Let's all take a deep breath here folks. This is audio, after all, not politics. :)
I hereby request this conversation remain civil from here on out.
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Let's all take a deep breath here folks. This is audio, after all, not politics. :)
I hereby request this conversation remain civil from here on out.
There seems to be some confusion regarding bi-amping so I thought I will present an accurate explanation…
I have noticed that bi-amping seems to have two definitions lately, both similar, but with very dramatic differences as to how to achieve it and what benefits (if any)
From an engineering perspective, we define bi-amping as using different amplifiers (usually 2) each dedicated to reproducing a different frequency range. In reality, when you are using an AVR with the speakers set to small, and a powered subwoofer you are already bi-amping. The amplifier in your receiver is dedicated to a frequency range of, for example, 80 Hz to 20 kHz, while the amp in your sub is dedicated to 80Hz and below. This is achieved by using active high and low pass filters. Active meaning that the signal processing (filtering) is done on the low level signal (pre-amp level), before it is amplified, thus resulting in an amplifier only reproducing a portion of the bandwidth.
To achieve this type of bi-amping with a loudspeaker (which has many proven benefits), one would have to design an active crossover for the speaker and bypass the internal, passive (high level) crossover… This type of beneficial bi-amping is simply NOT possible with typical loudspeakers that are bi-wire capable. You can not bypass the internal crossover of the speaker. Using 2 amplifiers (each one dedicated to a different frequency range) will have no benefit and can hurt performance.
In fact, even if you were able to bypass the internal crossover, and use an electronic crossover to separate highs and lows thus sending them directly to the tweeter and woofer, I would NOT recommend it. Reason for this, at least in our crossovers, there are many optimizations and impedance compensation circuits designed to contour and control the response and dispersion of the speaker, not just send the highs to the tweeter and the lows to the woofers. Naturally, bypassing our crossover would also bypass these circuits, thus critically hampering the performance of the loudspeaker….
Where confusion seems to develop is that many people now define bi-amping simply as using more than one amplifier feeding the same signal into the speaker. This can be done with our CMT-340 series speakers, however, there is much to be considered before attempting this..
It is critically important to use the exact same amplifier. As you know, not all amplifiers sound the same or have the same gain… In fact, there are probably as many different amps as there are speakers. Imagine using an amplifier that sounds different from another, and one of those amps is feeding the tweeter while the other feeds the woofer. Do you think the loudspeaker would perform within specification? Certainly not, plus, different impedances of the amplifiers could greatly affect how the crossover “blends” the tweeter response with the woofer response. Crossover point might be moved higher or lower, the delicate phase alignment might be thrown off.. All greatly hurting the performance…
Some receivers offer a “bi-amping” feature so that if you are not using that 3rd pair of speaker outputs (7.1) you can run another set of cables from that output to the speaker. This used to be called “amplifier bridging” and I guess the marketing geniuses decided that bi-amping is a more exciting term, even though it is technically incorrect. This type of bi-amping can present a slight performance improvement in power and dynamics only. However, keep in mind that all the amplifiers in your receiver are running off the SAME power supply so technically speaking, the benefits you might achieve in added power and dynamics are severely limited by. It is NOT the same as using two separate amplifiers…
I hope this explains what bi-amping truly is… thanks for your time!
Whew! Thanks Dave! I really appreciate you providing technical explanations as this. Stuff I didn't understand beforehand and now have a better grasp on.
Randy
I have been lurking on this forumn for a few days and getting educated on speaker technology and I have a question for you. I am no expert but it seems you are making the argument that Ascend speakers should not be bi-amped due to the complications one may face. If this is indeed the argument that why offer the feature in the speaker to begin with?
Quote:
Originally Posted by davef
For those that would to try bi-wiring, not bi-amping.....which is a whole other debate. With bi-wiring, some say they hear differences, some don't. So it is an option you can choose to use or not.Quote:
Originally Posted by khoi911
Some how this thread went from bi-wiring to bi-amping. I guess you can bi-wire a speaker with one amp but this does not really make sense. But to really bi-wire a speaker you need 2 amps but doing so means you run into lots of potential issues. It is late and I am lost. :(
Quote:
Originally Posted by curtis
Hi Kkoi911... welcome to our forum!Quote:
Originally Posted by khoi911
First off, one comment I would like to make is that my recommendation against bi-amping is not just for Ascend loudspeakers, this is for 99% of ALL loudspeakers that use a passive non-bypassable crossover network (which are the vast majority of loudspeakers out there)...
Active bi-amping (true bi-amping) is not possible with this type of loudspeaker because it would require bypassing the internal crossover of the speaker and sending a high-level signal directly to the tweeter and a separate high-level signal to the woofer.
Passive bi-amping is possible, but as I recommended in my original post, you MUST use (2) identical amplifiers thus sending the exact same signal to the high-frequency input of the crossover and another signal (from the other amp) to the low-frequency input.
The feature offered (and what we advertise) is called bi-wiring. This is completely different then bi-amping….
Again, this is not specifically for Ascend loudspeakers, but for the vast majority of loudspeakers out there.
Hope this helps!
[QUOTE=davef]
Passive bi-amping is possible, but as I recommended in my original post, you MUST use (2) identical amplifiers thus sending the exact same signal to the high-frequency input of the crossover and another signal (from the other amp) to the low-frequency input.[QUOTE]
So one would do this by spliting the pre-out signal from the receiver via a Y cable. Then each cable going into 2 identical amps. The signal is then amplified and sent to one speaker where one amp is decicated to the tweeter and the other amp drives the mid-range. I am painting the correct picture here?
BTW, Thank you for responding to my post. I will be ordering some speakers soon from you. I definitely want 340s up front (L,C,R) but still deciding on the rears. Not sure if I want 340s or the 170s.
Thanks again,
Khoi
Hi Khoi911,Quote:
Originally Posted by khoi911
You are exactly correct on the connection. However, be aware that both amps are reproducing and outputting the exact same signal. This would be considered passive bi-amping. The output if each amp goes to the corresponding input of the speaker's crossover. Some 7.1 receivers offer "bi-amping" if the rear surrounds are not used.
An active bi-amping connection would resemble having the low-level signal (pre-amp signal) going to an electronic crossover. The low-level high frequency output of the crossover would drive the amp which would then connect directly to the tweeter (bypassing the speaker's own crossover), the mids would also go to an amp and then connect directly to the midrange drivers. Each amp is reproducing only a portion of the bandwidth... This is true bi-amping and is quite complicated, something that can only be properly implemented with active loudspeakers.
Bi-wiring uses a single power amp with a pair of speaker cables. One set of cables connects from the amp to the high-frequency inputs, and the other set connects from the same set of amp outputs to the low-frequency inputs of the speaker's crossover. The theory behind this is that by by separating the delicate high-frequency signals from the higher energy low-frequency signals within the speaker cable, intermodulation distortion is reduced.
I think you've got it now :D
Glad to help :p
Can Dave or anybody else please confirm if I am thinking correctly about this setup to use the "bi-amp" feature on my Pioneer 1015? The process would be as follows.
1: Remove the jumpers between the binding posts on the 340's.
2: Run speaker cables from the L/R on the reciever to one set of binding posts on the 340's.
3: Run speaker cable from the unused surround posts on the receiver to the other set of binding posts on the 340's
4: Set the Pioneer to "bi-amp" and re-set levels.
5: Sit back and try to convince myself that I hear a difference. :p
Thanks