Getting the Right Drivers... Impossible?

[DogBox]

I am sure many have been faced with the decision when "having a variety of speaker drivers" - which one's DO 'go together' as a "group" to
make up a "System"???
Always intrigued by "How JBL Does It"; and also the different designs and combinations from different contributors... leads me to ask:
" How Do You Get The Right Drivers?" can't they be combined with a crossover successfully? - and not necessarily an 'Active' one?
I have seen one crossover where you can use an 18" or a 15" AND a 1" Compression Driver or 2" Compression Driver... and THAT was in
the SAME network design??!!!
How DO you get the "Right Drivers?" :blink:


DogBox

[BMWCCA]

I have seen one crossover where you can use an 18" or a 15" AND a 1" Compression Driver or 2" Compression Driver... and THAT was in the SAME network design??!!!
How DO you get the "Right Drivers?" :blink:


Maybe "close" doesn't only count in horseshoes? :dont-know:

[honkytonkwillie]

A good place to start is with driver specifications, and driver size is largely irrelevant. The drivers' electrical and mechanical parameters are far more important.

First you'd want to find drivers that have some overlap in their raw frequency response - at least an octave, two octaves overlap is easier to work with. Then a crossover network is designed to work somewhere in this overlapping region so that one driver starts doing work while the other has begun to roll off. You'd also want to start with drivers that are approximately equal in loudness for a given input signal, but it's pretty simple to quiet down a too-loud driver with a few extra parts in the crossover network.

That's a first approximation. It can and often does get vastly more complicated. As there is no such critter as a perfect speaker, loudspeaker design is always about trade-offs, compromises, trying different things to see what works best, and often just making the best of what you have to work with.

Sounds like you have a pile of drivers you feel like doing something with. This is a great place to ask for suggestions to get you off the ground. Is one of your drivers a JBL 077 tweeter, perhaps?

[DogBox]

Maybe I just don't put my questions properly...
In considering the 43xx range and doing a bit of reading and checking out the Technical Manuals [which include the crossover network] you
get to see that most of the designs were focused on that particular model. From cabinet to baffle lay-out to crossover; they were all dealt with
as individual models. However, they all do have a similarity all the way through the line..
An excerpt from one of the JBL Reference Sheets says.. " It often happens that the proposed group of components and enclosure design need modification for smoothest possible response, at which point the engineers go back to the drawing boards and try again. Several systems may be designed in this manner until acceptable results are obtained.
If no transducer is available with characteristics suitable for the required application, a totally new transducer will be designed and built specifically for this purpose. The midrange drivers in all three of JBL's four-way monitors are examples of this."
This is the type of thing I was meaning...
Many able builders have laid out a number of accumulated drivers from different models of JBL speakers and have found that "certain ones" go
together really well - following the complete design of a JBL model; or, sometimes not. Some have even "interchanged" certian drivers in
certain models with vastly improved results; often 'only' after modification to the original crossover network design as well. Still, some drivers really lend themselves to this change!
Which is what I was trying to ask: Which ones?


DogBox

[Mr. Widget]

Many able builders have laid out a number of accumulated drivers from different models of JBL speakers and have found that "certain ones" go
together really well - following the complete design of a JBL model; or, sometimes not. Some have even "interchanged" certian drivers in
certain models with vastly improved results; often 'only' after modification to the original crossover network design as well. Still, some drivers really lend themselves to this change!
Which is what I was trying to ask: Which ones? If I read what you are saying correctly, you are asking for suggestions for driver combinations or modded drivers where Forum members have produced speakers that are superior to those commercially available from JBL?


Widget

[DogBox]

Thankyou Mr Widget, yes. I know many builders are 'purists' at heart, and I agree with them totally - the original has the 'status' factor.
However, knowing that you can 'change-out' the 2426J for a 2441 in a 4345 is a very interesting change. And I am sure there are many
other changes applicable to different models - even if only for the sake of "finding out" ; of "any improvements to be had - at what cost?"
The change to a charge-coupled crossover is another "less obvious" in appearence... but sonically, superior by all accounts. [am yet to
discover this one] ; the 'actual baffle layout' another one...
But starting with drivers, - which way is the best way to go..? And, how to get there... eg. No 2235H? find a 2225 and have it reconed.
No proper HF, get a 2425/2426 and use a D16R2421 diaphragm. Also, things like these.
"The drivers and parts that will sum to make a good result." I have read many threads where some wonderful work has been accomplished
along the way of a certain build; that is just a part of the finished result. Ideas that could be utilised in another project.
So along the lines of the 43xx models, what "can" you do, without raising the 'ire' in the purist, maybe...?



DogBox

[Mr. Widget]

Sounds like you are answering your own questions... I would add that swapping out Ti or Al diaphragms for Be is another positive "tweak". That said if sonic improvement is the goal, I'd strongly suggest looking at the current vertical "Array" horn and break free from the 43XX limitations.

Then again without years of experience, proper test equipment, and the willingness to rework a design a number of times, I wouldn't recommend breaking away from the tried and true.


Widget

[more10]

I have had the same problem. The solution is to get all the drivers, mount each driver in a separate box, and try. I have concentrated on 15 inchers, but I also have a few 12, 18 and 8 inch drivers. Still on the shelf unfortunately. So far I have decided on 2220A (over K130, E120 and 2118) for midrange. You will need an active crossover and a few power amps.

