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biamping

Discussion in 'AV Receivers & Amplifiers' started by digitalmonkey, Sep 17, 2002.

  1. digitalmonkey

    digitalmonkey
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    My receiver has a 6-channel output for connection to a power amp. If I took advantage of this facility, would I be able to biamp any biwirable speakers in my home cinema setup?

    I know that biamping is quite common in 2-channel hifi setups, but I have never heard of anyone doing it in a home cinema setting. Is there any reason why I should not be able to do this?

    Has anyone else had any experience with biamping their home cinema speakers?
     
  2. MikeK

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    It's certainly possible, but you may well run into some issues.

    I always thought the real advantage to bi-amping was getting rid of the speakers passive crossover and using an active type xover between the pre and power amps.
    Can't say I've really bothered with biamping that much though - the only time I tried it (a few years ago now), I noticed little difference, although it was with a pair of integrated amps and still used the crossovers in the speakers.
    Using pre/power combos with active xovers (and no xover in the speaker) could well make big differences - couldn't really say for sure though - never tried it!


    The way you've suggested will still need the passive crossover in the speakers, so that's one issue. The other issue is volume adjustment - getting the two (presumably dissimilar) amps to work in unison at the correct relative level for each won't be easy.
    I'll just say you can easily end up creating nothing more than an expensive tone control, but some wacky effects are possible. :)

    If you already have a spare amp you can experiment with, then try it, but personally I'd have to think hard before shelling out any money to do this.
     
  3. buns

    buns
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    I think more positively about biiamping, i think it is very worthwhile.......with a couple of provisos! I would personally not try biamping with 2 amps which are likely so different, there will most likely be difference in gain and other things which mean you wont be able to get a well integrated sound.

    If your amp isn't of a high end nature, you would still likely experience benefits by using an external power amp and forgetting about the power of your current amp.

    I dont know about external crossovers, all i know is naim do them and naim are a pet hate! :D

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  4. Nic Rhodes

    Nic Rhodes
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    Yes I have run many biamped set up both hifi and AV. Strongly recommended. Stick with L and R, then C I wouldn't both about rears.
     
  5. buns

    buns
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    Nic,

    Why wouldnt you biamp the center first? Is it not the channel which has the most action?

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  6. Reiner

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    If I took advantage of this facility, would I be able to biamp any biwirable speakers in my home cinema setup?

    Note that most AV amps/receivers disconnect the internal amps when using those pre-outs.
    Thus it would be of an advantage (necessity) to have mains in/out.

    However be aware that a power amp of a different make/type will not match with the internal amps due to different gain and tonal characteristics.
     
  7. MikeK

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    As there are many ways to accomplish bi-amping, and each can be very different, perhaps people should explain exactly what they mean by bi-amping in their particular case.

    When I tried it (and I entirely accept that this is probably the most rudimetary form of bi-amping possible), I couldn't detect any real improvement at all (or any real difference for that matter).
    I used a a pair of integrated stereo amps (one mine, one borrowed, but the same model).
    The split was left channel of each driving bass, and right channel driving treble.
    I also tried it with one amp doing the left speaker (left to bass, right to treble) and the other doing the right speaker.
    The input was straight from a CD player, using phono Y splitters, to each amp.


    While I accept that this isn't exactly exhaustive research, it does lead me to suspect that some myths "may" be circulating about bi-amping, and exactly what people mean when they talk about it.
    I know one guy who went the full hog down the bi-amping route, and thinks the results were well worthwhile! (but then he did spend a fair wad converting :) )
    Following his observations - I suspect the key may be the crossovers (ie the removal of the passives from the speakers, to be replaced with actives between the preamp and power amps)

    Perhaps there's bi-amping and there's bi-amping! :) :)


    In any case, it would be interesting to hear of other's experiences and how they did it - perhaps a pattern may emerge!
     
  8. buns

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    I am hoping to finally stop testing it and getto biamping my front 3 in a fairly major way. Testing has led me to think that a power amp per speaker sounds best, but that depends how you are doing it. With rears included, i felt that doing it between rears and fronts was best, i assume because the rears consitently 'took less juice' so left more headroom for my fronts.

    Biamping is another example of 'the more you spend, the more you have to spend to get the same', the law of diminishing returns.

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  9. digitalmonkey

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    Thanks for the responses!

    Just to clarify what I was thinking of, my idea was to add a dedicated power amp from the same manufacturer. I would then use the receiver to drive the treble part of the speakers and the power amp to drive the bass.

    The idea is to provide more 'grip' and 'control' over the speakers, as well as giving greater reserves of volume.

    So it looks like there may be some possibility of doing this with positive results, but there would also be a few pitfalls to negotiate. So maybe I will look into this in the future.:)
     
  10. Steve.EX

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    I too would wholeheartedly recommend bi or even tri-amping where-ever possible, i have found it too offer gains in over-all dynamics, far superior grip on bass response and a smoother mid performance and this is using quite modest power amps indeed coupled to quite expensive speakers, agree with Nic re: rear channels even though my 34ds do not allow anything other than single wire i am not sure it would be worth the expense given what they are doing.

    Steve.
     
  11. Reiner

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    Perhaps there's bi-amping and there's bi-amping!

