The Difference Between Bi-amping and Bi-wiring

Discussion in 'Amps, Pre-Pros & Receivers' started by admin, Jan 23, 2014.

  1. admin Audioholics Robot Staff Member

    admin
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    Recently a reader of Audioholics asked us about the differences between bi-amping and bi-wiring, and what kind of effect they could have on his system. Read on to see our reply.

    [​IMG]

    Discuss "The Difference Between Bi-amping and Bi-wiring" here. Read the article.

    So how are you connecting the main left/right speakers in your system? Please share your hookup, reasoning and images here.
    Last edited by a moderator: Jan 23, 2014
  2. RichB Audioholic General

    RichB
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    Thanks for the good summary article.

    I tried passive Bi-amping uses a PR-SC5507 preamp with its Bi-Amp setting to duplicate the signal.
    I listen to music using Pure Direct the 5507 appears to do additional signal processing to duplicate so I feel degraded the sound quality.

    The Marantz AV8801 does not have this capability so I split the XLR outs and I detected no difference.
    Both processors were driving a Sunfire 7400 and Revel Salons.

    Now, I use the AV8801 with a Parasound A51 no bi-amping and I feel this is an upgrade.
    If I want more power, I'll just get mono-blocks.

    - Rich
  3. haraldo Audioholic Spartan

    haraldo
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    I guess one benefit of bi-amping is that if you like to run hard.... any clipping on the amps that run the woofers is not in any way going to burn off your tweeters, as long as the mid/hi amplifier is not clipping; so maybe in some cases, additional safety can be a benefit :p
  4. mtrycrafts Audioholic Slumlord

    mtrycrafts
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    Just don't forget that is you are running it hard, you have already increased the power to the tweeters as well. Most speakers are not capable of much power before dying. ;) Even clean signals but over powering will burn them up.
  5. BoredSysAdmin Audioholic Warlord

    BoredSysAdmin
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    I used a simple short runs of bare wire "terminated" cheap 12 gauge cord and never had any issues :)
    BI-What? I would rather enjoy what I have and get better speakers if I wanted to spend any money
  6. cwall99 Full Audioholic

    cwall99
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    Just curious... I was talking to a guy who runs a local hifi / home theater shop a couple of weeks ago, and he was saying that when current hits the woofer, it drives it back, but when the woofer travels in the opposite direction, it creates a current that goes up the wire into your amp.

    He was saying that by bi-amping and bi-wiring you remove this noise from the tweeters' and mids' circuit.

    He was telling me that if you do bi-amp, that's a benefit that few people talk about (I don't even know if it's audible, though it certainly seems like it might make a more audible difference than a $2,000 power cord).

    Superficially it makes sense, but I don't have the knowledge of amplifiers and their electronics to know if he was just pulling my leg.

    Here's a question (and I suspect I already know the answer)... If I'm using a 7-channel AVR (oh, just for grins, let's say it's a Pioneer Elite VSX82-TXS... no reason, no reason, I'm just sayin'....), but I'm only driving five speakers, and I go into that AVR's menu system and I configure the AVR to bi-amp my main left and right speakers (let's just say they're B&W DM603 S3s.... since they have two sets of binding posts)... Do AVRs that let you do that do active bi-amping? (I'm guessing not since you don't tell the AVR what each amplifier is doing in terms of low frequencies or high frequencies).
  7. Sathishdholic Audiophyte

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    Under powering is more detrimental to speakers

    In most cases speaker damages occur due to under powering them than more power. In case of speaker with lower nominal impedance the risk of blowing the amp is greater (especially the mass market AVR amps). When you are bi-amping, even with identical amps, we are creating a variation in how the amp sees the load. Higher frequencies and drivers - tweeters will have higher impedance compared to the midrange driver, the woofer or lowrange driver will have the lowest impedance more closer to 4 ohms and below. So careful attention should be given to amplifier's ability to drive these loads separately when using any mass market amps / AVRs that have bi-amp capability. In the long run one may end up damaging the amps driving the MF/LF drivers.
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  8. walter duque Audioholic Samurai

    walter duque
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    I've been messing around with my new towers which are designed to be bi-amped. They can also be used by adding one of

    [​IMG]

    these between the the tops and bottoms if using a single channel amp. They sound great when using just one amp. Now I went and bi-amped them with two Cinepro amps, just to make sure that there are 2 different power supplies and they sound a lot better to me. Recommended power is 1000+ watts to each of the 4 modules, but at 500 watts with 3.5 db head room these do sound good. Better than just with one amp. Once you get passed that +3db you know you've got something there.

    [​IMG]
    Last edited: Jan 23, 2014
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  9. gene Audioholics Master Chief Administrator

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    He is talking about back EMF into the amp. Not really an issue. Personally I do like passive bi-amping in some cases. Back in the day I used to biamp with my Denon 5805 for my front towers. That receiver had a ton of reserve and it helped to drive my towers better than the single amp connection. However, I could have achieved the same results simply using a higher power external amp in a single wire connection.
    gene,
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  10. PENG Audioholic Warlord

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    May not be word for word like he told you but generally true in terms of electrical theory but most people don't believe such minor difference would contribute to audible difference, I do agree the chance would still be greater than using $1000 power cord or even between a $3000 and $20,000 class A/B power amp but it is like coming the probability of 1,000,000 to 1 and 100,000,000 to one, what's really the difference!!


