[Brian Cheney]

What part of I'm Done Here don't you understand?

[JoshK]

This is why I gave up trying to discuss this a few posts back.  I generally have to say that I agree with most of what Danny said, some of which I was going to say myself but started thinking it was pointless.  

Brian believes what he believes and he isn't going to convince any of us nor are we going to convince him.

[Dan Banquer]

I would like to take a moment to remind both Brian and Danny that many months ago I asked the both of you to submit data showing that there is a measureable difference due to speaker break in. I have not heard from either Brian or Danny.
Gentlemen: if you've got the data it will be published. If you don't then some of us will seriously doubt your claims.
              d.b.

[Brian Cheney]

"Brian believes what he believes".

Dan, that sums it up nicely!!

I do 50 hrs of breakin on each new pair of speakers because I like fish
(the halibut).

[Dan Banquer]

Then go fish.
             d.b.

[Danny Richie]

I have actually kept that in mind for you Dan.

I recently took a new woofer (about three months ago actually) and measured the T/S parameters. Then I took it and stretched the suspension each way and took them again. There was little change. I then ran it hard for about a minute and noticed a slight change again, mostly due to heat, but some due to initial loosing. I have then planed to test that same woofer again after it has been in use for a while, but I have yet to put it into a design and use it yet. Sorry for the delay.

I might have to just start over with another woofer. I am about to put together a new sub for personal use so it will be around for a while. I'll do some before and after on it and post the results.

I had one of those subs come back that had the dust cap blown off from heavy use. There was some mass on this dust cap and it worked the material that it was made from pretty hard and when over driven it shot it off. Anyway, I warranted the woofer and sent out a new one to the guy.

The suspension on it had loosened up a bunch. It was much softer then a fresh one out of the box. If I could have gotten the dust cap back on it I would have taken its T/S parameters right then to see just how much it had changed.

Hang in there and I'll get to it.

[Brian Cheney]

Dan:

I see you swallowed that one hook, line, and sinker.

[Dan Banquer]

I'm really impressed guys: I get one fish story and one warranty story. Trust me when I tell you I got plenty of both.
Any of you guys do an fishing for gefilte fish? It's tastier than halibut.
                  d.b.

[Brian Cheney]

The gefilte, a rare and wily native of Western Jackalope country, is  hard to catch but once landed, thankfully requires neither cooking nor cleaning.

BTW it prefers to spell its last name "Fisch" and is quite sensitive about thoughtless engineers who mangle the word.

[Dr. Krull]

The trimming procedure actually compensates for all the driver, wiring, and parts differences, which is why no one value is correct even for matched parts and drivers...

The trimming has to be done with each pair of speakers after 50 hrs breakin.  It's a lot of work, but rewarding.

Interesting.

So what happens when one of your speakers arrives on a doorstep with a defective midrange driver?  Your past actions seem to indicate that you simply ship the customer a replacement driver.  While that's great customer service, it seems to defeat what you're advocating.

Are each of your drivers serial numbered and stored in a customer database?

-Krull

[TheChairGuy]

As this particular post and topic is populated by mostly DIY, speaker professionals and/or engineers...and is certainly of a technical nature...it has been moved to The Lab.

Up to you what you want to do with it, Occam  

Many thanks,

John / TCG (Moderator/Audio Central)

[diy_freak]

What part of I'm Done Here don't you understand?

But you keep coming back for more, so in case you change your mind, here are some issues that remain unaddressed by you and that directly contradict your claims:
- after you tweak the filter, you replace the trimcaps with preferably one value. Practically, this is impossible, because the replacing cap will have a tolerance of its own, so you would need to trim that cap as well... ad infinitum
- so far, nobody has referenced any value below 0.2dB as being an audible difference in loudness. The references I found on the web indicate a larger minimal difference, especially when it comes to listening to music as opposed to test signals and lab conditions. What is even more remarkable, is that you insist that the effect of the bypass caps has nothing to do with 'a bypass cap' being present, but that it solely relies on the 'exact value'. Deducted from the sim values I posted of a parallel filter, the difference in spl due to a 0.01uF on a 100uF change would have to be well below 0.01dB, in fact closer to 0.001dB... one thousands of a dB.
- The series filters that you use are even more robust to changes in component values than the parallel filter I presented
- Defective units are replaced but apparently without going through the trimming sessions
- There are many sources of tolerances in the loudspeaker design that swamp the tiny differences of tweaking the filter with a single 0.01uF trimcap:
   ..Just touching the base cap (warming it up) will change it's value more than one trim cap
   ..Moving a speaker a fraction of an inch will change the spl more
   ..Turning/shifting your head a degree/cm will change the spl more
   ..A change in ambient temperature will influence the spl more (do you tweak the filter at the customer's average temperature?)
   ..One sneeze or cough, and the pressure change in your inner ear will change the perceived spl curve more

In fact, I think a mosquito's fart will change the spl more. All you have stated is that you can hear it anyway.