If you really want improvements I would recommend horn loading even for bass and low midrange. It will take a lot of time, but it is great fun.

[Ear4life]

I am sure many have been faced with the decision when "having a variety of speaker drivers" - which one's DO 'go together' as a "group" to
make up a "System"???
Always intrigued by "How JBL Does It"; and also the different designs and combinations from different contributors... leads me to ask:
" How Do You Get The Right Drivers?" can't they be combined with a crossover successfully? - and not necessarily an 'Active' one?
I have seen one crossover where you can use an 18" or a 15" AND a 1" Compression Driver or 2" Compression Driver... and THAT was in
the SAME network design??!!!
How DO you get the "Right Drivers?" :blink:


DogBox

It is a funny thought, which drivers DO go together? Well as long as the speaker is technically good enough and measures as intended, all components together creates a group. Is it perfect? No, and it will never be perfect. So in other words are there such a thing as an upgrade to a technically perfect speaker? I would say no. Then why do we then sometimes find drivers that feels like an upgrade to our system? Because we like the component! It creates a thing to that we are missing at the moment or delivers a better result from a perspective that we like. But that upgrade does not make it technically better, because many upgrades are related to personal tastes. My system has developed to the point where it is today because of my choices along the way.. others would most likely have done things different, and that´s okay!
Trying different components like a different sized driver is possible even with the same passive crossover, but it will need to have the same impedance curve and sensitivity and of codes respond in the same way to the cabinet as the other driver to blend in. Then the result afterwords would be a new "group" that "goes together", but sounds a little different maybe... maybe better?

Just some of my thoughts :)

Best regards

[gasfan]

Thankyou Mr Widget, yes. I know many builders are 'purists' at heart, and I agree with them totally - the original has the 'status' factor.
However, knowing that you can 'change-out' the 2426J for a 2441 in a 4345 is a very interesting change. And I am sure there are many
other changes applicable to different models - even if only for the sake of "finding out" ; of "any improvements to be had - at what cost?"
The change to a charge-coupled crossover is another "less obvious" in appearence... but sonically, superior by all accounts. [am yet to
discover this one] ; the 'actual baffle layout' another one...
But starting with drivers, - which way is the best way to go..? And, how to get there... eg. No 2235H? find a 2225 and have it reconed.
No proper HF, get a 2425/2426 and use a D16R2421 diaphragm. Also, things like these.
"The drivers and parts that will sum to make a good result." I have read many threads where some wonderful work has been accomplished
along the way of a certain build; that is just a part of the finished result. Ideas that could be utilised in another project.
So along the lines of the 43xx models, what "can" you do, without raising the 'ire' in the purist, maybe...?



DogBox
I have never logged onto this forum without learning something important or having new doors opened. I also have the same questions you have that I've acquired tentative answers to via the very dedicated and experienced group of JBL experts here. I say 'tentative' since I've yet to build my own fully active 4345 clones according to the very specific and exacting recipe these guys'n gals have worked out for me to accommodate the changes I have in mind. I've had a bit of a financial set back so I'm a bit behind. I have everything but the cabs. I love adventure. 2206 for mid-bass, and 2390 for HF. However, I'm thinking to build in the provision to reverse the 2441 and use it as a direct radiator also since I've noticed a thread on the Westrex here. But I'll need to have damping plates machined for the diaphrams. Apparently reversing the 2441 has been tried here. Not sure how successfully, though. I have not done a search on that yet. But it might make for an interesting near field 4345.:)

[Mr. Widget]

I'm thinking to build in the provision to reverse the 2441 and use it as a direct radiator also since I've noticed a thread on the Westrex here.I wonder how that would compare with the 4" dome from the XPL series, the 095Ti or 093Ti... a few folks here have played with them or the Auto Sound variant. The 2441 is aluminum and has a much more massive magnet... but they both use somewhat similar geometry. :hmm:

I'm not sure why the XPL series was relatively short lived, by all accounts they were very fine speakers... but then the Westrex is a phantom of history too. One would think if either was the holy grail, there would be legions of similar speakers, even if manufacturing costs were prohibitive. No doubt both are great speakers, but why aren't there more like them?


Widget

[gasfan]

Could be more than one answer to that question. The inevitable destruction of the diaphragm? The 095Ti makes me wonder if the plate on the Westrex is actually a damping plate. Will the 2441 need one?

[JeffW]

I'm pretty sure somebody here posted about JBL using compression drivers as direct radiators, not sure how to find it in a search.

[ivica]

I am sure many have been faced with the decision when "having a variety of speaker drivers" - which one's DO 'go together' as a "group" to make up a "System"???
Always intrigued by "How JBL Does It"; and also the different designs and combinations from different contributors... leads me to ask:
" How Do You Get The Right Drivers?" can't they be combined with a crossover successfully? - and not necessarily an 'Active' one?
I have seen one crossover where you can use an 18" or a 15" AND a 1" Compression Driver or 2" Compression Driver... and THAT was in
the SAME network design??!!!
How DO you get the "Right Drivers?" :blink:


DogBox

For me this is very interesting question, so I want to ask some of our forum members do they have any experience with possible solution such as:

2245H
2202H
2441J & 2311 & 2308
077 or 2405A or 2405H

I can say that it is almost 4345 with larger mid-bass and mid-rage compression driver.

regards
Ivica

[DogBox]

