Truextent 4" diaphragms available soon

[Guido]

FR is one thing. The impedance looks quite a bit nicer on the 476Be.

Have you any CSD and distortion measurements to post?


-Tim

This is a post for information only. These dias are available and they are worth a try.
All other measurements you'll have to do for yourself. It's anyway better to try and listen on your own.

[timc]

It's anyway better to try and listen on your own.

I 100% agree with that, but to compare quality with the 476Be (or even TAD-4003) It would be nice to see more measurements.

It's quite an expensive experiment you are sugesting

-Tim

[4313B]

Sorry I don't have any $10 waveguides.

H9800 and EV2 Horn clones are available. No idea why so few members use them :dont-know

Because they probably cost money...

[pos]

Guido, have you tried to put the Truextent dia in the 476 ?

[4313B]

Guido, have you tried to put the Truextent dia in the 476 ?

Give me an effing break!!! You'd have to have rocks in your head to pull apart a $5,600 pair of drivers just to eff around with them...

I rue the day I sold a pair to Guido. It was an effing favor...

[pos]

Keep cool 4313b, that was just an effing joke

[Guido]

I rue the day I sold a pair to Guido. It was an effing favor...

They are in good hands, no worrys. And you know that!

Guido, have you tried to put the Truextent dia in the 476 ?

I will not pull apart the 476Be's. Well, maybe when I blow the dia one day.

[Oldmics]

Any guess"s as to which of our favorite speaker manufactors B/W is currently supplying the Be product to

Oldmics

[Robh3606]

TAD??

Rob

[4313B]

TAD uses the toxic version, JBL uses the non-toxic version.

In any case, there is no way to make a 476Be from any of the other JBL cores. We discussed it back in 2006 when it was relevent and it just won't happen. And hoping and wishing and dreaming won't make a difference. JBL would have been all over simply sticking a Be diaphragm into some older core to save costs if it would have done the trick. It didn't. Anyone who posts on a public Internet forum that they too can have 476Be performance simply by putting a Be diaphragm into an older JBL core is automatically discredited. These guys rightfully take their designs quite seriously and don't appreciate misinformation propogated by forum hacks.

That said, these Be diaphragms are a excellent option for other JBL cores. Plan on reworking any existing passive filters accordingly. Rather than wasting time comparing a 2451 (or any other core) against an "unobtainable" 476Be how about comparing a stock 2451 against a 2451 with a Be diaphragm. That would actually be relevent. Of course, no one can actually hear a driver or a diaphragm on a forum regardless of how many pretty graphs are posted.

I'm done with this irritating thread.

[Mr. Widget]

Any guess"s as to which of our favorite speaker manufactors B/W is currently supplying the Be product to

I believe Brush Wellman manufactures the Be material for virtually all of the audio market except for TAD who use vapor deposition (Yamaha used to use this method as well). There are also a few less reputable manufacturers who claim their Be dusted diaphragms are true Be... they are not.

Toxic? All Be is toxic, but the sheet material that Brush Wellman manufactures isn't prone to shattering and releasing the toxic Be dust particles that can happen with a TAD diaphragm. Both types can be toxic, but when used properly neither is inherently dangerous, but if abused, the Brush Wellman material is significantly safer.


Widget

[Mr. Widget]

Rather than wasting time comparing a 2451 (or any other core) against an "unobtainable" 476Be how about comparing a stock 2451 against a 2451 with a Be diaphragm. That would actually be relevant.

Of course, no one can actually hear a driver or a diaphragm on a forum regardless of how many pretty graphs are posted.

There are real benefits to using this material. It is pure physics not hi-fi hogwash. That said, as 4313B points out, the real proof is in the listening. With filter tweaks you can produce almost any plot... you can't make Ti sound like Be.


Widget

[Ian Mackenzie]

There was an embargo on Be material in some areas and this is most likely the reason why its use is not more wide spread.

