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In Reply to: Re: Well I did... posted by theaudiohobby on January 12, 2006 at 09:04:58:
"you listened to a speaker you did not like what you heard"In one sense you are right, I have heard several models of Nautilus speaker using this midrange and crossover concept and I do not like what I hear. I have heard several differnt models with many different kinds of amps with the same negative results. The one constant is kevlar midrange and that all Nautilus speakers use the same crossover concept and disparate materials for each driver. As I said, I am a scientist and I know a pattern when I hear one.
Having heard the same problem more or less in all the Nautilus speakers I investigated the design further to see if I could see a reasonable cause. I have presented those reasons. Those reasons are backed by my scientific understanding of materials and practical speaker building experience.
As to the cone noise, this is a well known phenomenom (was once upon a time called "cone cry") is the main reason that the generally considered best driver is the "perfect piston" that is infinitely rigid and infinitely light. It is the reason why many companies now use lightweight metal drivers because at least below breakup they have good behavior (of course if the breakup is excited...well they sound metallic). It is why materials such as Aerogel, ceramic, and various sandwich constructions have been developed as cone material. By B&Ws own admission, they made this cone flexible so in essence it flaps. This flapping can be seen by the way the dispersion of sound changes with frequency with this cone. This is not conjecture.
Remember I told you to try the sheet of paper experiment. You can also try it with a sheet of aluminum foil and a sheet of plastic. You will notice that they all three have quite distinct sounds. Which makes the loudest sound? Probably the aluminum foil but the paper is quite loud as well. What do these two have in common? A high degree of structural rigidity as does Kevlar. The normal polymers have much less as they are generally mostly amorphous. Kevlar is also a polymer but with a high crystalline content (this is chemistry and physics not conjecture). This high rigidity means that when it does give it will give with substantial noise.
The problem is not that 1+1=3 as you have said it is that you are incapable of putting various piece of evidence together to generate a whole picture. You would make a poor investigative researcher.
As a speaker builder, my latest design I played with high order vs low order crossovers (using a digital xover and equalizer). I found from MY OWN experiments that a high order filter makes the character of disparate materials more obvious when an instrument is handed off from one driver to the other. It is exactly what I hear with the B&W and it uses very steep filters. Have you ever taken it upon yourself to do ANY experiments in audio to better understand what you are hearing? Don't blather at me about conjecture when I have real experimental experience with a subject. If you have some data to the counter, produce it or stop blowing smoke.
Notice you have nothing more to say about amplifiers?? Still think the Brystons were inadequate and that what this gentleman heard was his amps clipping?
Follow Ups:
Notice you have nothing more to say about amplifiers?See the link to my response about amplifiers. As for the rest of your response, There are numerous holes in your response, but I do not have to time wade through copious reams of conjecture and pontification, so would not bother. On the Kevlar issue you are barking down the wrong tree, the new 800 series clearly attests to that, there were some issues with old design, but they did not arise as result of the use of Kevlar.
Music making the painting, recording it the photograph
From Wikipedia.com:para-aramid fibers such as Kevlar and Twaron, which have a slightly different molecular structure, also provide outstanding strength-to-weight properties, and have high tenacity, and high Young's modulus.
Young's Modulus: http://en.wikipedia.org/wiki/Young's_modulus
As you can see most plastics have a low Young's modulus.
Here is a website talking about why Kevlar is so strong. It is exactly what I told you about crystallinity.
http://www.lbl.gov/MicroWorlds/Kevlar/KevlarPutting.html
All stiff crystalline materials have a high Q and of course the stiffer the higher the resonance will be in frequency (for things of the same size and thickness) and likely the more severe the problems.
Now since B&W admits it is operating their midrange in breakup mode and its a stiff fiber then how can you argue that its not a problem? Apparently B&W tries to damp it a bit but it is still there nonetheless.
"the new 800 series clearly attests "Is that so?? There are some comments in this thread by those who have heard the D series who have heard otherwise. I will have to hear them but what I expect is better driver integration (because of the shallow tweeter xover slope) but still the same overly dry mids that irritate rather quickly.
"There are numerous holes in your response, but I do not have to time wade through copious reams of conjecture and pontification, so would not bother"
There are not copious reams of arguments. In fact the argument is very simple. The Kevlar driver flaps and the self noise from the Kevlar flexing makes objectionable sounds. That is all there is to it.
Once again, you claim there are holes and prove nothing. You claim conjecture because you don't understand the argument. Typical non-sense you cover your own lack of understanding by "I don't bother". Yet look how much you have posted saying the same thing. So obviously you have bothered but what is disturbing is that you have ZERO to add to the discussion beyond "its not the Kevlar". Show me you are right, I respond just fine to evidence.
"See the link to my response about amplifiers"
I read it and already debunked it with Stereophile's measurements of this amp showing that into 2 ohms it delivers nearly 700 watts and into 4 ohms almost 1000 watts. Not only that but neverenoughmusic has 2 of these monsters on EACH channel. This means one of the amps is free to drive only the mids and tweeter (overkill power if ever I have seen it) and one for the bass, which is the most difficult part to drive, not the mids as you claim...bass energy and a large current hungry motor require MUCH more current than the midrange...sorry you are wrong again. You really don't understand loudspeakers very well, do you? If this is not enough clean power to drive this speaker properly then what is?? The Hoover Dam? Really you are ridiculous.
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