    First of all, to do active biamping right you have to have in depth knowledge, not for the average person who just want to enjoy music and hi fidelity. Passive biamping with an AVR is no better than just biwire, very little difference even in terms of electrical theory.
    PENG,
  11. Swerd Audioholic Ninja

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    Thanks for that article. It answers those questions that we so often see posted here, and the diagrams are excellent.

    I was especially glad to see it made clear that active bi-amping has the potential to make a change, but does not guarantee better sound. In threads where bi-amping is discussed, I often see someone claim, categorically, that bi-amping with active crossovers is the only way.

    Thanks for that careful and correct wording.
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  12. utopianemo Junior Audioholic

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    The issues in the article make a good case for powered speakers, especially well-designed ones like the golden ear series.
  13. utopianemo Junior Audioholic

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    Gene,
    Why is it "not really an issue"?
  14. gene Audioholics Master Chief Administrator

    gene
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    The electrical connection the amplifier sees in a bi-wire situation is virtually identical to a single wire connection since the amp side gets both sets of wires connected back to it. If back EMF was an issue in a single wire connection, it would still be an issue in a bi-wire connection too.

    More info on bi-wiring here:
    Bi-Wiring From Amplifier To Loudspeaker | Audioholics
    gene,
  15. chas alex Audiophyte

    chas alex
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    Back emf is not a problem in an amplifier with a low output impedance (high damping factor).
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  16. Ampdog Audioholic

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    Reply depends on whether you are bi-amping after an electronic cross-over or before, using the respective cross-overs in the loudspeaker cabinet. If each ampliier handles only its respective frequency band i.e. after electronic cross-over, you will be having a constant driver load on each amplifier all the time and there is no problem (the driver internal cross-over will be disconnected). There will only be signal output to the drivers in their specific bands, outside which the amp will simply be "quiet".

    A problem might arise if each amplifier works into the cross-over network of its respective driver(s) in order that they only see their particular frequencies (both amps therefore working full-frequency). Generally an amplifier will then see a high impedance outside its driver's pass-band, which will be reactive to boot. Point is whether each amp will be stable under these conditions. One amp will be high-impedance inductively loaded at h.f., the other high-impedance capacitively so at low frequency. I have not heard about problems regarding this but my experience of commercial power amplifiers is limited. There is certainly a possibility than some amplifiers might not be happy.

    The magnitude of the impedances will depend on the cross-over designs. I have some difficulty in seeing how the amplifiers can be damaged output magnitude wise except for the above consideration. They should be able to handle any output within their spec, again subject not to the magnitude of the signal at any time, so much as to the 'abnormal' load seen.

    Not sure I understood your question then; hope this helps.
  17. Ampdog Audioholic

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    Chas - er .... true of course, but I would like to point something out here (let's say as an aside):

    There is a great misconception regarding damping factor. One tends to look at the usuall figures: 10 rather low, 30 mmmm, >80 well, decent. The problem lies with the classic definition of (loudspeaker impedance)/(amplifier output impedance).

    That is in fact meaningless.

    Speaking (in this case) of the effect of loudspeaker back-current, it circulates in the total output circuit, which consists of amplifier output impedance, cable resistance and loudspeaker voice coil resistance. In the classic definition the latter suddenly disappears! It is in fact the major limiting resistance in the circuit, being about 5,5 ohm for an 8 ohm loudspeaker system. That means that it is the major element limiting loudspeaker back current, which then has even less effect on the amplifier proper. [This 'analysis' means in fact, that the real practical damping factor (in terms of 'braking' the loudspeaker etc.) can be no more than some 1,5! Needs a bit of consideration vis-a-vis all that boasting about so-called D.F.s of many dozens or >100....]

    In this case, to support your statement.
  18. PENG Audioholic Warlord

    PENG
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    Aren't we all tired of this biwire/biamp/active biamp pros and cons in terms of audible difference or not thing already? So I'll stick to theory only. In theory, as Gene said the back emf part of it is common to all scenarios so there is no need to over analyze it. I am more curious about the effect of having the high or mid & high depending on the speakers, separated to folow in its own wires. In theory, the mid/mid & high will be less affected by the electromagnetic field (i.e. potential interference) created by the heavy woofer, or mid & woofer (again depending on the speakers). I can't hear any difference so to me it is easier for me to consider any such effect as a non issue as well.
    PENG,
  19. little wing Full Audioholic

    little wing
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    I went back and looked at the manual for my speakers, which are going on 15 years old now. But I thought this was an interesting quote from the manual.

    "Many audiophiles recommend using two connecting wires instead of one because two wires share current through a greater conducting area (and for many additional reasons that we cannot verify but which we accept as true because we hear a difference in favor of bi-wiring)" And then they go ahead and give you instructions on how to bi-wire.
  20. GimpsterSJ Audiophyte

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    Pleased with Active System

    For what it's worth, I designed my 4-way active system properly and am very pleased with the results. The only downside (beside the extra associated equipment) is the extra precautions I've had to take to minimize grounding noise. I was able to combine different kinds of drivers that I would not be able to do in a million years with a single crossover network, and I can perform suble corrections when I move the system from one location to another.

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