PDA

View Full Version : newbie: 2226H and 2426H DIY, thanks!



manolito
11-13-2011, 03:55 AM
Hi everybody, this is my first post here, though I´ve been visiting the forum from some time ago.

Some months ago I tried the lansing plunge and bought a pair of A7s: 828 cabinets, 515-8G woofers, 511B horns, 808 compression drivers and 1631A active crossover w/500hz module.

I do like some things that these speakers do very well: dinamics, huge sound, presence, etc

However, there are other aspects that make them sound like a 1970 movie (that´s what they were intended to ...) and I think that are not up to modern hifi standards, in particular, a shout around 1-2 khz and one-note-bass from 100 hz down

I plan to do all the standard updates: brace the bass cabinet and horn, reduce the vent surface and tune it to 40 hz, damp the 511 horns, try a 800-1200 hz XO, maybe 902-8C drivers ...

And here comes my question.

2 audio buddies have listened to these A7s and suggest a different approach, to build a DIY classic combination, with JBL 2226H woofers and 2426H compression drivers

they have the drivers as a spare and will borrow them for free, and the cabinets will be proffessionally done

The target is to get strong and "flat" 35/40 hz to 16-18 khz, around 95 db sensitivity

the idea is:
3 - 3.5 ft3 reflex cabinet
bass port tuned to 35-40 hz
passive XO around 900-1100 hz
no EQ
this tractrix 350 horn: http://www.horns.pl/tractrix350.html

they are sound engineers and know what they talk about
however, as sound engineers, they have wooden ears (hey folks, if yoy read this, I´m just kidding, no offense here ... :p)

As I live in a small corner of the world, I can´t listen to the stuff, and have many questions about this project:

My amplifier is a 4 watt SET amp (Fi WE421)
Shall I drive the 2226H with it?

What about GPA 515 LF or 416-B woofers, instead of the 2226?

How will the 2426 driver work with the tractrix 350 horn?
Can I get "flat" 900-18000 kz to 95 db with it?

Right now the 2426 have aftermarket diaphragms
Is there a lot of difference between aftermarket, D8R2425 titanium and D8R2421 aluminium?

For the price of 2421 aluminium diafragms I can buy brand new BMS 4552nd drivers, so what about BMS 4552nd compression drivers against 2426H?

What about the XO point?
maybe 40-900 is too much for the 2226 and 900-18000 too much for the 2246?

Any help and ideas will be appreciated

thank you very much in advance :)

Eaulive
11-13-2011, 11:08 AM
2226H and 2426H DIY



this is a very common combination in PA, look for specs on JBL 4704 and 4725, that should give you some ideas.

However don't expect deep low bass and UHF with this setup.

Allanvh5150
11-13-2011, 12:01 PM
Hi, the 2426 will perform perfectly fine if you use the right crossover with equalization on the top end.

Allan.

Lee in Montreal
11-13-2011, 12:36 PM
2226 will be boomy, more so than a 2225. If you keep the A7 cabinet, you could tune it by blocking the lower opening and porting it to perhaps 40Hz. But don't expect to be flat to 35Hz. :D BTW I wonder what would happen if a 2235 was used in an A7 with BR porting? It won't be able to offer as much SPL as the 2225, but the sound will probably be more hifi. It'll go lower.

Allanvh5150
11-13-2011, 12:42 PM
I have used 2235 and 2425 together and you can make them sound pretty good.

Allan.

badman
11-13-2011, 11:30 PM
2226h and 2426h are both sweeeeeet drivers. 2226h wants a little bigger box, 4-5 cubes, tuned to 35-40hz. A couple dB at 50 goes a long way to having "oontz". The 2426h needs impedance compensation aplenty on a CD horn, but on tractrix, you can probably use parallel resistance for impedance compensation. http://www.enjoythemusic.com/diy/1110/oblate_spheroid_waveguides.htm

manolito
11-14-2011, 05:47 AM
Thanks!

my main concerns are:

1.- I don´t like high SPLs at home, just around 85-90 db average and maybe 100 db peaks, but even so, can I drive the 2226 with just 4 watts, from a single WE421 SET amplifier?

I have listened to some JBL woofers, fairly sensitive at 95db, but they needed punch from the amplifier to come alive, at least a 300B tube, a 2A3 did not the job ...

