How do people control volume in bi amp setups

[newlash09]

Hi all,

Just wondering how people control volume in a biamp or triamp amp setup, if they use different amps. Recently read that some people use SS amps for bass, and tube amps for mids and highs. The levels can be matched in the active cross over at a fixed volume level. But it the listener wants to increase the volume, will there not be a mismatch in the gain of each different amp, considering that one is solid state and another is tube.

So how does one control volume changes in such setups. Thanks for your advise.

 

[lindsayt]

I use a Pioneer SF 700 adjustable active crossover with my Bozak Symphonies. Solid state amp on the bass drivers. SET for midrange and treble.

I used to use an LDR passive pte-amp before the crossover to adjust volume. Until I tested connecting my sources direct to the active crossover. System sounded better that way. Less is more. So that's how I use it now.

This means that every time I turn the volume up or down I have to adjust two volume knobs: one for below 400hz, one for above 400hz. For tonal balance I do this by ear. There's a wide enough range where the system will sound fine to my ears.

Clarity, transparency, dynamics, pitch are all more important to me than getting the frequency response flat to the nearest 1 db. Main thing is that no instruments are excessively filtered in, or filtered out of the mix. And that the instruments and vocalist sound as if they there in the room.

 

[andyjm]

Hi all,

Just wondering how people control volume in a biamp or triamp amp setup, if they use different amps. Recently read that some people use SS amps for bass, and tube amps for mids and highs. The levels can be matched in the active cross over at a fixed volume level. But it the listener wants to increase the volume, will there not be a mismatch in the gain of each different amp, considering that one is solid state and another is tube.

So how does one control volume changes in such setups. Thanks for your advise.

Hifi amps are supposed to be linear - if they weren't then they would distort. In laymans terms, that means the gain is constant irrespective of input level (within reason).

If (say) you applied a 1Vrms 1KHz tone to both amp inputs, then adjusted the gain on the amps so you got 10Vrms out. If you now double the input voltage to 2Vrms you would then get 20Vrms out of each amp, they would stay in step with each other.

Now, depending on why you are biamping, you may not want this to happen for all frequencies (if you have a woofer / tweeter split for example), but the default position for two gain matched amps is that they will remain in step irrespective of the input signal.

 

[lindsayt]

It's the Level Low and Level High that I adjust with every volume change.

If the system were actively tri-amped I'd have to adjust the Level Mid too.

edit: sorry about the horrible image distortion. It's too wide to fit properly into the What Hi-fi forum.

 

[andyjm]

It's the Level Low and Level High that I adjust with every volume change.

If the system were actively tri-amped I'd have to adjust the Level Mid too.

edit: sorry about the horrible image distortion. It's too wide to fit properly into the What Hi-fi forum.

Lindy, you shouldn't have to do that from a technical perspective if everything was working properly, however you may prefer a different bass/treble mix at different listening levels - rather like having a 'loudness' button on an amplifier.

If you google 'fletcher-munson' there is a good description on Wikipedia of this effect. What may sound balanced at low volume, sounds different a high volume. This was the reason for the (now unfashionable) loudness filter. I would guess you are peforming the same function manually.

 

[newlash09]

Understand now.

@ lindsayt : Thanks for the pic. Was much easier to understand after seeing it. I still have one doubt, in the past when you were using the pre amp into the pioneer cross over, would increasing volume on the pre amp increase volume on both your other amps as andyjm mentions it should happen. Or did you still have to increase the volume manually on both the amps.

@ andyjm : Thanks for the reply. So if two amps are fed through their pre amp bypass inputs, from an external active cross over like the minidsp. And once both are level matched, with gain settings in the minidsp. Then the volume control of the minidsp should increase the volume on both amps equally. Considering that both the amps are decent kit. Am I right in thinking so.

 

[lindsayt]

Newlash, when I was using the passive pre-amp before, I set the volume level on the active crossover at the highest level for the SET amp, which has less gain and adjusted the active crossover volume pot for the low frequencies once.

After that I left the active crossover alone and used the volume knob on the passive pre-amp for all volume adjustments.

 

[lindsayt]

Spam filter won't let me post a text diagram of my system, explaining to andyjm why I do need to use the volume pots on my Pioneer SF700 adjustable active crossover.

It's because I have no traditional pre-amp in my system.

The SF700 is doubling as a pre-amp.

I don't prefer having to adjust 2 volume knobs for different parts of the frequency spectrum from a user friendliness point of view. I prefer it from a sound quality point of view.

 

[newlash09]

Newlash, when I was using the passive pre-amp before, I set the volume level on the active crossover at the highest level for the SET amp, which has less gain and adjusted the active crossover volume pot for the low frequencies once.

After that I left the active crossover alone and used the volume knob on the passive pre-amp for all volume adjustments.

