Having recently installed a new plasma TV, I am thinking seriously of
moving towards a surround sound setup. My cuurent speakers consist of 2
Rogers LS3/5A's plus an Audiopro subwoofer. I would use these both for
video and audio.

In terms of adding a pair of rear speakers and a center channel, I was
thinking of sticking with the LS3/5A's and picking up three more off of
Ebay.

Any reaction to this approach? Or might I be better off flipping the
Rogers to the rear and doing something different for the front?

The general recommendation is to use all identical speakers for SACD
multichannels though I wonder why you need full range for the rear or
center. Anyhow, depending on your budget. Top priority is front
channel followed by the Center. Get a good subwoofer with volume and
crossover at cut off point of 120hz.

I have just gone in into Multi/surround. and I don't use identical
speakers. I am using my old front speakers for rear and my best for
front(full range) and dedicted center speaker.

IMHO, unless you own a system costing tens of thousand, it doesn't
really matter whether you are using identical speaker or not. Of
course, adjustmnet for various impedence and efficiency of speakers
can be tricky and maybe that's the reason all identical speakers are
recommended.

(Lawrence Haber) wrote in message . net...
Having recently installed a new plasma TV, I am thinking seriously of
moving towards a surround sound setup. My cuurent speakers consist of 2
Rogers LS3/5A's plus an Audiopro subwoofer. I would use these both for
video and audio.

In terms of adding a pair of rear speakers and a center channel, I was
thinking of sticking with the LS3/5A's and picking up three more off of
Ebay.

Any reaction to this approach? Or might I be better off flipping the
Rogers to the rear and doing something different for the front?

Kalman Rubinson wrote in message ...
On 9 Jul 2003 14:31:02 GMT, (TChelvam) wrote:

The general recommendation is to use all identical speakers for SACD
multichannels though I wonder why you need full range for the rear or
center.

That depends on whether you have any bass management control for SACD.
If not, there are many discs which have significant bass in center and
rear channels. (The Linn SACD of the Poulenc Organ Concerto has the
organ in the rear channels.)

Yes, I agree with you. unlike Dolby prologic surround the SACD rear
output carries more than ambience retrieval. Track 4 of Dark Side of
the Moon will vouch for that.

Anyhow, depending on your budget. Top priority is front
channel followed by the Center. Get a good subwoofer with volume and
crossover at cut off point of 120hz.

Too high. You want the cutoff between main and sub to be 80Hz or
less. The lower the better.

I think 120Hz should be reasonable. Sony SACD players' cut off point
is 120hz and redirect all signals below that to the sub in the event
your other speakers are too small to output low frequencies. Me,
despite having a full range front speakers (38hz) still using sub with
the crossover cut off point set to 55 to 65hz. The volume is at 10. I
think for a true high wnd system the lower the sub cut off the better
it is but on budget level I would bet for the higher would probably be
better. At least the other speakers and amp can concentrate on the mid
and high.

I have just gone in into Multi/surround. and I don't use identical
speakers. I am using my old front speakers for rear and my best for
front(full range) and dedicted center speaker.

That can work just fine.

And a sub...

On Thu, 10 Jul 2003 01:07:47 GMT, (TChelvam)
wrote:

Yes, I agree with you. unlike Dolby prologic surround the SACD rear
output carries more than ambience retrieval. Track 4 of Dark Side of
the Moon will vouch for that.

And DSOTM has full range info on the center channel, as well.

Anyhow, depending on your budget. Top priority is front
channel followed by the Center. Get a good subwoofer with volume and
crossover at cut off point of 120hz.

Too high. You want the cutoff between main and sub to be 80Hz or
less. The lower the better.

I think 120Hz should be reasonable.

Too high unless the inadequacy of your main speakers requires.
There's yet too much direction info at that frequency and even 100 is
high.

Sony SACD players' cut off point
is 120hz and redirect all signals below that to the sub in the event
your other speakers are too small to output low frequencies.

Doesn't make it right.

Me,
despite having a full range front speakers (38hz) still using sub with
the crossover cut off point set to 55 to 65hz.

I have been setting the crossover at 50Hz with the Meridian Ref DVD-A
as the source but use the mains/center/surrounds as fullrange with the
SACD players. Both work well.

The volume is at 10.

????

I think for a true high wnd system the lower the sub cut off the better
it is but on budget level I would bet for the higher would probably be
better. At least the other speakers and amp can concentrate on the mid
and high.

It should be as low as possible but that is determined by the
capabilities of the speakers.

I have just gone in into Multi/surround. and I don't use identical
speakers. I am using my old front speakers for rear and my best for
front(full range) and dedicted center speaker.

That can work just fine.

And a sub...

OK.

Kal

(TChelvam) wrote:

Kalman Rubinson wrote in message
...
On 9 Jul 2003 14:31:02 GMT, (TChelvam) wrote:

The general recommendation is to use all identical speakers for SACD
multichannels though I wonder why you need full range for the rear or
center.

That depends on whether you have any bass management control for SACD.
If not, there are many discs which have significant bass in center and
rear channels. (The Linn SACD of the Poulenc Organ Concerto has the
organ in the rear channels.)

