jdm56 Posted November 8, 2004 Share Posted November 8, 2004 I'n mot sure this is the proper forum for this question, but here goes: My Pioneer Elite VSX-55TXi will allow configuring the back surround channel amps as "B" speaker outputs, which seems, for the most part, to put out everything the "A" speaker terminals do, when "A & B" speakers are selected. Since I am now using this receiver strictly for two-channel music, I was wondering if these "B" or back surround channel amps are really up to snuff for bi-amping purposes. Or to put it another way, are they really the equivilant of the front main pair? I know that all seven channels in this receiver are rated the same, but that doesn't mean that they ~are~ the same. I guess you could consider this in a more general sense: Are typical A/V receiver's amplifier channels all created equal? Or are the mains a little more equal than the other channel's amps? I have already tried this bi-amping scheme, and though nothing blew up, I didn't think the sound was quite what it ought to be. So now I am still bi-amping, but I am using the receivers main front L & R amps to drive the mids and tweeters (100W/channel), and my trusty old Sony TA-N55ES amps to drive the woofers (300W/channel, bridged mono mode). I'm still not sure the sound is enough better to warrant the extra hardware, cause I just don't push'em that hard too much of the time. But at least I shouldn't have to worry about clipping. Quote Link to comment Share on other sites More sharing options...
ironwoods Posted November 9, 2004 Share Posted November 9, 2004 Hi, if the front and rear manual specifications don't indicate otherwise, I'd assume they are equal. Your system profile does not mention a cross-over network used for bi-amping purposes, or is this internal to the VSX-55TXi? I'm not up to date on what these things are capable of, at the moment. Quote Link to comment Share on other sites More sharing options...
jdm56 Posted November 9, 2004 Author Share Posted November 9, 2004 I can bi-amp through the speaker's crossover. The only thing maybe unique about the receiver is the ability to configure the back surrounds as "B" speakers instead. And maybe that isn't so unique, either; I dunno. Quote Link to comment Share on other sites More sharing options...
psg Posted November 9, 2004 Share Posted November 9, 2004 What speakers are those? How did you match the level of all amplification channels? Quote Link to comment Share on other sites More sharing options...
ironwoods Posted November 9, 2004 Share Posted November 9, 2004 Please bear with me as, if I understand correctly ; you're sending the *same* full range signal to *both* high and low speaker inputs? I don't think this is bi-amping proper. In my little world, I thought the HF and LF were seperated with an external x-over devise, *then* sent to each power amp and then on to each respectable post on the speaker. Almost sounds like you're "*bi-wiring* with 2 amps"(?) and letting the speaker's own x-over seperate the signals for HF and LF *after* amplification. The whole reason I mention this is because you stated in the current configuration the sound was not quite what it ought to be. I either spotted a problem or don't have a clue. I'm hoping the former. Quote Link to comment Share on other sites More sharing options...
jdm56 Posted November 9, 2004 Author Share Posted November 9, 2004 ---------------- On 11/9/2004 2:06:31 PM psg wrote: What speakers are those? How did you match the level of all amplification channels? ---------------- Don't make me tell you what speakers they are, please! They'll beat me! The amps I am driving the woofers with have level controls, so I just match the woofer output to the output of the mids/tweeters as driven by the two main channels of the receiver. Ironwoods, The speakers, like a lot of'em now, have dual inputs pairs, which allow splitting the crossover by removing the jumper between the hi and low frequency pairs. True, the amps are sending a full range signal to each input pair, but the crossovers send only a low-passed signal to the woofers, while the mids and tweeters get a high-passed signal that is then split again between midrange and tweeter drivers. In my speakers, the crossover points are at 350Hz and 4000Hz. I suppose some amplifier power is being wasted this way, compared to the more pure form of bi-amping you are talking about. Quote Link to comment Share on other sites More sharing options...
ironwoods Posted November 9, 2004 Share Posted November 9, 2004 Okeedoeky, then I'm clued for the time being. What do feel was lacking in the sound, that prompted your original (before I sent us on the wild goose chase)question? Quote Link to comment Share on other sites More sharing options...
