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Can I bi-amp? How?


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Okay, I admit it. I have a problem. The stereo bug has bitten me and I'm hooked. Because of that I find myself wanting to experiment a little, but don't have the technical know-how. I need your expertise to help me with my curiosity about whether or not I can bi-amp with my existing equipment, whether or not there would be a valid motive for doing so, and how I would do it. Here is my equipment list:

Klipsch KLF20 speakers (wish they were Cornwalls, but whose complaining. And the date for placing Cornwalls back into production is when? I'm there with my check in hand when that happens!)

NAD 3020 integrated amp (rated about 35 wps)

NAD C740 stereo receiver (also about 35 wps)

NAD 515 CD changer

NAD 613 tape deck

Kimber braided cable

Intend to buy some Radioshack cable if bi-amping or bi-wiring

Notice the NAD theme? Anyway, both amps have pre-out and main-in connections. So my list of questions is long:

- Can this equipment be connected in a way that would provide bi-amping?

- Again, if I could, is there a valid motive for doing so?

- What improvements, if any, might I expect, and would they likely be dramatic, or subtle?

- Which amp would I use for highs, and which for lows? Both have the NAD soft clipping feature. I always listen at volume levels not much beyond normal conversation levels.

- Which cable would be most appropriate for the highs, and which for the lows, given that I think the speakers sound a little bright on the top end?

- Would both volume controls come into play, or could it be done so that one volume control or the other would control all?

- Which component would receive the source devices (CD, tape deck, turntable, VCR)? Currently running the turntable through the 3020 since the C740 doesn't have a phono preamp).

- Can you give me idiot proof, step-by-step instructions (i.e. connect component A to B using the X out from A to the Y in on B, and so on)?

If these are dumb questions, I apologize for wasting your time. If it can be done, I look forward to your feedback, and thank you all in advance!

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True biamping requires an electronic crossover, probably with level controls, and bypasses the passive crossover in the speaker. You have most of the equipment to Biamp. Bypassing the internal xover is an "own-your-own" situation. I'm SURE it can be done, but I have never seen inside your speakers.

To get started, cheaply, go buy 2 pair of F-Mods from Harrison Labs (search with Yahoo or at a car audio shop). Buy a pair of high-pass and low pass at the design xover frequency of your woofer to squawker (800 hz?).

I'd use the reciever as the "master". Connect a Y-adapter to the receiver's pre-outs and use the high pass F-Mod to feed the receiver's power section. Use the low-pass F-Mod on the other branch of the "Y" and feed the Aux in of the integrated amp. Connect seperate speaker wires from the receiver's speaker terminals to the squawker and tweeter and connect the integrated amp to the woofers. Use the integrated amp's volume to balance the sound.

This should work well. You can try passive biamping by omitting the F-Mods and unstrapping the biwire terminals on the speakers. Passive biwiring requires the speaker's xover be UNmodified.


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Whoa! It didn't take much for you to get over my head on this, but thanks for the advice gentlemen. John, I am confused about the solution you offered. You mentioned that 'true' biamping requires the internal speaker x-overs to be bypassed. Does that mean that in addition to the F-mods I would need to get inside the speaker to disconnect the x-overs, or are the F-mods a way of effectively bypassing the speakers x-overs (i.e. by separating the frequencies before they get to the speaker you are eliminating the need for the speaker x-overs to do any work)? I don't think I'm willing to open up the speakers and make any changes at this point. Would your solution allow for one volume control (the receiver) to rule, or would I have to play with both to get the balance I'm looking for? It might actually be kind of cool to have that ability! Would I need to remove the straps on the speakers under your senario? You mentioned two pairs of F-mods, and I think you are suggesting that both the high pass and low pass be purchased at the same x-over point, correct? The way I'm reading your instructions, however, I only see one of each F-mod being used (i.e. one high pass, and one low pass). What am I missing? Do you really mean that the low pass line should be connected to the 3020 aux in, or did you intend to say that it should be connected to the main in? Would it make any difference? What do you mean by 'passive' biamping or biwiring? What does Harrison Labs mean when they talk about F-mods being 12db/octave, or 24db/octave when stacked?

Sorry for all the stupid questions, but I really don't know much about this stuff. I'm very eager to learn though, so your adice is very much appreciated!