    Nope, there is vertical bi-amping and horizontal bi-amping however. ;)

    Just to clarify what I was thinking of, my idea was to add a dedicated power amp from the same manufacturer. I would then use the receiver to drive the treble part of the speakers and the power amp to drive the bass.

    That would make sense and should give some benefit. However keep in mind what I said about disconnecting the internal amps.
    If there is no in/out for the front channels than it's a no-go ...
     
  12. digitalmonkey

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    Thanks for the advice Steve. My system is not as grand as yours:( (Marantz SR4200 receiver, Wharfedale Diamond 8 speaker package) but I don't see any reason why I should not be able to biamp and get similar benefits. As the receiver is already starting to look a bit outdated against all the latest 6.1 budget receivers, I may add the power amp as my next upgrade, and then get a fully up to date receiver (with full pre-outs) after the latest surround formats have been fully established.

    One other thing that I was wondering about: I will shortly be adding a sub to my system, and intend to send the signal to my front 2 speakers through the sub, using the high level in/outputs. I assume that using a sub in this way mixed with biamping would not complicate things too much would it? Presumably I would simply route the cable from the power amp to the sub, and then on to the speakers?
    I suppose I am just a bit worried that if I send the signal through so many different bits of equipment, it might adversely affect the quality in terms of subtle details being lost.
     
  13. digitalmonkey

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    Reiner, thanks for the advice, but I think I will be ok because the internal amps do not cut out once the preouts are in use (though you may be right in that some other products may do this...but I wouldn't know).
    I know this because I was using them with a little speaker package that connects to a 6 channel output, and I know the amps were still functioning because it blew out the centre speaker!

    Also, I was just thinking, if what you were saying was correct, then how is it that a subwoofer that is connected to a pre-out can be influenced by the volume control on the amp? Surely that shows that the internal amp must still be working?
     
  14. Plump

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    I would not recomend bi-amping to anyone . . .
    . . .unless you get some great savings offer for two amps of the same type (or for second amp if you have one already).

    If you are buying a NEW amp (amps) for the normal price, then it is ALWAYS better to buy one amp that is twice more expensive than each of the two amps for bi-amping.

    Noone in the world can convince me in opposite.

    Cheers
    Plump

    p.s. here's one for bi-amping: if you have two amps and 4 speakers and someone steels two speakers from you, then you should bi amp the pair you still have!
     
  15. digitalmonkey

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    Plump, I see exactly what you're saying, and I had been thinking the same thing myself. But like I said in a previous message, what I would probably do is add a power amp as my next upgrade, as I won't want to commit to an new receiver for quite a while - I have got 5.1 sound as a 'base', and now I just want to wait and see how the future sound formats develop. I don't want to splash out on a 6.1 receiver now, only to find that 10.2 (or whatever) is the norm in a few years.

    So during that time, if I want to upgrade then biamping would seem to be a logical step. Then when I am ready, I can add a new receiver (would have to be from the same brand, but I have a lot of confidence in Marantz) and that should suit me very nicely!:)
     
  16. buns

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    Plump:

    There is an opposite view to that..... i ersonally am ridiculously picky about what sound i like and what i dont, I dont know any amps at twice the price of mine that i would prefer, hence for me biamping is not really a question!

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  17. MikeK

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    There's also active and passive bi-amping!
    What I was particularly interested in was whether people who rate biamping highly had gone for active crossovers between the preamp and power amps with the passive crossovers removed from the speakers (active biamping), or the simpler preamp to dual power amps driving the same speakers as before (ie with the passive crossovers still in place - passive biamping).
    That's quite a difference in setup - however you decide to then wire the power amps (vertical or horizontal)

    I suppose digital crossovers are a possibility too, after all they already do something similar with the bass management in AV receivers!
     
  18. Reiner

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    Also, I was just thinking, if what you were saying was correct, then how is it that a subwoofer that is connected to a pre-out can be influenced by the volume control on the amp? Surely that shows that the internal amp must still be working?

    The subwoofer does not have a dedicated internal amp (power amp stage) in the AV amp/receiver as opposed to the other channels. Volume control is done in the pre-amp stage, thus it affects all pre-outs.
     
  19. Orac

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    The results from Bi-amping depend a lot on the design of the speaker crossover. Bi-wireable speakers (and most are nowadays) don't have crossovers as such - just hi-pass and lo-pass filters on the inputs. These filters can have have varying 'slopes' - 3, 6, 9 or 12 dB per octave - known as 1st, 2nd, 3rd or 4th order. Most high performance speakers go for 1st or 2nd order filters, with generally 1st order responding best to bi-amping.
    When a single amp is connected to a speaker, it has to deal with a conflicting inductance and capacitance from these filters. However, when you bi-amp, the bass amp just sees a steady inductance, while the treble amp sees a steady capacitance.
    Follow the manufacturer guidelines. I use Neat Acoustics speakers, with a 1st order crossover, and bi-amping is recommended (in fact you must at least b-wire them - they don't supply bridges between the input terminals). Similarly, I use Arcam AV50 and 8P amps, as bi-amping is recommended. The result is a beautifully matched sound, with a mid and treble so sweet it's astonishing given the budget.
     

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