From: kim@Software.Mitel.COM (Kim Letkeman)
Newsgroups: rec.audio
Subject: Re: Pro-Logic rear speakers
Date: 17 Nov 92 13:30:21 GMT
Organization: MITEL Public Switching, Kanata, Ontario, Canada
In-reply-to: marc@venus.clearpoint.com's message of 16 Nov 92 17:29:54 GMT

In article <1992Nov16.172954.18663@nighthawk.clearpoint.com> marc@venus.clearpoint.com (Marc Gregory Washburn) writes:

| I have recently moved, and my new entertainment room has shrunk
| considerably.  This has forced me to purchase new rear speakers due
| to space consideration.  My previous rears were an old set of
| Technics (junk), and hoping to better my system I invested in
| KEF-120s'.  BTW I listened to Polk, Boston Acoustics HD-7s, and
| Mirage equivalents and none of them sounded right with exception of
| the Polks which were a bit more expensive ($240 vs $200).
| 
| I am really disappointed.  I am driving them with a Denon AVC-1000
| Pro-Logic amp, running 25 watts per channel to the rears.  For some
| reason, the sound really hasn't improved very much.

This is strange. I use an AVC1000 with lowly Radio Shack Minimus 7
speakers in the rear and they sound fine. I thoroughly enjoy moviews
and I use them in Hall mode now and again with good results.

One thing you must do is to make certain that all the speakers in the
system have as close a tonal balance to each other as possible.

| Why is the quality of rear sound from surround movies such as
| 'Waynes World', 'Batman', 'Dances with Wolves' etc. so awefull?  It
| gets better switching to Hall or Live mode, but even there the sound
| is unbalanced.  Running a CD or other music sound source through the
| system, the front speakers seem to get the clear sound and with a
| good balanced spectrum of sound all the way from treble to bass.
| The rears on the other hand seem to drive only certain parts of the
| sound spectrum.  Is this due to the nature of a surround sound amp?

This is normal pro-logic. The surround channel only gets from 100 to
7000 hz, which is much less than the rest of the channels. That's how
the amp is supposed to reproduce it.

I had Camber Laser 3 speakers in the surround channel for a while and
hated them because they had a big mid-bass hump above 100 hz, which
screwed up the tonal balance of the whole system. The Minimus 7's have
a reasonably tight bass line, if a bit thin, but that makes them sound
quite nice in the rear.

In hall mode, you'll find that the system sounds much better when the
rears are only barely noticeable when they are switched off. If they
are noticeable all the time then they are much too loud and will throw
off your overall tonal balance.

| I am happy with how the movies sound, its just as good as any
| theater system, just the quality of sound coming from the rear
| speakers is not as good as i would have expected it to be.

Your expectations for the quality of sound in the surround channel in
pro-logic mode was in error.

| At this point I'm still convinced listening to music sounds only
| right by switching the rear and center channel off (no matter what
| surround mode I'm in).

No. When listening to music, use bypass mode only. Hall mode if you
balance the sound just right. The sound will be mediocre in all other
modes because most CDs are not recording with the correct encoding and
are not engineered for reproduction with 4 to 6 speakers.

| Am i suffering from an un-balanced speaker system?  

Well, you never told us what front and center speakers you are using.
Since the old rears were junk, perhaps your existing front and center
speakers aren't so hot either, in which case the Denon will never
achieve its potential.

| (BTW I have tried switching the rear speakers to the front etc. with
| same results.)

This confuses me. Why would you want to run the little Kef's in front?
Does this mean that they are better than the existing fronts? No
matter what speakers you run in the rear, the pro-logic limits will
cause the sound to be essentially AM radio quality. But that's normal,
and sounds fine with dolby encoded sources.
--
Kim Letkeman	kim@Software.Mitel.COM