Yes, I agree with you. unlike Dolby prologic surround the SACD rear
output carries more than ambience retrieval. Track 4 of Dark Side of
the Moon will vouch for that.

Anyhow, depending on your budget. Top priority is front
channel followed by the Center. Get a good subwoofer with volume and
crossover at cut off point of 120hz.

Too high. You want the cutoff between main and sub to be 80Hz or
less. The lower the better.

While 120 Hz may be too high for some systems there are no general rules here.
It depends on the subwoofer, its placement, the room and the listening
position.

For example my personal subwoofer system will produce 120 dB from 12 to62 Hz
with less than 10% distortion. Yet I use a 120 Hz electronic crossover. Why?
Well the main subwoofer is rolling off naturally around 70 Hz, which fits
prefectly with the mains at nominal levels.

But I have this dynamic compression problem at 80-120Hz because my mains (twin
active 6.5's); center (single Active 6.5) and 4 surrounds (Active 6.5 pairs in
each) cannot keep up dynamically with the subwoofer. My solution is a pair of
powered 10-inch 'subwoofers' running between 45 and 100 Hz and the 120Hz XO for
the sub.

There is no locational penalty; no resolution penalty and no response penalty
using a 120Hz XO frequency. It just works.

I think 120Hz should be reasonable. Sony SACD players' cut off point
is 120hz and redirect all signals below that to the sub in the event
your other speakers are too small to output low frequencies. Me,
despite having a full range front speakers (38hz) still using sub with
the crossover cut off point set to 55 to 65hz. The volume is at 10. I
think for a true high wnd system the lower the sub cut off the better
it is but on budget level I would bet for the higher would probably be
better.

A typical problem with small systems is that the 'subwoofer' often doesn't have
enough higher freqeuncy capability to mach satellites that are dynamically
challenged below 150 or 200 Hz.

At least the other speakers and amp can concentrate on the mid
and high.

I have just gone in into Multi/surround. and I don't use identical
speakers. I am using my old front speakers for rear and my best for
front(full range) and dedicted center speaker.

That can work just fine.

And a sub...

That's a fine way to step into multichannel. It also doesn't hurt that the
original 2-channel set-up was often optimized for position and balance as well.

"Kalman Rubinson" wrote in message
...
On Thu, 10 Jul 2003 01:07:47 GMT, (TChelvam)
wrote:

I think for a true high wnd system the lower the sub cut off the better
it is but on budget level I would bet for the higher would probably be
better. At least the other speakers and amp can concentrate on the mid
and high.

It should be as low as possible but that is determined by the
capabilities of the speakers.


I agree with you Kal. The sub crossover should be as low as possible.

Logically it would seem to me, to avoid phasing problems the crossover
should be set at the lower LF limit of the main speakers.

Nousaine's 120Hz crossover seems to be on the high side.

TChelvam wrote:
The general recommendation is to use all identical speakers for SACD
multichannels though I wonder why you need full range for the rear or
center.

Because some artists/mixing engineers like to put full-range material in
those channels too.

Anyhow, depending on your budget. Top priority is front
channel followed by the Center. Get a good subwoofer with volume and
crossover at cut off point of 120hz.

Better yet, a variable crossover. Variable phase adjustment
is nice to have too.

--
-S.

TChelvam wrote:
Kalman Rubinson wrote in message ...
On 9 Jul 2003 14:31:02 GMT, (TChelvam) wrote:

The general recommendation is to use all identical speakers for SACD
multichannels though I wonder why you need full range for the rear or
center.

That depends on whether you have any bass management control for SACD.
If not, there are many discs which have significant bass in center and
rear channels. (The Linn SACD of the Poulenc Organ Concerto has the
organ in the rear channels.)

Yes, I agree with you. unlike Dolby prologic surround the SACD rear
output carries more than ambience retrieval. Track 4 of Dark Side of
the Moon will vouch for that.

Dolby Pro Logic II carries more than ambience material. It synthesizes
a stereo surround, and depending ont he source, these can definitely be
more than just 'ambience'. (I've just been reading on a Quad forum
today about how QS or RM encoded quadrophonic recordings decode pretty
well with DPL II, if the DPL Ii parameters are set right.)

Anyhow, depending on your budget. Top priority is front
channel followed by the Center. Get a good subwoofer with volume and
crossover at cut off point of 120hz.

Too high. You want the cutoff between main and sub to be 80Hz or
less. The lower the better.

I think 120Hz should be reasonable. Sony SACD players' cut off point
is 120hz and redirect all signals below that to the sub in the event
your other speakers are too small to output low frequencies.

Keep in mind, tough that it's not a brickwall filter. At any
setpoint, you're still getting some mains output at frequencies
near but below the setpoint. Depending on how steep the slope is,
it could be a lot. If the slope is shallow, and the mains woofers
really small, then a high cutoff as you suggest might be indicated.
Than again, if you set your crossover point that high, and the slope is steep,
it could result in a 'hole' in the listening spectrum, since subwoofers
aren't going to be be very good at outputing stuff in the 100 kHz range.

