From: bill@verdix.com (William Spencer)
Subject: Re: The great speaker debate: 15 vs 18
Organization: Verdix Corp
Date: Tue, 26 Jan 1993 01:10:52 GMT

grego@bit.UUCP (Greg Sanguinetti) writes:
>In article <TILL.93Jan22003258@acid-rain.lucid.com> till@lucid.com writes:
>>Of all the things that contribute to the sound, the diameter of the driver
>>is probably of absolute least importance.  Far more important are various
>>driver parameters, the cabinet type, cabinet size and tuning, how the
>>cabinet matches with the speaker, and the high frequency properties of the
>>speaker.                                  ^^^^^^^^^^^^^^^^^^^^^^^^^

>Except in reality, at least available reality. When I go and try out
>[...]
> The cabinets with the
>multiple, smaller drivers produced a crisper sound with much better attack.
>This was true even with the horn turned off.

Don covered that with his last sentence, but yes, driver size does tend to
affect highs and upper mids, along with other aspects of the design. It's 
more important to note that the bass end is not as dependent on driver size as
it might seem. But here there really is a matter of "availiable reality".
Intuitively, it will take more 8" drivers for a certain bass output power than
it will take 15s. Unless the maker of the 8s expects the drivers to be used
in multiples, the design will likely be better suited for smaller installations
and the limited bass extension expected. Likewise, larger drivers tend to be
designed for deeper bass.

Drivers designed for high power instrument and PA use also restrict bass
extension. With this type of speaker, the larger drivers in a maker's
line tend to go deeper. A PA 18" will go deeper than the same maker's 15" --
but a 12" or 15" made for hi-fi use, with less power handling, will go deeper
than either.

The E-V instrument line of speakers have good highs. The relatively good
HF and high power handling of the EV 15B and 15L have made them popular. 
But the lows don't go very deep or very loud without distortion. 

>I used to think that I would biamp with a 15 or 18 on bottom but I have
>since changed my mind. I would (if I could!) use a 4x10 for the bottom
>and a 2x10 or 4x10 on the top.

>like for bass, the arrays of smaller drivers provides the tighter sound, if
>that's what you want.

There are possible some minor differences in distortion and such between
various setups with different size drivers, but mostly the differences are
simple matters of frequency response. Subjectively, things can be hard to 
evaluate, and terms such as "tight" and "crisp" probably don't help much.
Since the highs don't matter much in a woofer [*], using 4-10s as the bottom 
in a bi-amp setup is only going to be "tighter" if there's less bass or
less boom. It's quite possible that even better results could be achieved
by a better designed cabinet, whatever the driver size -- or just realizing 
what the problem is and tweaking the EQ.

The bottom line is, of course, to go with what sounds right. But the 
search is not aided by making assumptions that 10" speakers are better 
or whatever, even if it happens to be true in a particular case. Instead, 
try to listen to analyze: too much bass? boomy in the upper bass? boomy AND
no deep bass? no midrange?
doesn't go deep so needed bass boost turns sound to mud? ETC.

Bill s

[*]Note about this point: common electronic crossovers aren't made to deal with
nonideal drivers, so in a real situation, this might actually not be true.
Newsgroups: rec.music.makers.bass