[rec.audio.high-end] LS3/5As: Subwoofer Recommendation Wanted

jost@ridley.coyote.trw.com (Patrick Jost) (08/07/90)

I've got a pair of Rogers LS3/5As, and would not have anything else...
however, as you know, they don't do bass all that well. As a bassist,
this is frustrating; what is also frustrating is that I've heard that
getting them to work with a subwoofer is difficult, the beginning of
the difficulty being locating a suitable subwoofer.

Has anyone done this? I'd like to hear about your experiences and
recommendations...


Thanks,



PJ

dhs@cs.utexas.edu (Douglas H. Steves) (08/07/90)

In article <5596@uwm.edu> jost@ridley.coyote.trw.com (Patrick Jost) writes:
>I've got a pair of Rogers LS3/5As, and would not have anything else...
>however, ... getting them to work with a subwoofer is difficult ...

Yes, it is. The main problem is that the LS3/5A spec includes a rise in
the mid-bass frequency response to simulate deep bass, since they were
originally designed to be control room monitors for the BBC. When a      
subwoofer is included, the result is usually muddy.  
A company named Satterburg produced a subwoofer especially designed
for the LS3/5A a few years back - among other things, it was a stereo
pair which crossed over reasonably high - I think about 225Hz.
If I were designing a subwoofer for the LS3/5A's, I would:
	- use fast drivers (consider using 2 8" vs. 1 12")
	- use sharp (Linkwitz?) crossovers
	- cross over at a higher than normal frequency
	- use stereo subwoofers 

Of course, this may be rather expensive. You may want to consider
another mini-monitor instead. The LS3/5A is no longer the state of
the art, however fondly some of us may remember it.

Doug

paul@uunet.UU.NET (Paul Homchick) (08/07/90)

In article <5596@uwm.edu> jost@ridley.coyote.trw.com (Patrick Jost) writes:
>
>I've got a pair of Rogers LS3/5As, and would not have anything else...
>... a suitable subwoofer. ....  experiences and recommendations.

I've had a pair of biamped LS3/5As for about 8 years now.  My
(sub)woofers are a pair of KEF B200 drivers in a pair of home-built
transmission-line enclosures.  The LS3/5As sit on top of the woofer
cabinets.  (The LS3/5A "woofer" is a KEF B110, I think).

The active crossover uses op-amps to cross over at 110Hz using a
second-order butterworth filter (12db/oct).  I seem to remember
hearing that the 5As had a peak at 60Hz, and I picked the 110Hz to
avoid that peak.  A Conrad-Johnson amp drives the LS3/5As, and an
Adcom drives the KEFs.

The enclosures are built from particle board and are 15.5w x 12.75d x
38h (inches).  The transmission-line is folded (3 legs), triangular,
and stuffed with dacron fiber.

This set-up has kept me happy 'lo these many years, although I am now
itching to improve things.  One reason for my current dissatisfaction
is that I have  recently noticed that the two LS3/5As sound
different, perhaps they have aged differently, or I zapped one of them
once.

One thought for improving things is to get a better crossover with a
better power supply, active devices and passive components.  Perhaps,
I'd even try a first order filter, but that would mean moving up the
crossover to about 300Hz and this is going to give a lot of lower
midrange to the B200s.

If anyone has any suggestions for a good crossover design, or a good
commercial crossover, I'd certainly like to hear about it.

In the meantime, I was just this evening trying the Stereophile CD
warbletone tracks.  Output from the KEFs is strong down to 31.5Hz, and
although it falls off at 25 and 20Hz, it still has output.  When I put
on something which is sinfully bassy (like the recording of the
Partch Delusion of the Fury) I am amazed what 2 8" drivers can do.
-- 
Paul Homchick                    :UUCP     {rutgers | uunet} !cbmvax!cgh!paul
Chimitt Gilman Homchick, Inc.    :Internet                   cgh!paul@dsi.com
259 Radnor-Chester Rd, Suite 140 :MCI                               PHOMCHICK
Radnor, PA  19087-5299           :GEnie                              HOMCHICK

sxm@bebop.Philips.Com (Sandeep Mehta) (08/08/90)

In article <5605@uwm.edu> dhs@cs.utexas.edu (Douglas H. Steves) writes:

   In article <5596@uwm.edu> jost@ridley.coyote.trw.com (Patrick Jost) writes:
   >I've got a pair of Rogers LS3/5As, and would not have anything else...
   >however, ... getting them to work with a subwoofer is difficult ...

   [...]

   Of course, this may be rather expensive. You may want to consider
   another mini-monitor instead. The LS3/5A is no longer the state of
   the art, however fondly some of us may remember it.

This may not warrant a high-end posting, but being a Rogers fan I would
recommend an upgrade to something like the Rogers 7a (alpha). I listen
to acoustic jazz and classical and haven't really found the bass
lacking. This after auditioning many many speakers more expensive than
the Rogers. The 7-alpha may be discontinued but I believe there is a
sibling in the same price range.

/sandeep
--
sxm@philabs.Philips.Com                  	"Jazz is Happiness" - Le Sony'Ra