Passive Monitor Thread

[Robh3606]

I started setting up to build a new system. I was lucky to be able to purchase a pair of 476Mg's and was gifted a pair of 2216Nd's by my friend 4313B. I am going to use my favorite waveguide PTH1010. It has certain advantages similar to the 2344 because it is very short and has a rapid flare compared to the other PT Waveguides and is 100x100 which works very well in my room. I started taking some preliminary measurements on a temporary baffle of the raw drivers on the PTH1010.


It actually measures very well and has a distinct advantage over the 435Be in this application. It has a rising high frequency response which makes it much easier to set-up with systems using higher sensitivity woofers. With the 435Be on this waveguide you have to trade woofer sensitivity to get a usable last octave response. Attached are plots for the 476Be no network and 435Be with nework and raw.

Rob:)

[Robh3606]

After the raw measurements I looked for a suitable network and chose the 9900 which uses the 476Mg. I simplified the crossover from a Charge Coupled Network and put that into LEAP. Then I copied it and added switches so I could take out the 3 notch filters to see what each did. First is the Schematic then the network response with all the notches in place.

Rob:)

[Robh3606]

Here is what the response changes are as you take out the notches one by one. The first is Notch 1, then Notch 2, then the Sereis Notch /HP The Blue curve shows the changes from the original circuit.

Rob:)

[Robh3606]

The next 2 attachements show all the changes and the last is with notches 1 and 2 removed. This became the baseline for a modified crossover.

Rob:)

[Robh3606]

New schematic which shows the final network for now until I can take actual baffle measurements. As you can see from the previous post the response with both notches 1 and 2 removed was not bad. What I ended up doing was changing the values of the inductor and capacitor in the series HP filter and adding a low Q 1.5 notch filter centered at 1.6K. The notch took out the bump around 2 K and the changes in the HP smoothed out the response in the upper octaves.

Attached are the results after the changes. So far they look good. I need to build up a network to see what the actual measurements look like.

Rob:)

[4313B]

:bouncy:

[JuniorJBL]

Looks very good Rob!!:D

[grumpy]

Nice work.

[pos]

Impressive job and great result so far!
What crossover frequency and slope are you considering?

[Robh3606]

Thanks!

Now I have to build up a filter to see how close the sym is to the real deal. That slope is with an 18b electrical filter. It's quite a steep crossover around 900hz is where I think it will end up.

Rob

[Jakob]

Interesting thread! Are all 476Be and Mg's 16 Ohm?

[Robh3606]

Are all 476Be and Mg's 16 Ohm? Yes they are both 16 Ohm drivers. A bit less but not 8 that's for sure.

Rob:)

[Jakob]

Sorry if it's off topic, but what's the most important gain when designing speakers in using higher impedance CD's as JBL do?

Regarding your measurements; how close to the horn mouth are they made?


Have you come up with any possible box designs yet?

Really looking forward to see your progress in this project.

[Robh3606]

Hello Jakob


Sorry if it's off topic, but what's the most important gain when designing speakers in using higher impedance CD's as JBL do?

Not sure aside from the fact that the overall impedance curve stays reasonable even with the parallel notches. I doubt that's the reason though someone else is going to have to answer that one.


Regarding your measurements; how close to the horn mouth are they made?

They were 2 sets one close about 18" the other out about a meter or so. There is not much of a difference between the 2 measurements. Once I get a network built I will remeasure with the horns and woofer in the enclosure to see what happens compared to the test baffle that the waveguides were measured on.


Have you come up with any possible box designs yet?

Now that spring has sprung here, I hope anyway it's been a long cold winter, I have my table saw set-up so I can finally cut some wood. I am going to try something along the lines of my Array set-up. Curved front edges on the woofer cabinet with a separate waveguide enclosure also with the waveguide flush mounted with curved front edges there as well. The idea being I can try to time align with a physical offset on the upper enclosure.

Not sure exactly how yet. I am concerned about how to visually integrate the two cabinets as well as not causing diffraction issues as I am sure it will end up back a bit from the woofer. I have to really take a good look at where I think the centers are with the two drivers. I have always used the pole piece and thats easy with the 476Mg. Not so easy with the 2216.

The discussion about the M2 in the other threads is getting me really curiuos about what the 2216's are going to sound like.

Rob:)

[Robh3606]

Now I get to start all over again with the right M2 waveguides!

Rob:)

[Ed Zeppeli]

Ha. Keep us posted!

[srm51555]

Now I get to start all over again with the right M2 waveguides!

Rob:)

Good for you Rob. Were you planning on building the M2 cabinet as is or something different?

[pos]

So you are going to build a passive M2?
That together with Mr Widget's cabinet design (http://www.audioheritage.org/vbulletin/showthread.php?33972-JBL-Master-Reference-Monitor&p=379478&viewfull=1#post379478), JBL consumer will have some inspiration to draw from you guys :)

[JuniorJBL]

Now I get to start all over again with the right M2 waveguides!

Rob:)

That should be a fantastic system Rob!!

I am still waiting on my 2216's but my horns came!! :)

I am going down your path as well with my 476Mg's. I do however plan to use a DSP with my levinson 331 and 333 for the top and bottom.

What will you power yours with? Will you do DSP or just passive?

Your projects always turn out nice so this is exciting to see!! :D

[Robh3606]

Hello guys been a while. The plan is to try a passive version see what happens. It's a no brainer that the DSP route is really the way to go as it's a done deal. I am really curious about how the horn/waveguide will measure with the 435Be and the 476Mg. As far as the cabinet same volume not sure on the tuning and the look will be different. This is going to be an evolving project so nothing is written in stone. It will be fun to do no matter what the outcome. I can always fall back to turnkey if I can't get it to work.

With any luck I can post some raw measurements soon and the impedance curve on the waveguide. Going to be a real PITA to mount the 476mg. I modified the plates to take #10 flatheads and put helicoils in the waveguides so I can play with the plates and not wear out the threads.

Rob:)

[grumpy]

put helicoils in the waveguides

you read my mind :) looking forward to measurements.

[Robh3606]

Just did a quick point and shot to see what the M2 measures like with a 2435Be. Well I will be damned I was able to take an existing nework simulation with a crossover for the PTH1010 and tweeked it a bit. It isn't perfect notch at 2.5K but I am delighted how similar the raw measurements were between the 2 waveguides. I find this really encoraging can't wait to try a 476Mg

First one is on the M2 second is on the PTH1010.

The Clio is raw the red is the M2.



Rob:)

[pos]

Interesting!
So same "problem" with the phasing plug and horn throat interaction in the UHF.
Maybe you could try adding a little tube like in the the 2432, using something like a 1" MDF plate?

[Robh3606]

Hello pos

If you overlay them it seems to be a bit better. Green is the M2.