Just reading this thread for the first time being in general audio discussion I am not sure why there is all the fess -up over this. I mean its not like JBL cares or has any actual control over what a diy blogger does or does not do in their spare time. Radian have been selling after market diaphragms for years, some Tad users quote they prefer them and that is their business. Some people prefer Acoustic Elegance drivers to Tad and that is their business.

But there is no free lunch and the more transparent the driver, the more flaws it will illuminate from the lesser quality mass market electronics. I recall Scotty discover this after trialing Bryston active crossovers.

(Last time I heard a Focal system using Be I was not that impressed.)

Therefore, unless you have the means to upgrade the entire signal path to that of the driver don't expect a miracle.

[herki the cat]

there is no free lunch and the more transparent the driver, the more flaws it will illuminate from the lesser quality mass market electronics. Therefore, unless you have the means to upgrade the entire signal path to [any] driver don't expect a miracle.

Well said, Ian Mackenzie; this also applies, especially in very low audio frequency transmissions & sub woofer speaker performance. It also severely impacts evaluation & comparison procedures of conventional wire against professional quality speaker cables and interconects. To begin with, conventional wire generates "phase shift-non linearity" & "phase shift-distortion", two distinct entities, which generate smearing of complex audio signals and increase of transmission delay time inversely proportional to the signal frequency. Phase Shift is related to Group Delay.

Group delay in the audio field from Wikipedia, the free encyclopedia
Group delay is a measure of the transit time of a signal through a device under test (DUT), versus frequency. Group delay is a useful measure of phase distortion, and is calculated by differentiating the insertion phase...
en.wikipedia.org/wiki/Group_delay_and_phase_delay - Cached

Group delay is a useful measure of phase distortion, and is calculated by differentiating the insertion phase...Group delay has some importance in the audio field and especially in the sound reproduction field. Many components of an audio reproduction chain, notably loudspeakers and multiway loudspeakers crossover networks, introduce group delay in the audio signal. It is therefore important to know the threshold of audibility of group delay with respect to frequency, especially if the audio chain is supposed to provide a high fidelity reproduction. At the time of writing no extensive data is available, and the concept is often treated by "rule of thumb" or based on hunches and received wisdom. The best thresholds of audibility table below has been provided by Blauert and Laws:

FrequencyThreshold
500 Hz 3.2 ms
1 kHz 2 ms
2 kHz 1 ms
4 kHz 1.5 ms
8 kHz 2 ms

The table above has been published into the following article:
Blauert, J. and Laws, P "Group Delay Distortions in Electroacoustical Systems", Journal of the Acoustical Society of America, Volume 63, Number 5, pp. 1478–1483 (May 1978)

With professional cables correctly implemented, illumination of system components defects does facilitate the ability to locate & identify equiment system component defects to locate & identify problem areas for repair or upgrade, which were originally masked by conventional wire grunge.

New professional quality cables & interconnects requires a "break in" or "burn In" period of many hours & even days, which has to be repeated to a certain extent every time the cable is physically distrubed including disconnection & reconnection to the audio components. Bypassing this procedure renders cable comparisons "meaningless."

Bruce Brisson, Ceo of MIT Interface Technologies, has proven "If you can hear it but can't measure it, you are measuring the wrong thing." That is what you learn when you read his white papers and patents. See the "Skywalker 'Avatar" Movie applications credentials at this link:

http://www.mitcables.com/pdf/mit_movies.pdf.

At MIT Interface Technologies, you dont need to spend a fortune for 1st class professional speaker cables. Bruce Brisson will engineer your cable applications to match your specific system components. MIT cables are also are available for evaluation from the MIT lending library.

MIT Teflon cables, of performance identical to the $1000.00 Teflon Cables, are available under $100.00 with garanteed satisfaction or your money back.

Cheers, herki the cat

[Ian Mackenzie]

Holly Toledo (headquarters of Jeep) Robin.

I should have charged for that post!