Maybe these drivers are aimed to obtain high SPLs with powerful amplifiers in a PA environment, but not the best for low volume at home?

2.- Are the replaceable aluminium D8R 2421 diaphragms, to be used with 2426H drivers, worth the price for hifi home use?

please note that, with 4 watts at home, I should not overdrive aluminium diaphragms

For the price of a pair of 2421 diaphragms, I can choose a whole bunch of new drivers: BC 250, BMS 4552-4550, Beyma CP380M, GPA altec 902 ... but I have not heard any of them ...

Lee in Montreal
11-14-2011, 06:13 AM
1.- I don´t like high SPLs at home, just around 85-90 db average and maybe 100 db peaks, but even so, can I drive the 2226 with just 4 watts, from a single WE421 SET amplifier?

This is why I was disgarded the 2226 as a candidate. It was designed for high SPL and to be fed by big amps. When filtered by a bass reflex enclosure, the ipper bass is cut and the sound is a bit smoother, but it won't go below 40Hz. While on the other end, the 2235 was designed for studio monitoring and home duty, offering the full bass spectrum, down to 20Hz.

2235 drivers are rare, but if you could get some 2225 baskets, then those can be reconed into 100% 2235, except for the rear foil cap.

Mr. Widget
11-14-2011, 01:26 PM
This is why I was disgarded the 2226 as a candidate.I agree... the 2226 has more in common with your old A7 system than it does with a modern Hi-Fi.

The 2426 with the right horn and network can sound great... there are better choices, but the 2426 offers a very high bang for the buck quotient. The "right horn and the right network" however are not trivial and much care and research will be required.

I will second the recommendation for the 2235H. I also really like the LE14H-3. Both of these woofers will not play as loudly as the 2226 and need a bit more power to achieve the same loudness as the 2226 and especially the A7, but they are both far more nuanced, neutral, and have a much deeper and better low end.


Widget

Mr. Widget
11-14-2011, 01:30 PM
2.- Are the replaceable aluminium D8R 2421 diaphragms, to be used with 2426H drivers, worth the price for hifi home use?I would say yes, but it is a very expensive upgrade for a fairly subtle improvement. If you have a perfect pair of 2426s, I'd wait for the folks at Truextent to make beryllium diaphragms available for the 1" JBL family.


Widget

jbl
11-15-2011, 11:50 AM
I agree... the 2226 has more in common with your old A7 system than it does with a modern Hi-Fi.

The 2426 with the right horn and network can sound great... there are better choices, but the 2426 offers a very high bang for the buck quotient. The "right horn and the right network" however are not trivial and much care and research will be required.

I will second the recommendation for the 2235H. I also really like the LE14H-3. Both of these woofers will not play as loudly as the 2226 and need a bit more power to achieve the same loudness as the 2226 and especially the A7, but they are both far more nuanced, neutral, and have a much deeper and better low end.


Widget
I had the 2225H in the 4507 cabinet. Sounded great. The only drawback was that the system had to be played loud to get the woffer going. I changed to the 2235H in 2008. Day and night difference in the low bass at any volume level.
The 2235H has about 10 dB greater output below 40 Hz.

manolito
11-15-2011, 12:22 PM
well, it seems that the combination "JBL woofer + low power amplifier + low listening level" will not work

so ... is there a safe bet out there?

the specs should be like:
- efficiency around 100 db
- 35-1500 hz bandwith
- to be used with low power amplifier, passive crossover, 2-way, reflex cabinet around 5 cft

maybe, inside lansing tradition, an Altec 416-B?
maybe other brands/models: beyma, BC, AE ... ?
:dont-know:

about the 2426 tweets: I´ll stick with the aftermarket diaphragms and wait for the new Berillium ones

Mr. Widget
11-15-2011, 01:00 PM
the specs should be like:
- efficiency around 100 db


well, it seems that the combination "JBL woofer + low power amplifier + low listening level" will not work...
It isn't JBL, it is physics. There is no woofer made by anyone that has accurate deep bass and a sensitivity greater than 93dB-96db. Anyone who says their woofer will do what you are asking are stretching the truth or have a different definition of deep bass.

