Rotel PowerAmp Advise For Driving B&W CM7 Speakers

[pramod]

Hello List,

Will RB 1552@120RMS would drive B&W-CM7's adequately? or I should go for RB1582@200RMS?
I'm planning to also connect the B&W PV1 Sub in stereo mode, but I do not know how to do that, so help/advice is need for it... (my Pre Amp is Burson-HA160D, for the setup)
so if I use a subwoofer to send all the low frequencies to it, will RB-1552 would suffice for the job? or still need to go for RB1582.


Thanks in advance for your time.
Warm Regards
Pramod.

[pramod]

Any One Please....

[madmac]

Not being familiar with the amps or your setup, I can honestly say that using a sub with the amp's speaker settings set to 'small' will free up a HUGE amounts of power for your speakers above 80hz, so I am certain you will be fine power wise. Also, there is no point setting up a sub or subs in 'stereo mode' as all bass in music and LFE's in movies are mono only and come out only that way.

[wkhanna]

...there is no point setting up a sub or subs in 'stereo mode' as all bass in music ........(is) are mono only and come out only that way.

? Bass information loses directional imaging under a certain frequency threshold; however this by no means implies that the bass in music is recorded in mono.

In fact, i have two subs in my system configured for true stereo.
I find it helps greatly in preserving the imaging in the mid –low bass region for music. As an example, an acoustic double sting bass may appear to move around the stage in a frequency dependent manner when a single sub or two subs mixed to mono are crossed over at too high a level.

As for power, I have yet to hear an example of where more power did not result in better sound quality when the quality of the amps were similar.

[PewterTA]

I agree with Bill.

If you can afford to get the more powerful amp... it's never wrong to have more power than you need!!! However if money is an issue... the RB-1552 should have no problem driving them at all.

I'd also recommend you (for the price) look into Odyssey Audio and something like the Khartago as it would be very similar to your amps you're looking at and might end up costing you less. The price/performance ratio is very good and Odyssey sounds AMAZINGLY close to Rotel & Classe's sound.

Not trying to sway you from Rotel mind you. Just thought I would give you another option.

If you have the space, there are two Rotel RB-1090's on Audiogon... might be able to see if you can work with the guy to get the price down on one and get a BEAST of an amp.

[madmac]

? Bass information loses directional imaging under a certain frequency threshold; however this by no means implies that the bass in music is recorded in mono.

In fact, i have two subs in my system configured for true stereo.
I find it helps greatly in preserving the imaging in the mid –low bass region for music. As an example, an acoustic double sting bass may appear to move around the stage in a frequency dependent manner when a single sub or two subs mixed to mono are crossed over at too high a level.

As for power, I have yet to hear an example of where more power did not result in better sound quality when the quality of the amps were similar.

Well, my opinion is that bass below 80-100hz is largely mono, and recorded as such in the studio. Nothing wrong with subbing in stereo, but I think the benefits are quite minimal. Even as a sound space itself, bass will tend to fill a room with sound and imaging below 80-100hz is just not really there. That's why most receivers and amps that have 1 or 2 sub outputs are outputting essentially the same LF signal.

[wkhanna]

Well, my opinion is that bass below 80-100hz is largely mono, and recorded as such in the studio. Nothing wrong with subbing in stereo, but I think the benefits are quite minimal.

I can only speak from actual experience in my own system.
The improvement is significant.
AFA bass being 'recorded in mono', if this were true, all bass would always image as if it were at the center of the sound-stage.

That's why most receivers and amps that have 1 or 2 sub outputs are outputting essentially the same LF signal.

The reason 'receivers' output in mono is because they are primarily intended to be used for LF movie sound FX which is V low frequency & has no directional characteristic. Such information is not normally found in music
This can be acceptable as most AV 'receivers' are primarily used for movies & surround decoding.
However, if one has the xo point set rather high, it will certainly effect music playback on the same system.

For those who do not normally listen to music, or who do not care as much about high-quality music reproduction it will be of little to no concern.

[pramod]

I agree with Bill.

