Bi-amping
rharleytpv -- Sun, 02/12/2006 - 11:46
I have a question. I recently read (and then misplaced) an article
talking about “bi-amping.” In trying to recall what it said, I tried
the following:
I set up my system so that my Cary CAD 300-SEI supplied the signal for
the treble and mid-range of both of my Q11 KEF speakers, and my Antique
Sound Lab MG-SII5 supplied the signal for the bass of both speakers.
Results: amazingly clear strong sound! It appears that the 300B tubes
in the Cary can now concentrate on supplying sweet clear sound to the
treble and midrange, and the KT 88 tubes in the Antique Sounds Lab amp
can focus their power only on the bass.
What is your view of this approach to “bi-amping” using two very
different amps? Have you encountered this before? Did I set it up
“wrong?”
My personal response is that, right or wrong, my system has never
sounded better. (Compared to using only one of these amps to drive the
full range of both speakers.) My source is a “tweaked” version of the
Philips 963 SA playing regular CD’s and SACD’s.
I am interested in your response.
Cordially,
Dave Barstow
You seem to have bi-amped correctly and are now reaping the sonic rewards. Relieving the Cary amplifier and its 300B output tube from the burden of driving the woofer leaves that sweet little amp free to power the much less demanding load of the midrange and tweeter.
Using one amplifier type or brand to drive the woofer and a different amplifier to drive the midrange and tweeter is actually a good strategy, provided that you gain-match the two amplifiers. Each amplifier will have its own “input sensitivity”, the input signal required to drive it to full power, requiring you to decrease the input signal to the amplifier that has a higher input sensitivity. In many such bi-amped systems, a solid-state amplifier drives the woofers and a tubed amp drivers the midrange and tweeter.
I lived with a bi-amped system using the Cary 300SE-I. The loudspeakers had a built-in powered woofer, which made the system naturally bi-amped. The system was intensely musical and involving, and would play as loudly as I liked, owing to the loudspeaker’s 95dB sensitivity.
I’m surprised that the high-end has not more readily embraced bi-amping (and indeed, active loudspeakers).
Robert Harley
Editor-in-Chief
The Absolute Sound
The Perfect Vision
Are there real benefits to bi-amping if you use the same amps for high and low frequencies? With the example cited above, we're talking different amplifiers, with different sonic signatures. But if you use two identical amps per channel, that benefit goes away. Are there other advantage, e.g. when the bass amp clips, the mid/high frequency amp doesn't or something like that?
Absolutely. Using two amps that are the same brand on the top and bottom can offer significant sonic benefits.
Some manufacturers like Genesis (Genesis Vs) and the old Infinity (Betas, RS1B) require bi-amping, and in my experience with these speakers sounded better with tubes on top and transistor amps on the bottom. (In the case of the Gen Vs, a 400-watt transistor amp was supplied by the manufacturer). Yet there are folks who had very good success using something like a pair of Classe DR-9s on the top and bottom of the Infinities. There was less "discontinuity" between the tweeter/midrange panels and the bass towers.
Likewise, if one were to use a speaker like the larger Maggies, bi-amping using an amp on the bottom, and the same brand (power?) on the top can be quite good. It allows each amp to operate over a narrower range, placing less strain on each, with lower distortion, etc. Clipping is less likely and if it does occur, say in the bass, the tweeters are unaffected and won't take your ears off.
The dual amp approach might even save you money. Rather than having to buy one gargantuan amp, you can get away with two less powerful ones. Depending on the speakers, you can buy a smaller amp for the top and a larger one on for the woofers, provided they are from the same family. (Some folks say they must also be the same power, but that has not been my experience)
It's worth performing the experiment with your speakers.
Jim
Absolutely. Using two amps that are the same brand on the top and bottom can offer significant sonic benefits.
Some manufacturers like Genesis (Genesis Vs) and the old Infinity (Betas, RS1B) require bi-amping, and in my experience with these speakers sounded better with tubes on top and transistor amps on the bottom. (In the case of the Gen Vs, a 400-watt transistor amp was supplied by the manufacturer). Yet there are folks who had very good success using something like a pair of Classe DR-9s on the top and bottom of the Infinities. There was less "discontinuity" between the tweeter/midrange panels and the bass towers.
Likewise, if one were to use a speaker like the larger Maggies, bi-amping using an amp on the bottom, and the same brand (power?) on the top can be quite good. It allows each amp to operate over a narrower range, placing less strain on each, with lower distortion, etc. Clipping is less likely and if it does occur, say in the bass, the tweeters are unaffected and won't take your ears off.