There are countless "music lovers", "audiophiles", "audio enthusiasts" or whatever term you find is positive and not a damning title who believe their high efficiency system has great bass... and that is fine, but the fact is that it will not have a linear response. If you can accept some gross inaccuracies in response, and many avid listeners who are members of the previously mentioned groups above seem quite accepting of them, then you have a number of choices, but since you were not lulled into audio nirvana by the A7 sound, I'm going to guess you will not be happy with any of these high efficiency offerings.


Widget

manolito
11-15-2011, 03:41 PM
It isn't JBL, it is physics. There is no woofer made by anyone that has accurate deep bass and a sensitivity greater than 93dB-96db. Anyone who says their woofer will do what you are asking are stretching the truth or have a different definition of deep bass.

There are countless "music lovers", "audiophiles", "audio enthusiasts" or whatever term you find is positive and not a damning title who believe their high efficiency system has great bass... and that is fine, but the fact is that it will not have a linear response. If you can accept some gross inaccuracies in response, and many avid listeners who are members of the previously mentioned groups above seem quite accepting of them, then you have a number of choices, but since you were not lulled into audio nirvana by the A7 sound, I'm going to guess you will not be happy with any of these high efficiency offerings.


Widget

Estimated Mr Widget,no pun intended to JBL woofers, I get your point and truly welcome your advice.

Lee in Montreal
11-15-2011, 04:18 PM
- to be used with low power amplifier, passive crossover, 2-way, reflex cabinet around 5 cft

I am trying to understand the parameters around which you want to work.

30 wpc amplifier. Okay. Why not?
Two way system. Why not?
Passive crossover? Sure.

But perhaps deciding now what size cabinet is too early in the decision process. What could be tempting is using two 2235 woofers per bass reflex cabinet. One does full spectrum (20-800Hz) and the other only does 20-50Hz) for that deeper bass (and using two woofers will raise the efficiency by 3db. Then use a 2426H on top with a 2344 baby butt horn and you'll end up with a 4435 ;-). Build it. Have fun with it. If you want to improve, then build another one, and another one. After all, that's what most of us have been doing for a few decades. Personally, I think the most fun is in the process. Not with the end result...

Each 2235 requires a 4,6cft volume. each one will give F3 at 36Hz, and this is why you'd use two woofers. The one that only does 20-50Hz will flatten the bottom...

53652

badman
11-15-2011, 04:27 PM
There are some that push the limits and need a LOT of box accordingly. Some of the GPA altecs have >600L Vas, as they have low Fs, moderate Qts, and high efficiency.


It isn't JBL, it is physics. There is no woofer made by anyone that has accurate deep bass and a sensitivity greater than 93dB-96db. Anyone who says their woofer will do what you are asking are stretching the truth or have a different definition of deep bass.

There are countless "music lovers", "audiophiles", "audio enthusiasts" or whatever term you find is positive and not a damning title who believe their high efficiency system has great bass... and that is fine, but the fact is that it will not have a linear response. If you can accept some gross inaccuracies in response, and many avid listeners who are members of the previously mentioned groups above seem quite accepting of them, then you have a number of choices, but since you were not lulled into audio nirvana by the A7 sound, I'm going to guess you will not be happy with any of these high efficiency offerings.


Widget

Mr. Widget
11-15-2011, 05:34 PM
There are some that push the limits and need a LOT of box accordingly. Some of the GPA altecs have >600L Vas, as they have low Fs, moderate Qts, and high efficiency.Even in an infinite baffle, I don't think you can find a driver that goes against what I was saying... The old EV 30" woofer does go fairly low and is high efficiency, but it has other issues.

I suppose if cost were no object and sensitivity the primary goal, someone could build a large diameter driver with a field coil motor that would satisfy the sensitivity requirements at frequencies below 40Hz... but??? I also agree that with a properly large, read that very large horn there are possibilities, but again???

I think Lee's suggestion of going a bit larger and going the 4435 route is likely the best compromise... for a fairly simply two way of exceptional sensitivity and using the 2426.


Widget

badman
11-16-2011, 10:05 AM
Have you reviewed the drivers I mention? I agree that there's a balance to be struck between factors, but you can up the motor strength and achieve more deep stuff with high sensitivity, at the cost of having to go to very low clearance gaps, and usually give up some Xmax too. These definitely put a limit on how loud it'll go low, but they'll do low at home levels, assuming you take appropriate care in system design.