Rob:)

[ivica]

Just did a quick point and shot to see what the M2 measures like with a 2435Be. Well I will be damned I was able to take an existing nework simulation with a crossover for the PTH1010 and tweeked it a bit. It isn't perfect notch at 2.5K but I am delighted how similar the raw measurements were between the 2 waveguides. I find this really encoraging can't wait to try a 476Mg

Rob:)

Hi Rob,

I would expect that 476Mg would perfectly match....waiting....

ivica

[Robh3606]

Hey Guys

Well just tried out the 476Mg on the waveguide and all had to do was tweak the existing network and it looks good. Ignore the chop up front just did a quick measurement to get an idea. Dialed right in after about 30 minutes playing in LEAP. Had to play with the series notch and change the parallel notches Q and Frequency.

Rob:)

[ivica]

Hey Guys

Well just tried out the 476Mg on the waveguide and all had to do was tweak the existing network and it looks good. Ignore the chop up front just did a quick measurement to get an idea. Dialed right in after about 30 minutes playing in LEAP. Had to play with the series notch and change the parallel notches Q and Frequency.

Rob:)

Hi Rob,

Nice,
I have been surprised how good is M2&476 combo under 1kHz (seems can be used from 600Hz)
Can You show us final network version???

regards
ivica

[Robh3606]

Hello Ivica

Here is a revised measurement and a copy of the schematic. Just understand this is preliminary it is likely to change once I get everything in cabinets and the try to get the transition to the woofer right. For information here you go. Has anyone measure a 2452 on this waveguide? My thinking is it should dial in very nicely. If I remember it has a similar raw curve as the 476Mg. Have to just love this driver it just goes all the way out I am getting usable response out past 20K!

[JuniorJBL]

That's impressive Rob!!

Should make a fantastic system!! :)

[ivica]

Hello Ivica

Here is a revised measurement and a copy of the schematic. Just understand this is preliminary it is likely to change once I get everything in cabinets and the try to get the transition to the woofer right. For information here you go. Has anyone measure a 2452 on this waveguide? My thinking is it should dial in very nicely. If I remember it has a similar raw curve as the 476Mg. Have to just love this driver it just goes all the way out I am getting usable response out past 20K!

Hi Rob,

Many thanks for the detailed presentation of M2 & 476Mg driver, with passive network applied.
Seems to me that driver response compensation is not so difficult as can be expected if we are looking active network compensation of M2 & D2430K.
Interesting that some 'periodic' holes in the FR,

http://www.audioheritage.org/vbulletin/showthread.php?36789-Compact-monitor&p=373896&viewfull=1#post373896

http://www.audioheritage.org/vbulletin/showthread.php?36789-Compact-monitor&p=375970&viewfull=1#post375970

[ we have seen here on AH forums starting around 2.8kHz, 5,7.kHz, around 9,....kHz]
of M2 & 2450-1.5Be(Trex) is not present here on your measurements.

regards
ivica

[pos]

Something interesting is that to obtain the same 36dB/oct LR acoustical target the 476Mg requires a 18dB/oct electrical filter, whereas the D2430K requires a 6dB/oct electrical filter.
That tells a lot on the difference in the capabilities of these two drivers in the lower part of there range...

[pos]

476Mg vs D2430K voltage drive for the same 800Hz 36dB/oct Linkwitz-Riley acoustical target :hmm:

67204

[pos]

Rob, could the 1.6kHz and 3.2kHz notch also be done in the passive filter?
It looks like the 476Mg would also benefit of these, together with a broad and gentle boost in the 2k-5k range

There appear to be a periodic pattern here: 800Hz, 1600Hz, 3200Hz...

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=67195&stc=1&d=1443060117

[Robh3606]

Hello Pos
476Mg vs D2430K voltage drive for the same 800Hz 36dB/oct Linkwitz-Riley acoustical target :hmm:
That is the electrical only does not include the 6db for the protection capacitor or the roll off of the driver on the waveguide. Rob:)

[Robh3606]

Hello Pos
Rob, could the 1.6kHz and 3.2kHz notch also be done in the passive filter?
It looks like the 476Mg would also benefit of these, together with a broad and gentle boost in the 2k-5k range

There appear to be a periodic pattern here: 800Hz, 1600Hz, 3200Hz...
Don't put too much stock in these measurements up front. I really need to do these outdoors. I just got the new CLIO Pocket system for laptop. You would need high Q filters to take the 1.6 and 3.2 out. At this point I am trying to best fit the curve and even worst case I am about 2db out Rob:)

[Don C]

Has anyone measure a 2452 on this waveguide?
In my "Experiments with M2 horns" thread I'm using 2452s, with coated 16 ohm diaphragms. I like the sound so much that I still haven't bothered to put the Be diaphragms in yet. Hopefully things will slow down a bit at work and I'll find time to try those soon.

[pos]

Hello Pos That is the electrical only does not include the 6db for the protection capacitor or the roll off of the driver on the waveguide. Rob:)

According to yours and JBL's measurements, both voltage curves should show the same thing, and make their respective driver reach the LR 36dB/oct target within a few dBs.

I included the protection cap in the M2 voltage curve (1st order at 209Hz)

[Robh3606]

Hello Pos

Oh I got you now.

So what are you thinking?? The 476 has more output down on the low range??

Rob:)

[pos]

Yes it looks like it has much more output, which is a really good thing.
But on the other hand it is difficult to get accurate measurements in the stop band with a horn as so much parameters come into play (distance, reflexions, gating, etc.)

[Robh3606]

Just bringing this back to life. Starting to cut wood on the cabinets wondering how some of you have used your 2216nd's. I am going passive and not trying to clone the M2. Same with the cabinet I am building a ported woofer cabinet and a separate upper cabinet for the M2 waveguide and 476Mg.

Using 2" quarter rounds on the bass and upper horn cabinet to lower diffraction of the bass cabinet and to "round over" the waveguide. The wavequide actually fits very well into the 3/4 grove in the rounds. The horn is 7/8 thick at the edge so the round will give a smoother termination than the abrupt edge of the waveguide.

I am looking at 4.7 cubic ft tuned to either 26Hz or 32Hz. I am liking the 26Hz tuning as I can easily just add a bit of EQ @ 25Hz to bring up the low bass level in the room. The sim is 6dB same as a B380 and you end up with a relatively flat and extended low end. If you try to EQ the 32Hz box you get a peaked response which I definitely do not want.

Rob:)

[Ian Mackenzie]

Hi Rob,

Interesting. My 2216 woofers are yet too be put to work.

[Robh3606]

This is how the round overs work with the waveguides. Not bad it's not flush but the proud portion of the waveguide I don't see as an issue. Working on the bass cabinets over the weekend with all the panels cut. Time to glue and screw!

[grumpy]

Looking good Rob!

:lurk:

[Robh3606]

Happy Easter!

Today I finally get to put my cabinets together. A heads up on proper storage of the 2" round overs I am using. I left mine in the shipping container and never opened them. That ended up being a big mistake. When they shipped them they tightly shrink wrapped the ends and it bowed the 4 I had ordered. So needless to say after a couple of years in storage them are set that way.

Still OK but not without some work. Usually they are completely straight and you can easily use the the glue to temporarily hold everything in place until you get straps on. Not now with the bow. The straps will pull them straight and flush but I had to build a jig so I could get the side panels together so I had a rigid box to get the straps onto without the whole thing falling apart. Had plenty of scraps so I built a fixture to hold the side panels in place to glue and screw cross braces in place while keeping everything properly aligned and square.

