Stereo Pre-amp with HT Pass Thru. Can someone explain this?

[benleeys]

While reading your comments on analog bypass in a preamp, the thought occurred to me that different power amps might have different gains in response to a particular signal input level from a preamp or processor. So, if we are to use different kinds of power amps for front, center and surrounds, wouldn't the sound volume from the various speakers be out of balance at signal levels other than that which we used to calibrate the processor?

Is that the reason why we have 5-ch amps?

 

[Rich]

While reading your comments on analog bypass in a preamp, the thought occurred to me that different power amps might have different gains in response to a particular signal input level from a preamp or processor. So, if we are to use different kinds of power amps for front, center and surrounds, wouldn't the sound volume from the various speakers be out of balance at signal levels other than that which we used to calibrate the processor?

Is that the reason why we have 5-ch amps?

No. I think five-channel amps are really more for space convenience and cost efficiency than anything else. A good home theater surround processor will allow you to set the output levels for each speaker using a microphone and test tones, and will also set the signal time delay to account for positioning of the speakers relative to each other and the listener. I think it is still a good idea to use identical or at least similar amps to drive all of your speakers, though. This way you get the same type and tonality of sound coming from all the speakers, which gives you a more unified surround sound field.

 

[Jeff Zaret]

Rich,
I think you are correct. I have three different amps and in my case, they are not alike at all. I originally set them all by ear then through my surround processor I can fine tune the volumes for each. It works great. NO microphoes needed.


Jeff

 

[Spike]

I think it is still a good idea to use identical or at least similar amps to drive all of your speakers, though. This way you get the same type and tonality of sound coming from all the speakers, which gives you a more unified surround sound field.

My following comments apply to critical, multi-channel music listening only. I don't really care much for home-theater so I'm much more tolerant in home-theater mode. While having identical or similar amplifiers is an ideal set-up, it remains just that, an ideal. I found out the hard way since the center speaker (Cinema i) is quite different than my front left & right speakers (ReQuest). I have Classe' amplifiers for the front 3 channels but the Cinema is out-of-character when trying to match with the ReQuests. The best I can describe it is that it has a boomy (weighty) mid-bass that seems to drag the center channel from keeping up with the faster ReQuest panels. That may be due to the higher crossover point of the Cinema i (300Hz) vs the ReQuest's 200Hz. The higher crossover point on the Cinema causes the (lower) mid-bass to bleed into the woofers and I can definitely hear the discrepancies between the Cinema and the ReQuest. There's also the "tizziness" of the Cinema's tweeter that does not match with the ReQuest panels. In my case, the Cinema is always drawing my attention to itself, especially the flanking 5 1/4" woofers, just due to the fact that it's built differently. I had the same experience when I brought home the Logos and the Theater for auditioning, close but no cigar!
In my opinion, the "ideal" set-up would be to have identical amplifiers AND identical speakers, for example, 3 ReQuests for the front-channels in my system!

Spike

 

[amey01]

While this works (tried it), it just does not provide that cohesive surround sound field which the HTPT gives you - IMO.

Better yet, to not deal with all of this, just buy a top of the line Pre/Pro and do away with the other pre all together.

Dan

I too, would not want to substitute a pre-pro for an alalogue preamp given that 2-channel is my priority. To be fair, a movie soundtrack doesn't require the same resolution of music anyway, and is usually not recorded with as much care - but we all have different priorities!

 

[jfm]

An enjoyable side benefit of a preamp with HTBP is that you can listen to concert DVDs through the preamp only, in 2ch mode, bypassing the pre-pro.

To my ears, there are many such discs that sound better in PCM stereo mode (or even Dolby 2.0) than they do in 5.1 mode. Of course, there are also discs that sound great in 5.1. HTBP makes it easy to experiment and find your own preferences.

I use an ARC preamp and I just love its feature set for this purpose. Its multiple main outs enable me to set up my Depth both ways too - LFE when the pre-pro is engaged, and through the RCA inputs for stereo; setting different crossover points for both applications is a snap. It's got balanced ins and multiple balanced outs too; lots of options for experimenting.

 

[asindc]

An enjoyable side benefit of a preamp with HTBP is that you can listen to concert DVDs through the preamp only, in 2ch mode, bypassing the pre-pro.

To my ears, there are many such discs that sound better in PCM stereo mode (or even Dolby 2.0) than they do in 5.1 mode. Of course, there are also discs that sound great in 5.1. HTBP makes it easy to experiment and find your own preferences.

I use an ARC preamp and I just love its feature set for this purpose. Its multiple main outs enable me to set up my Depth both ways too - LFE when the pre-pro is engaged, and through the RCA inputs for stereo; setting different crossover points for both applications is a snap. It's got balanced ins and multiple balanced outs too; lots of options for experimenting.

JFM,

Are you saying that your prepro allows you to set up different xover points for the sub depending on the selected source? Without an EQ device like the Velodyne SMS-1?

Anthony

 

[jfm]

Anthony - yes.

For 5.1 music my NAD lets me run the Aeons full range and crossover the sub at 40Hz.

For DVDs, I set all speakers to small and crossover at 80Hz.

For straight stereo from my preamp (sources: universal player in stereo, cdp, tt) I use the Depth settings at the lowest crossover point, which is 30Hz.

I think this would be a standard feature on many pre-pros and receivers?

 

[Pcar928fan]

I too, would not want to substitute a pre-pro for an alalogue preamp given that 2-channel is my priority. To be fair, a movie soundtrack doesn't require the same resolution of music anyway, and is usually not recorded with as much care - but we all have different priorities!

Well, now my Rotel RSP-1098 and I bet many others have a TRUE analog By-pass mode, so in THEORY anyway, you should be listening to the source, amps, cables, and speakers, and NOT the processor.

Also I just found out if you leave a Rotel 1098 unplugged for to long get ready to reprogram it! Thankfully I had not made a lot of strange changes to digital inputs or anything like that...all is well now and awaiting the BIG TV!

 

[benleeys]

..... I found out the hard way since the center speaker (Cinema i) is quite different than my front left & right speakers (ReQuest). I have Classe' amplifiers for the front 3 channels but the Cinema is out-of-character when trying to match with the ReQuests. The best I can describe it is that it has a boomy (weighty) mid-bass that seems to drag the center channel from keeping up with the faster ReQuest panels. That may be due to the higher crossover point of the Cinema i (300Hz) vs the ReQuest's 200Hz. The higher crossover point on the Cinema causes the (lower) mid-bass to bleed into the woofers and I can definitely hear the discrepancies between the Cinema and the ReQuest. There's also the "tizziness" of the Cinema's tweeter that does not match with the ReQuest panels. In my case, the Cinema is always drawing my attention to itself, especially the flanking 5 1/4" woofers, just due to the fact that it's built differently. I had the same experience when I brought home the Logos and the Theater for auditioning, close but no cigar!
In my opinion, the "ideal" set-up would be to have identical amplifiers AND identical speakers, for example, 3 ReQuests for the front-channels in my system!

Spike

Spike,

Have you tried the Stage with the Summits? They blend pretty well when I listen to SACDs. I do agree, however, that identicals all round would be best.

Ben