I like how Ivica has also mentioned the 2202 as a lower-mid speaker. So, you "could have" a choice: 2121, 2122, 2123, [ 10" ] or the "love it or hate it" 2202 [ 12" ] to do the duty....
So, is the choice MORE determined if you have a 18" or a 15" as to "what will integrate smoother" or "what is easier to crossover to" ? After all, if you are going to be putting together a 4-way ; "to have seamless transition" and gaining the power factor by four drivers - it should have to have the "Best Voice" as that will be a large part of its 'producing' duty/range.
Then, do you go and just use a 1" Compression Driver ? or, is there real benefits in using a 2440/2441, 2445/2446, or go the 2450 Neo' ?? The real "response" coming from WHAT diaphragm you end up putting in; as they all share common fitment.. The 2440 now extinct, I think - except for those who may have some stored! Be it the 2441 has just got the diamond pattern to differ it - same thing. After that , what else could do the "top end" more suitably than the 2405. All equals: 4.
Only when you consider using a "Three Way" does it get more complicated. Dual 15's or, 18"? Which horn? or "Horns" - one for Mid and one for Top?
The "range" of transducers made by JBL seems to cover many combinations... I feel like I am back at the start! WITH the same question...



DogBox :blink:

[Mostlydiy]

I believe the 2202 would complement the 2245 rather good considering its exellent midbass properties. Didnt 4313b recommend switching the 2421 to the 2440/2441 if you were to go the 4345 diy way. The 2202 would be to stretch it a little more. If its for the better Im not sure though.

Trying different configurations is what the diy community do isnt it :) its part of the fun.

I myself is considering a LE15a, D130, 375/2397, 075or077 in the future. Mostly because its the most epic JBL vintage drivers of course but if the filter is succesful I think they could sound rather good.

/Mostly

[more10]

There are 4 categories of drivers. Hifi, monitor, sound reinforcement and sound production.

HiFi drivers are better left aside.

All the monitor drivers work well together. Just check what used to be in JBL monitor systems.

Sound reinforcement drivers are more sensitive than monitor drivers, but have an uneven frequency response. These drivers where used in Cabaret and SRX boxes.

Sound production drivers are basically the same as sound reinforcement but with an aluminum dust cap. These drivers should be used with care.

So it all depends on your taste. Do you like HiFi qualities or do you like dynamics and presence you will get from SR drivers?

[ivica]

There are 4 categories of drivers. Hifi, monitor, sound reinforcement and sound production.

............... Sound production drivers are basically the same as sound reinforcement but with an aluminum dust cap.
These drivers should be used with care ............

Hi more10,

I think that the internal driver construction ( here I want to emphasis) for the "sound production drivers"
has been done in the way to produce some kind of distortion I believe 2-nd THD, in order to make "more volume"
(or....) of the sound, so ....

Regards
Ivica

[1audiohack]

The "range" of transducers made by JBL seems to cover many combinations... I feel like I am back at the start! WITH the same question...DogBox :blink:


What's currently in the dog pile?

[more10]

Hi more10,

I think that the internal driver construction ( here I want to emphasis) for the "sound production drivers"
has been done in the way to produce some kind of distortion I believe 2-nd THD, in order to make "more volume"
(or....) of the sound, so ....

Regards
Ivica

Good to have someone with an eye for details in the forum. Where you prefect in school :-)

Of course you are right. The sound production drivers have an "equal coil and gap" arrangement, causing the voice coil to be out of xmax as soon as there is current through it.

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=52981&d=1316744480

[DogBox]

More10, that Technical Notes paper is one document with a "lot" of information that takes more than one read.. It is on the top of my pile of
reference paperwork along with all the Spec. Sheets and Model Sheets from the library together for Theile/Small and test measurement info.
When I started reading through the many, many, many posts about different drivers - their qualities, behavior in the role JBL used them and
how some builders have "expanded" on that theme has given me a study course on the design and integration of very clever and passionate
people at the top of their game. And to benefit from that wealth of knowledge is one of the best "feel good" gains I have been able to make.
And now to 'almost' rub shoulders [not too close!!] with those people is very gratifying and indebting at the same time.
Most of what I listed at the beginning was Home Use/Hi-Fi/Studio Monitor drivers as one thing realised by JBL and most of the Lansing Community was to "have the Studio Monitors in the home"; the Century L100 consumer model and the professional 4310/4311 models were acoustically
identical. The transducers in these succeeding models is what I am looking at.
I thought I mentioned 2225 waiting to be reconed, 2235 already done, 2202H, E110 Alnico & ferrite to be 2122; 2441, 2445, 2425HS, 2427H,
2470 - dia. change to..D16R2421, 2405H -2 with/2without dias. gives you ...oh and a E155 r/c to 2240-4; gives you a fair amount of choice
BUT not all sections will be happy together, I know.
So I want to do it RIGHT. AND continue to learn... :)


DogBox

[more10]

2225 waiting to be reconed, 2235 already done, 2202H, E110 Alnico & ferrite to be 2122; 2441, 2445, 2425HS, 2427H,
2470 - dia. change to..D16R2421, 2405H -2 with/2without dias. gives you ...oh and a E155 r/c to 2240-4;

Only put on a new cone on a broken driver. If the driver is working there is probably someone looking for that driver. Do not mix alnico and ferrite (thinking E110 here).