Now with that done I can get things going on them.

Rob:)

[Robh3606]

Got one strapped up with the glue drying. Took every bit of tension in those straps to get those quarter rounds to flatten out and be flush with the front and side panels.

Rob:)

[Mr. Widget]

Looking good... 4.7 cu ft looks bigger than I was expecting in your photos, but then I guess it never was a small speaker.

Will you also have 2 by 4 braces between the baffle and the rear panel?


Widget

[Robh3606]

Will you also have 2 by 4 braces between the baffle and the rear panel?


Hello Widget

Thanks

Yes there is a missing brace that goes across the back that will have a brace attached that goes to the front baffle just under the woofer. Basically a T brace. It's a big box figure 30 X 22 x 16 overall plus the horn enclosure up top so it's going to be a big speaker when all is said and done. The baffle is cut to match the horns width so with the round overs on each side of the waveguide it will exactly match the width of this cabinet. The top is going to be open back with the crossovers inside for easy access.

I have to see if my mass coat is still good. I plan to use that on the inside to help deaden the un-braced sections of the cabinet. Used that when I built my Array cabinets and it did a great job on them.

So have you ever played your clamp webbing?? Mine a so tight they sound like guitar strings when you hit them!


Rob:)

[Mr. Widget]

So have you ever played your clamp webbing?? Mine a so tight they sound like guitar strings when you hit them!
Mine always seem to be out of tune. :banghead:


Widget

[Robh3606]

Got my second cabinet strapped and glued. Have to make T braces, tops and bottoms and make holes for my ports in the rear panels. So just a couple of hours work left for functional cabinets. Have to start on the tops for the horn next. Found an entire 2 gallon pail of Mascoat for the inside of my cabinets! Been so long forgot I had it.

Nice surprise!

https://www.mascoat.com/sound-damping-and-control.html

Rob :)

[Robh3606]

Tops done now I can get them together and coat the insides with the Mascoat before I fiberglass. Luckily the weather is going to be good enough to work outside. With any luck by the weekend I will have the drivers in so I can run sweeps to verify Fb. Going for the 26Hz box.

Rob:)

[Mr. Widget]

They are taking shape nicely!


Widget

[jmpsmash]

looking great! do you plan to reinforce the front baffle?

[Robh3606]

looking great! do you plan to reinforce the front baffle?

Hello jmpsmash

Thanks

I use a T brace that attaches right bellow the woofer cut out to stiffen the front baffle. I have to cut the rear panels for the ports and terminals. Other than that ready to start the tops which should be a bit more challenging.

What hardware was used to attach the horn to the baffle?? I couldn't find it in the M2 clone threads.

Thanks in advance

Rob:)

[srm51555]

Nice progress!. Try this in the Project M2 DIY Thread:

#51 (http://www.audioheritage.org/vbulletin/showthread.php?37659-Project-M2-DIY-Thread&p=385351&viewfull=1#post385351)

[Robh3606]

Hello srm51555

Thanks so much for the link. Great idea to use self tapping screws! I was concerned because they were not tapped.

Rob:)

[srm51555]

No problem, glad I could help. It was DonC’s who found the screws. I should probably reference that post better on post one of the thread.

Thanks,
Scott

[Robh3606]

Got a lot done will have cabinets by the weekend. Got two coats of Delta dB inside the cabinets, ports installed. Just have to add a shoulder inside to mount the back baffle against and add fiberglass. Then I can fire them up and see where the Fb ended up. Can't wait to finally hear these drivers.

Going to lug them upstairs and drop my HEIL's on them to see how the bottoms sound.

Those 1/4 rounds are going to work really well with the waveguides. With the ledge on the bottom of the waveguide it lines right up with the front baffle and nests right into the 1/4 round.

Rob:)

[grumpy]

:banana::cool::banana:

[Flodstroem]

Gorgeous and an advanced work Rob. :applaud:
It will be an easy job to swap the CD if you want to try several types of CD or Dias. :)

[Robh3606]

Thanks Flodstroem

Had to adjust the port length as I cut them too short miss read the instructions! Got one up and tested to see where the Fb was and it's on the money. First time using CLIO Pocket and like it! Fb also verified with my old and trusty WT2. Now have to finish the second one and lug them upstairs for a listen!

Rob :)

[Robh3606]

When did I restart this thread!? Well I got the cabinets finished so I could load them up and actually listened to the 2216's. One thing I did not expect was the in room bass extension. They are low tuned in 26Hz boxes so they should be rolled off but to my surprise I had real room pressurization all the way down to 20hz??!!!

I was doing sweeps to look for issues with the cabinets. Fortunately they were rattle and buzz free. With a predicted F3 at 47Hz I was expecting them to crash quickly after 30Hz or so but they just kept on going! Have any of you had similar experiences with these drivers??

Well that is actually a good thing I can always up them to 32Hz to see what happens easy enough to do just change out for a shorter middle section with nothing permanently glued up.

In a word WOW! I dropped my Heil's on top and turned them on. Balanced them out level wise and started to play some tunes. These drivers really are something! I can see why they get such good reviews the speed and clarity is really something and they hit so damn hard!? Listening to someone just strumming guitar strings was a real eye opener.

So a good day have to start the tops and find some more music to listen too!

Rob:)

[Mr. Widget]

I have never experimented with the 2216, but in giving the M2 an extended audition, I was really impressed by that woofer. It is articulate, punchy, and dives deep into the lower registers. If I ever do another DIY project, I’ll likely play with a pair of them.


Widget

[BMWCCA]

Thanks for sharing the pics!

I've always been fond of the beauty to be found in the aesthetic simplicity of the Crown PS-series' industrial design.

Makes me think of the late departed Scotty Fitlin and Tom Loizeaux.

Remember this one?

https://live.staticflickr.com/65535/49800276421_bf5681d901.jpg

[srm51555]

Nice work!

[Earl K]

Oh Man, you guys are killing me with your reviews on the 2216nd.

:)

[Robh3606]

Getting my tops built! Glued up the corners to the side panels and doing some dry fitting to make sure I have a close fit to the horn and determining the best way to put in a horn mounting panel into the enclosure. I really need to get some measurements of the 2216's in there enclosures to start working on a low pass filter in LEAP.

Rob:)

[Mr. Widget]

I bet the Mg on that waveguide is going to sound amazing... and with that 2216, these should be a formidable pair of speakers!

Thanks for keeping us posted.


Widget

[Flodstroem]

Wow, what a nice build

And I really like those corners too........... :p

[dkalsi]

Rob,

Beautiful build! Can you comment on the combo with Heil? Did you feel like something was missing jumping from a 15" driver straight to the Heils?

Since I'm home these days, I was just looking through unused speaker parts pile and found a pair of JBL 2226H. I wonder if they would work well with Heils crossed around 1.1Khz/1.2Khz.

[Ian Mackenzie]

Hi Rob,

I have a pair of M2 horns on the way.

