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Guido
03-22-2005, 02:40 PM
If I would drop a 2421 dia into a 2426 and keep away the alnico ferrite debate, would it result in a 2420like driver?
Or are there significant changes in the phase plug?

Ok Ok, I could just try it but what is the opinion about this?

spkrman57
03-22-2005, 03:24 PM
I just bought a pair of JBL 2426J's and have been using Altec 802/806/807/808's for some time now. I also picked up a pair of 902's lately and trying to compare the difference. Hard to tell so far, they are different, just can't put my finger on it.

So when I get the 2426's mounted on horns, I will see how they compare to the Altec 802/806 drivers(alnico), and the 902(ferrite).

Still looking for different crossovers to try out. Currently using 3rd order w/HF compensation networks.


Let me know how it all comes out. I am curious!!!

Ron

Mr. Widget
03-22-2005, 04:56 PM
Let me know how it all comes out. I am curious!!!


I am too. I would be interested in both subjective and if possible objective comparisons.

Widget

Guido
03-23-2005, 03:37 AM
The 2426 drivers I bought w/o dia on ebay will arrive next week. I'll then equip them with brandnew 2421 dias and do a comparison to my 2420 that also have brandnew 2421 dias.

I just dont want to part my existing 2426. So we need to wait a bit.

spkrman57
03-23-2005, 06:53 AM
Has anyone actually tried it out?
Ron

Earl K
03-23-2005, 07:49 AM
Well I know first hand that a 2410 diaphragm fits nicely into the newer ferrite magnets .

I see no reason why the 2420 or 2421 wouldn't also fit into the newer ferrites. JBL hasn't changed the magnets gap sizes or mounting hole spreads / etc. .

Note : the 2410 ( le175) diaphragm installed into a 2420/1 or 2425/6/7 magnet isn't a JBL authorised combo . ( It's a slightly lighter diaphragm )

:)

Guido
03-29-2005, 12:31 PM
Argh!

This was hard work. After sticking 20 minutes INSIDE my 4343 and couldn't get out this 2420 I decided to open the front baffle. I tell ya...

OK, here are the results:

Impedance
Blue = 2426 with fresh D8R2425 on 2344
Red = 2426 with fresh D16R2421 on 2344
Orange = 2420 with fresh D16R2421 on 2344

Guido
03-29-2005, 12:33 PM
Response:

Blue = 2426 with fresh D8R2425 on 2344, Clear extended HF-Response
Red = 2426 with fresh D16R2421 on 2344

Pure drivers

Guido
03-29-2005, 12:36 PM
Response with 3135 network

Violet = 2426 with fresh D8R2425 on 2344, extended HF-Response
Green = 2426 with fresh D16R2421 on 2344
Orange = 2420 with fresh D16R2421 on 2344

Zilch
03-29-2005, 12:57 PM
I'm finding old LE85's (16 Ohms, though they say 8) play fine on N3134, have more extended HF response than 2426H or J, and sound better (smoother).

Thinkin' about springin' for a pair of D8R2421 aluminum diaphragms to put in a pair here....

[I think that's the number, the original 4430 diaphragm....]

YIKES! $244 per each! :(

Why'd you get D16R2421's?

Guido
03-29-2005, 01:16 PM
Why'd you get D16R2421's?

I use them in my 2420 for the 4343.

Mr. Widget
03-29-2005, 01:24 PM
Could you make comparisons with no network ahead of the drivers? The impedance mismatch is most likely affecting your results. It would be interesting to see all of the drivers on the 2307 as well.

Your plots do show that the aluminum diaphragm has reduced that (nasty) peak at 4KHz....:hmm:

Widget

Guido
03-29-2005, 01:45 PM
Could you make comparisons with no network ahead of the drivers?

See Post #8


It would be interesting to see all of the drivers on the 2307 as well.