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True bi-amping requires the removal or modification of the internal crossover, yes. A 3-way system could be tri-amped, or the crossover modified so that the HF amp sees the mid to tweeter crossover. One point is to get rid of the passive xover and its impact to sound. Properly done, the electronic xover is a high quality, expensive piece about the cost of a good pre-amp.

I don't think this is done much, anymore, outside of LARGE pro audio systems; the outdoor or stadium stuff.

I suppose "stacked" means plugging one F-mod into another and then into the power amp.

The configuration mdeneen and I suggested would only use the receiver's volume AFTER the system had been balanced using the integrated amp's volume. For this reason, the "Y" and F-mod must be connected to the AUX in.

Passive bi-amping uses no electronic xovers and thus fails to reap the benefits of eliminating the passive xover components. It is an easy way to put unused equipment to use and get more power (giving more headroom).

If used for this, both the high-pass and low-pass F-mods MUST be at the same frequency. You must have one for each channel.

Unstrapping the bi-wire terminals will allow bi-wiring, of course, and passive biamping (no F-mods). True Bi-amping will require extensive modification to the crossover and you will end up with, most likely, a similar looking pair of terminals on the back.


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Slowly but surely I think this is all starting to sink in. So if I am understanding correctly, if I elect not to mess with the xovers in the speaker, then my only options are biwiring or passive biamping. And, it sounds as though what mdeneen is suggesting is in fact passive biamping. Correct? If I choose passive biamping as suggested by mdeneen, then all I really need to purchase is two Y-connectors, and another set of speaker wires. Since all of my equipment is already connected to the receiver, I would simply make the following connections;

1. Plug one Y-connector into the left channel pre-out on the receiver. Plug one leg of that Y-connector into the left channel main-in on the receiver, and the other leg into the left channel main-in on the integrated amp (or maybe the aux in on the integrated as suggested by John? Still not clear which is correct).

2. Repeat step one for the right channels.

3. Remove the terminal straps on the KLF's and run a set of speaker wire from the receiver terminals to the top, HF terminals on the KLF's.

4. Run another set of speaker wire from the integrated terminals to the lower, LF terminals on the KLF's.

5. I imagine I could leave my turntable connected to the integrated phono inputs, with a connection from the tape out on the integrated to the aux in on the receiver. It shouldn't make any difference that the signal from the turntable is going first through the integrated preamp, then out the tape-out to the receiver preamp, then BACK to the integrated main-in (aux in?), right?

Did I get it right?!?

Can I hurt the speakers, or any of the equipment if I, say, don't get good balance between the volume on the two amps and end up boosting the bass a little too much?

Will this all be an exercise in futility, or can I expect to hear REAL improvements (tighter more prominent bass balance for example, or better imaging)? Here's the real question; given the same equipment in your home, would you opt for a passive biamp setup like this?

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Thanks! One last question. The thing that got me started on this whole train of thought is that I kind of feel like the highs on the KLF's overpower the lows a bit. I got to wondering if there might be something I could do with my existing equipment to get better balance between the highs and the lows. Would it be unreasonable to think that with this passive bi-amp setup I could INTENTIONALLY set the volume levels between the integrated amp and the receiver incorrectly in order to boost the bass relative to the highs, or reduce the highs relative to the lows? Would this simply be a round about way of creating a very basic equalizer, or would this avoid the colorization of the signal that many of you have suggested is the downfall of equalizers?

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Thanks mdeneen. Actually, the only gear currently running through the integrated is my turntable, and that is going into the phono inputs, then out through the tape-out. This is because the integrated HAS a phono preamp, but the receiver does not. The volume on the integrated shouldn't effect the phono preamp or tape-out should it? So in conclusion, running the "y's" into the aux instead of the main-in on the integrated will allow me to independently set the volume of the highs vs. the lows, then once I've got the balance I want I could just use the volume on the receiver to adjust the whole rig up or down.

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  • 4 years later...

PS - it is also worth noting that an "electronic crossover" is

every bit as much a crucial component as a preamp or power amp when it

comes to sound quality. Cheap crossovers can and will screw up your

whole scheme of having great power amps and preamp. i.e. I have seen

such things as exotic tube preamp and two exotic tube amps being

combined with a skimpy kit-built Solid State IC crossover! Might as

well pour your money down the drain at that point.

Just catching up on reading posts from 2001.

Mark makes an excellent point, as he so often does.

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