Do you mind if I clone you design?

Ian

[Robh3606]

Ian Mackenzie
Hi Rob,

I have a pair of M2 horns on the way.

Do you mind if I clone you design?




Hello Ian

No not at all we have been sharing ideas for years :) Glad you were still able to get a pair!



dkalsi
15" with Heil
Rob,

Beautiful build! Can you comment on the combo with Heil? Did you feel like something was missing jumping from a 15" driver straight to the Heils?

Since I'm home these days, I was just looking through unused speaker parts pile and found a pair of JBL 2226H. I wonder if they would work well with Heils crossed around 1.1Khz/1.2Khz.



Hello dkalsi

Thanks! About the Heils I had them set-up with a pair of 12's and just stuck the new box under them. I am using an 850Hz 24db L/R active crossover with a notch to smooth the response. This woofer has a rising response so they are not really dialed in as well as they could be. They still sound very good so I don't see any reason why they would not work well with 2226's and some TLC.

Rob:)

[Ian Mackenzie]

Hello Ian

No not at all we have been sharing ideas for years :) Glad you were still able to get a pair!

Rob:)

Your rounds got me inspired.

[jmpsmash]

Hi Rob,

I have a pair of M2 horns on the way.


Where did you get them?

[Robh3606]

Where did you get them?


https://reconingspeakers.com/product/jbl-m2-horn-lens-5025594/


Rob:)

[Ian Mackenzie]

That’s it.

[Robh3606]

So here is a weird one. Why would you have lowered HF response measured at about and 1" from the dome than say 18" away?? And if you move out further the measurement gets rough as to be expected but HF stays??? I always though the HF were predominantly from the dome?? Guess not??

Here take a look Red is at the dome??

Rob:)

[Mr. Widget]

When I have performed near-field woofer measurements, I typically place the mic 1/4” away from the woofer cone midway between the surround and dust cap.

You will get a measurement that bumps up the lower bass a bit.


Widget

[Ian Mackenzie]

Easy.(sorry)

At one inch you have some equidistant cancellation from other points across the surface of the dome or the cone at the location of the microphone cell.

If you put tiny phase plug in there it would be similar to the 18 inch measurement. (this is why cone based horns have a phase plug depending on the design of the throat adapter).

Having thought about it a bit more the large dust cap and its shape might have something to do with it.

Looking at your graph and the calculation of 344/1600= 0.215m where 344 is the speed of sound and 0.215 metres is the wavelength at the first cancellation frequency of 1600 hertz.

The distance at reflection is 0.1075 metres or about 4 inches.

Looking at the dust cap if you have the mic centred there will be cancellation at reflections from points forming a circle around the mic cell.

At reflective points closer to the mic cell you have cancellation at progressively higher frequencies.

I think if you smooth the 18 inch measurement it will be fine.

My tip is to try a 24 db slope to avoid break up from the 2216nd and reduce 2nd HD from the Heil.

That will keep you occupied over the weekend.




Ian

[Robh3606]

Thanks Guys!

OK I will go closer and move off the dome. Give it whirl tomorrow. I am relearning LEAP :banghead: forgot the sequence to load the text files for the measurement!! Oh well! I used the longer distance measurement and got what looks like a good solution in LEAP but I don't trust it. Have to do some more measurements as I am combining stuff done years ago on a different measurement system CLIO 7 vs CLIO Pocket. If this is real I am a happy camper.

Rob:)

[Ian Mackenzie]

Nice.

I use old measurements all the time.

Yeah you need to have your wits about you with Leap when exporting and importing files.

Don't forget the minimum phase transform and to change the columns for impedance.

Its easy to screw it up.

[Robh3606]

change the columns for impedance.

LOL bingo!!

Rob:)

[Robh3606]

Well did some measurements and it didn't matter where I measured or how close. Close in it rolled off! So I redid some measurements made sure all the offsets were entered properly and minimum phase transform done and it still looks good. The only way to see for sure is to get it all together and repeat the measurements from scratch. At least it seems I have a starting point. Impedance looks good. With any luck I can get a top finished before the weekend.

Rob:)

[Robh3606]

Been working in LEAP simplifying the parts count, adding DCR to the inductors and adjusting any series resistors as required to help compensate for any changes. It looks good still need to verify if I have the horn padded correctly and get another assembled set of measurements to do that. Tried a couple of variations on the low pass and 18db seemed to give the best solution with the measurement set I am using. Really curious how this will actually measure as it looks good on paper after doing the changes.

Rob:)

[Ian Mackenzie]

Excellent!

[Robh3606]

Finally had some dry weather to get my horn mount boards done. It's been nuts here we had snow early Saturday morning in May!? Wake up temps today were a cool 40's with wind chill into the 30's! At least it will warm up into the 50's so I can use the table saw out back.

Couldn't get lumber everything closed so tried to use 3/4 mdf as a brace. Couldn't pre-drill so even dead center it split:banghead: Found some really nice 8' 2x4's in my local ACE that doesn't normally carry lumber. Have to trim them up a bit and use them for braces instead. Lucky I found them all the Home Depots are closed pick-up only. Crazy times!

Rob :)

[srm51555]

Looking Nice!

[Mr. Widget]

Looking Nice!
+1

Watching with interest.


Widget

[Flodstroem]

Amazing :yes:

[Robh3606]

Thanks Guys!

Set up a bi-amp version of the crossover. Have two measurement sets one in close the other at 4 ft. Looks good with both just some expected roll off in the last octave with distance. Going to build this first to hear how the compensation sounds on the compression driver. I already know how the woofer is. I what looks like a good solution using the 4ft measurements but don't want to pull the trigger just yet.

Rob:)

[Robh3606]

Got really lucky had all my parts delivered yesterday before the weekend, got one built and measured. Now lets see what it sounds like! It looks close and both measurements are in the ballpark for what the sym predicted. Have to plug them in later to see how much of a delta there is.

Rob:)

[grumpy]

:thmbsup: :lurk:

[Robh3606]

Well got it all built together and working! Only took 5 years to actually hear the drivers! Rainy today so perfect for sitting and listening. Had issues ordering parts with values not available had to shift resistor values and parallel up caps to get the values. Looking at the schematic I realized because of the bypassed attenuation I didn't have a series cap to protect the driver from DC. Salvaged some old networks and have 66 uF in series with the networks. I deleted my old schematic and voltage drives. Did a comparison of actual vs predicted and damn LEAP never ceases to amaze!

When I set them up I used the voltage drive as a reference for how much additional attenuation to use on the CD on the HF crossover level. I didn't realize just how efficient the 2216's are running with no network, quite a difference from what I had in this system before. These will take some getting used to! They sound kinda unique! With this waveguide it is actually hard to get out of the sweet spot in a smallish room like they are in now. I experimented with toe in and got the best results with them pointed at each ear. Really wanted to move them out into the room but can't too small a space. This is not the best room for them but it's all I have so that's that.