The dual amp approach might even save you money. Rather than having to buy one gargantuan amp, you can get away with two less powerful ones. Depending on the speakers, you can buy a smaller amp for the top and a larger one on for the woofers, provided they are from the same family. (Some folks say they must also be the same power, but that has not been my experience)
It's worth performing the experiment with your speakers.
Jim
Of course, in stead of buying two amps per channel, I could buy one more powerful amp. Would that be better? I mean, with bi-amping I've set up a situation where bass or treble may clip, but with one amp of 2X the power, that clipping wouldn't occur?
Thanks.
Hi all,
I'm just wondering if a speaker will really benefit from passive bi-amping since the passive crossovers still present and there is no active crossovers involved (meaning each amp has to generate a full frequency bandwidth anyway). The idea of passive bi-amping has tempted me for years that I have been close to buy a new amp to bi-amp my speakerseveral times. Can you guys let me know if it is really working or has a substantial improvement? I have been using a carver amp driving my KEF reference1 for years and believe that the sound could improve.
Tom
I'm reacting to RH's comment about the inability of the high end to embrace active loudspeakers. It seems that audiophiles are intrinsically wedded to the components substitution or "tweak" philosophy where systems are constantly in a state of flux. I admit it can be fun plugging in new cables or swapping amps but often we confuse changing componenets for change's sake and actually improving the listening experience-that is, arriving ever closer to the absolute sound.
I'm a big proponenet of the potential for active speakers since all the components are "known" quantities the resulting amplifier/crossover/transducer interface can be optimzed in a way that passive speakers cannot. And apparently professional recording studios tend to agree. However, the major stumbling block is the perception that any company that produces a great speaker can't make a great amp. Or, that a great amp company is in over its head if it tries to market its own speaker line. I don't think that's necessarily true. Partnerships between amp companies and speaker companies are free to occur at any time yet they don't
Finally the reason why passive speakers will continue their popularity is because it's the audiophile that wants to remain the only true "active" component in the system.
Neil Gader
Assoc Editor, TAS
Neil Gader Associate Editor The Absolute Sound
To address Tom's question about whether passive bi-amping is worthwhile, I suggest that it is. First, you can choose each amplifier for specific attributes; as JH suggested, using a tubed amp on the top end and a big solid-state on the bass. Second, you greatly increase the system's power with bi-amping (usually). Third, power demands in the bass won't affect the midrange and treble. When an amplifier starts to run out of power, the soundstage shrinks, instruments congeal, and timbres become hard. That doesn't happen with passive bi-amping.
Neil Gader makes some good points about active bi-amping. Think about this: the amplifier designer has absolutely no idea what load the amplifier will be asked to drive. Consequently, he engineers it for the worst likely load, resulting in over-engineering (and wasted money) when the amplifier drives an easy load. Amplifier output current is expensive. With an active speaker, there's no guesswork; the load is known precisely and the amplifier can be optimized for that load.
Powered subwoofers are the "Trojan Horse" of active loudspeakers. Everyone now accepts amplifiers in subwoofers. I think we will see more and more active loudspeakers, particularly as DSP loudspeakers make greater inroads.
Robert Harley
I 100% agree with the last paragraph by rharleytpv.
With the fast growing technology of DSP and class-D amplification, they will make a better amp-speaker system which is immune from room accoustics.
Think about this way.
Source(especially digital)---> Digital Preamp (with room-correction, volume control)--> Active Speaker (in which has a digital cross-over, PCM-PWM modulator and class D amplifier or DAC+Class D amp with feedback chain).
All the cables are of simply digital.
Sounds like Beolab5?
But I guess such a active speaker system soon at an affordable price.
seungmok
I found when I bought a further Power amp at Christmas and bi amped my speakers, driving the Woofers with one power amp and the Mid range and ribbon tweeters with the other power amp, not only did I get a noticable improvement in the bass. :)
But a huge improvement in the midrange and highs. :shock: This was completely unexpected. The soundstage moved forward and vocalists seemed 1-2 feet closer than before. Something I hadn't been expecting at all. Both power amps run in class A for the first 10 watts.
ShengYa S10 Tube CDP. ShengYa SAT-3 Tube Pre Amp. ShengYa SP- T300 and SP-333 Hybrid Pwr Amp XINDAK FS-1 Loudspeaker cables, XINDAK AC-01 Interconnects, XINDAK PC-03 Power Cables. AURUM CANTUS Music Goddess Spkrs G&W TW-02D Power Supply Filter.
Post new comment