ALL woofers have "other issues" ;)

I'd prefer to stick with a single higher-sensitivity midwoof, since if you want the sensitivity matched through the midrange, and without introducing extra lobing, you'd need to go 2226h or some such in a decent size vented box. True deep bass would require subs. Anyway, if a 2235 is pumping out deep bass it's not going to sound very good at 1kHz, and if you have 2 of them run full-range, you're going to have horrid polars.




Even in an infinite baffle, I don't think you can find a driver that goes against what I was saying... The old EV 30" woofer does go fairly low and is high efficiency, but it has other issues.

I suppose if cost were no object and sensitivity the primary goal, someone could build a large diameter driver with a field coil motor that would satisfy the sensitivity requirements at frequencies below 40Hz... but??? I also agree that with a properly large, read that very large horn there are possibilities, but again???

I think Lee's suggestion of going a bit larger and going the 4435 route is likely the best compromise... for a fairly simply two way of exceptional sensitivity and using the 2426.


Widget

spkrman57
11-16-2011, 10:21 AM
I use 2226's in my system and enjoy the efficiency and I'm content with LF response down to approx 50hz in my 12' x 16' room.

I use tubed amps with < 10 wpc because I don't ask my system to provide unrealistic demands.

Most of my music does not have notes below 40hz and when that situation does occur I can live with the result.

It is all a compromise of one sort or another. The dynamics of a high-efficiency spkr system coupled with using SET (300B) amps is more important "to me" than the bottom end LF response.

You have to decide on what your compromise will be!

Just my 2 cents worth!

Regards, Ron

Mr. Widget
11-16-2011, 11:21 AM
Have you reviewed the drivers I mention?No, but I have used similar drivers...


I agree that there's a balance to be struck between factors...Yes, all of this is about compromises... some will accept some compromises and other folks prefer a different set.



...but you can up the motor strength and achieve more deep stuff with high sensitivity, at the cost of having to go to very low clearance gaps, and usually give up some Xmax too. This is where we differ... you can throw all the flux density in the world at it and you won't get a linear response from 30-35Hz to 1KHz and a sensitivity above 96dB... with a cone diameter of 15" or less.... you just can't. Perhaps I should define linear... I like to keep it within a couple of dB. Down 10 or more dB just isn't linear in my book.


Anyway, if a 2235 is pumping out deep bass it's not going to sound very good at 1kHz, and if you have 2 of them run full-range, you're going to have horrid polars.Have you heard about the 4430 and 4435? Have you heard them? The 4435 does not use 2235Hs or run two all the way up to 1KHz... and I don't think anyone was advocating that solution. I personally like these 44XX systems more than any of the high efficiency designs that I have heard... though they do not have that ultra tenth degree of dynamics that some of the more efficient designs have.


Widget

badman
11-16-2011, 12:09 PM
No, but I have used similar drivers...

Yes, all of this is about compromises... some will accept some compromises and other folks prefer a different set.


This is where we differ... you can throw all the flux density in the world at it and you won't get a linear response from 30-35Hz to 1KHz and a sensitivity above 96dB... with a cone diameter of 15" or less.... you just can't. Perhaps I should define linear... I like to keep it within a couple of dB. Down 10 or more dB just isn't linear in my book.



Actually, you can. It requires rebalancing of other components, but the rising response and decreased Qts can both be dealt with with rebalancing the moving assembly. More flux can allow more bass or more efficiency, so a higher flux density would allow someone to increase the bottom end of a driver like the 2226h by decreasing Fs and raising Qts with added mass. Naturally there are limits here, but it's possible and has been done, as evidenced by the Altec drivers, which have several more dB of sensitivity available in the bottom octave while retaining similar axial sensitivity to some of the more sensitive JBLs like 2226h.

The tradeoffs are in what you have to do to get there. The boxes needed are huge, the drivers have limits in displacement that are more confining than the more practically oriented drivers without the effort made towards doing both deep and sensitive.




Have you heard about the 4430 and 4435? Have you heard them? The 4435 does not use 2235Hs or run two all the way up to 1KHz... and I don't think anyone was advocating that solution. I personally like these 44XX systems more than any of the high efficiency designs that I have heard... though they do not have that ultra tenth degree of dynamics that some of the more efficient designs have.

