4343 crossover modifications

[B&KMan]

No worries,

Just get a ruler on some graph paper and draw a 12 inch line.

Frankly I find stuff that particularly boring, people read too much into measurements before they listen...
Ian

My teacher of unniversity repeated unceasingly
"science is not the response to all! but
Between good hands, it is the surest means and rapid between the idea and the realization...

it also makes it possible to evaluate quickly and objectively all and
allowing the repeatability of the experiment.

It is the basement who start art...


For my part, Bright Engineer Greg Timber has in his hands right-hand side a
laboratory and genius in the left...


"B&KMan"

yukyukyuk.


seriously, it is hard to fit criterium on just WOW no ???

But maybe I missing again somes substilitys..




Jean.

[Zilch]

You must normalize the drive curves to determine the actual crossover frequencies....

[B&KMan]

You must normalize the drive curves to determine the actual crossover frequencies....

I dont understand...

it is possible to explain more what is normalize curve ???

thanks...

[B&KMan]

BTW Zilch,

I have maybe a response what is notch of 2K of 2420...

the first pict : upper expose the old electric response keeped on post of driver (all drivers connected on network...) the bottom expose the new electric response at same condition...)


the second pict : upper expose the new response electric on post of 2420 the bottom expose the impedance curve of driver...

Look the notch of impedance is corrolar to notch of electric response...

As your feeling it is possible the peak impedence is create this effect ???


Thanks again...

[Zilch]

I do not know the answer to your impedance peak question. What you suggest makes sense.

Regarding "normalizing," I do not know how your are determining your theoretical and actual crossover frequencies, but see post 398. You have your cursor positioned where the two response curves cross. BUT, since your upper midrange driver has about 8 dB more sensitivity than your lower driver, if you raise the upper response curve that 8 dB to approximate the same output from both drivers, the crossing point and cursor would be moved to a lower frequency.

Normalizing means adjusting so that the outputs are the same, which is the desired objective. As a designer, I believe you would characterize the frequency each filter according a particular point of frequency attenuation in the knee of the curve. In practice, of course, it's where the actual responses "cross."

A member more knowledgeable than myself may be able to clarify these points....

[B&KMan]

Ok now I undertand more what is normalized curve....

1 ---

The impedance of the 2420 selected in white corresponds enough
to the point which appears in the electric response of the 2420.
One would be easily to try to believe that this bump in the impedance
deteriorates to the top frequency response of the 2420....

2 ---

Indeed the answer is standardized and not normalized.
The electrical measurement is based on the calibration of L-Pad
according to best the acoustic answer than I then to obtain...
Thus the 2420 is not in the same way dynamic.
for example if one refers to the diagram of origin that Giskard A
provides it is seen that different the curves are not with the same
height... it is according to these curve and of these cut which I to look at
if, in-sutu, my answers are good...

am I in the error???

[Zilch]

am I in the error???

No, you are fine. They are neither the design nor the actual frequencies, is all. As long as you are comparing under the same conditions, it is valid....

[B&KMan]

OK but for the impedence it is possible to corrected the electrical curve with addition of zobel ??



the 2421 is probably not same impedance step peak ???


anybody have impedance curve of 2421 for comparison of 2420 ???


what your feeling....

[Ian Mackenzie]

Jean,

Refer to the PDF of 3145 schematic and the voltage drive measurements.

Do those measurements to verify if your crossover is right/wrong (use an 8 ohm resisters load when measuring DBA of voltage).

If you do this it will resolve all your Questions.

Ian

[Ian Mackenzie]

Several senior members will be opening a new thread shortly "How to Upgrade your 4343 to 4344 Specs".

I can promise you it won't take 372 post to write.

Ian

[B&KMan]

Several senior members will be opening a new thread shortly "How to Upgrade your 4343 to 4344 Specs".
Ian

YOUPPI !!!

I can promise you it won't take 372 post to write.

Ian

Still again a Australian humour???



euh we are with 414 post!!!



and I do not be finish to post the results of the second network, nor of the final result of the first filled with sand of beach

in fact the first does not have to even finish its burn-in yet...

and testimonial of all members...


Moreover, yesterday, it passed with brio a next step of burn-in.


The sound is clearly big and spacious, it contains definitely more details and of articulation. The holes that there was by the lack of integration is dissipated...
unfortunately, the metal sound persists. in fact it is not ringing or other distortion, but really a color metal in the sound... As same, I changed the caps in the 3143 by film and foil of Solen. This effect should be dissipated completely in 4 weeks...


to follow soon for all fan of this soap thread...








Jean.

[Ian Mackenzie]

I am not sure if you saw my earlier post about asking you to measure using BL test Jig.

Have you done that yet?

You appear oblivious to posts offering assistance that is why no one is here anymore.

Even if i made the new equivalent design (I am very short of time) that does not solve the issue of your network being validated as correct?? ...that is the issue at the moment so it would be best if you can prove that your nework is functioning correctly using the JBL test procedure before making any claims about the boutique aspects of filter performance.

You can't have any pie if you don't eat your pudding!

So go to your room and don't come out until you have done your homework...

[4343mod]

I just stumbled onto this thread. Is there any news to share?

[B&KMan]

I just stumbled onto this thread. Is there any news to share?

hey hey, hey,

well,

Last new , I check of course many aspect: cable, soldering, phase and ....

I have a couple idea what is wrong....


1----

I compare the network and response driver of 3143 and 3145 no surprise I have look the nature of the problem.

If you loof the pict , the hf original 2420 is poor response compare at 2421 the 2421 is more linear and flat, in this circunstance, the hf diaprharm is a issue of the problem of drop in high frec... Normally in original design the uhf is start really more below in fr and support bad response of 2420 so i I cut the uhf in 10 K the section of 6,7,8K is too much drop and create a ole sound in this area...

2---

because the 2121 is too unstable at high frec it is imposible to mach 2420 and 2121 with-out notch upper arround 800K --unfortunately the first notch peak impedance of 2420 create impossibility to cut more down the 2420 for compasation of limit upper of 2121.

So, the bignet amplified this effect and create more feeling of hole sound.

Actually My conclusion is : it is look not very possible to create this network with original diaghram because the limit and difference response of old diaphram react good and bad with new network.

of course the new network is more snaps, fast, details, and because the driver in hf-uhf is rapidly cut, the blur effect of overlaps is really decrease. result more signifiant coherence, less horn effect, and error in time phase...




my last only mysterious problem is the problem of uhf ... I dont know but I cancel the last set of resistor in end of uhf circuit and I pout pot in max for generate correct spl... ???

I know this is same effect with just change original caps on 3143 by caps Solen film and foil... Solen explain the power handling is invert proportionnal at the sensibility. so I feeling due to very power in this section the caps of 400V is too much for the small signal...


Anybody have experienced this effect ???


Anyway I hope you appreciate this part of conclusion... and dont hesitate to expose your point of views.... all is appreciates.

Jean.

[Ian Mackenzie]

Can you verify the voltage drives using 8 ohm resisters please per the table in the 3145 nework?

Ian