So how do they sound?? Damn nice but different if that makes sense. It's the combination that seems to work so well. The 2216's are really clean and extended and the compression driver just seems to add to it. The 476Mg is one nice sounding driver! Will run them like this for a while until I can get some outdoor measurements on the system.

Wish 4313 was still here! Never would have been able to do this without his generous gift of the 2216's also thanks to Jerry Moro and for getting me the 476 Mgs.

Rob:)

[rusty jefferson]

Nice work Robh! I know it'll take some time breaking them in mechanically, and your brain to them as well, but I'll be curious to know if you'll find the midrange (say 200hz up to crossover) as natural sounding as your E-145 system.

[Mr. Widget]

Nice work Robh!...
I'll be curious to know if you'll find the midrange (say 200hz up to crossover) as natural sounding as your E-145 system.+1

I will definitely be waiting for your impressions as you dial the system in.


Widget

[Chas]

Looking good Rob and ditto what Widget said. Wholeheartedly agree with your sentiments about 4313 too.

[rusty jefferson]

Nice work Robh! I know it'll take some time breaking them in mechanically, and your brain to them as well, but I'll be curious to know if you'll find the midrange (say 200hz up to crossover) as natural sounding as your E-145 system.
Sorry, I think maybe you used a mid-woofer in that system? Not applicable if that's the case.

[Robh3606]

Hello Rusty, Widget

Thanks! So you reading my mind?? That's funny you said that because that is exactly what I was using as a reference to help get the horn level right. I was using the overall E-145 system balance and now completely understand why JBL uses such subtle attenuation steps in Everest as an example. It took a while and lots of different music to find the sweet spot where I felt it was balanced by carefully adjusting the trim pots on the active crossover. I stared high and dialed down.

It's weird if you are up a little too much horn on the surface it's listenable but just not right and once you get it right there is no going back. It's now obviously off once you go through the effort. In the E-145 system I have 3 drivers in the range covered by the 2216 a 2235/E-145/2123 so it's actually a 3 to one comparison! The E-145 is my mid woofer in that system. I will let you know once I have more time and running up and down stairs is some much needed exercise in the lock down!

Rob:)

[toddalin]

The cabinets came out very nice with a unique, but definitely JBL look. :thmbsup:

Will there be an actual plot of the woofer/horn combination?

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=86747&stc=1&d=1590258596

[Robh3606]

Will there be an actual plot of the woofer/horn combination?

Hello Toddalin

Thanks! Having too many issues measuring in room an octave below the crossover point to be sure it's correct. The transition level needs to be spot on and I am not sure with the ripple what's going on. I am going to do some outdoor measurement's to verify what I already have. If I use what I have it looks really good but I would rather wait to see what's up. Once I get a passive lowpass built I will take a measurement and post it.

Rob :)

[macaroonie]

Hi Rob , is that you in room at sweet spot response or is that a LEAP prediction.
If it is the room response it is outstanding.

[Robh3606]

Hi Rob , is that you in room at sweet spot response or is that a LEAP prediction.
If it is the room response it is outstanding.

Hello Macoronie

That is a Leap prediction at 4ft based on a set of in room measurements at that distance. The actual vs predicted are 1 ft from the horn/close. The close is to verity the on axis CD compensation. I would never expect an in room listening position measurement to be that smooth without doing a multi position listening window and averaging.

Rob:)

[Robh3606]

Here is a warts and all snapshot measurement slightly behind me over my left shoulder. No where near as nice as the LEAP sims. This is not gated and you can clearly see the room modes are different Left vs Right. This is through the entire system including the +6 db boost at 25Hz.

Rob:)

[toddalin]

Point of reference:

This is the spectrum for the Ethyl Mermans where I sit on the couch among the cushions. This is from the pink noise source in the Behringer DEQ2496 and there is no sub, eq, or digital processing of any kind being used.

Note how smoothly my treatments to the Heil (lens/foam) let it blend with the 2251J. No easy feat! Also, the L-pads for both the 2251 and Heil are maxed out so could be removed from the circuit; a testiment to how well I was able to match the volume of the Heil and 2251 though component selection.

There is no way that my L200/300 variants are anywhere near that smooth from ~300 Hz. :barf:

Of course every time I look at the spectra, I modifiy the crossovers to make them smoother. For example, the dip at 4kHz is where the Heil crosses over to the 2251J. I can create a dip or peak depending on the selected by-pass resistor value in parallel with the choke. A smaller value reduces the 2251J's roll-off and I am using 2.34 ohms. After seeing this, I'll probably reduce it to 2 ohms letting the 2251 sing just a hair higher.

And I may even add another 0.1 mfd on the Heil to let it sing a bit lower. But if I go too far, I'll create a peak at just under 4kHz. Everything is a trade-off/compromise.



http://www.audioheritage.org/photopost/data//500/medium/DSC_000910.JPG

https://youtu.be/JpjCAtrBjTI

[macaroonie]

Thanks Todd. Still pretty darn good.

M

[cooky1257]

Great work (again!) Rob. I STILL haven't got round to making a passive network for my 2206/2435Be/SAM1's and have been running them active via AllDSP LMS controller.
One thing I have noticed is I can flatten the response of the HF to within a dB or so but find extensive eq robs the life out of them, counter intuitive I know but they definitely sound better with a few 'warts' left in if you get my meaning.

[Robh3606]

One thing I have noticed is I can flatten the response of the HF to within a dB or so but find extensive eq robs the life out of them, counter intuitive I know but they definitely sound better with a few 'warts' left in if you get my meaning.

Hello Cooky

Thanks! Yes I do almost like looking at an airbrushed model! I tried an early auto digital EQ once and it measured great but just didn't sound right, go figure!? As rough as those in-rooms look they sound better than you would expect looking at the measurement.

Rob:)

[Mr. Widget]

One thing I have noticed is I can flatten the response of the HF to within a dB or so but find extensive eq robs the life out of them, counter intuitive I know but they definitely sound better with a few 'warts' left in if you get my meaning.I have experienced that with virtually every system I have had. And it doesn't seem to matter if the EQ uses analog or digital filters.

Once you get the crossover filters (slopes, knee points, frequencies) and levels balanced and set up properly, additional corrections start to kill the "life" of the system.

I remember the first time I heard DEQX. It was a demo being preformed by Kim Ryrie where he took a small B&W bookshelf speaker and showed us the in room response. He then "corrected" it using the automated room correction built into DEQX. The resulting curve was textbook beautiful, but the result, to my ears at least, was a sound that was far less compelling. At the time I assumed it was simply a hurried demo being done at a trade show, but subsequently I've had similar experiences with virtually every type of system I have used... and I have used quite a few. The systems that limit their correction to the LF room issues and leave the "warts" at the higher frequencies tend to sound the best.



Widget

[Kreativlos]

Like with many things in life, less is more! In my opinion massive and big passive crossovers do not sound as nice as simpler once, that have been build with similar attention, even if the response is not as flat. Let the driver sound like what they are supposed to sound like... problem is, to achieve great results sound wise one will need great components. But then the crossover part is not about perfect linearity but about good balance between each component. The good sound comes from the driver itself, not the frequency response!