Widget

I'm familiar with them, and my point was that to get the sensitivity of the midwoofers higher with 2235s you'd have to run them both up to the horn, which would be a mess. The 2.5 way design of the 4435 is certainly one way to go about it, but I tend to feel that one is better accepting a low frequency limit and keeping sensitivity higher, and add subs. This shouldn't be a surprise since I'm a long-term advocate of multisubs, so subwoofers are assumed anyway. If you want a standalone speaker, then the 4435 method might be more viable. Focusing upon good bass extension, though, tends to make for a midwoof, in a 2 way, that's not performing as well as it can be near the higher crossover points required for a 2 way.

I've made a few CD 2 ways like the 4430, and just did a survey of 15" woofers, including the JBL 2226h, Eminence Magnum 15HO, and BD BD15.

I think the key component is that you want more deep bass from the mains, at the cost of sensitivity, where I feel the better compromise is a more efficient loudspeaker and subs if you need more bass (better anyway). Just a philosophical difference.

I couldn't live with a 4430. The breakup of the 2425h is too much for me, I'd rather have given up the >10kHz top end and added a cheap supertweeter, but naturally that's more XO. I don't know if it's the diffraction slot (I believe it to be), but there seems to be another source of harshness there too, at higher levels. My own CD waveguides were commented by a forumite here, who owns and uses the 4430, to be the best sound he's heard from the 2425/6 driver family, and didn't have this problem much. They had a top end that was allowed to roll off instead of trying to squeeze 18k out of a diaphragm in breakup.

Mr. Widget
11-16-2011, 12:28 PM
The tradeoffs are in what you have to do to get there...I think we are agreeing more than we are disagreeing... :)


...but I tend to feel that one is better accepting a low frequency limit and keeping sensitivity higher, and add subs. I don't disagree at all about the benefits of multiple subs and quality midbass speakers but, this thread is about two-ways to be used in the home with a small amp at moderate to low SPLs. ;)



I couldn't live with a 4430. The breakup of the 2425h is too much for me, I'd rather have given up the >10kHz top end and added a cheap supertweeter, but naturally that's more XO.Again, 95% in agreement... I don't like cheap tweeters... OK, I don't have a problem with cheap tweeters if I can get an excellent tweeter inexpensively. :D

Good old Zilch and I chased this issue round and round for years as he advocated squeezing the last bit of break up out of every HF unit he could and I would cringe in the listening... he generated nice looking plots, and I don't think he could hear the problem with the razor edged highs he created. Ultimately he was an engineer, and inventor, and a tinkerer and his goal was somewhat different than mine. I agreed with him that a two-way is an elegant solution and some are better than others, but pulling it off well was tricky.

Only once while listening to a pair of his creations did I hear a pair of CDs that sounded good stretched up top... he was using a particularly clean pair of unmolested vintage LE85s. Those drivers happened to be tame enough to actually work. He gave that pair of drivers to me before passing and one day I hope to build a pair of Zilch memorial two-ways with LE14H3s below... he and I always agreed on those woofers. :bouncy:


Widget

4313B
11-16-2011, 01:28 PM
Good old Zilch and I chased this issue round and round for years as he advocated squeezing the last bit of break up out of every HF unit he could and I would cringe in the listening... he generated nice looking plots, and I don't think he could hear the problem with the razor edged highs he created.That was the whole point. People don't like graphs that aren't flat from 20 to 20k.

badman
11-16-2011, 01:35 PM
I think we are agreeing more than we are disagreeing... :)


<<BREAK!>>>
He gave that pair of drivers to me before passing and one day I hope to build a pair of Zilch memorial two-ways with LE14H3s below... he and I always agreed on those woofers. :bouncy:


Widget

I hope you get to do a project around them, they sure seem to be superb. And yep, we're agreeing much more than disagreeing.

Mr. Widget
11-16-2011, 04:26 PM
I hope you get to do a project around them, they sure seem to be superb. And yep, we're agreeing much more than disagreeing.As it turns out, I could use a new pair of speakers for my shop... something "quick and slightly dirty" should do the trick. ;)


Widget

grumpy
11-16-2011, 04:58 PM
My own CD waveguides were commented by a forumite here, who owns and uses the 4430, to be the best sound he's heard from the 2425/6 driver family

I'll nut-up... I'm guessing that was me :). A non-fatiguing sound indeed.
I still need to drop the 2421's I got from Earl G into the 4430's and see how that goes...

badman
11-18-2011, 09:17 AM
I'll nut-up... I'm guessing that was me :). A non-fatiguing sound indeed.
I still need to drop the 2421's I got from Earl G into the 4430's and see how that goes...