No chance! It's back into the 4343 :(


Your plots do show that the aluminum diaphragm has reduced that (nasty) peak at 4KHz....:hmm:

This peak is app. +3 or +4 dB so its inside the range I think

Ian Mackenzie
03-29-2005, 01:49 PM
Just shunt a 20 ohn resister on the drivers where the impediance is 16 ohms

Guido
03-29-2005, 01:54 PM
I'm finding old LE85's (16 Ohms, though they say 8) play fine on N3134, have more extended HF response than 2426H or J, and sound better (smoother).

I'll sure give my extra pair of 2426 with 2421 dias a try in my 4435 as soon as they are finished. The "smoother" sound many members refering to makes me curious :bouncy:
Maybe a nice (blind) A/B test with one side 2426/D8R2425 and 2426/D16R2421 at the other side? :)

The impedance missmatch could be eliminated by changing the parallel resistor in the 3134 network to 5.1 ohm (changing to 7.5 ohm in the 3135?). I discussed this with Giskard and it should not work 100% correct but it should work.

Ian Mackenzie
03-29-2005, 01:58 PM
I would like to see a curve of the 2420 with the D8R2425 on 2344.

Here's my result taken some time again.

Ian

Mr. Widget
03-29-2005, 02:55 PM
...I discussed this with Giskard and it should not work 100% correct but it should work.

I am no absolutist, but not working 100% is usually not working in my book.

Hey Ian,

What is your vertical scale?

Here is my quasi-anechoic measurement of one of Zilch's stock 2425Hs w/ 3135 and 2344.

Widget

Ian Mackenzie
03-29-2005, 03:04 PM
Sorry I don't recall, I think it was 12 per division, even so its very smooth on a properly mounted baffle at 1 metre.

regards

Ian

Earl K
03-29-2005, 03:04 PM
Guido,


Your plots do show that the aluminum diaphragm has reduced that (nasty) peak at 4KHz....

- Yes , regarding that peak around 4K on the 2344.

- Since you and Zilch are just "all-over" re-engineering the 2344 / & all other 2 way designs with new parts ,,, I think it's time you whipped up a "tuned" series type LCR filter ( shunted across the driver just before R5 on the 4430 network ) to hammer down that 4200hz peak . The "how-to" particulars are buried in the "Project May" area in the "bandpass" thread . Giskard & Widget can give you testimonials to just how effective these filters can be when they are zeroed in . Recently, I whipped up a "low-Q" type out of spare parts to "hollow-out" a bulge on a 2441/horn combo I've been working on ( I didn't really know what I was doing - but it worked very well despite that handicap ). :o:

Give it a try .

:p

Mr. Widget
03-29-2005, 03:36 PM
I corrected differences in scaling and changed the color and superimposed my 2425H on 2344 Quasi-anechoic plot from the post above and placed it on top of Guido's. It is fairly similar to his 2425 plot. Some of the differences could be due to different pot settings as well as unit to unit variance.

Widget

Zilch
03-29-2005, 05:54 PM
Response:

Blue = 2426 with fresh D8R2425 on 2344, Clear extended HF-Response
Red = 2426 with fresh D16R2421 on 2344If you normalize them, 2421 has better response, both high and low....

Zilch
03-29-2005, 06:03 PM
Since you and Zilch are just "all-over" re-engineering the 2344 / & all other 2 way designs with new parts ,,, I think it's time you whipped up a "tuned" series type LCR filter ( shunted across the driver just before R5 on the 4430 network ) to hammer down that 4200hz peak . I think we're abandoning N3134/35, at least the HF section, in favor of newer crossover topologies for use with 2431 and PT waveguides.

We're still at the "gross" stage in this, but we may be able to get away without any additional notch filters. Wishful thinking, perhaps.... :p

Guido
03-29-2005, 09:59 PM
I am no absolutist, but not working 100% is usually not working in my book.


OK, it will work!
I see no reason why not.

B&KMan
09-12-2005, 05:59 AM
Hello Guido,

What news on this faboulus comparison ???

