackenzie]

No problem here. No ones asking you to leave.

But your response is at odds with Roberts observations:

Quote
“When I crank it up the clip/limit light on the 550w Crest 2445 amp are my limiting factor. When I was quad amping I used a 25w multi channel McIntosh amp on the top three. I could never make the power guard lights come on.

I was assuming a 25w amp would be fine? I guess you can't have too much power.“

My response addresses why Robert did not see the clip indicators on his 25 watt amps.

Would a larger amp on the top three drivers in Robert’s room make it more dynamic as you imply? Or is that placebo or intuition.

In my experience l factually know a Phase Linear 700B is more dynamic under real listening conditions than a Marantz 140 power amp (70+70 watts) driving a fully passive Jbl 4343. I also know Biamping at 300 hertz adds another 6 dB head room according to the amp Vu meters. The interesting part is understanding why? I address this with the reference to the Rod Elliot website.

My opinion on the question of power is it’s relative to your listening distance and just how loud you like to play your system most of the time. That’s the bit you missed. 115 dB is 10 dB louder than 105 dB and requires 10 times the power. 105 dB is 6 dB louder than 99 dB and requires 4 times the power. With that in mind the user can then make a reasonably educated guess on just how much power he proposes to use. Crown has calculators on their website for this purpose. The 6 dB headroom rule is a nice to have if you need it like in a studio environment. Distortion and burnt out drivers is the trade off under those conditions. But will the typical domestic home user be stretching his system in that way day in and day out or just turn it up occasionally to impress his mates and piss of the neighbours?

If he’s over 60 probably not. Let’s be honest. But there will be exceptions. There always are.

If the focus is on a cleaner more transparent hi resolution sound upgrade then the priority might go towards a somewhat less powerful but otherwise superior amplifier for the top three drivers. That’s more likely to be the 60+ year old. He’s won the Daytona race 5 times and has nothing to prove. For some this the pathway forward if they aspire to a audiophile listening experience using HQ digital or vinyl recordings. The Tidal MQA master series comes to mind if you have a suitable streamer. A VPI Prime Scout TT made in America and a suitable moving coil cartridge will also serve as a hi resolution analogue source. Finally the challenge of setting up the system correctly should not be underestimated.

The rest is up to the user.

Ian Mackenzie
Copyright

[grumpy]

... add to that, most people don’t realize that 10dB louder is only perceived as a 2x increase in volume.
easy to go from 1w avg to 1000w peak when a bass boost is attached to a knob. Feel free to giggle.

[Mr. Widget]

... add to that, most people don’t realize that 10dB louder is only perceived as a 2x increase in volume.
easy to go from 1w avg to 1000w peak when a bass boost is attached to a knob. Feel free to giggle....and even though I have known that for decades, it is still difficult to really wrap your brain around it.

This logarithmic aspect of SPLs is likely the primary reason why speakers with higher sensitivity often sound more dynamic since most of us don't have a 1000 spare watts or speakers that can handle that level of power without dynamic compression.


Widget

[Mr. Widget]

Below is a simplified electrically model of a source component, a preamp and an interconnect cable.Yes, Nelson Pass has been reminding us of this since the early '80s. A traditional single ended audio cable is by industry standard meant to be a 75 ohm cable.

I imagine many audiophile cables are not. And then there are cables like those built by MIT and Transparent with complicated L, RC circuits connected in both series and parallel to the cable. Yes, they will affect the sound, and yes they make it sound better if you own the correct gear connected to it. Other gear can easily go the other way... personally I prefer not to flavor my system in this rather random manner.

Regarding the cables I was comparing many years ago, I don't remember what I had in the system at the time or even what I compared them with, but my recollection was that "I" didn't hear a change in that instance.


Widget

[Ian Mackenzie]

... add to that, most people don’t realize that 10dB louder is only perceived as a 2x increase in volume.
easy to go from 1w avg to 1000w peak when a bass boost is attached to a knob. Feel free to giggle.

First line yes.
Second line no.
A bass tone control typically has +- 10 dB on audiophile equipment but there aren’t many that do these days. The Hafler 101 has tone controls.
Vintage integrated amp had bass tone controls up to 15 dB.

Now you know why subs have very powerful class D amps

[Ian Mackenzie]

Hi Widget,

I had a similar situation with audio visitors.

One guy bought over a $500 rca interconnect. Only he could hear a difference and went red faced when the majority said they could not here a difference with the stock cable my Luxman 105U CD play came with. That was actually very good CD player in its day but not hi end.

It is one of those things. I made a diy cable once with flat copper ribbon wrapped in Teflon plumbers tape when that style of cable was popular. Of course l thought it sounded great...Lol.

Making your own interconnect is not difficult btw.

Hey, l saw a Blow Torch preamp on Audiomart recently. You might use exotic cables with that.

