On Thu, 5 Mar 2009 07:24:19 -0800, codifus wrote
(in article ):
On Mar 5, 6:22*am, "Arny Krueger" wrote:
"codifus" wrote in message
...
On Mar 4, 12:16 pm, " wrote:
The greatest benefit of bi-wiring, as I've come to understand, is its
ability to isolate the back emf generated by the woofer from the mid-
range/tweeter.
You should ask yourself - what is the physical impact of back-emfs? They
cause the impedance of the drivers to vary with frequency.
*emfs are generally very small, but the emf generated by
a relatively large 8 or 12 inch woofer can have a significant effect
on the much smaller mid-range and tweeter.
That's why there are such things as crossovers. *The crossovers for the
midrange and tweeter not only isolate them from the large voltage that
drives the woofer, but also from the so-called back-emf.
We've been here before. Of course that's what the circuit is designed
to do, and in a perfect world, the circuit would do it.....perfectly.
You know that all electrical designs do not behave perfectly, but
pretty much perfectly. I think that bi-wiring helps the crossovers to
better isolate the woofer's signal from the id-range and tweeter's
signal.
Nonsense! The capacitors in series with the tweeter will not pass a low
frequency signal below the crossover point and any "Back EMF" from a
low-frequency driver will be below the crossover. The characteristics of LC
networks in conjunction with AC signals is well understood as is the
interaction of speaker back EMF with amplifier output stages.
I tried bi-wiring and won't go back. The effect is quite subtle, but
it's there.
You expected an improvement and your expectations created the perception of
an improvement. Or, your original speaker cables were techically inadequate.
I use relatively fat 12 gauge cables. I don't know if you recall, but
in another thread where my speakers kept dying and you had later
advised me on how the impedance switch was designed in my Yamaha
amplifier. The switch had 2 settings, 6 ohms and above, or 4 ohms and
below. I kept the setting at 4 ohms and below, illogically thinking
that the amp would drive the speakers harder. After several times of
having my speakers blowing their crossovers, I tried it at the other
setting and immediately noticed that the amp actually drove the
speakers harder in the 6 ohms and above setting. This correlated with
how you later described the impedance switch from looking at the
service manual. Basically, you said the switch "selects different
paris of taps on the secondary winding of the power transformer" etc.
Also, I have a Behringer SRC 2496 DAC which is pretty much just
sitting there doing nothing. I've listened to it and hate it. I bought
it because of all the wonderful mods I've heard on the net that could
really bring the SRC to life and make it a credible inexpensive DAC.
It turns out that mine was a newer version where practically
everything inside was consolidated into 3 or 4 ICs on a board, and
therefore un-modifiable. Earlier versions had 2 or 3 boards with
capacitors etc which made modding easy.
My point is that I don't always believe in every change that I make. I
try to keep myself objective. This bi-wiring I believe in, and it
makes itself apparent in certain types of music. If you don't listen
to that type of music, you may not notice it. I certainly didn't
notice it in most of my collection. But in some songs, it is quite
apparent. Like I said earlier, music with very strong mid-range and
bass power will bring out the effects of bi-wiring. On classical
music, I wouldn't really notice, unless someone can suggest some
classical music that would fit that criteria. I am more than willing
to give it a listen and compare.
I think you will tend to hear the effect of bi-wiring on music which
has very strong mid-range and bass dynamics.
There should and are no actual strong effects due to bi-wiring if your
speaker cable is adequate to begin with. You would always be better off
simply running the second bi-wire cable in parallel with the original cable
and forget about bi-wiring.
Two sets of 12 gauge cables would seem a bit over-done in my setup
Well, it won't hurt anything and probably looks impressive. :-)