[G.C.]

Hi All, I'm currently in the construction phase of my dedicated home theater and I'm already thinking of an upgrade. My current set-up is 7.2:
Fronts - Paradigm Studio 100 v.5
Center - Paradigm CC-690
Sides/Rears - ADP-590
(2)Subs - SVS PB13-Ultra
Amps - Emotiva XPA-2, and (2) XPA-5's (for future Atmos speakers)
Pre/Pro - Marantz AV-7702

My plans are to do Atmos so I bought an extra XPA-5 to power those. So when this is all done I'll be at 7.2.4 system. My problem is that I'll have an unused amp channel. I was considering upgrading the amps to two (2) Outlaw 7-channel amps to power the entire system. That would leave me with three (3) unused channels, which I thought about using to Bi-Amp the front sound stage. My questions are:
1 - How could I go about hooking this up? If I'm not mistaken, I'd be using all my pre/pros XLR outs for all 11 channels and wouldn't have any left over to Bi-Amp?
2 - Is there a "T" or something to split the signal to 2 different amp channels? Would that even work?
3 - Would this whole idea be a waste of time and money since what I have now would work just fine and I'm attempting to re-invent the wheel for no good reason?

Thanks,
G.C.

 

[Frank Derks]

1 See 2
2 Yes there is: you can use an rca splitter cable for this.
3 The big cost is already sunk in the spare channel so it's only a waist of time and some additional cost for 2. There is practically no advantage in biamping a speaker and it doesn't harm if you do. And if you biamp do not forget to remove the connection between the loudspeakers connection terminals.

 

[Bill Fitzmaurice]

There is practically no advantage in biamping a speaker

+1. True bi-amping does the signal splitting before the amplification, and has no passive crossovers in the speakers. Since so called 'passive bi-amping' does neither the very term 'passive bi-amping' is an oxymoron, and isn't worth the bother, or the extra wire.

 

[IKM]

I tri-amped a 3-way system once and the improvement in bass response was honestly day and night. Other benefits were thought to be afoot, but there was no debate about the bass - it was a wow moment.

Incidentally, when we bi-amped it the benefit went away. The bass and the mids shared the same amp in the bi-amp arrangement. All the amps were of the same make and model.

 

[G.C.]

Thanks for the help guys, I'll just stick with what I've got going then. If there isn't going to be a big difference I'm not going to mess with it.

 

[Glimmie]

Been running Biamped LCR's for years. And this past month I decided to move to triamped LCR's.

First I used a DIY OPAMP based analog crossover. 24db slope. Then a tube based unit. Next was Berhinger DCX2496. Now I run a farm of MiniDSP units and stay in the digital domain up to the power amps.

I found an excellent reference on bi/triamping here:

http://sound.westhost.com/bi-amp.htm (be sure to read both parts)

It's a lot more tricky to get right then first thought. The sensitivities of the amps (if different models) and the speaker drivers apparently have a significant effect on performance. I too have done the "use the crossover as an equalizer" approach and now agree with ESP that is is not ideal.

 

[Glimmie]

Incidentally, when we bi-amped it the benefit went away. The bass and the mids shared the same amp in the bi-amp arrangement. All the amps were of the same make and model.

I have read that as well. The biggest benefit is the woofer / midrange crossover. A passive crossover on the tweeter seems to be perfectly acceptable.

 

[G.C.]

So just to be clear, if I came out of my pre/pro with an RCA cable and split it, sending one leg to amp 1 channel 1, and the other to amp 2 channel 1, then running my speaker cables from amp 1 channel 1 to the top posts of my speakers and amp 2 channel 1 to the bottom posts of the same speaker, would that be considered "true" bi-amping or "passive" bi-amping?

 

[G.C.]

Also, I would see no benefit from setting up my front 3 speakers this way?

 

[Glimmie]

So just to be clear, if I came out of my pre/pro with an RCA cable and split it, sending one leg to amp 1 channel 1, and the other to amp 2 channel 1, then running my speaker cables from amp 1 channel 1 to the top posts of my speakers and amp 2 channel 1 to the bottom posts of the same speaker, would that be considered "true" bi-amping or "passive" bi-amping?

That would be passive biamping as opposed to the useless "biwiring".

Passive biamping does provide a sight benefit in that some extra power is available but as the tweeter needs so little power anyway in relation to the woofer, I say there is no practical benefit to passive biamping.

Now one could argue that a smaller cleaner class A amp could be used for the tweeters (which is what I do but with an active crossover). But now you have the possible mismatched amp gains to correct for (see the ESP article) so is it worth the effort?

If you are going to biamp, you might as well do it right with a line level crossover and with the crossovers bypassed in the speakers. And IMO, this is not something a novice can do and get performance that exceeds the passive crossover. To squeeze out the extra performance of a true bi/triamped system, much care and effort is needed to get it right.

The whole idea of HiFi biamping is to get rid of the passive crossover that has unstable frequency response in the face of the changing speaker impedance to level and frequency. The only way to address this minor problem is with an active crossover.

Biamping is used on stage sound systems primarily for a different reason which is very high audio power requirements.

 

[Frank Derks]

So just to be clear, if I came out of my pre/pro with an RCA cable and split it, sending one leg to amp 1 channel 1, and the other to amp 2 channel 1, then running my speaker cables from amp 1 channel 1 to the top posts of my speakers and amp 2 channel 1 to the bottom posts of the same speaker, would that be considered "true" bi-amping or "passive" bi-amping?

That is passive bi-amping.

 

[G.C.]

Thanks for all the help. I try to search for answers before asking silly questions, but this one had me stumped. It sounds like my idea would be a waste. The good news is you just saved me some cash!!

Thanks again,
G.C.