What diaghrams you prefers objectively (mesured) and for subjective listening ?? with your 4343

For the 4343 (2420) what is the final best choice ???

As you know I have a problem of my old 2420 because the pressure is really drop in arround of 8K.

If I look the response curve on your test, the 2421 is look the better linear response (arround 5-6 dB variation).

Thanks.

Jean.

Earl K
09-12-2005, 08:25 AM
Jean,


If I look the response curve on your test, the 2421 is look the better linear response (arround 5-6 dB variation).

- I believe you are misreading and misinterpreting Guidos posted curves. That "lighter green" curve was added by Mr. Widget. It's a 2425H on a 2344 horn . It does have 5 to 6 db better UHF response when compared to the older 2420 ( or the 2421b for that matter ). The curve of the 2420 or the 2421b diaphragm with this network (N3134/5) does show UHF droop. This is to be expected when these diaphragms are measured with the wrong network .

- These response curves are misleading you . This N3134/5 network was specifically designed to work with JBLs' low impedance 8 ohm diaphragms ( like the 2421a or the 2425h ) not the higher impedance 16 ohm diaphragms such as the original 2420 or the 2421b or a 2425j . It's dangerous to draw conclusions from these posted graphs. For an effective comparison; the high impedance diaphragms should have been combined with a 3134 type network that had had, all its' values reworked for use with the higher impedance ( 16 ohm ) diaphragms.



As you know I have a problem of my old 2420 because the pressure is really drop in arround of 8K.

- IMO, you are better off to look elsewhere for a fix to that response hole that is occuring between your horn driver and your 2405 UHF driver .

- I see Giskard came back this summer out of exile and provided you with a bunch of clues as to how to proceed to fix your problem . That was nice of him . I guess you didn't pick up on those clues . FWIW; for a Canadian, changing diaphragms will be your most expensive solution. OTOH, learning to manipulate crossover design by understanding the theory will ultimately be much cheaper and more rewarding.



- What diaghrams you prefers objectively (mesured) and for subjective listening ?? with your 4343

- For the 4343 (2420) what is the final best choice ???

- Well, I too will wait for Guidos answer. After all, he did eventually get rid of his 4343 speakers .


:p

B&KMan
09-12-2005, 10:26 AM
Jean,
- Well, I too will wait for Guidos answer. After all, he did eventually get rid of his 4343 speakers .
:p

Thanks for reply Earl,

It is sense for me but the variation of impedance it is really big change in signature of spectrum ???

do you have mesured any motor with 16 vs 8 ohms diaphrams for comparison ??

I understand this is not exactly same set-up but maybe the reactance is look a little bit same ??

I know the final solution is corrected the network but because the 2420 is more than 20 years, maybe it is interesting to adaptive network solution in fresh and more accurate diaphrams ???

I'm not feel to extend for couple of years this research...

:D

Jean.

Earl K
09-12-2005, 04:33 PM
Hi Jean


but because the 2420 is more than 20 years, maybe it is interesting to adaptive network solution in fresh and more accurate diaphrams ???

- I realize you are searching for some solutions to the mismatch between your new network and your older ( non recommended ) components .

- If I were you, I wouldn't jump to conclusions that your 2420s are worn out and the source of all your problems . Afterall, Zilch has showed recently that his old , venerable le85 ( 2420s ) actually have quite extended response in the top and bottom end / when compared to some others ( like the 2426 ).

- So, I would recommend measuring the frequency response of your 2420 drivers without any of your crossover in the circuit. Measure with those 2307 horns on the drivers using pink noise . Set your RTA to some resolution that is recognizable to Zilch and myself. I use pink noise high passed at around 300 hz for this sort of testing. Test with the 2308 lens off . I do this test at about 1 foot away / on axis to the horn mouth / and only loud enough to get a respectable reading .

- When you have done this / publish some pics of the response curves here, so that we can try to gauge the health of the diaphragms in those drivers . I have 2307/8 combos here - but unfortunately, no le85/2420 drivers / just 2410/2425 types etc.

