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Post by bonscott on Nov 29, 2019 18:05:51 GMT -5
Looking to purchase a multi channel amp. Wondering if purchasing a 7 channel over a 5 channel to bi amp the fronts would be worth the extra $420 plus speaker wire to do it.
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Post by 405x5 on Nov 30, 2019 9:09:53 GMT -5
Looking to purchase a multi channel amp. Wondering if purchasing a 7 channel over a 5 channel to bi amp the fronts would be worth the extra $420 plus speaker wire to do it. Doing that for the express purpose of bi amping the mains won't necessarily gain you any benefits however, there are reasons out there why it's not a bad idea.... Over time some of us end up with an odd number of amps. and channels etc. looking for a home, or it gets tricky matching an amplifier channel configuration. So, if you already have a 7 channel amp. and only 5 speakers (and so on) and your mains have a bi amp. or in rare cases, a tri amp configuration option then its a good choice to make. The mains, or a really serious center channel often need more power than the back channels, so with bi amping those extra channels can really do some good. I may consider it myself in the future because my amplifier of choice is only available as a 7 channel, and I have no plans to increase my configuration in the (present room) beyond a 5.1 layout. There are those systems out there with active crossover networks engineered to have separate amps for each section. Bill |
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Post by brubacca on Nov 30, 2019 10:57:35 GMT -5
I have biamped several speakers over my time. Mostly tried it because I had the spare amp channels.
Can't say I ever thought it actually made a difference.
I'd say save your money or make sure you buy decent speaker wire/cables. I know this is controversial and I don't mean spend thousands on cables. I find the entry level Analysis Plus or Chord Cable to be very good.
Many don't hear a difference in their systems. I have heard a major difference. Literally deciding I like a component vs being ready to sell something off.
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Post by donh50 on Dec 2, 2019 15:24:55 GMT -5
So-called "passive" bi-amping implemented by most AVRs/AVPs will not benefit as they do not include a crossover to split the frequencies going into the speaker. That is, both outputs are putting out the same full-range signal, so you are limited by voltage headroom i-amped or no. The argument that it reduces back-EMF modulation depends upon the impedance of the cables and amplifier's output impedance, both of which are normally much lower than the speakers themselves, so again hard to make a case for doing it.
Also note bi-amping, active or passive, does not double the power unless you double the individual amplifier power. If you have a 100 W amp no driver in the speaker can see more than 100 W. If you bi-amp using two 100 W amps, again no driver can see more than 100 W; it is not the same as buying a 200 W amp.
If you need a rationale for more channels, a better one IMO is to have the extra channels available for additional speakers.
FWIWFM - Don
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KeithL
Administrator 
Posts: 10,261
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Post by KeithL on Dec 2, 2019 17:50:42 GMT -5
In a typical home setup, where most of the power is used by the low-frequency drivers, the benefits of bi-amping and bi-wiring are quite limited. If powerful amplifiers were terribly expensive, using different power for the different frequency bands might make sense, but that isn't really an issue these days.
It's worth noting, however, that some of the claimed benefits actually exist... but only in specific circumstances.
For example, in professional installations, being able to play very loudly with minimum distortion is often a priority. With most music, it is the lower frequencies that require the most power, and so are the most likely to clip if you play things too loudly. However, with most music, it is the middle and upper frequencies that contribute the most to "clarity" and "intelligible dialog". Therefore, if you turn a system that isn't bi-amped up until it clips, the clipping caused by the overloaded bass causes distortion that also muddies up the midrange and upper frequencies. When you bi-amp a system you separate those two frequency ranges and power them with separate amplifiers. Therefore, if you crank things up way too loud, and cause the low-frequencies to clip, that clipping doesn't affect the more critical middle and upper frequencies.
(In fact, in a well designed system, the "bass bins" have very limited high frequency response, so clipping by the bass amps is even less noticeable.)
This gives you a much wider range of loudness over which "the bass gets a little muddy but the voices remain clean and clear". And this is a worthwhile benefit for a moderately good quality public address system... and makes it seem "more powerful" than it actually is.
However, in a home high fidelity system, where we do our best to avoid distortion altogether, and so don't run anything into clipping, this ability isn't especially useful.
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Post by donh50 on Dec 2, 2019 20:28:46 GMT -5
The problem is that the vast majority of home AVRs do NOT separate the frequencies; when you bi-amp that way, the only crossover is in the speakers themselves. No, I never thought of them doing it that way either, but that's the way they work. The exact same signal is sent to both "hi" and "low" power amps and on to the speakers. The actual power delivered depends upon the crossover, so current (and thus power) is usually lower in the tweeter amp (depends on the speaker's crossover and impedance, natch), but the same voltage swing is applied to both speaker inputs. And when the voltage clips it also clips on both amps so net improvement is nil in the AVR's "passive bi-amping" design. Yeesh.
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Post by MusicHead on Dec 2, 2019 21:07:26 GMT -5
I think the best true "bi-amping" at home is to just add a subwoofer (or two 😁)
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Post by repeetavx on Dec 2, 2019 21:10:04 GMT -5
I vertical passively bi amp my system because when I tried it, I could hear a difference. There are arguments for bi amping, but most of them are poo-pooed in this forum.
One of the reasons that I do it is because I can use one amplifier chassis per speaker just like the "real" monoblock people do.
I do agree with the crowd when they say to not spend a lot of money to try it out. But if you can scrape together some cheap cables to try it, and maybe repurpose your surround amps just to try it. I think you should.
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Post by 405x5 on Dec 3, 2019 8:57:32 GMT -5
I think the best true "bi-amping" at home is to just add a subwoofer (or two 😁) I like that...rather simple and to the point. The average “full range “ loudspeaker does not go down to the frequency range most of us go to the subwoofer for, and that takes amplifier power that’s built in (hence “biamp”). Once that load is taken away, the main amp works easier to deliver the goods without clipping or straining. Small setting can provide even greater relief. Using it or not depends a lot on the available power of those amps and the selected crossover point. Bill |
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Post by dust770 on Dec 3, 2019 23:52:40 GMT -5
Looking to purchase a multi channel amp. Wondering if purchasing a 7 channel over a 5 channel to bi amp the fronts would be worth the extra $420 plus speaker wire to do it. A couple things to consider. What speakers are you using? What is their sensitivity rating? How far is the main listing position from the bi amped speaker? |
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