Hook up question

[Rolf]

Hi all.

I ask for opinions of the following: For my 4343B's I use active x-overs and two stereo amps. (Same type) One for the woofers, and one for the rest.

I wonder if I use one amp, located by the left speaker to drive left woofer with right Ch, and dive the rest with left Ch, and the same on the amp located by the right speaker to drive the right speaker.

Will this be as good as using my current setup? Any complications doing this? What I want to achieve with this is shorter speaker cables. Anybody has experience with this?

I guess at low volumes no problem, but what when I push the amps?

Thanks in advance for advice.

[boputnam]

... I ... two stereo amps. (Same type)...

Hi, Rolf...

But are the two amps the same output? If so, your plan is fine. On my 4345's, the only reason I use one amp for sub and the other for the upper-range is the difference in amp output. I use the larger output amp for the subs and the smaller of the two amps for the upper-range.

[BMWCCA]

I've seen this type of set-up before and it seems to be the norm in boutique photos of ultimate systems. But I've always wondered whether the required longer line-level output from pre-amp (or other source) to the remote amps might be worse for fidelity than speaker-level long runs of wire between amp and speakers.

I'm asking more than commenting. :dont-know

[jblbgw_man]

Hi all.

I ask for opinions of the following: For my 4343B's I use active x-overs and two stereo amps. (Same type) One for the woofers, and one for the rest.

I wonder if I use one amp, located by the left speaker to drive left woofer with right Ch, and dive the rest with left Ch, and the same on the amp located by the right speaker to drive the right speaker.

Will this be as good as using my current setup? Any complications doing this? What I want to achieve with this is shorter speaker cables. Anybody has experience with this?

I guess at low volumes no problem, but what when I push the amps?

Thanks in advance for advice.

Hey Rolf,

If your amps are the same model then this is probably the prefered method, the reason being is that you have half the power supply energy demand when feeding one LF section with one amp, if you are feeding another LF section with the same amp then it stands to reason you would have double the demand in power supply energy, expecially since most LF is mono therefore limiting LF transient or VLF reproduction. In connecting this way you will have more reserve energy which will come in handy when repoducing low frequency "punchy" signals. The HF will put much less of a demand on the power supply than the LF.

The above opinion assumes that the amps you are using have 1 common power supply for left and right channels (which most do) and not one that uses 2 power supplys. It is all subject to how good a power supply is installed in the amps you own, but most are under rated or border line so this proposed set up should work fine for you and give you the best outcome for transient LF reproduction or VLF reproduction........ have fun!

[louped garouv]

But I've always wondered whether the required longer line-level output from pre-amp (or other source) to the remote amps might be worse for fidelity than speaker-level long runs of wire between amp and speakers.

I'm asking more than commenting. :dont-know

i think it depends on the considerations the designer took in building the unit being used....

the crossovers I have been using are designed to have long cable runs to the amp racks...

the last complete paragraph on the third page of an old AES paper hosted here discusses the crossover:
http://www.deepattitude.com/convention_aes.htm

[grumpy]

Same amps, you say? I would do it. I have done it.
Having shorter speaker cables is a good thing.

Likely improvement in bass and large transients
(completely separated power supply per bass driver).

If amps are well designed, I don't see a down side.
Worst case, the MF/HF range could be slightly degraded,
but I wouldn't expect that, going in.

-grumpy

[boputnam]

Worst case, the MF/HF range could be slightly degraded, but I wouldn't expect that, going in.

Hey, Dave - why do you say that? Would it be because the MF/HF "channel" would be operating at low relative gain?

[Robh3606]

As long as they are identicle amps why not??

Rob

[grumpy]

why do you say that? Would it be because the MF/HF "channel" would be operating at low relative gain?

Hey Bo.

That, (extra line-level attenuation) which on -some- systems, seems to suck
the magic out of well recorded material played back on particularly 'revealing'
speakers... not that it sounds -bad-, but something gets lost in the process
that doesn't equate to normal descriptions of frequency response, dynamic
range (or SNR or -extra- noise)... which sucks, as I like to explain "magic"
when I can. Probably not noticeable on many very fine systems, ... just
something I've said BS to, and then proceeded to experience first-hand .

...and the -possible- modulation of the MF/HF signal by the amp's
second channel LF signal (where before, both channels were MF/HF and
relatively unburdened). I would expect this not to be a problem for most
quality amplifiers, or for amps (as someone else posted above) that have
dedicated power supplies for each channel.

Again, I've biamped a system this way and was very pleased with the
result. Recommended

[Rolf]

Hi, and thanks for replies.

Yes, the power amps are the same. Perreaux 350. 350W/Ch - 80Ampere/Ch.

The reason I ask is that I have been told (by some) that by doing this, the amp will get "in trouble", since the LF demands a lot of power (W), and the heights demand a lot of amperes. As said, being told this is a no win satiation, and it is better to use one for LF and one for HF.

Very confused

[Rolf]

I've seen this type of set-up before and it seems to be the norm in boutique photos of ultimate systems. But I've always wondered whether the required longer line-level output from pre-amp (or other source) to the remote amps might be worse for fidelity than speaker-level long runs of wire between amp and speakers.

I'm asking more than commenting. :dont-know

I use balanced cables, so I do not believe there can be much difference between 1m or 3m (3ft of 9ft)

[Rolf]

The above opinion assumes that the amps you are using have 1 common power supply for left and right channels

Yes one toroidal supply (a very large one).

[Guns]

This method of bi amping is called vertical biamp. i have done this to my lsr6332 but passive the result is the bass becomes more tight and mids and highs are smooth. there is lot of reserve power which will be used when the music or transients call for it. however the only question is how is the power distributed inside the amp if the single transformer send power to both the channels depending on the requriement of the channel then the best results will be obtained as more power will be used by woofers and less by mid and high.

[jblbgw_man]

.
The reason I ask is that I have been told (by some) that by doing this, the amp will get "in trouble", since the LF demands a lot of power (W), and the heights demand a lot of amperes. As said, being told this is a no win satiation, and it is better to use one for LF and one for HF.

Very confused

Well giving consideration to what you have been told, then it's a wonder how any amp will go driving the full audio bandwidth with both channels driven? Again considering what you have been told if you apply some logic then an amp (not bi-amped) is normally having to drive a mix of LF and HF x 2 (channels), the proposed way it is only driving 1 x LF and 1 x HF, therefore the demands on the power supply are halved compared to driving 2 x the audio spectrum, gotta be better off ........ oh and ask them to define the term "trouble", it's a little broad, as far as LF demanding a lot of Power and HF demanding a lot of amps, if we apply simple Ohms Law we realise the 2 are related, can't have one without the other ......, it may be more appropriate to say that LF may impose more peak current demand from the power supply than HF, either way using some logic to what you have been told then you are still better off, or of course you could try it "both ways" so to speak and post your findings

[yggdrasil]

Hi, and thanks for replies.

Yes, the power amps are the same. Perreaux 350. 350W/Ch - 80Ampere/Ch.

The reason I ask is that I have been told (by some) that by doing this, the amp will get "in trouble", since the LF demands a lot of power (W), and the heights demand a lot of amperes. As said, being told this is a no win satiation, and it is better to use one for LF and one for HF.

Very confused

For this to be correct the HF section would need to have lower impedance than the LF section while being approximately equally sensitive.

Yes one toroidal supply (a very large one).

One toroidal can still feed two power supplies(separate capacitor banks).