:)

B&KMan
09-12-2005, 06:02 PM
first thanks for reply and offert to check response...



Hi Jean


- I realize you are searching for some solutions to the mismatch between your new network and your older ( non recommended ) components .

- If I were you, I wouldn't jump to conclusions that your 2420s are worn out and the source of all your problems . Afterall, Zilch has showed recently that his old , venerable le85 ( 2420s ) actually have quite extended response in the top and bottom end / when compared to some others ( like the 2426 ).


well I perform completely electrical test with supervision of Mr mackensie and no problem in electrical response. (really close to theorical) so next step is the membrane ...




- So,

1---- I would recommend measuring the frequency response of your 2420 drivers without any of your crossover in the circuit.
2---- Measure with those 2307 horns on the drivers using pink noise .

3---- Set your RTA to some resolution that is recognizable to Zilch and myself.

4---- I use pink noise high passed at around 300 hz for this sort of testing.
5---- Test with the 2308 lens off . I do this test at about 1 foot away / on axis to the horn mouth / and only loud enough to get a respectable reading .

- When you have done this / publish some pics of the response curves here, so that we can try to gauge the health of the diaphragms in those drivers . I have 2307/8 combos here - but unfortunately, no le85/2420 drivers / just 2410/2425 types etc.

:)


===== what is ( 4 ) pink noise in around 300 Hz ????

pink noise is white noise but attenuation by the number of frequency include in each band 1/3 octave.

===== it is necessary to put resistance in serial ?? or in parrallele ???

===== what resistance to put 8 ohms or 16 ohms ????

thanks for more complete details before I unbuild again my speakers....

B&KMan
09-12-2005, 11:54 PM
Hello again,

I perform test

pink noise 60 secondes at 200 to 200K Hz for 1/3 octave analyse RTA

and white noise 1000 averages records at 200 to 200K Hz for FFT analyse.

this is result in 4 mesures.

I mesure 2420 and 2405 in this I save another open speakers :D :D :D

let me know your feeling Earl , zilch and any other members.

thanks for all.

(I persist to sign this problem is better information on thread 4343 but as you wish earl.)

B&KMan
09-13-2005, 12:10 AM
look the response of UHf is increase and the 2420 is stable (little drop...)

Earl K
09-13-2005, 04:05 AM
Thanks Jean,

(a) 2420/le85
- The response of your 2420 looks very normal to me ( with maybe the exception of that dip at 2000hz ) . It would be nice to see a comparable measurement from someone else with this same horn/driver combo .

- A 2420 on the 2307 horn should have a rising response, which your screen capture clearly shows . Once the 2308 lense is placed over top of the horn, this rising response is nicely levelled out .

(b) 2405/077
- I'm not much of a tweeter guy but that 2405 response looks consistent with the response curves published for the 4345 system .

EarlK :)

B&KMan
09-13-2005, 06:05 AM
Thanks Jean,

(a) 2420/le85
- The response of your 2420 looks very normal to me ( with maybe the exception of that dip at 2000hz ) . It would be nice to see a comparable measurement from someone else with this same horn/driver combo .

- A 2420 on the 2307 horn should have a rising response, which your screen capture clearly shows . Once the 2308 lense is placed over top of the horn, this rising response is nicely levelled out .

(b) 2405/077
- I'm not much of a tweeter guy but that 2405 response looks consistent with the response curves published for the 4345 system .

EarlK :)




:banghead: ARRHRHRHRHRHRHRHR :banghead:

:biting: IIIIIIIIIIIIIII :mad: :spchless:

URHHRHRHRHRHR :die:

OF THE :flamed: THEN :thnkfast:

===============================
AHHHH I drop a few pressure with this obscur problem:

driver response OK Network response OK ......

so what the F... on Bignet integration ???

Earl K
09-13-2005, 06:23 AM
driver OK Network OK so what the F...

on Bignet integration ???