I didn't want to "out" you :D. I'd be very interested to hear the 2421 phragms in your rig- they certainly seem to be the closest we'll be getting to truExtent for the 2425/2426 for a while.

Off topic, we need to touch base sometime soon. I'm listening to a quite different set of speakers than last time- I have since implemented my dipolar heil AMT horns with larger, vented, low diffraction bass cabs.

Ack... bad pic!
53695

manolito
12-13-2011, 05:54 AM
Thanks to everyone for your kind information.

We´ve found 4 nice alnico 2205 15" drivers, so we´ve changed our project to:
- d´apolito design
- approx 8 cubic feet box
- bass reflex
- 2 x 2205 (maybe these will be reconed to 2235)
- 1 x 2426H (maybe with radian 1225 diafragms)
- autotech tractrix 350 horn
- XO point around 800 hz
- probably biamped with a Crown DC300A amp (or Sansui BA-2000 or BA-F1) and a tubed SET amp for the horns

I don´t know:
- 2205s seem to be OK, are they worth reconning to 2435?
- how will radian diafragms work?

ivica
12-14-2011, 06:28 AM
I am trying to understand the parameters around which you want to work. ...... But perhaps deciding now what size cabinet is too early in the decision process. What could be tempting is using two 2235 woofers per bass reflex cabinet. One does full spectrum (20-800Hz) and the other only does 20-50Hz) for that deeper bass (and using two woofers will raise the efficiency by 3db. Then use a 2426H on top with a 2344 baby butt horn and you'll end up with a 4435 ................ Each 2235 requires a 4,6cft volume. each one will give F3 at 36Hz, and this is why you'd use two woofers. The one that only does 20-50Hz will flatten the bottom... 53652 I just want to pay your attention that in such configuration , where are two bass near each other [ under 'normal condition' ] that would produce the rise of +6dB for the frequency whose 'wave length" is larger the double distances ( d ) between the speakers, so for 15-inch drivers mounted 'nearby' mentioned rule would be applicable up to about 200Hz.
That is presented in figure with 'blue' line.
More can be find in:
http://www.zainea.com/mutualcoupling.htm

I think that was the reason why JBL in 4435 there are a pair of 2234 used instead of 2235 pair.

Not to mention here that such LF boost in TWO-box combination (usual stereo), has the same ADDITIONAL effects, but for the frequency up to about 50Hz (for 3m speakers apart).
So for very low region that would be +12dB boost if we have 2 boxes with a pair of driver in each.

manolito
12-14-2011, 01:09 PM
thanks ivica

in this new idea, the woofers are intended to be in a vertical d´apppolito enclosure, reflex loaded: one woofer down + tweeter horn in the middle + one woofer up (something like the K2-9500, but a tractrix horn in the middle)

the front of the cabinet would seem like this (not exactly of course, it´s just an idea about the drivers placement ...)

54044

for bass it could be, per cabinet:
- one 2205 down, (maybe reconed to 2235) from bottom to less than 200 hz, to avoid coupling
- one 2205 up, full range from bottom up to 800 hz or so

ivica
12-15-2011, 02:39 AM
thanks ivica

in this new idea, the woofers are intended to be in a vertical d´apppolito enclosure, reflex loaded: one woofer down + tweeter horn in the middle + one woofer up (something like the K2-9500, but a tractrix horn in the middle)



May be tracktix horn would be too narrow (dispersion) at mid and hifh frequency

manolito
12-15-2011, 05:34 AM
May be tracktix horn would be too narrow (dispersion) at mid and hifh frequency

here is the link with horn specs (tractrix 350):

http://www.horns.pl/tractrix350.html

it should be installed to make it "time aligned" with bass drivers

ivica
12-15-2011, 06:03 AM
here is the link with horn specs (tractrix 350):

http://www.horns.pl/tractrix350.html

it should be installed to make it "time aligned" with bass drivers

As I understand the presented data, on 10KHz attenuation of -6dB about +/-30deg.
May be 2312 & 2308 or 2307 & 2308, would be better solution with 2426 drivers...
My experience with some kind of tractrix horn is that , for my feeling, it is too "beaming",
while mentioned 2312 & 2308 is fare more wide, even at over 10KHz.
In any case 2405 or some other UHF driver would be 'well-come'....

