[net.audio] Reply to Andrew Koenig

mohler@druxu.UUCP (MohlerDS) (04/24/85)

Andy,
	It is very hard to refute someone's claims, if you don't understand
what they are saying. The reason Herb and others have spent time explaining
BOSE design flaws is as follows.

	The measurable differences between many CD players are such things
as: very small high frequency response differences, very large phase response
differences, filter ringing (that is further excited by fast (high frequency)
transients), low level high frequency distortion and a few other items.

	If you take a speaker that even with its equalizer is not flat at
high frequencies, has non-linear phase response, has driver energy storage
effects that cause lots of ringing, has an order of magnitude more high
frequency distortion than monitor quality speakers how can you expect to
hear any result of the above measurable differences?

	The BOSE 901 also has the problems that multiple drivers and
mostly reflected sound provides much worse room interaction, severe
cancellations within the room and no possibility of any retention of
image. Several dynamic and electrostatic speakers show far fewer problems
in these areas. These differences are audible to most listeners. One thing
you did correctly point out, is that the room will effect any loudspeaker,
however some speakers try to minimize the interaction not maximize it like
the BOSE. By the way, that is probably part of why Herb mentioned the Stax
pro headphones, they are impecable transducers and you only have ear canal
interaction rather than room interaction.

	Now, go re-read Herb Chong's or George Labelle's or my explanation
of the design flaws and you might begin to understand that while you
were demanding proof, you were getting it and didn't know it. I further
suggest that you brush up on your knowledge of experimental practices.
Also an electrostatic driver has in the range of 6 milligrams of mass
for a 1 foot by 4 foot diaphram and is driven over it's entire area. It
also has very good phase response and if properly designed no significant
ringing, and if crossed over with another driver for the bass has very
low frequency modulation and other distortions.

	Since you are one of those "prove it types" like Dick Grantges
please see my next Article (hopefully 4-24) I plan on giving you enough 
references to satisfy any reasonable curiosity. I also plan on dealing
with Dick's comments!

		David S. Mohler
		AT&T Information Systems Laboratories
		!druxu!mohler

seifert@mako.UUCP (Snoopy) (04/25/85)

In article <1476@druxu.UUCP> mohler@druxu.UUCP (MohlerDS) writes:

>Also an electrostatic driver has in the range of 6 milligrams of mass
>for a 1 foot by 4 foot diaphram and is driven over it's entire area. It
>also has very good phase response and if properly designed no significant
>ringing, and if crossed over with another driver for the bass has very
>low frequency modulation and other distortions.

A driver 1 foot by 4 feet is going to beam like crazy at hi freqs.

This *may* be what you want, but you should be aware of it, as there
is going to be a very small listening area.

        _____
        |___|           the Bavarian Beagle
       _|___|_               Snoopy
       \_____/          tektronix!mako!seifert
        \___/

herbie@watdcsu.UUCP (Herb Chong [DCS]) (04/28/85)

In article <731@mako.UUCP> seifert@mako.UUCP (Snoopy) writes:
>In article <1476@druxu.UUCP> mohler@druxu.UUCP (MohlerDS) writes:
>
>>Also an electrostatic driver has in the range of 6 milligrams of mass
>>for a 1 foot by 4 foot diaphram and is driven over it's entire area. It
>>also has very good phase response and if properly designed no significant
>>ringing, and if crossed over with another driver for the bass has very
>>low frequency modulation and other distortions.
>
>A driver 1 foot by 4 feet is going to beam like crazy at hi freqs.
>
>This *may* be what you want, but you should be aware of it, as there
>is going to be a very small listening area.
>

if you sum the wavefronts from the 8 rear drivers already in a 901, you
get a similar one to a bent 1x4 panel.  it's reflecting off the walls that
gets around this problem.

Herb Chong...

I'm user-friendly -- I don't byte, I nybble....

UUCP:  {decvax|utzoo|ihnp4|allegra|clyde}!watmath!water!watdcsu!herbie
CSNET: herbie%watdcsu@waterloo.csnet
ARPA:  herbie%watdcsu%waterloo.csnet@csnet-relay.arpa
NETNORTH, BITNET, EARN: herbie@watdcs, herbie@watdcsu