Bi-amp question

blairfrischx

I have been considering buying some Monitor70's (they are $180 on Newegg right now), and was wondering how I would go about bi-amping the speakers. I have a Harman/Kardon AVR-254 receiver and two Harman/Kardon PA 2000 amps, both of which are currently bridged to 2x100watts. I imagine the setup would go as follows:
AVR-254 pre-outs for the left and right channel (actually Zone 2 left and right in my setup) are sent out to an electronic crossover. Electronic crossover splits the signal into a low frequency and a high frequency. These split signals are sent to independent amps. The left and right channel outs on the amps are run to their respective terminal posts (low frequency amp goes to woofers, high frequency amp goes to mids/tweeters). The speakers sound fantastic. The listeners cheer.

But, would I have to disconnect an internal crossover in the speakers? I understand it would be the one that splits the signal between the woofers and mids/tweeters rather than the one that filters between mids and tweeters, but I don't understand how to go about doing that.

I'm just trying to figure out how to put my second amp to use (currently it is being used as my friends TV stand, which is simply insulting to it). Well, that and I want more Polk speakers; they sound awesome.

cnoat

You need to rmove the metal jumpers on your terminals.

blairfrischx

But is that the only change that is required on the speakers in order to allow them to be bi-amped?

Outfitter03

If I was setting this up, here is what I would do. I would use the Preouts on the AVR-254. I would split the Preouts signal using these:

http://www.audioadvisor.com/prodinfo.asp?number=AQFLX-XMF

http://www.audioadvisor.com/prodinfo.asp?number=AQM22FHRD

I would then operate the PA-2000 in bridged mode. Instructions are on page 8 of the owner manual.

http://www.harmankardon.com/EN-US/Products/Pages/ProductDetails.aspx?PID=PA%202000&accT=1&tsT=1&ovT=1

I would run the left channel of the PA 2000 to the tweeter connection on the Monitor 70's and the right channel to the mids and woofers on 70's. Make sure you remove the shorting bar. You are biamping off of one amp (but two 2 bridged internal amps) to a speaker.

This is the setup for right front channel. Repeat for the left front channel using the second PA 2000. The advantages of this setup is that you are placing the power load equally on the two power amps, still using the internal crossover ckts. and not utilizing the relatively cheap shorting bars that comes with the monitor 70's.

Your parts list would be 4 splitters of your choice. 4 RCA to RCA Analog Preout interconnects and either one pair of biwire speaker cables or two pairs of speaker cables. The PA 2000 has a weight of 23.6 lbs so must be a good high current amplifier. I believe this will sound really good!:):D:)

blairfrischx

So an electronic crossover in the line before the amp is not necessary? Wouldn't that be more efficient than just splitting the signal, which would still have both bridged channels dealing with both low and high frequency signals? I thought the entire point of bi-amping was to separate the signals so that an amplifier could more efficiently amplify a signal since it would be dealing with a smaller range of frequencies?

tonyb

Just hook up one amp per speaker and forget about bi-amping monitor 70's. If I was you,I'd sell those old amps and get one with some real muscle. Running in bridged mode will be ok for 8 ohm speaks,but if you ever move to a 4 ohm, forgetaboutit.

F1nut

tonyb wrote: »

Just hook up one amp per speaker and forget about bi-amping monitor 70's. If I was you,I'd sell those old amps and get one with some real muscle. Running in bridged mode will be ok for 8 ohm speaks,but if you ever move to a 4 ohm, forgetaboutit.

Especially true considering that this is for HT and therefore any benefits from bi-amping will be completely wasted.

blairfrischx

F1nut wrote: »

Especially true considering that this is for HT and therefore any benefits from bi-amping will be completely wasted.

This is actually for music listening purposes. I do a lot more of that than I do movie watching.

F1nut

Apologies.

In that case, Tony's suggestion to get one good amp is even more important. I'd also suggest getting a good pre amp with an HT pass thru or a good pre/pro. Those are going to net far greater gains than bi-amping ever will.