Bi-Amping RF-7II's

[TasDom]

I recently added an additional XPA-5 amp as I was upgrading from a 5.2 set up to possibly a 9.2
I decided that 7.2 was sufficient for now so I now have 3 channels unused.

I
was thinking about bi-amping my mains (Klipsch RF7II's) and wondering
if there is any sonic benefit in doing this. I know the best way to find
out is to try it and listen but wanted to get some opinions from the forum......

Thanks in advance for any opinions!

[Zen Traveler]

Hi Tasdom,

I would leave the jumpers in place and run one set of wires...Fwiw, I don't think you would gain anything unless you were going to change to an external/different crossover.

[derrickdj1]

Hi Tasdom,

I would leave the jumpers in place and run one set of wires...Fwiw, I don't think you would gain anything unless you were going to change to an external/different crossover.

What he said! I tried the horizontal, vertical and bi-wiring, I thought it work right after I did it but over a peroid of time seen that it did not make any real difference. It did not make things worse, just not better.

[moray james]

Tasdom: I do not have RF7 ll but I have biamped vertically with two very nice very modified Quad 405 amplifiers on a pair of modified H3 and a pair of modified KLF20 and a pair of modfied CF3 and I cannot imagine going back to a single amp set up ever. As they say YMMV and you guessed it there is only one way for you to know for yourself. Have some fun and experience what you are wondering about. Best regards Moray James.

[TasDom]

Thanks all. I'll try it in the coming days as I have extra wire and cables so no out of pocket expenses. Worth a try to satisfy my own curiosity.

[jtubbs6117]

Tas this is something I wrote a while backt that will support your thought. I havechanged a few things in the setup My NAD now powers the HF and my B&K powers the LF on the RF7s. Very nice Much more impact than only running one amp. Just thought you might like another opinion. The more clean power you can run the better. I don't like the idea of distortion creeping up just to try and get close to the RMS power.

Guys
I have the RF7's like a lot of members. I think people should look at
the spec sheet for this large floor standing monsters. The spec sheets
states 250watts RMS, this is an understatement. I am running 375 to each
one of mine and they will take way more on the LF side. The way I have
found to get the best performance from mine is to Bi amp. Running them
this way really makes everything flat and nice!. The problem I had with
my Mac only on the RF7's it would sound great at low volumes but when
turned up the horn would over power the LF to the point it seemed
obvious to me. If think about electricity following the path of least
resistance or the sensitivity after the power hits the crossover the
horn will be louder every time. Using two channels of amplification on
each you have two separate sources so the horn does not rob from the LF
drivers, or when the LF drivers ohm dips the horn is not affected. Let
me explain the 375 Mac MC250 (250x2) runs the HF on the RF7s and NAD 925
(130x5 give or take) runs the LF. This has given me such a good result I
don’t normally have my Paradigm Servos turned on. This is just what has
worked best for me I really want to get another amp to run the LF side
that is a better match for the MAC something that will put out closer to
250 so everything will be equal. Feed the monsters!!!!!!LOL

[moray james]

horizontal biamping has it disadvantages and is further complicated if you are using different amps as is very often the case. That in itself shoud be obvious in that they will not sound the same. If you use a stereo amp to drive the left and right woofers then you are asking the supply of that amp to deliver the bulk of its power to both channels at the same time which maximizes the draw on the supply. When you use two identical amps the gain is identical and the sound is identical. If you biamp vertically then only one channel of each amp is asked to deliver peak power to the woofer section while the other channel is doing next to nothing driving the horn section. This then frees up available supply to the channe driving the woofers if it should be necessary. The only thing better than a stereo amp with a common supply to do this job is a stereo amp which is in fact a dual mono amp in one chassis or mono blocks. I agree that once you have fully experienced biamping especially vertical mode biamping You are not likely going to be interested in switching back to a single stereo amp again. Best regards Moray James.

[derrickdj1]

I wish I could be in the room with my RF 7's near RMS. I have never seen mines go past 60-80 watts on the Yamaha M 80 or M 70 meters, or the power console. As far as power distribution, around 300 Hz the power to the HF and LF is pretty even but the HF is not working at that low a level in the RF 7/7II. Most of the time the horm is using less than 10% and closer to maybe 5% of the power. Without the active XO, most of the power from passive biamping is dissapated in the xo network. At higher volume, the horn can be louder due to due to power consumption by the woofer making the HF 3-5 db louder than the woofer. At best, yymv with passive biamping. I wonder if it is not wattage but, current that causes part of the HF/LF mismatch? Passive biamping may help with xo performance according to avr makers.

I do run my RF 7's full range since the Yaqin integrated tube amp has no bass management and is for 2 channel. But, I still find myself listening to 2.1 for a lot of things because the subs are the best bass producers in the system.

On my power console the highest watt read was around 850 hitting 120 db in the room with some intense LFE going . I had the Yamaha M 70, M 80, Carver amp, avr, BDP, TV app going. Most of this power usage was the subs, the Dayton amp on the subs did not work after this, lol.

[Kev the ironworker]

hi,

I know that this post is a bit old (6 months) but I have to toss in my 2 cents....I got the biamping bug and spent a lot of money on it....a pair of bryston 7 b-st monoblocks, an audio research vt-50 tube amp for my horns, a luxman a-2003 tube crossover (and $ 1000 worth of upgrades on it) a Richard grey power conditioner, a monster voltage regulator and another conditioner....antique sound lab tube preamp....jolida tube cd player...new rf-7ii's, rc-64 center, a sw-115 sub and my back speakers are rf-82's...(that are powered by a Yamaha m-85 ....sever overkill)... for movies, all this is powered from a cheaper onkyo ht-rc 370 through it's preout jacks. for music everything goes only through the tube pre....does it sound good ? you bet ! would I ever do it again ? no way !...lol....at low volumes there really isn't a noticeable difference in biamping....but every time I turn it up I have to take a step back and smile...the luxman lets you adjust the low, med and high octave range (the horns are almost not even on) but what it's done is now the speakers aren't at all bright....beautiful sounding and powerful.....detailed....I listen mostly to r&r and some female singers as well ....all I need now is a better preamp (looking for an audio research sp-11 if anyone has 1.....) and a much bigger house too...if anyone is interested I have a luxman a-2002 (2 way) tube crossover for any reasonable offer....to sum it all up...I think biamping does make a difference in sound but it's expensive...

[TasDom]

Glad to hear you noticed a difference. I wound up buying some RS7's and never did try to bi-amp mine. I actually forgot about this post but maybe some day I will give it a try. For now tho, I'm quite content as is.