2225 will happily go into 4530 or 4520.
2202 is an excellent low mid horn driver. 2206 is better as direct radiator.
2445 is crap but with a Radian diaphragm it can be used in a straight 200 horn (2360).
2441 is excellent. Can be used from 500 Hz. I have heard it on a 200 Hz horn down to 300Hz. Get a larger horn for this one.
2425HS. I know the 2425H, typo? If 2425, this is the one to put aluminium dias into.
2427. Unusual. Should get some money from collectors.
2470. Phenolium! At some point you will probably want to listen to its sound.
2405H. You want the version with alnico magnet.
E155. Good horn driver. Can also be used in a huge MLTL cabinet.

From your other thread I understand that you want to put the drivers into a monitor like box. The monitor format is intended for music studios. Close listening to speakers mounted on a wall. You have the option to have floor standing speakers. You should put the high midrange driver at the same height as your ears. 90 cm is ok. Bass and low mid drivers below. Tweeter above. You have space for a 18/15 inch and a 12 inch below your midrange horn.

Put each driver in a separate box. Then you can easily swap them and test new combinations.

[ivica]

More10, that Technical Notes paper is one document with a "lot" of information that takes more than one read.. It is on the top of my pile of reference paperwork along with all the Spec. Sheets and Model Sheets from the library together for Theile/Small and test measurement info. When I started reading through the many, many, many posts about different drivers - their qualities, behavior in the role JBL used them and how some builders have "expanded" on that theme has given me a study course on the design and integration of very clever and passionate people at the top of their game. And to benefit from that wealth of knowledge is one of the best "feel good" gains I have been able to make. And now to 'almost' rub shoulders [not too close!!] with those people is very gratifying and indebting at the same time. Most of what I listed at the beginning was Home Use/Hi-Fi/Studio Monitor drivers as one thing realised by JBL and most of the Lansing Community was to "have the Studio Monitors in the home"; the Century L100 consumer model and the professional 4310/4311 models were acoustically identical. The transducers in these succeeding models is what I am looking at. I thought I mentioned 2225 waiting to be reconed, 2235 already done, 2202H, E110 Alnico & ferrite to be 2122; 2441, 2445, 2425HS, 2427H, 2470 - dia. change to..D16R2421, 2405H -2 with/2without dias. gives you ...oh and a E155 r/c to 2240-4; gives you a fair amount of choice BUT not all sections will be happy together, I know. So I want to do it RIGHT. AND continue to learn... :) DogBox

Hi DogBox,

I can understand your 'hesitation', as some of the mentioned drivers are 'laying' on my shelf too.
After all experience up to now, some of them are getting 'their position on the top'.

If you do not have 077 then 2405A would be 'acceptable' and 2405H would deserve 3-rd place on UHF list.

On the VHF list (up to 10kHz): 2441J ( with original AL- diaphragm D16R2441 ), but its horn would become very, very, great problem.
I do not like "beaming" horn so I am mainly concerned with wider-spreading (horizontal) horns.
Up to now my first candidate would be 2311_&_2308 combo (H93) .The "only problem" for mentioned combo is its "inquisitive nature",
if record is good everything is perfect, but any 'malfunction' is enlarged.
As I think it has to be used , say over 1kHz, and keeping in mid that the driver has internal about 7cm long horn,
and adding about 11cm length of 2311 , and including about 3cm of the length of the phase-plug horn,
so about 20cm total horn length can be get.
On the other side using large diameter (4-inch) diaphragm for the frequency over 1kHz, I think that would be ,
for the home listening levels, (with us of high sensitivity driver), acceptable solution ( not to mention that 4350/55 was based on such solution)
I have no experience (unfortunately) with Yuichi-A290 even a lot of nice words have been said, and it is said to be "more forgiving" .
May be some "low-diffraction" CD horns would be a good candidate too
(an example 2450SL & PT-H90 combo, but not directly applicable to 2-inch driver such as 2441 ).
In order to 'investigate such field' I have "push myself" to make my own horn construction-horn called it: JAN45-2 (1.5)
( based on H66000 understanding applied 'ideas', but not so wide->60cm/24cm),
http://www.audioheritage.org/vbulletin/showthread.php?34180-2445J-with-2311-Horn&p=353522&viewfull=1#post353522

Unfortunately, I have not finished appropriated network for use. ( Looking to DD66000 VHF network my problem can be understandable).

I have done some measurements with 2441 with the original D16R2441 AL-membrane and with the Radian1245, using 2311 horn and my JAN45-2.
when using 2308 lenses I have used about 1/4-inch 'open-cell foam' between 2308 and 2311( in order to "make sound more soft"), so may can help you.

Any how , I think that a kind of mid-bass has to be involved in the construction.
Firstly, in order to prevent the usage VHF drivers for too low frequency, and to accept upper mid-bas section from the bass driver.
I think that 12-inch driver ( even its cone is almost 9.5-inch diameter ( 24cm) such as 2202 ( light cone, 4-inch Voice coil, high BL)
would be good solution.

On the bass section I an not sure, is it E155 better then 2245 (E155 not r/c to 2440, but it has to be r/c to 2245H,
on my opinion that would be a better solution) , or TWO 2235 working in-parallel. I have had very nice experience with (single per box)
2231A driver until using original foam, but after re-foaming, the sound "signature" become quite different
("light years BEHIND" original).
2235H (r/c) is somewhere in-between mentioned 2231A before, and after r/c. For sure 18-inch driver would need almost twice larger box then single 2235H,
but "large sound" of 2245H is quite different thing.
For the bass section with low (lower then 300Hz) passive network, some compensation of about 100Hz peak would be well-come (as I have mentioned earlier).