My understanding is that ~5-6 inch woofers should be crossed over circa
80 Hz. My own 'small' speakers -- NHT SuperOnes -- are rated flat to
at least 80 Hz. I run the subwoofer 'wide open' (125 Hz) so that
I'm not doubling up on the crossovers.

Btw I don't remember where that recommended
figure came from -- is there any
official (ITU?) recommendation relating crossover point and slope
to woofer size to?

--
-S.

"Schizoid Man" wrote in message
news:mehPa.23351$GL4.5818@rwcrnsc53...
"Kalman Rubinson" wrote in message
...
On Thu, 10 Jul 2003 01:07:47 GMT, (TChelvam)
wrote:

I think for a true high wnd system the lower the sub cut off the
better
it is but on budget level I would bet for the higher would probably be
better. At least the other speakers and amp can concentrate on the mid
and high.

It should be as low as possible but that is determined by the
capabilities of the speakers.


I agree with you Kal. The sub crossover should be as low as possible.

Logically it would seem to me, to avoid phasing problems the crossover
should be set at the lower LF limit of the main speakers.

Nousaine's 120Hz crossover seems to be on the high side.


Let's distinquish here between a LFE sub and a sub used to extend the bottom
end of a center channel speaker. if the latter, and if the sub can be
position near the center (eg) under or next to the tv, and roughly in line
with the center speaker, then a little directional sound emanating from the
sub would not be all that detrimental, and the higher crossover *might* mate
better with some center channels than otherwise would be the case.

I agree that it is not ideal, but I can see where with cheaper speakers it
might be practical.

Steven Sullivan wrote in message ...

Better yet, a variable crossover. Variable phase adjustment
is nice to have too.

Yes.that's really important. At 180 ( my sys), the sound clearer and
the bass is tight with good punch. Unfortunately, not many can tell
the diff. In fact, speaking of the phase, i remember that for the DAC,
I could only tell on certain music which phase is better but in
majority of them I am unable to tell correctly. Wonder how important
is phase is?

On 11 Jul 2003 14:27:12 GMT, (TChelvam) wrote:

Steven Sullivan wrote in message ...

Better yet, a variable crossover. Variable phase adjustment
is nice to have too.

Yes.that's really important. At 180 ( my sys), the sound clearer and
the bass is tight with good punch. Unfortunately, not many can tell
the diff. In fact, speaking of the phase, i remember that for the DAC,
I could only tell on certain music which phase is better but in
majority of them I am unable to tell correctly. Wonder how important
is phase is?

I think what SS meant was fully variable phase, not just an inverting
switch. I agree. It really helps.

Kal

Kalman Rubinson wrote:

On 11 Jul 2003 14:27:12 GMT, (TChelvam) wrote:

Steven Sullivan wrote in message
...

Better yet, a variable crossover. Variable phase adjustment
is nice to have too.

Yes.that's really important. At 180 ( my sys), the sound clearer and
the bass is tight with good punch. Unfortunately, not many can tell
the diff. In fact, speaking of the phase, i remember that for the DAC,
I could only tell on certain music which phase is better but in
majority of them I am unable to tell correctly. Wonder how important
is phase is?

I think what SS meant was fully variable phase, not just an inverting
switch. I agree. It really helps.

Kal

I've set and installed dozens of subwoofer systems and have yet to find a
continuously variable phase control to work any differently than a switch. IOW
rotating the control will exhibit no difference until you hit a certain point
and then the polarity suddenly changes and there will be no further change
through the remainder of the rotation.

Do we have some other experience to share?

On Fri, 11 Jul 2003 18:23:26 GMT, (Nousaine) wrote:

I've set and installed dozens of subwoofer systems and have yet to find a
continuously variable phase control to work any differently than a switch. IOW
rotating the control will exhibit no difference until you hit a certain point
and then the polarity suddenly changes and there will be no further change
through the remainder of the rotation.

Do we have some other experience to share?

Not explicitly. Using the control on the Paradigm X30, the
between-speaker tones on the Chesky test disc seem to snap in at about
100deg but I do not recall if there's much change after. When my
system returns to normal (new speaker system under audition), I'll
give it a more careful try.

Kal

Kalman Rubinson wrote:

On Fri, 11 Jul 2003 18:23:26 GMT, (Nousaine) wrote:

I've set and installed dozens of subwoofer systems and have yet to find a
continuously variable phase control to work any differently than a switch.
IOW
rotating the control will exhibit no difference until you hit a certain
point
and then the polarity suddenly changes and there will be no further change
through the remainder of the rotation.

Do we have some other experience to share?

Not explicitly. Using the control on the Paradigm X30, the
between-speaker tones on the Chesky test disc seem to snap in at about
100deg but I do not recall if there's much change after. When my
system returns to normal (new speaker system under audition), I'll
give it a more careful try.

Kal

I've used the X30 for years in testing autosound systems and sometimes passive
subwoofers and the action always seems to be as you describe: there's a knee in
the rotation that has the same effect as a switch. IOW you get the same results
if you just turn the control fully one way or the other.

I'n looking forward to more data on this. Thanks.