psg Posted November 9, 2004 Share Posted November 9, 2004 The speakers, like a lot of'em now, have dual inputs pairs, which allow splitting the crossover by removing the jumper between the hi and low frequency pairs. True, the amps are sending a full range signal to each input pair, but the crossovers send only a low-passed signal to the woofers, while the mids and tweeters get a high-passed signal that is then split again between midrange and tweeter drivers. In my speakers, the crossover points are at 350Hz and 4000Hz. I suppose some amplifier power is being wasted this way, compared to the more pure form of bi-amping you are talking about. You do realise that the great majority of today's speakers with double binding posts are for bi-wiring and not by-amplifying, right? Hopefully it's okay to do what you are doing, otherwise you'll adversely affect one of both of your amps. Quote Link to comment Share on other sites More sharing options...
ironwoods Posted November 10, 2004 Share Posted November 10, 2004 ---------------- On 11/9/2004 6:49:20 PM psg wrote: You do realise that the great majority of today's speakers with double binding posts are for bi-wiring and not by-amplifying, right? Hopefully it's okay to do what you are doing, otherwise you'll adversely affect one of both of your amps. ---------------- Hi, why do you say this? I don't see what bad effects this would have on an amp, however I'm still being schooled. Speakers.... 'nother story, but the filter should do what it was designed for. Quote Link to comment Share on other sites More sharing options...
doudou Posted November 10, 2004 Share Posted November 10, 2004 the benefit of this setup are: -less chances of clipping -the amps are used at a low level (instead of one amp at high level), so less distortion for the same output sound. you can test inverting the amps of the lows and mids/highs, may be the sound will be better. Quote Link to comment Share on other sites More sharing options...
psg Posted November 10, 2004 Share Posted November 10, 2004 ---------------- On 11/10/2004 10:32:34 AM ironwoods wrote: ---------------- On 11/9/2004 6:49:20 PM psg wrote: You do realise that the great majority of today's speakers with double binding posts are for bi-wiring and not by-amplifying, right? Hopefully it's okay to do what you are doing, otherwise you'll adversely affect one of both of your amps. ---------------- Hi, why do you say this? I don't see what bad effects this would have on an amp, however I'm still be schooled. Speakers.... 'nother story, but the filter should do, what it was designed for. ---------------- Well, it really depends on what the crossover is doing and how things are interconnected there. If there wasn't a likely problem, why would the speaker manual warn that the double posts are for by-wiring and not by-amp'ing? I'm think that if the levels aren't perfectly matched, you might be feeding the current from the higher level amplifier into the lower one. Ouch. But what do I know... Quote Link to comment Share on other sites More sharing options...
jdm56 Posted November 10, 2004 Author Share Posted November 10, 2004 The sound just seemed a little harsh and edgy, driving the mids and tweeters with the back-surround amps of the receiver. It could have been my imagination, the CD, or maybe the phase of the moon. The maker of the speakers says they can be bi-wired or bi-amped. I am a little dubious of the real-world benefits in my situation, though. The only thing I'm gonna really gain, I think, is about 6dB of headroom, which ain't a bad thing, of course. As for sound quality, I don't yet know as I'm hearing anything definite. Quote Link to comment Share on other sites More sharing options...
jheis Posted November 10, 2004 Share Posted November 10, 2004 Not to highjack this thread, but I was thinking of doing something similar with my RC7. I'm currently powering it with a Carver TFM-45 bridged to mono (claimed 1,000 watts - talk about headroom!). However, since I am sending the same signal to both channels of the amp, I was thinking of switching the amp back to two channels (380 watts/channel - more in line with my other amps) and running a speaker wire from one channel to one set of binder posts on the speaker and another speaker wire from the other channel to the other pair of binder posts. The binder posts are jumpered together now, so they are receiving the same signal. What difference would it make if the signal to the two sets of binder posts came from a separate channel of the amp (with the jumper removed)? Any thoughts? James Quote Link to comment Share on other sites More sharing options...
v3spitfire Posted November 10, 2004 Share Posted November 10, 2004 I'm passively bi-amping RF7 because I have an extra amp that is essentially identical. So instead of running 100 watts X2, I'm running 100watts into each tweeter and 100 watts into each bass section. Actually, because the amp is rated higher for lower impedances, I might be delivering less than 100 into the tweeter, and 150 or so into each bass section. I've never needed the power, but I sure like the sound and power. Quote Link to comment Share on other sites More sharing options...
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