Based on all the facts presented, let's call it what is really is... The tweaking you suggest is pure marketing. It suggests tolerances in the spl of a loudspeaker that are impossible to obtain or maintain (think about component drift). It's claims like these that degrade the image that consumers have of the audio industry. Nobody can force you into how to communicate with the market, but this is something you should strongly reconsider!

[Occam]

Hey ChairGuy,

Thanks a bunch!!! Crossover optimization and nekk'd mud rassl'n. Who could ask for anything more?

A mosquito's fart.... thats a good one.
If this continues as a pissing contest, I'm just going to lock the thread.

FWIW,
Paul
aka Occam, who does not believe in democracy (in the Lab), an NO ONE other than myself gets a vote hereabouts

[gitarretyp]

Arguing with Mr. Cheney over this is rather pointless. Even if he does agree with what's being said here (and i am NOT claiming he does), he can't admit it because it would cause great damage to his business. (What follows is complete speculation and should be taken as such) It's entirely possible he thought he heard a difference many years ago that turned out to be due to the bypass caps and honestly sold the trimmed caps as an upgrade. If this was the case, then by admitting he, in some sense, sold upgrades that were a waste of money, he could face lawsuits were he not to offer recompense to all previous buyers --not to mention making him and his business look pretty bad. Discontinuing the service would be a public admission of a mistake, so he must continue to offer it and defend it as a credible upgrade. So, this may not be a marketing ploy but a simple mistake that's spiralled out of control --or, he may actually hear a difference (though i have my doubts it's due to the small values added).

[OTL]

Measurements, shmeshurments........

Apply all the science, algebra, quantum theory and common sense you'd like to this discussion....but please, answer US this....keeping in mind that Brian's ear just may possibly posess skills that yours, or mine or others do not.  (Think Nat King Cole and Junior Kimbrough for a diverse example.  Yikes, these guys are certainly worlds apart, but there's not a doubt both these MF's were absolutely correct and magnificient in their own spaces.)

As a simple, but definitive example....when our existing science (within obvious and admitted limits) can measure it's frequency response, it's materials density, it's absolute dimensions as well as it's harmoic register, and then when any and all possible "replicas" are played by the best musicians on the planet, how could it be possible that the best of what our present science, industry and artisans have to offer continues time and time again to fail in reproducing the unique and beautiful sound of a  Stradivarius?  

Obviously, an artisan in the past had the tools, materials and an unmeasurable "something" that still eludes todays precise, quantitative measurements and our present ability to measure and replicate "that sound" is as of the present, not recognized.   The Stradivarius tone is unattainable by anything presently manufactured or understood by either industry or artisans.  Using your quantitative measures, the level of empathy, emotion and involvement acheived by a Strad cannot be attained becuause is cannot be measured, implying that it cannot be understood.  When a piece of music, no matter how imperfectly reproduced moves me emotionally and brings tears to my eyes, how much better do I need to quantitatively understand it?  I feel it, without any need to "measure" it.  My "math" works for me.

If Brian's stuff (or anyone else's for that matter) can reach this level of involvement, any quantitative measurements or accuracy concerns are likely meaningless.  

Although I do applaude your pursuit, I honestly do wonder what exactly it is you're measuring?


Listen, share and enjoy!

Mike B.

[Ethan Winer]

Mike,

> The Stradivarius tone is unattainable by anything presently manufactured or understood by either industry or artisans. <

On what do you base that? In fact, a lot of research has been done into what makes some Strads sound so wonderful. Note I said "some" Strads because they were/are not all uniformly great. Like any other artisan, some of his fiddles came out better than others.

The October 1981 issue of Scientific American published a ground-breaking article by luthier Carleen Hutchins where she described her experiments disassembling Strad violins and analyzing them electronically. Imagine being allowed to borrow a bunch of million dollar Strad violins and take them all apart!

My cello was regraduated (wood was planed to change its resonant frequencies) by one of Carleen's students under her guidance, using the techniques she developed based on this research. My cello is not as good as a Strad for a variety of reasons, but it's a lot better than it was before regraduating.