- Obviously, Bignet didn't integrate your drivers ( & their healthy FR responses ) as well as it could ( if it had been designed for your specific drivers ) .
- That shouldn't be a surprise to you , your past advisors consistently said that the newer network was designed for the 2421b and 2122h drivers .

- You're going to need to change-out some of the values of your passive components within "Bignet" .

- Start draining that sand . :beach: * ;)

Guido
09-13-2005, 07:11 AM
Hello Guido,

What news on this faboulus comparison ???

What diaghrams you prefers objectively (mesured) and for subjective listening ?? with your 4343

For the 4343 (2420) what is the final best choice ???

As you know I have a problem of my old 2420 because the pressure is really drop in arround of 8K.

If I look the response curve on your test, the 2421 is look the better linear response (arround 5-6 dB variation).

Thanks.

Jean.

Hi Jean!

I'm a bit slow on the forum as I still renovate my house.
Well the 4343 went to Forum Memer Rolf in Norway. This answers Earl K's question also.
I bought a pair of 250ti and will build a pair of 4435 end of this year.
As soon as I have them I'll experiment with Aluminium and titanium dias as well as with the 2431H drivers and PT Waveguides. See the quick an dirty 4430 thread of Zilch for infos about the 2431.

I'll also combine the 4435 Bass-section with an 2441/Smith Horn Combination in addition of an 2405. But this will sure be next year as the crossover is the problem here. Maybe I'll start a thread to look for assistance.

As said before, first the house ;)

According your concerns with the D16R2421 dias I can tell you that they sound exactly the same than the NLA D16R2420 dias IN AN 4343 envirnonment!

Zilch
09-13-2005, 08:48 AM
ACK!

Don't MAKE me mount stuff on 2307's, now.

[I'd hafta dig in the recycle bin here.... ;) ]

Robh3606
09-13-2005, 09:08 AM
Just to get a clear picture.

What network are you using???

I use 2416's with the 4344 network Giskard came up as an alternate to the tapped inductors. It works just fine. They are the same networks Ian used to post his original data. He used a 2420 with a 2425 diaphram if I remember right. I got almost the same or very similar readings after I set them up in my speakers.

What is the resolution on the vertical scale??? I don't get the peak at 8k or the repressed response at 2k.

Are those run without the network????


This is a previous run of yours. What changed since this measurement?? That is what I would expect to see.



Rob:)

Earl K
09-13-2005, 09:17 AM
Don't MAKE me mount stuff on 2307's here, now.

- Well my friend, only terminal curiousity has that type of power over ones' actions . ;)

- What I find the most intriguing about some of the info in this thread , are Guidos' posted impedance curves .

- ie ; the copper shorting ring, controlling flux modulation in the 2426 driver pushes the Zmax point down close to the diaphragms' stated resonance point . OTOH, the silver type shorting ring, as found in the 2410/2420/1/2425 drivers gives a Zmax point , somewhere up in the usual pass band of the driver . I had long thought that this characteristic of the latters' impedance curve ( seen as orange, C16R2421 in 2420 ) was a function of the diaphragm . Apparently not . Compare, to the C16R2421 operating within a 2426 magnet to see what I mean .

:p

B&KMan
09-13-2005, 09:36 AM
Just to get a clear picture.

What network are you using???

Rob:)

the first picture i expressly wirite the mesure is produce all driver connected in 3143 (with smal modification (cancel bi-amp switch and cps solens film and foil in upper section.)

the second pict is connection plain : direct on amplifier




What is the resolution on the vertical scale??? I don't get the peak at 8k or the repressed response at 2k.

Rob:)

mmmmm I do not shure your question...

the Y= value appear on each picture

1 = 40 dB each big hoz line is 5 Db value (5 thin line inter 2 big line )
so fine resolution is 1 dB

2 = 20 Db each big hoz line is 2.5 Db value (5 thin line inter 2 big line )
so fine resolution is 0.5 dB

Rob:)[/QUOTE]

better understand ???