If you can afford to get the more powerful amp... it's never wrong to have more power than you need!!! However if money is an issue... the RB-1552 should have no problem driving them at all.

I'd also recommend you (for the price) look into Odyssey Audio and something like the Khartago as it would be very similar to your amps you're looking at and might end up costing you less. The price/performance ratio is very good and Odyssey sounds AMAZINGLY close to Rotel & Classe's sound.

Not trying to sway you from Rotel mind you. Just thought I would give you another option.

If you have the space, there are two Rotel RB-1090's on Audiogon... might be able to see if you can work with the guy to get the price down on one and get a BEAST of an amp.

Thanks, I wish I was in reach of those RB 1090's but I'm at the other end of the planet, and here audio world is few and expensive, so I have very limited choice, however I like you suggestion about Odyssey Audio's Khartgo amp, and the best part was the also have a deal for the International customers, with the package shipping offer, so I have written to them and awaiting their response, let me see if that falls within my budget range inclusive of shipping.

Thanks for the time and input.

[wkhanna]

I realize this is a Rotel forum & I personally have been a Rotel customer & owner since 1994. I have especially found great value & performance from their amps.

But over the past few months I have had the opportunity to hear a few different Odyssey amps in multiple systems. Based purely on performance per dollar alone, I find it most difficult to recommend any other amp. Add to this the personal service as recounted by friends & others who have done business with Odyssey & it becomes easy to suggest their name to anyone looking at an amplifier.

[PewterTA]

Hopefully Rotel will step up to the plate and realize that there's now manufacturers that are giving great value on top of giving the great sound that Rotel does. I'd personally like to see Rotel step up the quality of parts in their equipment, do a few of the "added on 'niceties'" to their equipment and really make a run at people. I mean using better caps, resistors, wiring, silver solder, etc... that's what's needed to really bring people back... Only thing I wouldn't touch is the torodial transformer... they make great versions of that!

As for Odyssey, Klaus will probably call you back later in the evening (CST) for him, he tends to work all day building and then calls people back in the evening.

[madmac]

I can only speak from actual experience in my own system.
The improvement is significant.
AFA bass being 'recorded in mono', if this were true, all bass would always image as if it were at the center of the sound-stage.


The reason 'receivers' output in mono is because they are primarily intended to be used for LF movie sound FX which is V low frequency & has no directional characteristic. Such information is not normally found in music
This can be acceptable as most AV 'receivers' are primarily used for movies & surround decoding.
However, if one has the xo point set rather high, it will certainly effect music playback on the same system.

For those who do not normally listen to music, or who do not care as much about high-quality music reproduction it will be of little to no concern.

All's I'm sayin' is that lower end bass below 100hz or so is essentially omnidirectional.......will permeate a room.....and not image very well, if at all. When you refer to the 'XO point set rather high'......I am assuming your crossover is set above that?

[wkhanna]

No, my xo point is in the 60 Hz region & the imaging quality is still improved.
Obviously, the higher one sets the xo point the more imaging is lost.
I am simply saying that assuming all bass is omnidirectional below 100 Hz has not been my experience in my system in my room.
It is a moot point for most, especially when one is mostly concerned with movies.
But for maintaining realistic sound stage with music, it is V noticeable.

[madmac]

No, my xo point is in the 60 Hz region & the imaging quality is still improved.
Obviously, the higher one sets the xo point the more imaging is lost.
I am simply saying that assuming all bass is omnidirectional below 100 Hz has not been my experience in my system in my room.
It is a moot point for most, especially when one is mostly concerned with movies.
But for maintaining realistic sound stage with music, it is V noticeable.

Well that's very interesting. I have two subs so I'll give that idea a try. What do you use to send the stereo signal to your subs??. Tape outs from the amp?

[PewterTA]

Bill has two sets of outputs from his preamp, that's how he does it.

[wkhanna]

My pre-amp is configured with two 'main signal out' RCA outputs.

Remember to make sure both subs are in phase when you hook them up.

[wkhanna]

Also, just to clarify, my subs are positioned on either side of my main speakers.......