I can tell you the "secret" of Strad (and other famous name) violons and cellos right now because it's quite well understood: Just like listening rooms that have modes, where some combinations are better than others, string instruments are basically the same. The goal for both is to have many different vibrational modes spaced relatively uniformly.

Another contributor to the quality of a violin's or cello's sound is the Q of the resonances. Unlike a room where a low Q is better, with string instruments a high Q is desired because the goal is to create "character" of sound. In a room you want to reduce resonances because a neutral sound is the goal, not added character. But the basic principle of room modes and violin modes are identical.

A cheap plywood cello has few resonances because the grains go in different directions and the vibrations tend to cancel each other out. So the sound dies immediately when you stop bowing. A good instrument will continue to "sing" for some time after you stop bowing, and this is often used to great affect by skilled players.

So a good string instrument has many high-Q resonances at favorable frequencies. A cheap viola sounds more like a violin because its top and bottom plates vibrate at too high a frequency. A good viola has resonances much lower which imparts a warmer sound. When I hear a really good cello it reminds me of an electric guitar's wah-wah pedal set to various static positions. So a scale sort of sounds like "ooh eeh ahh" as each note excites the different high-Q resonances.

I'll be glad to continue in more detail about this stuff if you'd like. But the main point is a lot of new and old string instruments have been thoroughly analyzed, and there's no mystery about why they sound as they do.

Likewise, audio gear has been thoroughly analyzed, and there are no mysteries there either.

--Ethan

[diy_freak]

Ethan has already provided far more information on the Strads than I could. My line of music is... organs. My first lesson was about 25 years ago, when I cold hardly reach the pedals . So I know a story or two about attempts to rebuild/replace disfunctional pipes in the organ that failed eventhough the metal used in the originals was 'analyzed'. This is all very second & thirdhand info, so I can't really conclude anything from it, other than that they are quite frequently heard amongst musicians. I do wonder however, how the time factor fits into these kinds of stories. What would be the influence of several hundreds of years of corrosion and wear and tear by usage? How could you possible replicate that in detail (assuming that would matter)? What did the instrument sound like when it was brand new?

Apart from that, I'd like to emphasize that a loudspeaker is in no way a musical instrument, but a solid piece of engineering, even if the required skills go further than memorizing all the physics involved. The trimming suggested by Brian was presented by him as engineering, since it specifically entailed arriving at the 'precise value' after which a replacing cap of the same value would be fitted instead of the trimcaps. Pure physics, right?

If Brian's stuff (or anyone else's for that matter) can reach this level of involvement, any quantitative measurements or accuracy concerns are likely meaningless.

Since it's engineering, I would dismiss any comparison of it with an artisan skill of mystical or mythical proportion.

[diy_freak]

I'm serious, as I sit here, admiring my two Best of CES awards for High End audio (2002,2003). It's all delusion.

Fact: the CES awards 2003 was won by "The Trinaural Processor", not VMPS.

Hmmm... don't know how to say it...

[OTL]

Mike,

> I can tell you the "secret" of Strad (and other famous name) violons and cellos right now because it's quite well understood:  

While science has measured the end result of Stradivari's (and others) work, concluding that different materials, the treatment of these materials and the tuning of the instrument, etc. all combine to produce the overall, magical tone, todays scientists and artisans cannot yet reproduce it.  Though they continue to try. http://www.post-gazette.com/pg/06043/653755.stm

"His craftsmanship is still unexcelled. Few after the death of Stradivarius have managed to produce anything that even approaches his best work," says Mats Tinnsten, who, together with Associate Professor Peter Carlsson, is researching whether it is possible to copy Stradivarius violins with the aid of modern technology and powerful computers."

That's the simple reason Strad's sell for $1 - $4 million dollars.  And with prices like these, there is NO DOUBT if anyone truly understood how to reproduce them they'd be extremely well known and exceedingly rich.

I guess we'll just have to agree to disagree on how well this issue is truly understood.

Mike B.

[diy_freak]

That's the simple reason Strad's sell for $1 - $4 million dollars. And with prices like these, there is NO DOUBT if anyone truly understood how to reproduce them they'd be extremely well known and exceedingly rich.

This is assuming that people approach a Stradivarius in a rational manner. I don't think that is that case. It's a musical instrument as opposed to a loudspeaker. An instrument is expected to have a certain sound. A loudspeaker is supposed to have no sound of its own, while 'simply' reproducing the source signal. A loudspeaker can be 'understood'. An instrument made a few hundred years ago is likely to be a different matter.