B&KMan
09-13-2005, 09:52 AM
Hi Jean!
According your concerns with the D16R2421 dias I can tell you that they sound exactly the same than the NLA D16R2420 dias IN AN 4343 envirnonment!

thanks!!

I'm not shure the most recent diaphrams is inpedance compatible in motor of 2420...

B&KMan
09-13-2005, 09:58 AM
- You're going to need to change-out some of the values of your passive components within "Bignet" .


CURIOSLY,
If you remember I perform first modification on stock 3143 with flim and foil and I have posted my result who the response is drop in same place but little less and the UHF is loose the power..

this is mystery intriguism me at really high level.

I dont know if the nature of caps is the clue but it is strange...

question of power 400V is less sensitive of 100V as regards of Solens commentary. so maybe the breaking point is here....

any idea in this question???

Robh3606
09-13-2005, 10:02 AM
"the second pict is connection plain : direct on amplifier "

Hello Jean

Ok no crossover:hmm:.

better understand ???

Are you kidding?? :screwy: This is hard to do from thousands on miles away. Much easier face to face.

I don't understand the energy distribution. The 2307 is an exponential so it DI changes with frequency to compensate for the rolloff above say 2-3K or so. Even without a crossover I would expect the same basic curve. The driver has it peak response in the 1-3K region and then rolls off from there. Why 2K would be depressed with a peak at 8K has me :spchless:

I am thinking it's the input but I am not sure. Is that White noise or Pink?? Pink noise is shapped so you have the same energy octave to octave. White noise is not so you see a rising response. What did you use???

The drivers were fine from your original 4343 plot so why would they be bad now??

Confused as ever

Rob:)

B&KMan
09-13-2005, 10:32 AM
"the second pict is connection plain : direct on amplifier "

Hello Jean

Ok no crossover:hmm:.

better understand ???

Are you kidding?? :screwy: This is hard to do from thousands on miles away. Much easier face to face.

I don't understand the energy distribution. The 2307 is an exponential so it DI changes with frequency to compensate for the rolloff above say 2-3K or so. Even without a crossover I would expect the same basic curve. The driver has it peak response in the 1-3K region and then rolls off from there. Why 2K would be depressed with a peak at 8K has me :spchless:

I am thinking it's the input but I am not sure. Is that White noise or Pink?? Pink noise is shapped so you have the same energy octave to octave. White noise is not so you see a rising response. What did you use???

The drivers were fine from your original 4343 plot so why would they be bad now??

Confused as ever

Rob:)

first sorry if you offend you... it is absolutely not my idea.

I resume...

I have 4343 stock !!

After many listen thread I realize it is possible for me to refrest few part for accurate result.

I decide the change my UHF diaghram, the 2231 is fresh recone with 2235 and the 2121 is fresh recone with original 2121.

I changed caps on Hf and cancel the switch bi-amp. WOW really encouraging but I remark less power in upper spectrum... I try to send few questions of this phenomenon but nothing is have a response.

After many questions I decide to build 3145 dc but integrate cascade caps.

I build network and plug and realize the uhf is more loose power and the end of my hf is drop fast ... strange...

because this process is really long and trace is loose by many member Eark explain me to put each way of problematic in specific thread.

so the hypotesis of Earl is the driver is just not compatible and is ask for test to expose the point here.

yest pink noise concept is same energie at each band and white nois is same energie at each frec. so is go up 3 db by each band of RTA but if you run on FFT the pink noise is not recommended, white noise is good.

