Blah, blah, blah. You don't listen carefully. Ported cabs and sealed cabs sound different in the time domain, its not enough that the frequency domain measures okay.
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RNMarsh said:
Maybe you missed my question:
Could you give a link to the one resistor distortion reducer.
Hans
I know cell phones should still be in a small suit case and cost $5000, and computers should fill a room, cost $1M, and require liquid cooling. What makes you think all these IC's are nothing but "book learning" wielded by a bunch interchangeable disposable engineers?
Sorry to inform you that many of these folks are brilliant and these circuits are full of tricks that you would never understand. Some are "specialists" I guess in your eyes too bad for them, they probably don't blow dry their cars either.
Finally, something to talk about. Loudspeaker enclosure resonance.
Now here is an example of where most engineers fail to completely fix a serious potential problem.
Looking at the illustration of the inside of the rather complex JBL speaker that Richard Marsh owns, and has used in the past, and that Markw4 has use of at this time, it is not surprising that some resonant tendencies might develop somewhere.
Most people really ignore this problem with loudspeaker cabinets, and manufacturers sometimes even try to suppress any criticism of their efforts in this area. Hey, it is expensive to really control resonance in most loudspeaker cabinets. It is NOT just choice of material or even its thickness, although both can be factors.
Often a stiffer material or a thicker material just raises the RESONANT FREQUENCY and does little or nothing to reduce its Q. This is not intuitive, at least to me.
Back 55 years ago, when we made the Grateful Dead cabinets, we used the stiffest and the thickest (readily available) Birch plywood that is almost like cement when you banged into it (usually by accident '-) ) and we were pretty smug about it. Later, 50 years ago
I attended an AES conference in London where I heard several papers on the subject. Yes, we had overlooked several factors. Our cabinets were big, heavy, and strong (resistant to breakage) but they still resonated at a pretty high Q. Live and learn folks!
My reference speaker is especially designed for low Q resonance, but even it most probably has some measurable, (and perhaps audible) resonances. I shudder at what most of you out there put up with.
Secondly, Richard Marsh is right. Most input here is just small talk, and most here are not very informative in a useful way to improve audio quality. Real engineers like 'tricks and tips' on how to do something better.
Now here is an example of where most engineers fail to completely fix a serious potential problem.
Looking at the illustration of the inside of the rather complex JBL speaker that Richard Marsh owns, and has used in the past, and that Markw4 has use of at this time, it is not surprising that some resonant tendencies might develop somewhere.
Most people really ignore this problem with loudspeaker cabinets, and manufacturers sometimes even try to suppress any criticism of their efforts in this area. Hey, it is expensive to really control resonance in most loudspeaker cabinets. It is NOT just choice of material or even its thickness, although both can be factors.
Often a stiffer material or a thicker material just raises the RESONANT FREQUENCY and does little or nothing to reduce its Q. This is not intuitive, at least to me.
Back 55 years ago, when we made the Grateful Dead cabinets, we used the stiffest and the thickest (readily available) Birch plywood that is almost like cement when you banged into it (usually by accident '-) ) and we were pretty smug about it. Later, 50 years ago
I attended an AES conference in London where I heard several papers on the subject. Yes, we had overlooked several factors. Our cabinets were big, heavy, and strong (resistant to breakage) but they still resonated at a pretty high Q. Live and learn folks!
My reference speaker is especially designed for low Q resonance, but even it most probably has some measurable, (and perhaps audible) resonances. I shudder at what most of you out there put up with.
Secondly, Richard Marsh is right. Most input here is just small talk, and most here are not very informative in a useful way to improve audio quality. Real engineers like 'tricks and tips' on how to do something better.
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That's why I mentioned damping too. The drawing JBL released doesn't necessarily show everything.
IIRC, SL, when he was still into cabinets, reckoned 4" to be the maximum distance between bracing.
These are my speakers, pretty well "braced" 😉 http://www.ejjordan.co.uk/PDFs/Eikona_2_VTL.pdf
These are my speakers, pretty well "braced" 😉 http://www.ejjordan.co.uk/PDFs/Eikona_2_VTL.pdf
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It starts to become annoying however when these so called “real engineers” never disclose their own findings in detail but keep asking others for their solutions.
Hans
This has something to do with my post you quoted? Ah, of course, in your opinion and readers know that you are biased for your audio business.
These can be used in constrained-layer damping (CLD)
It has been posted several times in the past:
http://downloads.bbc.co.uk/rd/pubs/reports/1977-03.pdf
also this regarding size of enclosure http://www.keith-snook.info/wireles...ld-1980/An acoustically small loudspeaker.pdf
Have you ever paid a visit to loudspeakers threads to see how people build their speakers (and why they do it)?
George
“Secondly, Richard Marsh is right. Most input here is just small talk, and most here are not very informative in a useful way to improve audio quality. Real engineers like 'tricks and tips' on how to do something better.”
There you again JC. Talking down to everyone.
There you again JC. Talking down to everyone.
Richards trick is really neat. I ha e some B&W 703’s a d I’m going to try that tonight ( I have some heavy quilts I’ll use - no shipping blankets to hand).
The 703’s are reasonably well braced but it will be interesting to see what I come up with.
The 703’s are reasonably well braced but it will be interesting to see what I come up with.
He hears everything he wants to in his own listening method. 😉
Like praising for Bybee Quantum Purifiers and cable lifters?
I personally don't use cable lifters, but I am open to anyone who does. Bybee, Bybee, Bybee! That is the call to ultimate tweakdom!
Yes, your very own, private POV; as far as I recall, short of some misunderstandings due to loose control of the discourse, nobody said here that "no audible differences should exist". Do I need to say "FUD" again?
What was said is:
1. If we can hear it, then we can measure it; the thesis of audible but unmeasurable differences is bollocks.
2. We don't give a hoot if there are two persons in Myanmar that can hear X; there are people known to be able to see Mars satellites Deimos and Phobos bare eyed, so what? It's the psychoacoustic researcher duty to prove his results are of relevance and to specify the scope of the population it applies to.
That would be in fact "self admitted robbery" of ideas coming from "disposable engineers".
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In the time domain, sealed is 6dB/octave better. Better. Your point was that with the pipe stuffed, panel vibrations were worse. So thanks to your latest contribution we now know that stuffed is both better in the time domain and as far as panel vibratrions are concerned.
If you have any technical contribution to add, please do. My expose was quite to the point, so if you have further points to make, please do.
Apart from that: Who for Wohan Flue's sake are you to blame me for not listening carefully!!
Edit: 6dB in terms of phase shift, made a large step there.
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No, that was not my point. My point was that it was too blurry sounding not stuffed. Stuffing did not entirely correct the issue. Hence, I would like even more vibration control, that vibration is the only factor under consideration.
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