[davidc1]

I have a pair of Super Towers. I've been enjoying them since I built them as a kit in 1980. Driver's and crossovers upgraded by Brian in 1989. I' ve always run them with amps of about 100-150w RMS/ch, but have recently decided to up the power.

If I biamp the speakers, using one preamp, two  power amps, and the biamp switch on the back of the speakers for separating the passive crossovers inside, is this the same, as far as the amps power output, as using an external active crossover before the power amps?

Meaning, if I were to use an external active crossover after the pre-amp and before the 2 power amps, then each power amp will only be amplifiing it's respective frequency ranges. This will reduce the load on each amp, and also has the benefit that if the low frequency amp clips, it won't send a clipping signal to the tweeters.

But how about using the biamp switch on the speakers? Since the passive crossover comes AFTER the power amps, does that mean that each power amp is still producing the full frequency range? Or, is each amp only producing its respective range because the passive crossovers in the speakers are not presenting a "load" to the amp of all frequencies?

Thanks

[RSorak]

if they're wired like my Super Towers only the tweeter and supertweeter will be driven by the HF amp, Hardly worth doing IMHO. The passive crossovers cannot be split or changed w/o ruining them. In short I thought about biamping mine and came to the conclusion there was little to nothing to be gained.

[rollo]

  Not advised. Try a more powerful stereo amp or mono blocks. Have fun trying. Parasound, Mc Intosh, Classe, Bryston, Levinson. Not a dealer of such.


charles

[davidc1]

if they're wired like my Super Towers only the tweeter and supertweeter will be driven by the HF amp, Hardly worth doing IMHO. The passive crossovers cannot be split or changed w/o ruining them. In short I thought about biamping mine and came to the conclusion there was little to nothing to be gained.

Hmm...so Brians idea of bi-amping was more of a "sound" thing than a "power" thing?

The current amp I'm using is a rebuilt Carver PM-1200, which is 600 watt RMS/ch. I can get it to clip, just barely and occasionally, when listening loud and certain wacks on a drum set occur.

So, I could get a more powerful amp...vintage Carvers produce even more power, but I thought the internal bi-amp crossover was at 600Hz, allowing the mids to be powered by the same amp as the tweeters. But, I guess the crossover must occur at 4500hz?

[knotscott]

There are benefits to bi-amping, and there are a couple of different approaches (vertical bi-amping and horizontal bi-amping), each with pros and cons.  Obviously there's a cost of a 2nd amp, and another set of wires.  If you pursue active crossovers there's an added cost and complexity of that, with no guarantee it'll yield better results than the passive crossovers if they happen to be well executed. 

Vertical bi-amping is where there are separate amps for each side, with one channel driving the low end, and the other driving the highend....duplicated on each side.  One advantage is that the responsibility for driving the LF woofers is split between two power supplies, leading to better dynamics and more controlled bass.  Another is that only one output channel is responsible for driving the woofers, leaving the other channel with an easy task of driving the mid/HF drivers, which can lead to better clarity where its most critical.  Another added benefit is that there is zero cross-talk between the two amps, which can lead to better stereo separation. 

Horizontal bi-amping is where two stereo amps divide the LF and HF responsibilities.  That can allow you to put an amp that's better suited for bass on the woofer, and one that's better suited for HF on the top.  (often used with a tube amp up top, and a SS amp for LF).
Vertical seems best for two identical amplifier models, horizontal is best suited for using two different amps.  (You obviously wouldn't want to put one amp on the left side, and a different amp on the right side.)




If the speakers have a passive crossover, there's a requirement for the input to be split to separate the circuits, so that one channel drives the HF input, and the other drives the LF input.  If you wanted to add an active crossover into the system, you'd need to bypass the passive crossovers in your speakers.  Both philosophies can yield excellent results, depending on how good of a job is done with each.




How much benefit is heard from bi-amping depends on a lot of things.  If your system is fairly revealing, you should hear a notable improvement from bi-amping.  It doesn't really change the tonal balance or basic sound signature of your system unless you change amps completely, but offers some subtle but notable improvements to things like dynamics, clarity, and spatial separation.   If you're system has some weak links, the money for another amp might be better spent upgrading the system elsewhere first. 

