Oh sure, I was entertained by reading the article, especially the part where you claim there are obvious differences with bi-amping. I run my Salon2s bi-amped, because Alex dared me try it and I'm too lazy to undo it, but I can't hear a difference.
That's interesting. In the past, I have tried bi-amping and found little or no difference. I actually think it sounded worse when using the Marantz AV8801 internal bi-amped setting.
The configuration may be important. I use Y-Connectors (BJC) and stacking banana plugs to make the switch between single-amped and bi-amped (in <30 seconds) and I did so yesterday. I do this periodically as a sanity check. In this case, I chose Cassandra Wilson's "Another Country". Once again, the vocals are clearer and bass is better defined. It is really is quite remarkable. If you come to the Boston area, I'd love to demonstrate.
Useful links:
Cassandra Wilson's "Another Country":
http://www.hdtracks.com/another-country?___store=default&nosto=nosto-page-search1
Locking/Stacking Banana plugs:
https://www.parts-express.com/angled-locking-and-stacking-banana-plug-with-dual-set-screws-poly-carbonate-shell-and-insu--091-3608
My configuration is:
- Oppo UDP-205 USB DAC (no processing occurs in the Oppo)
- XMC-1 Balanced inputs in Reference Stereo mode (XMC-1 provides volume control only)
- Y-Connecters split the signal (no DSP processing involved)
- Stackable Banana plugs allow switching between single in <30 seconds and SBT
It probably does not matter, but the signal chain is fully balanced.
I don't believe that bi-amping should be put in the same class as other "tweaks".
Some seem to be against because the passive crossovers are still in place.
Yet, logically, there are the following differences between single and (passive) bi-amped speakers are apparent:
- Crossovers are not perfect, they interact. Revel places them on 4 separate boards to avoid Electromagnetic interaction. It seems logical that actually disconnecting them could yield positive results by fully eliminating interaction. I have seen amplifiers exhibit IMD when 60 and 7kHz signals are played together. It would not be surprising to find interactions within a passive network.
- The amplifiers experience different loads. I'd love to see impedance and phase measurements performance on speakers like the Salons2 with the straps disconnected. If there is a change, it could account for volume differences at the same voltage.
This is an interesting post on AVS (that I believe is attributed to Kevin Voecks):
http://www.avsforum.com/forum/89-speakers/710918-revel-owners-thread-267.html#post40821322
I too, have heard such effects from passive bi-amping. If the speaker is competently designed, you would never want to insert active crossovers, except for a rare case in which the transfer function required to properly “cross-over” the speaker is published and properly implemented. Otherwise, passive bi-amping can offer sonic improvements. One reason is likely that the impedance outside the pass-band rises dramatically—thus resulting in the amp not being significantly utilized outside the intended frequency range. So for example, an amp dedicated to the high-frequency section of a speaker (whether that is a tweeter alone, or perhaps a tweeter and midrange), will not have significant current draw at low frequencies, resulting in lower distortion.
I believe these comments are referring to amplifier distortion but I believe there is a case that there is less distortion introduced by the crossovers. This is not something I would expect a speaker designer to emphasize
It has been stated that speaker manufactures include bi-amping to sell more amps. I think it is the opposite. Mark Levinson is quite happy to sell a customer two $15K mono-blocks to go with the Salon2's. What I am expressing does not support this strategy.
As far as measurements, I have measured the voltage at the upper and lower halves and found a little difference.
Still, there is some difference and it is fairly consistent with both the AT6000 and Parasound A21 amps.
I have a few calibrated mic's and REW. Would it be helpful to do some in-room (perhaps near-field) measurements?
I do recommend, trying bi-amping using a single speaker, Y-Connector and
stacking banana plugs. All processing should be turned off (Pure Direct or equivalent). This is a very low cost experiment and can be tried in a SBT.
- Rich
