Axiom Home Page Forums General Discussion Home Theater Bi-amping M80ti Speakers does work!

I had written in an earlier post that I was going to bi-amp my front M80ti speakers. The Denon 3805 I have is a 7.1 channel AVR that I am using in 5.1 channel mode (because I don't have space for 7 speakers!). The unused two back channels are now being used to drive the woofers in the M80ti towers. And on the Denon 3805 I can adjust the levels of the woofers separately from the that of the tweeters! That's pretty cool! I can immediately hear the difference in the sound.

I know this is not rocket science, but I am happy!

Oops!! Somebody is going to be very skeptical on your findings on bi-amping here...

thyname, not necessarily true. If the biamping results in a different signal level going to the tweeters than to the woofers, then a noticeable difference in sound is not unexpected.

When biamping however, unless you're using an external crossover and have disabled the internal crossover, you should really take care to send the same signal to both sections of the speaker. Otherwise you're negating all the careful research that has gone into making the M80s such accurate performers.

Let us ask Richie: has he disabled the internal crossover at his Axioms?

Uh..No...I have not disabled the internal crossovers in my Axiom M80ti's! I only followed the directions given here:

http://www.audioholics.com/productreviews/avhardware/Denon-AVR3805_review04.php

So, what exactly have I done? :-)

I think I am sending the same signal to both sections of the M80ti Speakers.

I think what I am doing is referred to as passive bi-amping. I saw it defined like this in an earlier post on this site:

<<<Passive bi-amping refers to running two amplifier channels in parallel without an external crossover. For this, you leave the internal speaker passive crossovers intact. This offers the benefit of increasing total power, but basically nothing that will significantly affect the sound quality.>>>

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And on the Denon 3805 I can adjust the levels of the woofers separately from the that of the tweeters! That's pretty cool! I can immediately hear the difference in the sound.

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It does seem to me that you are altering the sound of the M80s. I assume you have adjusted the woofers of the 80s to receive a stronger signal than the mids and highs. What you have now would be rise in the upper to low bass region. You could also achieve somewhat of the same effect just using the tone controls, or bumping up the sub a few notches.

I'm not saying what you have done is either good or bad. If you like the results then what can I say.

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This offers the benefit of increasing total power, but basically nothing that will significantly affect the sound quality.

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This passive biamping you are talking about does not increase the power going to the speaker. When you leave the binding post straps in place the upper and lower part of the M80 is getting the same amount of power. When you remove the strap and biamp like you have the lower and upper part is sill getting the same rated power.

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Uh..No...I have not disabled the internal crossovers in my Axiom M80ti's! I only followed the directions given here:

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That is what I thought. Who would take the bother to move the internal crossovers of the speakers, unless one is a technician or something...

This is a very contraversial topic. While there are people who have tried it and liked the results, there are others that never tried it and still claim that achieves nothing. I always think that it is up to the people to decide what's good for them.

Richie, what Peter was referring to isn't something which is necessarily done by the user intentionally. Two different amplifier channels, even in the same receiver, may not be perfectly matched as to output. This can result in one section of the speaker having a slightly higher or lower sound level at the same setting than the other section, as compared to the situation when both were driven by the same amp channel. So, this could result in a slight audible difference, but wouldn't be an improvement as such, but simply an imbalance from what was intended by the speaker designer. Subjective impressions can be, and often are, misimpressions, but that isn't necessarily the case here, although that type of biamping has no factual basis for actually making an improvement. The same power available from the power supply section of the receiver is simply routed through the output transistors in two channels instead of one; no increase occurs.

I can see that bi-amping speakers is a very controversial topic! Thanks to everyone for responding to my original post. I am certainly learning a lot in this forum! :-)

Usually these guys around here know what their talking about, you might try talking to Axiom for further confirmation.

Enjoy Ritchie!