I am thinking (Only thinking) about getting an Aurender A10. How much should l spend on the power cable and interconnect? Lol.....

I left all that once l started building discrete class A preamps. The particular transistor, Fet or Jfet used has a much more audible influence on the sound. I serviced a 50 watt Sae power amp years ago. One channel was blown. I ended up replacing all the transistors with modern equivalent parts. According to the owner it sounded way better. It was one of the cleanest most detailed amps l have heard.

[toddalin]

My opinion on the question of power is it’s relative to your listening distance and just how loud you like to play your system most of the time. That’s the bit you missed. 115 dB is 10 dB louder than 105 dB and requires 10 times the power. 105 dB is 6 dB louder than 99 dB and requires 4 times the power. With that in mind the user can then make a reasonably educated guess on just how much power he proposes to use. Crown has calculators on their website for this purpose. The 6 dB headroom rule is a nice to have if you need it like in a studio environment. Distortion and burnt out drivers is the trade off under those conditions. But will the typical domestic home user be stretching his system in that way day in and day out or just turn it up occasionally to impress his mates and piss of the neighbours?


Ian Mackenzie
Copyright


These are theoretical values and in practice are under-estimates when dealing with high power levels near the limits of the speakers capabilities. In the real world, when you apply big power you heat up the voice coils and the resistance increases (power compression), requiring even more power to achieve a theoretical increase. In actually, "10X the power" may be more than 20X the power, and that's only for 3 dB of power compression. Actual values/necessary power could be considerably higher.

[grumpy]

Hi Ian.

I was careful to state average 1w vs peak (crest factor ranging from 6-20dB). Understood re typical tone control ranges.
Regardless, I think the point is made: it's easy to overdo a bass boost it without audibly seeming like it's 'that loud'.

-dave



First line yes.
Second line no.
A bass tone control typically has +- 10 dB on audiophile equipment but there aren’t many that do these days. The Hafler 101 has tone controls.
Vintage integrated amp had bass tone controls up to 15 dB.

Now you know why subs have very powerful class D amps

[1audiohack]

No problem here. No ones asking you to leave.

But your response is at odds with Roberts observations:

Quote
“When I crank it up the clip/limit light on the 550w Crest 2445 amp are my limiting factor. When I was quad amping I used a 25w multi channel McIntosh amp on the top three. I could never make the power guard lights come on.
Ian Mackenzie
Copyright

I understand no one is trying to run me off and thank you for saying it anyway. :)

I just don’t want to waste our collective time.

If one uses a current monitor and compares the current going through the 2245 and the 2123, as one may expect, considerably more current goes through the 2245. However if one monitors the voltage, I routinely see higher voltage peaks going to the 2123. Peak voltage, not average current.

I don’t know if his small amps are looking at peak voltage or the collapsing of the power supply to indicate they are approaching their limits but if he can clip a 500+ Watt amp on the 2245 and has no indication that the 50 Watt amp driving the 2123 has reached it’s limits, and there is a lack of “punch”, maybe an amp for the 2123 with the ability to swing higher voltage is in order.

I can explain my measurement methods and equipment if there is interest. I am a data guy.

I really need to re run all these measurements, photo document them and take the time to post them in their own thread. If only I could manufacture time!

Barry.

[robertg]

I was having problems with my power conditioner/sequencer and my Krell amp. It didn't want to turn on the Krell for some reason unless something else was plugged in to the same stage. I decided to buy a Furman CN-2400S and the sound difference is amazing. Way more crisp and it has way more snap. Obviously there was something wrong with the old conditioner. I have those tamper proof wall plugs also and it seems like the plug only connects in the last 1/8". It has to be plugged in all the way to work. Maybe there was a bad connection at the plug?

I can still make the clip lights come on on the 550w Crest amp, but that is only during a long Led Zepplin drum solo and it is extremely loud. On normal music I don't think i could make it clip without hurting myself.

I also bought a Bedini 250/250 amplifier. I don't have it yet, and I'm not sure what I am gong to do with it. My 50w Krell has enough for now. I have a feeling a 250w Class A might use a lot of power.

[grumpy]

...
I also bought a Bedini 250/250 amplifier. I don't have it yet, and I'm not sure what I am gong to do with it. My 50w Krell has enough for now. I have a feeling a 250w Class A might use a lot of power.

Not to worry... probably not as much as you might think. A two channel 250w Class A amp would need heat sinks the size of a small car (Ok, maybe a bit less). Very likely Class A to a point, but not 250w... maybe tens of watts (high-bias Class A/B?).

Still a nice amp (was well regarded, iirc) and it may very well run warm enough to warrant keeping the local airspace clear, but 2x250w Class A would pull around 8-10A from your wall... continuously.... Like a hair dryer.

Glad to hear most of your issues have been sorted! :)