Greetings

[Ian Mackenzie]

Boosting HF is problematic.

S/N and overload margin goes to hell.

[Robh3606]

Well after another week of :banghead: finally have the bi-amp set-up dialed in where I am getting closer to what the system is capable of. I thought I had it wrapped but I decided to start all over again from scratch and am glad I did. I shifted the crossover frequency down closer to the where the passive set-up would be and re-tweaked the levels which were actually close to where they were before. Listened to a ton of music using the King Crimson 40th anniversary box sets and ITCOTCK as a reference and it's better than before.

This is the first time I have really done some SPL and WOW! They just stay together and dynamic contrasts on well recorded material can be startling. Those darn woofers never cease to amaze. They have amazing definition. Well time to go outside and get some sun! Hear is a close and chair measurement. The 1K dip is a measurement artifact, just going for over all smoother in room. Looks like I have the horn down a bit trying to see through the room. Sounds good though.

Rob:)

[toddalin]

Interesting.

I also did more work on the Memans and decided that with 4mH/30 mfd on the 2241, I could get a better better blend between the 2241 and 2251 at the higher end of the range (~900 Hz), but the 2241 became too present and I felt was "clouding" the 2251 removing definition.

I changed this to 5mH/72 mfd and this takes the 2241 out of the range where the THD begins to rise (>1,200Hz), clears up the mids, and tightens up the bass. Also went from 3.4 to 6.0 mfd on the Heils to blend with the reduced output of the 2251 after the peak at ~2kHz. I.e., instead of a peak followed by a flat line, the peak now tapers down to the flat line.

Once one gets the frequency fairly flat, you can work with voicing to enhance to taste.

[Ian Mackenzie]

Agreed.

Did you use a congregate network on the woofer to flatten the rising impedance?

This will improve the network characteristics.

[Robh3606]

Had to move a speaker into a different room but finally got a decent measurement on the 2216 in the cabinet and redid the horn as well to start fresh and see where it goes.

Rob :)

[Mr. Widget]

Have you tried a <1/2" near field measurement of the cone and a port measurement?


Widget

[Robh3606]

Hello Widget

Yes and I had issues with it. I don't normally measure that way usually set-up 1-2 meters on the tweeter axis and shoot from there. I was having some significant room issues. Looking at an RTA measurement was telling me I could not trust what I was getting. Doing it from the drivers I was having phase issues where I could sim a flat response but the low pass 2216 didn't look right based on JBL networks and if I reversed phase no null!! So I did the passive comp as a temp so I could at least listen to them. Glad I did have been enjoying them.

Figured when I got the time I would move them into the other upstairs room where my L5's are and give it a shot. When I moved to a different room things got much better. I got a measurement that was almost in a 5db window down to 200Hz. I don't gate my measurements so they are really warts and all. I feel you loose way to much resolution. The best thing would be outdoors but that is difficult doing it solo. Especially when it's 90 and intermittent showers are in the forecast.

So I think I am OK! Won't know for sure until I actually do the build but I am much more comfortable committing and purchasing the parts. I now have a network that sims very well in LEAP, makes more sense value wise vs JBL and that gives me the expected null. Shifted the crossover lower as well. Fell better about the measurements still concerned about the attenuation match although it looks fine.

Take a look at these not bad! Didn't I say that before?????

Rob :)

[Robh3606]

And the fun begins!! Got my crossover components so I can see if the network is right. The caps in the high pass are going to be charge coupled so large values x 2 takes up a lot of space. Wish I could get the Radioshack pcb's I used to use. Going to use the thin plywood cut to size and painted black.

Rob:)

[Mr. Widget]

And the fun begins!! Got my crossover components so I can see if the network is right. The caps in the high pass are going to be charge coupled so large values x 2 takes up a lot of space. Wish I could get the Radioshack pcb's I used to use. Going to use the thin plywood cut to size and painted black.

Rob:)I don't know if your favorite pcbs are still available, but Radio Shack still has an on-line store and you can get many of their products.

https://www.radioshack.com

Recently I needed a specific RF modulator that they used to offer and amazingly it was still available from them.


Widget

[Robh3606]

Thanks Widget!!

I found them on the site!! For next time!! I have one PCB built and tested and it's good! Was really worried about keeping the level right for a max flat response. Did a quick measurement looks good!!!! Should be running tonight! I have attenuation worked out if needed.

https://www.radioshack.com/products/general-purpose-prototyping-board-2-200-holes?variant=20332061829

Rob:)

[Robh3606]

OK back to the build! So I got the passive crossovers done and installed. When I was doing the biamp passive comp on the CD it sounded really good on some material and not quite right with others. I know I had some issues going on below the crossover point 700Hz in this case and the passive network really makes a big improvement. If you look at the raw measurement there is a tilt with 100Hz down a bit and 300-700Hz is raised.

So when I was running the biamp set-up this tilt was there and messing up the overall balance. Now that it is gone things sounds "right". Definite improvement overall. Green is measured blue is the raw woofer curve.

Rob:)

[Robh3606]

Well it's great when a plan comes together and it all works out. The decision to build the cabinets low tuned with a bump filter is working out very well. I get the last octave fill with no boom at all. Just sounds fuller with more weight. Even low tuned there is a surprising amount of bass that works with a lot of music. It's essentially a 40Hz system without the bump and can tune in 1dB increments. Glad I was skittish on building the crossovers as it paid off the 7/5 measurements in the next room really made all the difference. Now I know just do it!

I am listening as I type this and with the upper mid bass rise gone they are really well balanced. They measure very well within a db or 2 over most of there range from the Leap sim. The real target was as close to M2 flat as I could manage. Obviously not happening without DSP but as close as I will ever get. Green is the LEAP simulation Red is the actual in room measurement @ 1 meter. Used a 700Hz crossover point and have stepped attenuation worked out if needed. Going to try them as is for a while first, Now I just have to tear them down to finish the cabinets. Winter project!

It's nice to have finally got this done and just be able to relax and enjoy them!

Rob :)

[Mr. Widget]

Well it's great when a plan comes together and it all works out....

Green is the LEAP simulation Red is the actual in room measurement @ 1 meter.

It's nice to have finally got this done and just be able to relax and enjoy them!
Amazing! Glad it is working out so well... wish I could give them a listen. Unfortunately I WILL NOT be boarding an airplane in the foreseeable future.


Widget

[grumpy]

Nice! :thmbsup:

[Robh3606]

Thanks guys!!

It's a rainy day here and I have off so have been listening to them. I am really impressed just how dynamic they are. I have been doing a shoot out between my basement system and this one. This 2 way is giving my 4 way active a run for the money dynamics wise so I am having fun! I had a feeling going out flat like that would sound a bit "hard" and it does to my ears at least. I dropped a 20 ohm resistor in parallel with R7 and it makes a significant difference. The change is about -1.5 db of attenuation. The change sounds like it brings up the low end and it sounds more balanced. Much better this way! Green is normal blue is attenuated,

Rob:)

[Earl K]

Nice work Rob!

