I am looking to purchase a 7125 and bi-amp my Polk Audio RTi10 with it and use the rest of the channels for my 5.1 system. I have a relatively small room 19'd X 15' w, actual listening area is 12'd X 12' w. I can not listen to movies or music loud because of my family but I am looking for better quality.

First of all, is this a good idea?

Other than Y-splitters do I need anything else for the Bi-amping?

Would I be better off purchasing 5 2200 monoblocks.

I like the cost of the 7125 and the simplicity of the hook up of the 7125.

Scott

What you are contemplating is the bi-amping approach called "passive bi-amping" (leaving the speaker's internal crossovers intact and using the high and low frequency binding posts to connect two amp channels to the single speaker). You would only need a pair of Y-splitters and some extra speaker cable to connect the four amp channels to the two speakers. It can effectively increase the overall power available to the speaker, which can be helpful at higher listening volumes but may not provide much noticeable improvement at lower volumes. I think the 7125 would be a good fit. There may be some other Polk RTi10 owners around here who could offer some more first-hand feedback.

I already have the speakers bi-wired so all I would need is the Y-splitters which I saw for sale on the site.

Again is this a better solution than running the 2200 mono blocks? Does bi-amping RTi10's mess with the ohm resitance to the 7125?


Scott

Bi-amping does not mess with the resistance at all, and both amps in question can handle much more difficult loads than the 8ohm RTi10's anyway. Bi-amping with the 7125 will probably be almost indistinguishable from running 2200's for your mains, and I don't know how much benefit the 2200's would give you for the center and surrounds. Either upgrade will be a nice move up from a receiver's internal amps.

Thanks Gonk.

I appreciate your feedback. I look forward to reaping the benefits of external amplification.

I am leaning toward the 7125 given my room size and young family.

Scott

Let us know which way you go, Scott. If you still feel unsure which way to go, you can always call Outlaw and chat with the sales crew - they have likely worked with other RTi10 owners and may be able to give you some feedback in relation to your speakers and room size that could take some of the uncertainty away. There's also the 30-day trial period, allowing you to return the 7125 and order M2200's if you feel the need to, although I suspect that once you get a 7125 in place and running you'll be happy right there.

Thanks for your help

Scott

Isn't true bi-amping running separate wires to each of the post pairs on the speaker?

My Martin Logan SL3s (I think) have four posts (two for the ESL panel) and two for the cone in the base.

I would assume what is being mentioned here is to use one of the plates that connect the two pairs of posts so that the output going to the first pair of posts gets also sent to the second?

I would assume that not only does it depend on which post pair gets the raw power from the amp to affect speaker performance but also how much it gets?

Bi-wiring is running two sets of wires from a single amp to a speaker's two sets of posts.

Passive bi-amping involves driving each set of binding posts with a separate amplifier channel. If both amps are identical, then the two posts are going to get the same magnitude signal - which corresponds to the way the speaker manufacturer designed the internal crossovers. After all, the two binding posts would get the same magnitude signal if they were jumpered together and connected to a single amp by a single cable. If you use different amps for the high and low, you would potentially need to balance the two signals so they are equal when they reach the speaker.

Active bi-amping involves ripping the crossover circuits out of the speaker, building new crossover networks located upstream of the two amplifier channels, and then amplifying the output of each crossover and passing that directly to the drivers inside the speaker cabinet. That particular approach is not one that is adviseable for the average person because of the level of knowledge needed in crossover circuit design and speaker design.