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Michaelholder1's picture
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Bi-amping
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Now I have a reasonably good understanding of speakers and electronics although I am pretty much a novice in the world of High fidelity. So I am looking at buying a stereo amplifier but am a little confused with Bi-amping. No I understand passive crossovers are not as affective as active crossovers as there is a small amount of distortion at the crossover frequency or something along those lines. However as I understand the use of active crossovers is not widely practiced in the hifi world so what is the purpose of bi-amping when using passive crossovers. Also do I need two amplifiers or do some stereo amplifiers offer the ability for bi-amping? My price range for a used amplifier is around £150-200, and I currently own a pair of B&W Dm603 S2s. Also I was wondering why active crossovers are not used in hifis? I was thinking when using a sub which I would like to, surely having an active crossover take away the harder bass frequencies from the main stereo speakers and give it to the sub would reduce the strain on the main speakers and give a better sound? Also using an active crossovers when Bi-amping would surely remove the inherent disadvantages of using passive cross-overs?

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RE: Bi-amping

There is not really any point in Bi-Amping IMO.

Either just buy one better amp or get a seperate active crossover and go DIY.

I doubt you will get any 'integrated' amps that Bi-Amp, some might say they do but will just parallel the outputs. It would need to be a 4-channel amplifier (or two 2 channel) to be able to bi-amp.

Active can be better, but will not always be. You would be better off starting with a better pair of speakers rather than modifiying them IMO, or going down the DIY route and go Active in the first place.

 

I hope this does not turn into the active slagging match that it usually does.....

Michell Gyrodec SE / RB300 / 2M Blue | Sony DVP-S9000ES | Bryston B60 | Rega R9

Michaelholder1's picture
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RE: Bi-amping

Well I may go down the DIY route later on in life when I have more money to spend but more for fun really. Ok so i just want a regular stereo amp with 2 outputs, I was looking at the arcam 9 which a lot of people have reccomended which has 2 outputs, so I could use one for hi and one for low? If there is even any point in the first place?

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RE: Bi-amping

If you Bi-amp your speakers (Assuming they allow it) then you are isolating the HPF from the LPF thus preventing any interaction between the two.

How much difference it will make will be determined by how good the design of the passive crossover is, the better quality (And more expensive) speakers will have a better crossover thus improvements will probably be minimal, (Some high end speakers don’t even allow you to bi-amp) however the cheaper ones may benefit more as their crossovers quality may not be as good. (Corners have to be cut to keep costs down)

Active crossovers are better as they are easier to design and control, however these are normally used in professional applications where the active crossover and amplification is built into the speaker.

Hope this helps

Bill

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RE: Bi-amping

That makes a lot of sense thanks. What exactly is the HPF and the LPF? I presume the H and L for high and low. Professional applications being live sound or studio sound? I know that most live sound set ups will have have a mixer to an active crossover to high and low amp/speakers sometimes even high mid low. I do not know much about studio sound but I think a lot of studio monitors are active, i know the studio I used to teach drums at some very nice active benelec speakers but I'm not too sure if they also had an active crossover inside. Sounds like an interesting design choice if studio monitors are designed like this.

So now I see there is benefits to Bi-Amping; should I be looking at stereo amplifier with two outputs? As I do not think my budget of £150-200 will allow me to buy a decent pre amp to two mono block combination unless i waited to find some idiot selling one on gumtree well below its worth. It does happen but it seems unlikely in the near future.

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RE: Bi-amping

High Pass Filter and Low Pass Filter capacitor for the first and inductor for the second (plus a few other bits!!)

If you are going to bi-amp you really should have 2 amps or an integrated with matching power amp such as Roksan's Kandy pairing etc

 

Tommo

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RE: Bi-amping

Ah ok that makes sense. Right so I either want to go integrated plus matching power, or pre plus two power amps. Ok; whats the problem with using an integrated amp with two outputs?
I also forgot to ask if there is much advantage in using an active crossover when using a sub to reduce strain on the main speakers? Or if there is any other way of doing this? Although I was thinking earlier does an active Xover have to convert an anologue signal to a digital signal and back again in order to seperate the frequencies; in which case that must have a reasonable affect on the sound?

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RE: Bi-amping

I would not see any problem with a single amp with speakers A+B out but with the caveat that normally this setting just parallels the outputs which will half the impedance seen by the amp therefore you will need to make sure the amp in question can cope with driving such a low load. The more exopensive ones usually can they are designed to drive high currents whilst usually the lower cost ones are not. this is a very general comment and you should check with the manufacturer of your choice of amp if you need too Smile

 

Tommo

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RE: Bi-amping

Tommo is correct in that unlike Bi amplification the LPF and HPF are not isolated, thus it is classed as Bi- wiring which is not recommended as it adds too many variables into the speaker chain.

Example: The connection resistance between the LPF and HPF is known by the manufacture and so the speaker design takes this into account, however if you Bi-wire you add the resistance of the cable between the LPF and HPF which could unbalance it, (As the resistance of the cable is unknown to the manufacture it cannot be taken into account) hence the reason why bi-wiring is not recommended.

Hope this helps

Bill

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RE: Bi-amping

Hi, I've been biamping for years- I've used NAD C350 integrated & C270 power, Roksan Kandy mk3 integrated & KM-A2/3 power, and currently on the stuff in my sig below.

Biamping, for me, improves control and focus and adds a little more overall clout to music. Also, I'm probably never going to be stuck for power. The general ethos I've known, is that if you can biamp, then do biamp. Trouble is, once you biamp, you can't go back to integrated...

If it were my budget to spend, I'd be on the lookout for a Rotel (oh what a surprise) RA971 (mk2 if possible) amp, and then an RB971 power amp to wobble the woofers with. Of course, the integrated will do a grand job on its own until the power amp can be acquired. Bear in mind though that this combo does not have remote control. A small point but important to many... 

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