:)

[toddalin]

I've also found that "flat" may not be the most musical nor the most intelligible. While the overall curve should decline slightly, I like a bit of "brightness" in the 1-4 kHz area and it only requires less than a dB to achieve or it becomes overwhelming.

Once you get to this point, you start to consider "voicing" to taste and the acoustics of the room.

[pos]

Amazing work Rob!
Have you had a chance to compare the 2453 with the 2450SL sonically?

[Robh3606]

Hello Pos

Thanks!! On the 2453SL no I actually don't have any 2450's the 476's would be the only valid comparison I have. The 2453's are going downstairs in my active set-up only going to use them above 1.5K. I even have the networks built so I should just get it done.

Rob :)

[Robh3606]

Been listening and having fun. Added an Impedance conjugate to tame a peak, and minimize phase angle to +/- 30 degrees. Retired the PS-200 and am using a pair of Emotiva HC-1's running with balanced inputs. Updated schematic Step, Wavelet and Waterfall .

Rob:)

[pos]

Thanks!! On the 2453SL no I actually don't have any 2450's the 476's would be the only valid comparison I have. The 2453's are going downstairs in my active set-up only going to use them above 1.5K. I even have the networks built so I should just get it done.
Sorry for the confusion!!
I will continue in your large format comp thread: http://www.audioheritage.org/vbulletin/showthread.php?42373-Large-Format-Compression-Driver-Listening-Impressions

[Robh3606]

It took weeks but I finally got my 1.8M resistors so I could charge couple the networks. Got them finished and they sound great! Now it's just the cabinets! Just did a verification to see if the impedance compensation worked as designed.

Rob :)

[Robh3606]

Been just listening. I have updated my system to include a refurbished Emotiva XMC-1 to use as my preamp in a stereo system. All of my sources are digital and I was looking for something that had digital parametric EQ and bass management if needed down the road. I also have Full Dirac in addition as an additional EQ option. I could not find any stereo preamps that had this kind of flexibility.

I have been living with the XMC-1 for about a week and it is working out very well. I have used one of the parametric band for the Q2 26Hz bump filter to extend F3 on the speakers. I still have 10 bands left per channel for room EQ if I want to use any. You can measure with REV and then import the filters into the preprocessor.

One thing that is surprising is how quiet this system is. I can't hear any hiss at all unless I literally have my ear inside the waveguide. I am running balanced connections so that I assume is helping.

Having fun!

Rob:)

[Mr. Widget]

Looking good... sounds interesting. Is it time for veneer?


Widget

[Robh3606]

Looking good... sounds interesting. Is it time for veneer?

Hello Widget

Yeah it's getting close on the veneer. Don't want to break them down but I should just bite the bullet and get it done. Never done it before so it will be a learning experience. What method would you recommend for a novice??

Rob:)

[Mr. Widget]

Well, not having done it this way myself it seems a little odd suggesting it, but I think the most forgivable method is to use paperbacked veneer and go with PVA and iron it on.

I have used a many other techniques with both successes and utter failures... I once ruined a bunch of Brazilian rosewood veneer. It has been decades and I still get upset thinking about that one!


Widget

[Robh3606]

Hello Widget

Now I went and did it got a 4x8 sheet of 10 mil flat cut paper backed walnut vernier that is pre-coated with adhesive so peel and stick. Getting 4x8 of flat black formica for top and bottom wear surfaces and no rings up top for an errant pint glass.

Rob :)

[Robh3606]

It's been rain, rain and more rain. Wish I could send some of it west. Just finished getting my second top routed and ready for veneer and formica. Doing walnut first then doing formica tops to protect the veneer edges and have a more durable stacking surface. Little concerned about the white edge but it actually look nice against the walnut. We shall see!

Rob:)

[Mr. Widget]

Yes, wish you could send us the rain!

Sounds exciting... keep us looped in.


Widget

[Robh3606]

Sanding filing and filling! Beautiful weather today! Getting a lot done both tops ready for sealing. Working on the bottoms. Have a flat black eggshell coming tomorrow for the backs and any exposed edges that won't get covered in either black formica or the walnut.

Have my formica all cut ready to contact cement. What a PITA that was try cutting a 4X8 sheet of thin and floppy material without a proper table!! Had to jury rig it but it worked!

With paper back veneer what is the best way to cut it?? I have a 10" 180 teeth fine saw blade but concerned about damaging the sheet because it's so damn awkward to handle as a full sheet. Anyone either razor cut or scissor??

Rob:)

[christo]

With paper back veneer what is the best way to cut it?? I have a 10" 180 teeth fine saw blade but concerned about damaging the sheet because it's so damn awkward to handle as a full sheet. Anyone either razor cut or scissor??


Hi Rob

I just use a sharp and sturdy box cutter with straight edge and a scrap piece of wood under where your cutting. I've never had an issue with 10 mil paper backed veneer. The tip of the blade will break off on the first cut but that's ok. Paper side down.

Chris

[Robh3606]

Thanks Chris

Rob:)

[Mr. Widget]

I use one of these and I change the blade often... a dull blade will follow the grain instead of your line when the grain shifts.

https://www.stanleytools.com/products/hand-tools/knives-blades/utility-knives/6-in-classic-99-retractable-utility-knife/10-099

After I have the panel glued up I use a sharp veneer trimming router bit on one of these offset laminate trimmers (https://www.ebay.com/i/124250103524?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=124250103524&targetid=935431405173&device=c&mktype=pla&googleloc=9032058&poi=&campaignid=10897989837&mkgroupid=106040609894&rlsatarget=pla-935431405173&abcId=9300403&merchantid=6419954&gclid=EAIaIQobChMI85O0lafv7AIVWiCtBh3RhwCeEAQYAyAB EgIwwPD_BwE).
My ancient Porter Cable router is in much nicer condition though. :D

I follow up with a brand new blade from the Stanley No99A and trim the remaining stubble left by the router and follow that up with fine sandpaper on a block of wood held at an angle.


Widget

[Robh3606]

Thanks Widget!

Rob:)

[Robh3606]

Well got a top finished and a bass veneered seem to match up well. Have to formica the bass cabinet top and bottom. Now for some lesson's learned.

I got 10mil backed veneer with psa? glue which is peel and stick. So you peel the back and your ready to go. They have a special tool to apply it because it is pressure activated.

Well let me tell you the stuff bonds almost instantaneously. You cannot let it touch when your are trying to pace the sheet. I did and almost lost the sheet. The glue is so strong it delaminated the MDF! Managed to save it and glad I have enough veneer for a whoops!

Going to try and finish tomorrow!

Rob:)

[grumpy]

Sure looking nice! :thmbsup:

[Mr. Widget]

Sure looking nice! :thmbsup:+1

Keep it up, looking good!


Widget

[Robh3606]

One done one to go!

Rob:)

[hoschibill]

Visually very successful. Like it a lot.

[Mr. Widget]

Looking good... you are in sync with the current JBL aesthetic.

How about the sound, still dialing them in, or are you pleased with the results?

Widget

[Robh3606]

Thanks!