Anyway the analyser choose correct noise in regard of type of analyse fft dft process or if you run in rms pwr of esd .

so in regard of all my pict the final ideal result is flat horizontale line...


but I have 3 machines analysers in regard of my research of acoustic architectural and I recognize it is not easy to understand...

sorry again.

frank23
09-13-2005, 12:23 PM
[QUOTE=Earl K- ie ; the copper shorting ring, controlling flux modulation in the 2426 driver pushes the Zmax point down close to the diaphragms' stated resonance point . OTOH, the silver type shorting ring, as found in the 2410/2420/1/2425 drivers gives a Zmax point , somewhere up in the usual pass band of the driver . I had long thought that this characteristic of the latters' impedance curve ( seen as orange, C16R2421 in 2420 ) was a function of the diaphragm . Apparently not . Compare, to the C16R2421 operating within a 2426 magnet to see what I mean .
:p[/QUOTE]

So, the same diaphragm in a 2426 would sound different than in a 2420 - 2421 - 2425, if only because the impedance match to the crossover of the two different drivers would be different then. I was amazed at the difference between the two impedance curves. I thought the measurements must have been be wrong.

Do you consider the differences possible?

Frank

Guido
09-13-2005, 01:47 PM
So, the same diaphragm in a 2426 would sound different than in a 2420 - 2421 - 2425, if only because the impedance match to the crossover of the two different drivers would be different then. I was amazed at the difference between the two impedance curves. I thought the measurements must have been be wrong.

Do you consider the differences possible?

Frank

The measurements are NOT wrong. I always thought the impedance differences where due to the different backcap volumes of the 2420 and 2426 motors.
Interesting is that the 2421 and 2425 where used with the same crossover in the 4430 and 4435 monitors.

frank23
09-13-2005, 02:06 PM
The measurements are NOT wrong. I always thought the impedance differences where due to the different backcap volumes of the 2420 and 2426 motors.
Interesting is that the 2421 and 2425 where used with the same crossover in the 4430 and 4435 monitors.

the 2421 / 2425 in 4430 / 4435 swap is interesting indeed

if these measurements were right, could these measurements maybe be influenced by the age of the 2420 motor and possible reduction in the magnetic force in the gap? or are you sure that all "motors" were up to spec?

I find the difference so great, thinking that JBL always stated the newer drivers had the same phase plug and were interchangable with the old ones.

greetings, Frank

Earl K
09-13-2005, 02:54 PM
Hi Guido,


I always thought the impedance differences where due to the different backcap volumes of the 2420 and 2426 motors.

- That's an interesting thought, that the back-cap size, influences those impedance curves .

- You could test for this by simply swapping back-caps around / just hold them down tight enough to make a decent seal and run new tests . Gaffer tape would work nicely .

- Do you have any 2425 drivers ?

;)

Earl K
09-13-2005, 03:02 PM
Frank


So, the same diaphragm in a 2426 would sound different than in a 2420 - 2421 - 2425, if only because the impedance match to the crossover of the two different drivers would be different then.

- Well I don't know, but I never underestimate the ability of people to hear small nuances caused by " whatever " .

- In this case, I'd have to say it would depend on the crossover. For instance; JBLs' widespread use of fairly low Z value conjugate-resistors goes a long way to mitigating the effects of these impedance spikes .

:)

Tom Loizeaux
09-13-2005, 07:18 PM
...According your concerns with the D16R2421 dias I can tell you that they sound exactly the same than the NLA D16R2420 dias IN AN 4343 envirnonment!

Is this really true? I am curious to know if the D16R2421 diapgragms sound any differant, or maybe better(?) then the original D162420 diaphragms in a stock 4343.

Tom

B&KMan
09-13-2005, 08:54 PM
Is this really true? I am curious to know if the D16R2421 diapgragms sound any differant, or maybe better(?) then the original D162420 diaphragms in a stock 4343.

Tom

well the problem in my eyes is the 2420 D162420 is not available !!!

my question is a compatibility question because it is shure 30 years of evolution technology groove a big deep step. and it iipossible to push out or support comparison....


in regard of flatness response or distortion or power handling. the evolution of technology is not a myst...

the best upgrade is go direct at case of 4348 studio monitor but in this case my question is track in your surprise ???

what is the best refersh diaprham for motor 2420 to perform better ???


Jean.