Is Bi - amping worth the trouble?


Hello all...

I'm on the fence with the thought of bi amping. A big part of me wants to go ahead with it... the 'wallet' part says "Not so fast".

There should be lots of folks who've biamped speakers before... When it was all said and done, "Was it worth the time and expense?"

I'm inclinded to add a tube amp for the upper end of my VR4 JR's ... or any other speakers for that matter... though in any case and reardless the speakers, tube amp on top, and SS on the bottom.

...and then there's the thought of keeping two dissimilarly powered amps matched at the same volume level... and the added IC's, PC, and stand... it does seem to add up.

... and at this point, I'm thinking BAT to keep things all the same... and am not sure there, wether even that matters too much...

I sure do appreciate the input.
blindjim
Perfectionist: Given the fact that you're using mono-blocks, you wouldn't be vertically or horizontally bi-amping. You would simply be bi-amping with mono-blocks.

Blindjim: How did you arrive at the figure of 3 dB? At radio frequencies, every connection added is a supposed .5 dB loss according to common teachings. In my experience, a good connection doesn't lose anywhere near that much. At audio frequencies, i'm quite certain that the loss is noticeably less.

Having said that, connection losses may not be linear in amplitude as frequency is varied. On top of that, other distortions may occur as a result of added connections. Obviously, the quality of connection will have a lot to do with how much loss is involved. The greater the variances between terminating impedances, the greater the loss and potential for increased distortion. Needless to say, part of "cable swapping" is a combo of all of the above, which partially explains some of the variable results we achieve in different systems.

I've often contemplated what would happen if one were to take a distortion analyzer and measure an entire system from source input cabling to speaker output cabling. After baselining the system as one normally runs it, one could then swap individual cables and re-run the same tests. I think that the comparative results would be very interesting to say the least. It would also be interesting to see how the system as it was would sound compared to the system as it measured lowest in distortion.

Obviously, one could conduct such testing component by component, swapping cables until the lowest distortion was achieved. From there, the next component and cable could be installed, taking the same approach. One could repeat this until the entire system had been pieced together using this approach.

Using this method, the cables would be acting as impedance matching transmission lines. Each cable would be fine tuned for the specific electrical interaction between the mating components that they joined together.

There's a LOT to think about on stuff like this. Quite honestly, i'm surprised that nobody has done anything like this and / or published research on this subject. Then again, most AF engineers don't think about cabling acting as a "transmission line". Could be why the subject has never been looked into that thoroughly.

Other than that, there are great sonic advantages to be had going "direct drive" i.e. no caps, resistors, inductors between the amp and speaker. Most of the guys messing with "full range" drivers know and realize this, but most of the "audiophile world" are clueless in this specific area. Sean
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Quite honestly, i'm surprised that nobody has done anything like this
Sean, FM Acoustics does this -- but for tis own products.

As you note, the designer hasn't published anything on this.

BUT, if you buy a complete system from FM (i.e. electronics + cables), that whole transmission line is optimised.

You can even buy speakers (made by someone else ASAIK) similarly "optimised" for the FM amp + spkr wire used. HOWEVER, I understand that the recommended solution is active multiamping... of course, one can order the spkrs with a passive xover in which case the spkr cable supplied is different (obviously).

So, the transmission line is purportedly optimised starting at the source output cable. Since FM's preamps allow some variability in their input impedance, this line can be tweaked soemwhat further upstream.

One snag is, the wires must be specific in lengths (apparently a small variability is OK). Another is the cost -- $~+10-15k per component: this may not look ruinous for some, but for a vinyl addict doing the simple maths, it adds up: Pre + phono+power amp = $+~40k. The cost of cables is minimal apparently:)
Oh yes, I forgot: you also need spkrs...

Oh yes: I actually listened to such a system, vinyl source -- with different spkrs. Admittedly, impressive, very impressive.
"Why not put all the money In a ecxellent stereo amplifier, instead of several lesser units with signal degrading from external crossover units."

First of all it is my impression that there are no Excellent stereo amps, excellent would apply only to mono amps...
What would a lesser or excelent amp be?
An excellent amp with 8 tubes per side on push pull? Thats a lot of tubes, and they do sound like it...IMNSHO a pair of pushpull tubes is best smaller is better then.
Also you get more power supplies with 4 monoblocks that with one stereo amp. I have even seen diagrams (and almost tried one) of one amplifier with a power supply per stage of amplification....that would make it 8 power supplies against...well one.

What we are also trying to avoid is the internal Speaker Xover and use line level XO inside each amp....cool!!

Do Bi-amp
Getting in a little late on this one, and, I have not read every thread in response so apologies in advance for any redundancy.

I am a big believer in byamping, have been for quite some time, in my opinion, it must be done using an active crossover. I have tried using a passive crossover and I think the gains are not worth the expense. It is quite a bit more expensive going with an active crossover over a passive crossover. You will need two amps, two sets of interconnect, three power cords (one for the mid/base amp, one for the tweeter amp and one for the crossover), an active crossover (all active crossovers have gain controls for the top and bottom, at least I have not seen one without) and two sets of speaker cable. The results are quite impressive. Going in this direction one can than pick amps that suit his/her taste. SET on the top for the sweetness of a SET, SS on the bottom for the dynamics, weight and overall slam, or SET on the top and SET on the bottom, etc, etc.

When using an active crossover you will have to run your speaker cable from your outboard crossover directly to the individual drivers of the speaker. You will be bypassing the internal crossover within the speaker. You can't just hook up to the binding posts on the back of your speakers because you would not be bypassing the internal crossover.

I have found, as so many have referred to the blacks, the blacks are blacker, and the noise floor is lowered beyond belief. Each artist is positioned and stands alone without competition from others or movement. Each artist has his/her space; even on coral pieces there is depth and width without haze. The highs are so clear, a brush on a snare, one can count the number of bristles, obviously an exaggeration but I can hear various bristles making contact, shocking.

I am sure that there are many who will say the expense is not worth the return and to many that is true. For me, I will not be going back to a single amp to reproduce the whole frequency range running through a passive internal crossover anytime soon. Good luck with whatever you decide to do…………Bob
Bmotorcycle: This is one of those things that people won't / can't understand until they experience it for themselves. After doing that, they can't believe they wasted all of that time before stumbling upon this "aural revelation". As i've called it before, "direct drive" i.e. amplifier to speaker cable directly to the raw speaker driver is the real deal. Sean
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