Regards Ivica

[DogBox]

Hi Ivica,
I did try to get a pair of Alnico 2405's.. but I never knew there was such a "huge difference" between released model types..??? I have read the
ferrite/alnice debate and differences and caveat emptor on them... But as far as sonic ability; the best way was to run them separately, having
their own small amplifier to run on with a simple filter... ? I have four 2405H and two genuine D16R2405 dias. to put in them and THAT will
have to be it. EVERY driver I have managed to get needs " something " done to it to bring it up to scratch to be able to use. Be it diaphragm,
the cone, a paint-job... whatever; it has been the only way I have been able to get together the pile I have. I bought the E155 already done
with the 4 ohm 2340 recone- my idea was to...eventually....change it. Not on the top of the list unless I was [BUT am not - at this stage] going
to use two for my LF drivers. As someone else hereabouts said: "I haven't got the 20 cu ft available for 4345's".... Me neither.... :(
The 2445's may not be liked [not said by you] but when it's on the end of a 2360 - I beg to differ!!! What a combo!
Thanks for those response results. they are helpful to me as the pair of 2445's I got HAD the Radian dia's in them! I also saw the horn you made -
Very Impressive!
What is the program you are using or the combined test equipment to get those results... curious..??!!
I am going to keep refering to the original before I begin straying too far to have " a live-in DogBox! " ;)


DogBox

[ivica]

Hi Ivica,
I did try to get a pair of Alnico 2405's.. but I never knew there was such a "huge difference" between released model types..??? I have read the
ferrite/alnice debate and differences and caveat emptor on them... But as far as sonic ability; the best way was to run them separately, having
their own small amplifier to run on with a simple filter... ? I have four 2405H and two genuine D16R2405 dias. to put in them and THAT will
have to be it. EVERY driver I have managed to get needs " something " done to it to bring it up to scratch to be able to use. Be it diaphragm,
the cone, a paint-job... whatever; it has been the only way I have been able to get together the pile I have. I bought the E155 already done
with the 4 ohm 2340 recone- my idea was to...eventually....change it. Not on the top of the list unless I was [BUT am not - at this stage] going
to use two for my LF drivers. As someone else hereabouts said: "I haven't got the 20 cu ft available for 4345's".... Me neither.... :(
The 2445's may not be liked [not said by you] but when it's on the end of a 2360 - I beg to differ!!! What a combo!
Thanks for those response results. they are helpful to me as the pair of 2445's I got HAD the Radian dia's in them! I also saw the horn you made -
Very Impressive!
What is the program you are using or the combined test equipment to get those results... curious..??!!
I am going to keep referring to the original before I begin straying too far to have " a live-in DogBox! " ;)


DogBox

Hi DogBox,

My personal experience in comparison 077 to 2405H (ferrite) is that 077 is less sensitive, but less 'intrusive sound signature'. On the measurements I can not say that (except the sensitivity) there are too many differences. If you have 2405 with the original membrane fist try to measure, before putting the new one, May be the old one is good too.
The problem with AlNiCo 2405 (either 2441 too) can be more or less 'demagnetization', so for the 'second-hand option' ferrite magnet is better (safer) option. In my country re-magnetization is not possible to be done, and transport to (and back) Germany or USA would cost too much.

My experience with 2450 with Ti - Non-ribbed ( D16R2445) diaphragms - on the F/R measurements were better then with Radian 1245-16 for the range OVER 10kHz.
{There are much larger 'spikes' over 10kHz with Radian1245-16 then with D16R2445, either with 2311&2308 or JAN45-2 ).
Unfortunately I have no experience with 2445 with Radian 1245-16 diaphragms. Only that I can expect that the behavior would be something look like 2450.

In order to understand and have a control what the measurements really is based of, I have made my own PC program (using Mat-lab) that is based on the reconstruction of the 'impulse response of the system' using 'complementary Golay binary sequences'.
Then using Behringer-ECM8000 microphone [http://www.behringer.com/EN/Products/ECM8000.aspx] and
[NATIVE INSTRUMENTS GmbH http://www.native-instruments.com/fileadmin/redaktion_upload/pdf/AudioKontrol1_Manual_English.pdf ] "Audio control-1" USB sound card I have done all of my measurements.

Good info can be get from the:
https://ccrma.stanford.edu/realsimple/imp_meas/imp_meas.pdf

Mentioned 'method' is "high resolution", I have to add a kind of smoothing (1/N octave smoothing) in order the results to be comparable to the others.

For the THD measurements I have made another program based on 'exponential-sweep sinusoidal signal'
Good info can be get from:
Angelo Farina:"Simultaneous measurement of impulse response and distortion with a swept-sine technique"
http://pcfarina.eng.unipr.it/Public/Papers/134-AES00.PDF

Both mentioned programs are based on generating 'stimulus signal' that are saved as wave files that has to be reproduced by the speaker "under test" and its response has to be recorded and converted into wave files, and then "off-line" would be calculated Frequency response or THD.
So the mentioned 'stimulus' and 'recorded' wave files can be sent by e-mail

Zipped file size is about 1 ~ 2 MByte, the exchange can done easily.