Because I already had two Dynaco tube amps that I added the VTA/Bob Latino mods to, I pursued vertical bi-amping using my passive speaker crossovers  ...I could clearly hear better separation, bigger sound stage, better clarity, and better dynamics after bi-amping.  In hindsight, I think the VTA mod upgrades made the more dramatic improvement in my system, but I'm pretty happy that I pursued the bi-amping approach too, because it's quite audible...icing on the cake that took my system to another level!  Not sure I could justify the cost of another whole amp to get that improvement, but since I'd had both amps for a while with very little money invested, it was sort of a no-brainer in my case.  I've considered bypassing the passive crossovers and going with active, but the current crossovers are extremely good, and I'd essentially be starting from ground zero with the active crossovers, so there'd be added expense along with a whole lotta tweaking to get things adjusted right (and it definitely get worse as a result!),so I'm very likely to stand pat and continue to enjoy the system as it is now.  If you've got the funds and the desire, I'd definitely recommend bi-amping.

[srb]

The McIntosh MC901 works well for vertical biamping with a 300W tube output and a 600W solid state output.

The best of both worlds ..... at a price! 

 

[PMAT]

Many VMPS speakers have a switch to allow biamping. The crossover is already split at the switch. Just use both sets of terminals with your two amps and put the switch in the right position. It is not the same as active in that passives do waste some of the power from the amp. That said, the only reason to biamp when you have that much power on tap is to change the sound. I know you from Carversite I think. I have a Sunfire Signature 625 x 2 that has two kinds of output taps. One set for low output impedance and woofer control and one set at one ohm output impedance like a tube amp for that tubelike sound. I have two way planars that I use with both sets. I run the big planar transducers with the tubey taps and the woofers on the slam taps.

[davidc1]

Many VMPS speakers have a switch to allow biamping. The crossover is already split at the switch. Just use both sets of terminals with your two amps and put the switch in the right position. It is not the same as active in that passives do waste some of the power from the amp. That said, the only reason to biamp when you have that much power on tap is to change the sound. I know you from Carversite I think. I have a Sunfire Signature 625 x 2 that has two kinds of output taps. One set for low output impedance and woofer control and one set at one ohm output impedance like a tube amp for that tubelike sound. I have two way planars that I use with both sets. I run the big planar transducers with the tubey taps and the woofers on the slam taps.

Yes, I'm on thecarversite as well, and asked the same question.

My plan was to horizontal biamp (using the switch on the back and the two terminals) and use two identical amps (a PM1.5a and a PM1200). I am doing this primarily to get more power, but I'm using the two amps instead of buying one amp that is more powerful only because I already have the two amps.

But, it looks like the switched biamp crossover puts the mids and woofers together on one circuit, and the tweeters and supertweeters on the other. So, it doesn't really spit the power requirments anywhere close to 50/50. But, I still have the two amps, so, I'll still do it.

[knotscott]

Yes, I'm on thecarversite as well, and asked the same question.

My plan was to horizontal biamp (using the switch on the back and the two terminals) and use two identical amps (a PM1.5a and a PM1200). I am doing this primarily to get more power, but I'm using the two amps instead of buying one amp that is more powerful only because I already have the two amps.

But, it looks like the switched biamp crossover puts the mids and woofers together on one circuit, and the tweeters and supertweeters on the other. So, it doesn't really spit the power requirments anywhere close to 50/50. But, I still have the two amps, so, I'll still do it.

Since you have two identical amps, and your mids connect with the woofers, vertical bi-amping should offer more improvement in the bass by splittlng the heavy work load of driving woofers (and mids in this case) between the two power supplies of the separate amps instead of just one.  You'd also get better separation with less crosstalk with the vertical setup.  I suspect horizontal bi-amping would lead to one amp doing a significant portion of the heavy lifting, while the other amp only has to drive the tweeters.

Are you up to separating the inputs from the mids/bass so that the mids mate with the tweeters instead?

[opnly bafld]

I am doing this primarily to get more power, but I'm using the two amps instead of buying one amp that is more powerful only because I already have the two amps.

You may notice a difference from passively biamping, but power remains the same.