I had them dialed in before I finished the cabinets although I haven't powered them up yet so I don't know how lossy my cabinets were using just a couple of screws. Also hopping I don't have any buzzes after adding the veneer and mica. Now the backs are glued and screwed so it should tighten things up a bit. I am running with 2Db of attenuation on the waveguide as I felt that gave the best overall balance in my room as you can see even with carpet it's a bit live.

Rob :)

[Earl K]

Very Nice Looking Rob!

:)

[rusty jefferson]

Agreed. Love the horizontal veneer and large radius corners. They look great.

[hoschibill]

Nice. Just beautiful. :thmbsup:

[Robh3606]

Thanks Guys!

Rob:)

[jmpsmash]

Incredible build and love that finish!

With the shallow depth of the M2 horn and the relatively deep 2216ND, did you measured if JBL designed them to be time aligned when mounted on same baffle depth?

[Robh3606]

Hello

Thanks!

They use a 270us delay to time align them using the DSP for the M2. So no they don't align you would have to push back the horn a bit but then you introduce another set of problems. My passive is flush and you can see the delay in the step response.

http://www.audioheritage.org/vbulletin/showthread.php?33972-JBL-Master-Reference-Monitor/page16

Rob:)

[jmpsmash]

Hello

Thanks!

They use a 270us delay to time align them using the DSP for the M2. So no they don't align you would have to push back the horn a bit but then you introduce another set of problems. My passive is flush and you can see the delay in the step response.

http://www.audioheritage.org/vbulletin/showthread.php?33972-JBL-Master-Reference-Monitor/page16

Rob:)

Oh I see. If I read that correctly, 270us (9.3cm) delay is applied to the 2216ND. That means the compression driver is further back away from the baffle when compared to the 2216ND.

What kind of problem do you see if trying to make them time align? other than 9.3cm is a lot to compensate.

[Robh3606]

What kind of problem do you see if trying to make them time align? other than 9.3cm is a lot to compensate.

My passive speaker is not time aligned and in my case the compression drivers leads. Not worried about the time alignment. As long the summation is good through the crossover region all is well.

Rob:)

[Robh3606]

I was doing some comparisons with with my basement system and these and I just couldn't match the sense of space I was getting from the PTH1010/2453SL and these speakers. After thinking about it just didn't make sense so I tried to figure out why. And of course it all boiled down to placement. In the basement there are no really prominent side reflections between toe in and placement and they don't have a 45 degree sloping ceilings in close proximity.

Looking a the ceiling I started thinking and realized reflections off them might be the issue. So I emptied the room and tried different placements and sure enough with the sloping ceilings behind and not on the sides made all the difference. This also brought me a bit more distance made the imaging even better and took out a suck out I was having issues with so the bass improved as well. It's an irregular shaped room and I went with what I thought would be the best position and made the mistake of not trying to flip the room during my original set-up.

That's what you get for being lazy! All better now!

Rob:)

[Mr. Widget]

That's what you get for being lazy! All better now! Yep, I learned that one myself some years back. Just because we think we know where a system will sound it’s best, it is a good idea to experiment with alternatives. And, rooms and room placement make a huge difference!

Glad to hear it worked out.


Widget

[Robh3606]

Hello Widget

Yes it was literally staring me right in the face. The key was a simple phase test. I had been running my Heil's in the room that way and just dropped these right into basically the same positions. When I ran a phase verification test on the out of phase portion you could could hear it but it was more diffuse and vague than what I would typically hear. With the di-poles and the back wave I didn't really think anything of it.

When I dropped these in and did the test I got similar results and frankly just didn't really think about it based on previous tests. Now I get a very clear and stable difference compared to the other positions in the room.

Rob:)

[toddalin]

Hello Widget

Yes it was literally staring me right in the face. The key was a simple phase test. I had been running my Heil's in the room that way and just dropped these right into basically the same positions. When I ran a phase verification test on the out of phase portion you could could hear it but it was more diffuse and vague than what I would typically hear. With the di-poles and the back wave I didn't really think anything of it.

When I dropped these in and did the test I got similar results and frankly just didn't really think about it based on previous tests. Now I get a very clear and stable difference compared to the other positions in the room.

Rob:)


Which is why I restrict the back wave on my Heils. It really helps imaging.

[rusty jefferson]

Rob, do you have a picture of the new positioning? I'm not sure how long the long wall is but the speakers were definitely too close to the side walls previously. If there's 3-4 feet distance now, eliminating those early side wall reflections should be a good improvement overall. If your seating area is now close to the other knee wall, some diffusors behind you to scatter reflections can be a big improvement also. Congratulations. :)

[Robh3606]

Hello Rusty

It's a weird shaped room with a large walk in closet filling one corner. One speaker is close but better the other has no wall close. There is no way to get symmetry with placement because of closet doors and aesthetics.

So here you go on the long wall slanted ceiling behind.

Rob:)

[marconi118]

476Mg is 16ohm?

if I go with 2452HSL 8ohm, I would put 8R in series to the driver to bring it up to 16ohm and use the same crossover as yours?

[Robh3606]

476Mg is 16ohm?

if I go with 2452HSL 8ohm, I would put 8R in series to the driver to bring it up to 16ohm and use the same crossover as yours?

I don't think that's going to work. As a minimum a different driver on the M2 is going to give you a different impendence plot. Take a look at this thread where I have 8 ohm 2453-SL's on the PTH1010. There is a network and more posted. Might be a better place to start as at least these are 8 ohm drivers and you can compare the Imp plots in this thread with the 476Mg to see how different they can be on the same waveguide.

That thread just does the CD comp and a protection cap for use in an active crossover system. You could drop a high pass in front but you would have to tweak it a bit for it to work.

http://www.audioheritage.org/vbulletin/showthread.php?42373-Large-Format-Compression-Driver-Listening-Impressions

Rob:)

[Ian Mackenzie]

476Mg is 16ohm?

if I go with 2452HSL 8ohm, I would put 8R in series to the driver to bring it up to 16ohm and use the same crossover as yours?

In typically the drivers labeled 8 ohms have an impedance of 6-8 ohms and those labeled 16 ohms have an impedance of 12 ohms. You could fiddle around with a simple passive EQ and get an okay result. Care needs to be taken with passive EQ that it does not load down the impedance too much at high frequencies using a capacitor shunt across a series resistance. A small value inductor (0.3-0.5 mH) with a small value series power resister (2-3.9 ohms) shunted in parallel with the driver would be a good starting point. Greg Timbers has used this approach and it acts to protect the driver. This approach does not load down the impedance. It attenuates frequencies below the shunt resonance of inductor at 6 dB per octave. Then you need to have a high and low pass crossover filter.

But beyond that it’s a lot of trial and error with test microphone. Dayton make a loudspeaker measurement set up. An active crossover with your diy passive EQ is a good option.

Alternatively you might want to try the Dayton dsp crossover first to get yourself up and going as a Diy effort. Tip. When you actively EQ a driver cut the frequencies below 3-6 khertz in preference to boosting the high frequencies. This will improve the noise and distortion performance of the Dsp processor.