Regards
Ivica

[more10]

The Radian 4 inch VC diaphragms are nice because of their mylar suspension allowing them to be used down to 300 or so. Breakup modes should be above the JBL titanium which break up at 4 kHz. JBL aluminium diaphragms starts to break up at 7 kHz. A large format driver should not be used above the breakup frequency. This is why you need a supertweeter :-)

[ivica]

The Radian 4 inch VC diaphragms are nice because of their mylar suspension allowing them to be used down to 300 or so. Breakup modes should be above the JBL titanium which break up at 4 kHz. JBL aluminium diaphragms starts to break up at 7 kHz. A large format driver should not be used above the breakup frequency. This is why you need a supertweeter :-)

Hi more10,

I have only explain MY personal experience with the measurements I have done with 2441, 2445, 2446, 2450, 2450SL, and 2451 , all of them as 4-inch 'membrane', using
D16R2441, D16R2445, D16R2450, Radian1245-16, D8R2450SL diaphragms, Be-Truextent coupled with 2311&2308, 2332, JAN45-2/1.5. Horns.
All of them are used under 'expectable home listening levels - I can say not more then SPL 100dB/1m/1W.
I do not know where membrane standing waves start to produce more or less interferences, but when F/R start rapid change (peaks and deeps) I can say that region would not be applicable for home-listening purpose.
It seems that horn "loading" (and directivity) some time have introduced more or less 'intrusive behavior', but it would be not easy to say which of the measure is "better".
Most of them in the region 1kHz to 10kHz behaves good.
Only un-expectable behavior under 1kHz I can notice was D16R2441 (AL). It seems to me that it would be not good to drive it too much under 1kHz, on the other side but it behaves very good up to 20kHz.
On the other side Radiona1245-16 behaves very good under 1kHz, but not so good over 10kHz.
D16R2445 (Ti) with 2445 driver seem to me would be the best candidate for 2-way system as it behaves 'stable' up to 15kHz , with very good behavior under 1kHz too.

Regards
Ivica

[DogBox]

The way I am seeing a lot of "systems" put together IS to find out where these distortions and anomalies lie so one can then: Figure Out The Best
Frequencies for crossing to the next driver in the "system"...No?
I saw some frequencies mentioned "...that above **kHz you get !@!@! ..." well that was the frequency intended FOR the crossover point!
Something to keep in mind so that you end up "Getting The Right Drivers! " With the advent of all the Technical Skills and Testing Equipment -
I am sure that there ARE other combinations of drivers "that can be matched together for a good result" if the overall design criteria is not
forgotten when getting response results of different drivers to possibly use.
And I am sure that by careful cabinet design, any 100Hz " hump " can be tamed so as not to be distracting... without resorting to such hefty
LCR networks...
Let's use the knowledge "gained" to good use - get it together!
2202H has 99dB Sens. & 2235H has 93dB. 6dB to play with or use; whichever way you like to look at it...
I will find the network that pleases "both" the 2235 AND 2245 in a CC network somewhere hereabouts.... all the driver No.'s came out in purple print...
Will look into it for a "wonderful comparison"...

Later,

DogBox

[ivica]

The way I am seeing a lot of "systems" put together IS to find out where these distortions and anomalies lie so one can then: Figure Out The Best
Frequencies for crossing to the next driver in the "system"...No?
I saw some frequencies mentioned "...that above **kHz you get !@!@! ..." well that was the frequency intended FOR the crossover point!
Something to keep in mind so that you end up "Getting The Right Drivers! " With the advent of all the Technical Skills and Testing Equipment -
I am sure that there ARE other combinations of drivers "that can be matched together for a good result" if the overall design criteria is not
forgotten when getting response results of different drivers to possibly use.
And I am sure that by careful cabinet design, any 100Hz " hump " can be tamed so as not to be distracting... without resorting to such hefty
LCR networks...
Let's use the knowledge "gained" to good use - get it together!
2202H has 99dB Sens. & 2235H has 93dB. 6dB to play with or use; whichever way you like to look at it...
I will find the network that pleases "both" the 2235 AND 2245 in a CC network somewhere hereabouts.... all the driver No.'s came out in purple print...
Will look into it for a "wonderful comparison"...

Later,

DogBox

Just to understand expectable SPL when 2.83V is applied

Regards
Ivica

[DogBox]

Just to understand expectable SPL when 2.83V is applied, Regards, Ivica

I notice you put the 2202H into a 50 L. box. From the only formula I had on hand, you need to reduce that volume 'down' to about "half" that so that
by using a smaller box, the driver will naturally "cut-off" at about 280Hz, still getting a bit as it tapers off - closed box @ 12dB/octave. So then, all
that would be required is to tame the 2202 down to a proper level - without upsetting the apple-cart! And the "top-end" has been done already by
yourself and others in the forum...
Possible?... :blink:

DogBox

[DogBox]

Found the diagram I was looking for...
http://www.audioheritage.org/vbulletin/showthread.php?16967-4345-References-Thread&p=171841#post171841
http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=26034&stc=1&d=1182738813
Note Ivica, the LF section for 2235H or 2245H.
Only with the 'Engineering Design Specification' sheet to go on; I would say the Sensitivity of the 2122H to be close to 92dB - I can't find a definite
figure for sensitivity for the 2122H anywhere. Going by the frequency plot - that's close enough for me. [To work off..]

DogBox

[Robh3606]

I can't find a definite figure for sensitivity for the 2122H anywhere.

