RE: [Harp-L] RE: Harp-L Digest, Vol 91, Issue 9 Cable Talk "VOODO"?

["Joel B. Chappell" <joel.b.chappell@xxxxxxxxxxxxxxx>]

OK here's the deal. Your 80-year old mic technology...JT-30, Green Bullet,
Blues Blaster, and what ever else you have, are all high impedance devices.
The cable you are using has a certain amount of capacitance per foot
typically about 29 pF per foot...so if you have an 18-foot cable you
effectively have a 522 pF capacitor across the mic element. This capacitance
will vary slightly with different style cables and this will definitely
alter the audio coloring slightly as different cables present a slightly
different virtual capacitor across the mic element. This coloring will
become more or less noticeable depending the style amplifier you're patched
into. A tube amp is high impedance whereas a solid state amp would have a
lower input impedance. The bottom line is a JT-30 crystal mic with 18 feet
of shielded cable coupled into a tube amp will have a rising characteristic
to around 2 KHz and then will roll off at a 6 db per octave rate. Variations
in cable construction will give different capacitances per foot which may or
may not be discernable to the listener [It's dubious to me that someone has
ears that good]. Most harps are 2-3 octave devices and it wouldn't take too
much additional capacitance to pull the roll off point into the frequency
range of a key of C diatonic, which once again may or may not be discernable
to the listener :-). Given my druthers I would opt for a good old Shure
SM-57 on low impedance shielded twisted pair cable with a good solid-state
mixer [Mackie, Carvin, etc.] I know the Blues Blaster and others are easier
to hold than the SM-57...and the crystal mics are omni-directional and
probably prone to feedback unless held tight to the harp. The SM-57 can be
put back on the mic-stand since it is uni-directional not a problem with
feedback with proper mixing and floor monitor placement. Anywho I hope this
takes electronics, mics, and cable out of the realm of some sort of "black
art" as there is a good scientific explanation for all aesthetic
observations.

Regards,
Joel

Joel B. Chappell
21 Billings Street
Milford, NH 03055

------------------------------
Ron wrote:

TO:Joel
Sorry to disagree but regardless of the how, there are some easily heard
differences.  From an engineering standpoint, we could all be listening to a
synthesizer and be happy, but we are not.  Wasn't it the engineers that said
the Titanic was unsinkable?  
Kidding aside, I don 't understand very much of your previous post but I am
sure you are very well schooled and experienced.  I only know what my ears
tell me, and I have heard a difference in cables doing simple a-b tests.
Could be like the Invisible Gorilla-if you don't expect to hear a
difference, you won't. I guess the scientific explanation is a difference in
quality components and design. Could it be my Miracle Ear? :)

Joel said:
Again if there is a
PERCEIVED difference audio quality, then there is a scientific explanation
and not some critics super sensitive ears...most of which, blasted theirs
out back in the '60s...I didn't and at age 72 mine still work great. I'll
refrain from commenting on the use of microphones that are 80-year old
technology for another time. :-)

Regards,
Joel