From: bill@verdix.com (William Spencer)
Subject: Re: Comments on Sci-Fi's "Tesla"?
Keywords: Tesla Stereophile
Organization: Verdix Corp.
Date: Mon, 6 Apr 1992 23:28:06 GMT

In article <1992Apr2.191046.14890@dg-rtp.dg.com> rossmanj@rafael.rtp.dg.com (John Rossmann) writes:

>In his manufacturer's comments, Mike Maloney (Tesla designer) said that the
>problems in the highs were caused by the ferro-fluid leaking out of the
>tweeter due to the speakers having been shipped by air freight. He said the
>problems with the lows were caused by his vendor changing the material used
>to damp the port.

More than one problem *is* suspicious.

>My impression (of the review and response) is that there was a definite lack
>of communication between Maloney and the Stereophile people

There was nonprofessional behavior on both parts. I got a feeling
things were going to turn bad when a pair of prototypes were delivered
to find speaker positions. These were not intended for review. Corey seemed
to turn against them and not try to get the most out of them yet did
not conclude that something was not as it should be.

The complaint of excess brightness also makes the review of DIY designs suspect
because the same complaints were made, although it does seem likely the
Teslas really did sound bad.

JA also dropped the ball with the measurements I think. Did he listen to them?
I have seen many worse curves published. Also the foam plug should have been
removed from the port for measurements, and the impedance curves proved it.

I don't think the review should have been published because it's all
inconclusive and you had to read all the way through the manufacturer's
comments to see that. I'm sure the Stereophile people see this as a way of
looking credible (publishing the whole story) but it was at the expense of the
reader. Take another month and make up your mind...

>On Stereophile in general: Sometimes I agree with them, sometimes I don't.
>But they are working very hard to hold the intelligent middle ground in the
>objectivist/subjectivist controversy, and it seems to me that their approach
>is the only viable one in that dogmatic and frequently ridiculous debate.

I don't know about "working hard" but I think they do take the middle ground --
to the degree there is one!

I normally think their reviews of speaker catch the major things, but now that
I think about it I'm not sure. For example, the Monitor 10 (?) review. They
caught the major frequency response variations toward the high end, but it was
really just because they ran the measurements routinely. They didn't expect it,
although that was part of the point, the speakers sounded good. (They had a big
hole in the 3-5K area, no surprise at all considering the use of a first-order
crossover near the woofer's band edge.)

Another example: I completely agree with Atkinson regarding 
the debate with Avalon over the 
Eclipse's 1 kHz distortion (a 1K tone above 100 dB caused measurable 
distortion and a hard sound on music). However he made no mention of the 
*reason* I agree with him: I calculated the excursion of the tweeter at that
frequency and level (crossover is at 700 Hz) and found it equal 
to the driver's linear excursion. 

Bill Spencer
From: kirk@hpcc01.corp.hp.com (Kirk Lindstrom)
Date: Sun, 12 Apr 1992 06:21:44 GMT
Subject: Re: Air?  Wossat? (was Re: Terms)
Organization: Shredding the water of SF Bay, HP-OCD