In the small midrange box of a 4344/45 about 98db . It's really nice midrange driver.

http://www.lansingheritage.org/images/jbl/specs/pro-speakers/1981-4345/page04.jpg

Rob:)

[ivica]

I notice you put the 2202H into a 50 L. box. From the only formula I had on hand, you need to reduce that volume 'down' to about "half" that so that by using a smaller box, the driver will naturally "cut-off" at about 280Hz, still getting a bit as it tapers off - closed box @ 12dB/octave. So then, all that would be required is to tame the 2202 down to a proper level - without upsetting the apple-cart! And the "top-end" has been done already by
yourself and others in the forum...
Possible?... :blink:

DogBox

Hi DogBox,
Yes I have given here a larger box for 2202H, as JBL have done on 4355/50 box, and a kind of passive (60uF, 4.8mH) or active hi-pass would mainly define drivers LF section response. In any case I will not 'overdrive' 2202H with full LF bandwidth , what would happen if no hi-pass network applied.

regards
ivica

[DogBox]

Hi DogBox,
Yes I have given here a larger box for 2202H, as JBL have done on 4355/50 box, and a kind of passive (60uF, 4.8mH).... what would happen if no hi-pass network applied.

regards
ivica

I am thinking Hi-Pass is still needed for balance to 2441; however, Lo-Pass on 2202 can be omitted as a "smaller box" [my original calculations suggested 10L !! but the roll-off frequency was good!] will actually do it acoustically. Why put in electronics when there is no way of getting a response out of a speaker because it has no room to move air? maybe only security... See where I am coming from?
It has been noted that the 45L / 4350 & 48L / 4355 sub-chambers are of a size to be a Acoustic Suspension - the box is only a shielding from the Main LF Chamber. In the JBL Professional Enclosure Guide it suggests a 1.5 cu ft / 42.48 L box to be 'vented' with a 4.2 hole in the baffle!
Remember, we are dealing with - in this instance - a woofer that doubles as a good Instrument Speaker.... We have to change the role... ;)

DogBox

[DogBox]

In the small midrange box of a 4344/45 about 98db . It's really nice midrange driver.

http://www.lansingheritage.org/images/jbl/specs/pro-speakers/1981-4345/page04.jpg

Rob:)

:applaud: Thanks Rob! Didn't know they went into "that much" detail on the other drivers. I saw the Engineering Design Specification sheet p2. Frequency response and made an 'un-educated' guess at "what it might be..
But this figure is, as you say "when it is inside the midrange box"...

Does the sensitivity of a driver "go up" when put into a small sealed box? That could change lots of things in working out a network...? Does it???

Many Thanks!!!

DogBox

[speakerdave]

I wouldn't spend a lot of money on the supposed sonic differences between the alnico and ferrite 2405's.

[DogBox]

I wouldn't spend a lot of money on the supposed sonic differences between the alnico and ferrite 2405's.

Hey SpeakerDave, I've just noticed I have become 'Senior' - now that's happened, I won't be able to tell "what" goes on up that high!
Do JBL do hearing aids?

If I couldn't get Alnico, it wasn't meant to be. I have four 2405 - all ferrite. Two came with dia's and two didn't. So I ended up getting a JBL set to go into one of the pairs. Lets me do up a set while listening to the other... Gotta have music to work to!
One thing on the "too hard" list was a set of 2405 perspex lenses! Now, do THEY make a 'sonic difference'... 'cause they sure look cool!!!


DogBox

[ivica]

I am thinking Hi-Pass is still needed for balance to 2441; however, Lo-Pass on 2202 can be omitted as a "smaller box" [my original calculations suggested 10L !! but the roll-off frequency was good!] will actually do it acoustically. Why put in electronics when there is no way of getting a response out of a speaker because it has no room to move air? maybe only security... See where I am coming from?
It has been noted that the 45L / 4350 & 48L / 4355 sub-chambers are of a size to be a Acoustic Suspension - the box is only a shielding from the Main LF Chamber. In the JBL Professional Enclosure Guide it suggests a 1.5 cu ft / 42.48 L box to be 'vented' with a 4.2 hole in the baffle!
Remember, we are dealing with - in this instance - a woofer that doubles as a good Instrument Speaker.... We have to change the role... ;)

DogBox

Hi DogBox,

I think that it would be not good to push the driver the signals that it can not to reproduce correctly. Under such circumstances a large amount of distortion can be generated, and the operating point of the VC can be offset-ed....so my suggestion is to use proper Hi-pass (say over 300Hz) either passive or active.

Regards
Ivica

[DogBox]

If I read what you are saying correctly, you are asking for suggestions for driver combinations or modded drivers where Forum members have produced speakers that are superior to those commercially available from JBL?


Widget

Yes, Mr Widget!
And before this thread gets too 'one-tracked'... (I am as much to blame here).. :o: but besides the commonly seen configurations coming off the "JBL" Drawing Board... Nothing wrong with these neither!
I have only partially explored the site and found 'some' of these and if it is a statement: What the People are after; AND, don't mind sitting "proud" in their living rooms!
Going through peoples 'Personal Systems' was a big eye opener in this regard. But all in the hope of "Having something a 'little different' that sounds really good too!" While configurations are many, some here on the forum "can just look-at-a-bunch-of-drivers" someone has gathered together in the hope of making something of them; and because of direct knowledge: be able to "tell straight away 'if' "it will" or "Wont Work"....
Wouldn't it be good to have those configurations: "down in writing?" so the prospective 'gatherer - builder' has a DEFINITE GUIDELINE, to stay within if
he/she is to have any sort of success...? These people are well-known and highly respected; their word trusted by their knowledge and experience.
I think this knowledge of these configurations would be good to see listed. And it would keep JBL - JBL!!! ;)


DogBox

[Don C]

I wonder how that would compare with the 4" dome from the XPL series, the 095Ti or 093Ti... a few folks here have played with them or the Auto Sound variant. The 2441 is aluminum and has a much more massive magnet... but they both use somewhat similar geometry. :hmm:

I'm not sure why the XPL series was relatively short lived, by all accounts they were very fine speakers... but then the Westrex is a phantom of history too. One would think if either was the holy grail, there would be legions of similar speakers, even if manufacturing costs were prohibitive. No doubt both are great speakers, but why aren't there more like them?


