From: till@acid-rain.lucid.com (Don Tillman)
Subject: Re: The great speaker debate: 15 vs 18
Reply-To: till@lucid.com
Organization: Lucid, Inc.
	<TILL.93Jan22003258@acid-rain.lucid.com> <571@bit.UUCP>
Date: 25 Jan 93 12:06:12

   From: grego@bit.UUCP (Greg Sanguinetti)
   Date: 25 Jan 93 02:26:35 GMT
   Organization: BIT  Portland, OR

   > 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
   different cabinets there are very distinct differences between the cabinets
   with 10's v.s. 15's or 18's. Even with very similar cabinet designs. Take
   the SWR line for instance. I noticed a world of difference switching between
   the 4x10, 1x15, 1x18 models. The 15 v.s. 18 was not as noticable as the
   change in detail between the 4x10 and the 1x15. The cabinets with the
   multiple, smaller drivers produced a crisper sound with much better attack.
   This was true even with the horn turned off.

If all else is equal, sure we can say interesting things about 18-inch
drivers vs. 15-inch drivers.  But all else is never equal -- it is
physically impossible to grow a driver larger and have any of its
parameters unchanged.  So if you're going to make comparisons you have
to hold some parameters or some set of parameters constant and tell us
which and how.

I have no doubt that you heard distinct differences between these
cabinets, but that doesn't mean we can extrapolate this to a general
rule; there are just too many exceptions.  And if you compare the
various models of one manufacturer's line, well of course the
manufacturer wanted to present a clear trend across the line.  But
that's marketing.

   There is also some intuitive technical factors, like the larger the cone
   the harder it is to keep it under control. The edges flex more, the
   voice coil is stressed more,... 

This effect is more dependant upon cone material, voice coil, magnet,
and other parameters than speaker diameter.  There exist 8-inch drivers
with worse high end than some 15-inch drivers.
				   
				   A lot has been written about this over
   the years. 

Yes indeed.

   On the other hand, any driver or combination of driver can be made to
   sound bad with a bad design. This is all assuming that the drivers and
   cabinets are well designed and manufactured.

Musical instrument speakers are notorious for being badly designed.
Typically the driver will too large for testosterone reasons ("urgh-
urgh") and the cabinet will be too small for portability.  So for many
systems on the market today, if you replace the driver with a smaller
one you might very well get a better low end!

My point is simply that generalizations are inappropriate here -- if you
have a technical explanation, sure; if you're speaking about a very
specific sample space, sure.  But otherwise it's very misleading.  A
speaker system is a *system* and a whole lot of variables are involved.

  -- Don

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