manolito
12-15-2011, 11:17 AM
As I understand the presented data, on 10KHz attenuation of -6dB about +/-30deg.
May be 2312 & 2308 or 2307 & 2308, would be better solution with 2426 drivers...
My experience with some kind of tractrix horn is that , for my feeling, it is too "beaming",
while mentioned 2312 & 2308 is fare more wide, even at over 10KHz.
In any case 2405 or some other UHF driver would be 'well-come'....

thanks Ivica

sometimes, horns seem to be more magic than science, or a trial-and-error procedure

the reason to use 2426s, is that I´ve got them for free, as a present from my friend Suso (thank you very much buddy!)

i´d like to listen to 2420s with original alu diaphragm, or something like that, but right now, economy makes me stay with my free 2426s :)

the horn data belongs to BMS 4550 drivers, though it is expected for the 2426 to behave in a similar way

my friend, who will make the crossovers, says that he´s confident to manage the 2426/tractrix HF attenuation with the XO, and obtain a "flat" response from the 2426, up to 15 khz (more or less) with 95 db or higher efficiency (I must admit that I have not checked the numbers, but I wish he is right about that, we´ll use 2x2205 LF drivers per cabinet, that are supposed to get 100 db, so we´ve got a little headroom here)

his advice is to try the speakers first, and then decide about the UHF driver (like the 2405), on top of the cabinet

I also think, like you, that we´ll have to use a UHF driver, because I´ve tried the 2426s at home with an altec 511B horn, and the HF rolls off very fast

and in a future, maybe a 2" driver and bigger horn for mids, lowering the XO point ...

Earl K
12-15-2011, 05:42 PM
Manolito,

For a bit of inspiration ( on the new direction of your custom project ) you might take a look at the thread behind the picture ( click it ).

You may want to see if you can converse with the builder ( Linear ) privately to get his thoughts ( 5 years down the road ) about his MTM project .


54078 (http://www.audioheritage.org/vbulletin/showthread.php?12390-Handmade-Ersatz-M9500-Speakers)


:)

manolito
12-15-2011, 11:34 PM
Manolito,

For a bit of inspiration ( on the new direction of your custom project ) you might take a look at the thread behind the picture ( click it ).

You may want to see if you can converse with the builder ( Linear ) privately to get his thoughts ( 5 years down the road ) about his MTM project .


54078 (http://www.audioheritage.org/vbulletin/showthread.php?12390-Handmade-Ersatz-M9500-Speakers)


:)

oooooops :o: ... we have stolen Linear´s design, that´s exactly what the speakers will look like (the fireplace is a little different, though :) ... )

Thanks Earl!

ivica
12-16-2011, 03:52 AM
thanks Ivica



my friend, who will make the crossovers, says that he´s confident to manage the 2426/tractrix HF attenuation with the XO, and obtain a "flat" response from the 2426, up to 15 khz (more or less) with 95 db or higher efficiency (I must admit that I have not checked the numbers, but I wish he is right about that, we´ll use 2x2205 LF drivers per cabinet, that are supposed to get 100 db, so we´ve got a little headroom here)
t ...

Concerning the mentioned 2205 x 2 , it is expectable that You would get about 103~104 dB with 2.83Veff applied (single driver efficiency is about 97.5dB ).
The efficiency of 2426 with 2370 horn is from 110dB to 106 dB( from 5kHz) on axis, and expect-able -6dB drop would be expected on +/-45 deg with mentioned horn, so there is almost no headroom if would like mentioned horn 2370....
but I totally agree with You that only listening tests would give 'personal feeling'....

more10
12-18-2011, 03:12 PM
- how will radian diafragms work?

I have Radians in 2420 on 2370 horns. I made measurements today, they seem to go higher than 2425 (http://www.jblpro.com/pub/components/2370a.pdf).

They sound good to me.

manolito
12-19-2011, 11:29 AM
thanks to everybody

we´ll begin the project after Xmas, I will keep you updated