Widget

From my own experience, these midrange drivers don't seem to age gracegully. I've had a few break the voice coil wires where they attach to the terminal. It nearly borke my heart when my great sounding one-off aquaplassed diaphragms broke down. They lasted two or theree years. There is no litz, they just extended the voice coil wire all the way to the terminal, with an S bend that doesn't seem to help. So It is my theory that JBL dropped the series in favor of more reliable and long lasting designs. It was probably the right decision. The newer inverted ti dome drivers with conventional voice coils have not given me any trouble yet.

[DogBox]

....It's really a nice midrange driver. (2122H)

http://www.lansingheritage.org/images/jbl/specs/pro-speakers/1981-4345/page04.jpg

Rob:)
Thanks again for that. If this 2202H doesn't work out, I may have to go back to my original plan of "original" 4343 with the 2121H...
I have heard about the 'cone break-up', but "How bad IS IT?" as you just can't swap in a 2122.. the phrase.."Won't work.." comes to mind...!
And when you look at the T/S figures you can see why! So, 'what does "cone break-up" sound like?' Isn't it "only" at high volume SPL's?
I have read it[2121] is the "best" speaker in the 4343, so how 'bad' is it?

On a different note but still with the 4343; apparently a CC Network wouldn't improve the 4343? I haven't "seen one by Giskard" so I am thinking that "all you can do to get the best out of it" is to "bias" the capacitors?
I was thinking of using a 2441 instead of the 2421 but I am not sure if that is proper? Has anyone done something like this ?

I dont want to be morphing anything, but for sound quality I was wondering ?


DogBox

[DogBox]

Hi DogBox,

I think that it would be not good to push the driver the signals that it can not to reproduce correctly. ....so my suggestion is to use proper Hi-pass (say over 300Hz) either passive or active.

Regards
Ivica

Hi Ivica,
I have had some computer hassles and too many other things going on... I also managed to download a copy of PSPICE to do some modelling of my own and also in the process of getting a microphone to go with the test set-up i've built. Not as Hi-Tech as your programs [wow!] but I hope to manage!
I think you are right in your Hi-Pass theory for the midbass. The other network you posted [trial] looks good. I did think some others may chime in, however, I think we are on our own on this one. I was nearly tempted to get another pair of 2202h from ebay as you can't get recones anymore. So sad, especially for a driver such as this. And no aftermarket that I have seen either...
If I can't use the 2202, I may have to revert back to my original plan/build of the 4343 'stock'! But like I told Rob, the idea of having a 2" compression driver sounds a feasable idea.. I have all the stock parts, but..
Looking forward to getting some time to 'spice' up my life! :blink:


DogBox

[Robh3606]

Thanks again for that. If this 2202H doesn't work out, I may have to go back to my original plan of "original" 4343 with the 2121H...
I have heard about the 'cone break-up', but "How bad IS IT?" as you just can't swap in a 2122.. the phrase.."Won't work.." comes to mind...!


Hello Dogbox

The problem with either the 2121 or 2122 is cone kits or just being lucky enough to find drivers in good condition. Worst case you could re-foam them. As far as the "cone break up" I wouldn't worry all that much about it. They incrementally improved the drivers from the 4341 up through the 4344. How loud are you going to play them, I bet you quit before they do. To swap out those mids you would need to change the crossovers. The best crossover of all was the 4344 and we have a solution that 4313B worked out years ago. My 4344's use his "equivalent" crossover and it's excellent.

Rob:)

[DogBox]

Hello Dogbox

The problem with either the 2121 or 2122 is cone kits....They incrementally improved the drivers from the 4341 up through the 4344. How loud are you going to play them - I bet you quit before they do.[Exactly!] To swap out those mids you would need to change the crossovers.[Do you mean:"All-of-it?" OR, just that leg???] The best crossover of all was the 4344 and we have a solution that 4313B worked out years ago.Design Cut ?] My 4344's [I wanted to keep to 4343 "if" I can - even if I would like to have a 2" HF Section! It hides behind the lens,etc....!] use his "equivalent" crossover and it's excellent. [I know & I'm tempted - "IT hides in the box!!!]
Rob:)

Sorry for writing "in the middle of your quote - I haven't quite mastered my "thread techniques! :o:
I have "passed-up" some 2122 [even with only about 15 left] for the 2121 recones. Which makes me sort-of committed to 4343. [Still have the 2202H's..] I am not going to worry about cone break-up. But as far as the driver above it..I don't know. I have my mock 2420 to put in..
The crossover has had me going for ages, I simply don't know enough to make design changes myself. Or, to test out any theories I might have.
Which is why I am forced to go with the standard design by using the original drivers. That much I have learned.
It would be nice to experiment though! :confused:

Thanks for your help and input!
DogBox