M-3SIs & MORE POWER! (and biamping discussion)

[brad1138]

This is about my latest revision in how I am driving my M3SIs. Also, to all the people who have said "why are you biamping?" (while leaving the speakers x-overs in tact) in all the discussions about biamping, "I give".

I am using a Citation 5.1 amp to run my M3SIs. It is a 4/3/2 chan amp, dual mono design, 4x100 or 2x300 @ 8 ohms. I had been running it in 4 channel mode, 2 channels to each speaker.

I was doing this partially because I have another nice 2 chan amp (BIAMP Systems-Eminance 300) that I wanted to switch the mids/tweets over to on occasion. They had slightly different characteristics (imaging/detail etc) and I thought the change wold be nice. I also thought it was the better way to hook it to my spks. I never really gave the bridged mode of my Citation much of a try.

Well I did give it a try, it turns out the increase in power output made a much bigger difference than any possible/perceived advantage of "biamping" (the way I was doing it anyway). The M3SIs are notoriously power hungry (83db @ 1watt/1meter) and many reviewers have said they need 200+ wpc to really come to life, man is that true. The spks are 6 ohm (4 ohm min) so I am probably getting ~400 wpc from the Citation in bridged mode, which has really opened them up. I have a definite improvement in dynamics and bass, two areas I had always thought weren't quite what they should be. I love the fact that I was able to make my spks sound even better, I already loved them.

I have started using my Eminence 300 to run my center channel, instead of the built in amp in my Yamaha rec. That made a big improvement in my home theater sound as well.

 

[PENG]

The spks are 6 ohm (4 ohm min) so I am probably getting ~400 wpc from the Citation in bridged mode, which has really opened them up

Typically when you bridge an amp that is rated for 4 ohms, it will be rated for 8 ohms only. HK rated it 2X300W at 8 ohms in bridge mode. Surely you can use it with 6 or 4 ohms speakers at your own risk. Adding an external cooling fan may help. I doubt you would get 400W but 350W may be possible. That should still be enough for the M3 si that is mostly a 6 ohm speaker for the most part.

 

[brad1138]

Typically when you bridge an amp that is rated for 4 ohms, it will be rated for 8 ohms only. HK rated it 2X300W at 8 ohms in bridge mode. Surely you can use it with 6 or 4 ohms speakers at your own risk. Adding an external cooling fan may help. I doubt you would get 400W but 350W may be possible. That should still be enough for the M3 si that is mostly a 6 ohm speaker for the most part.

I am aware of that, it has no problem running bridged at 6 ohms, barely even gets warm. I have seen posts about the Citation 5.1/7.1 running 4 ohm loads bridged without any problems, only getting a little warm (actually the 7.1 didn't even get warm). I believe it is stable at 2 ohms / 4 ohms bridged.

I just Googled and found this article of an interview with "Stephen Mantz" the designer of the amps. According to him they are stable to 1 ohm / 2 ohms bridged, producing 1Kw per bridged chan @ 2ohms. Man I love these amps.

Brad

 

[PENG]

I thought he was talking about the 7.1 that is a bigger amp. Anyway, to get 2 kW output you need to draw at least 3 kW from the main so you really should feed it with a 30A circuit (10 AWG wire). That kind of power is needhttp://www.canuckaudiomart.com/details/148337-_harman_kardon_citation_51_power_amplifier/ed mainly for the rare peaks. There is no way the M3 can handle that kind of current for any significant length of time. Actually the M3 only dips to 4 ohm at a narrow band of frequencies and the phase angle isn't that great so it simply can't draw that much current from even the 7.1 within its power handling capability.

I wonder why the guy uses such a seemingly nice amp for subs. There was this one for $650, was it a good price?

http://www.canuckaudiomart.com/details/148337-_harman_kardon_citation_51_power_amplifier/

 

[brad1138]

I thought he was talking about the 7.1 that is a bigger amp. Anyway, to get 2 kW output you need to draw at least 3 kW from the main so you really should feed it with a 30A circuit (10 AWG wire). That kind of power is need mainly for the rare peaks. There is no way the M3 can handle that kind of current for any significant length of time. Actually the M3 only dips to 4 ohm at a narrow band of frequencies and the phase angle isn't that great so it simply can't draw that much current from even the 7.1 within its power handling capability.

I think he was talking about the 7.1 also, but it doesn't really matter. The 7.1 is 50% more powerful, so the 5.1 could "only" put out ~650Wx2 @ 2 ohms. I don't need that much power and don't have a need to drive a 2 ohm load. It's just nice to know it is 1 ohm stable. The power it is putting out at 6 ohms (300-400W x2) is a perfect match for my M3s and it is working wonderfully.

I paid $550 for mine from CL, I think $650 is a good deal as well. The 7.1s are going for about $800 w/shipping on ebay at the moment (saw 2 in the last month). I had wanted one but the way I have it hooked up now I really don't have a need for it, the M3s can't handle anymore than what the 5.1 gives them anyway. I may try to pick up another 5.1 to run my center and surrounds.

I am thinking of running a dedicated 20 amp line to my system, I have a lot running on a shared 15 amp outlet currently. As far as why he is running subs with them, they be the most powerful amps he had and is using tube amps or something for the rest of the system, not worried about it.