Very clear now. I also understand that you are getting better sound by feeding the source direct into the pioneer, instead of a traditional pre amp. The improvement in sound quality is worth the inconvenience of manually changing volume once in a while I guess. Thanks again

 

[macdiddy]

of someone using six Naim power amps to tri-amp a pair of Neat speakers (not sure which model).

not sure how he controls the volume but it sure sounds good.

I would post a link but I'm at work and we're not allowed Youtube access.

maybe later when I'm at home.

*music2*

 

[newlash09]

of someone using six Naim power amps to tri-amp a pair of Neat speakers (not sure which model).

not sure how he controls the volume but it sure sounds good.

I would post a link but I'm at work and we're not allowed Youtube access.

maybe later when I'm at home.

*music2*

 

Would be interesting to see how he dunnit. 6 power amps is a serious statement of intent. Must have costed a bomb too

 

[davedotco]

Naim have made active systems for as long as I can remember.

Mostly they would involve either a 2 way (S)NAXO 2-4 or 3 way (S)NAXO 3-6 active crossover that was dedicated to a specific speaker system.

Leaving aside the power supplies, necessary as the NAXOs were not self powered, the setup was straight forward, ie pre-amp out to NAXO, NAXO out to 2 or 3 stereo power amplifiers. All preset so nothing to adjust, very simple.

There is a definite advantage to be gained by using a dedicated rather than a universal crossover as a dedicated device can be used to shape the response as well as perform crossover duties. That said, the Naim approach puts everything in separate cases and requires separate power supplies. This is ruinously expensive.

It also explains why 'integrated' active monitors and their hi-fi equivilents can offer such great value, not only can the crossover be optimised for individual models, but their are no extra cases or power supplies to pay for either.

 

[newlash09]

Naim have made active systems for as long as I can remember.

Mostly they would involve either a 2 way (S)NAXO 2-4 or 3 way (S)NAXO 3-6 active crossover that was dedicated to a specific speaker system.

Leaving aside the power supplies, necessary as the NAXOs were not self powered, the setup was straight forward, ie pre-amp out to NAXO, NAXO out to 2 or 3 stereo power amplifiers. All preset so nothing to adjust, very simple.

There is a definite advantage to be gained by using a dedicated rather than a universal crossover as a dedicated device can be used to shape the response as well as perform crossover duties. That said, the Naim approach puts everything in separate cases and requires separate power supplies. This is ruinously expensive.

It also explains why 'integrated' active monitors and their hi-fi equivilents can offer such great value, not only can the crossover be optimised for individual models, but their are no extra cases or power supplies to pay for either.

Almost got excited with Naim naxo till you mentioned the ruinous expense involved

Must be similar to linn's active setup. And expensive as always .

 

[lindsayt]

There is a definite advantage to be gained by using a dedicated rather than a universal crossover as a dedicated device can be used to shape the response as well as perform crossover duties. That said, the Naim approach puts everything in separate cases and requires separate power supplies. This is ruinously expensive.

That's true that there is an advantage in being able to apply tailored equalisation in the active crossover in a dedicated one a la Naim.

However that is outweighed by the significant disadvantage of the traditional Naim active approach in that the same power amps are used throughout. This to me is bonkers. As the sort of amplifier that is best for bass drivers is not the sort of amplifier that's best for midrange units and tweeters. It's a huge missed opportunity.

As Newlash alluded in the opening post of this thread: solid state for bass drivers. SET for midrange. Either for treble.

SET's are too hot and microphonic to be placed inside speaker cabinets.

And then there's the downside of the number of low quality active amplification devices (components: transistors) in the signal path in typical all in one active speakers - which is shockingly high...

 

[newlash09]

Seems to be the favoured combination. And most are again using SET for tweeters too. But mostly it is bi amping that I've come across. Either external pre amp to two power amps or line level after active cross over to two integrated amps. One SS for bass + one SET common for both mids and highs. And most of these people seem to be in favour of leaving the original passive cross over in the loop.

 

[davedotco]

Seems to be the favoured combination. And most are again using SET for tweeters too. But mostly it is bi amping that I've come across. Either external pre amp to two power amps or line level after active cross over to two integrated amps. One SS for bass + one SET common for both mids and highs. And most of these people seem to be in favour of leaving the original passive cross over in the loop.

Back in the '70s we were, on occasion, asked to use valve amplification with our monitors and we would often suggest solid state for the bass. The valve amps were not SET, not practical in this application, just regular 'push pull'. If I recall correctly, some big McIntosh amplifiers were the preferred choice, though this was something of a passing 'fad'.

If you are using an active crossover, I can see no reason to leave the passives in circuit, though with 'audiophiles' anything is possible. I would imagine that, were the components available, it would be great fun getting an inexpensive variable crossover such as the Samson S3 and giving it a try.