Audio Voodoo and Stuff
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Here's a letter I sent to an editor of
after hearing about AC power cords that make a difference:
Uh.. dude, you really don't want to get into
cable esoteric crap that the consumer audio guys do. In fact a few
years back AES
sponsored a blind test that a bunch of audiophiles failed discerning
opamps (one of the lowest-fi opamps out there, typ. used for DC servos)
together vs. their "golden-ears" Litz (sp?) cable.
A few things; one I worked in a hifi golden
ears (GE) shop.
As a test , we took an Advent tweeter, placed it on the used shelf with
generator/amp, starting at 19kHz...94dB @ 1M; every few days we'd drop
Now the GE's, sitting there telling people how
$130.00 3' pair of Litz cables would sound didn't hear a thing.
The only guy that noticed was the hippie dude,
mentioned (at around 13K) that he'd shut off all the old Advent
we also sold but could still hear the Horiz squeel... Hmmmm
OK... LISTEN - MAJOR POINT HERE:
Interconnect cables are not arbitrarily
certain cable with a certain characteristic impedance is used to
outputs with a certain (and hopefully matched) impedance and required
transfer function. This is
For instance, imagine a coax cable (similar to
stuff you just bought for your PT rig) except that it's 3" in diameter,
the connector weighs about 30 pounds and is as big as your head, hollow
nylon spacers placing the center at the exact distance for 50ohms, and
to gas it with anhydrous nitrogen to keep it from flashing over and so
push 40,000 watts with an 8,000 volt plate voltage thru it at 100Mhz.
This is what I dealt with
radio transmission facilities.
Here's a great photo:
That ain't me by the way; no association, just a cool pic - it's the
from the radio station on Mt Wilson
BTW: see those "pipes" in the background -
they ain't no pipes, that's 3" rigid transmission line.
Now tell me about your uper expensive BNC cable for your PT rig...
Just imagine how fucked something can get if
slightly off in matching the load?
It's happened to me on multiple
due to a lame-ass tower guy slightly screwing up the connection to the
antenna/transformer (you can see a CAD drawing at http://www.ajawamnet.com/ajawamnet/page4/towers.jpg
- the top right-hand drawing). Or, a hell of a
accumulates on the antennas ( those things in the aforementioned CAD
that look like convoluted arms - those are CP 40kW ERI FM bays) due to
There's a property known as VSWR (ask any ham
even a trucker with a CB, or any cable plant guy that installs CAT5
- why they use a Time Domain Reflectometer) this is what contributes to
the power that's reflected
the source from the load. It's always there and is expressed as a ratio
something like 1:1.18 is tolerable by a transmitter; which is a
amp that typically has a tube in it that's the size of a large coffee
Another great image:
That's a lot o' power. That tube goes in these:
Those are two Continental FM transmitters
- I used to work on those.
Now image the aforementioned bad
knows what. What happens when there's a slight mismatch is that MOLTEN
BRASS/COPPER falls about 400' on to peoples heads.
We actually had a mismatched 4 bay ERI (what's
my website mentioned above) that went FLAMING and dropping molten metal
senior citizens home that was co-located under the tower farm.
So AGAIN I STATE:
YOU DO NOT
ARBITRARILY SELECT A CABLE BASED ON
TYPICAL "VOODOO SHIT" PROPAGATED BY VENDORS THAT ARE NOTHING MORE THAN
MR. HANEY FROM GREEN ACRES. (Yea, Mr Douglas, gots me some o'
yer stereo ... http://www.maggiore.net/greenacres/gacast.asp )
Here's the thing, ask any pro that's working
processors running in the Ghz range and any guy that designs RF stuff,
he'll tell you that all the crap about this cable and that cable is
PLEASE NOTE: there are differences in cables -
calculable parameters that are used by actual engineers with the
back it up for use in specific circuit topologies that require the most
and coherent transfer of energy.
As to the guy from Requisite that states
break-in.." what you're hearing is actually components aging. For
instance, electrolytic caps exhibit a change as they age; in fact, if
at any of the catalog pages of electrolytic caps on Digikey.com you'll
rating for expected life at the Absolute Maximum thermal condition. See
- just type/paste ELECTROLYTIC CAPACITOR into the search box
OK, let's deal with a tuned circuit, running at
well beyond the paltry 20-20K audio guys deal with. This is what's in
802.11 card on your laptop.
Now, most vendors try to eliminate manual
They try to go with fixed values for resistors, capacitors, inductors.
gets the cost down in mfg; that's why it's $40 for B/G wifi card.
Now let's say this "breaks in". OK. Because
of the tight tolerances and tuning of
the RF circuits, the peak drive current to the final amp will be
causing as much as a 45dBv reduction to the input of the final.
EFFECT: NO MORE ONLINE PORN
If you really want to know what's up call me 703-618-2430
(yea, I know you're too busy) but
hey here's the chance to actually learn a bit about the underlying crap
duly use in your day-to-day stuff.
So I get a response from
one of the
editors at mediabase - asks if I got a response I reply:
Thanks... Naw, I
didn't think he would. My guess is he's
going thru the "rock star" mentality with his mag. Typical ....
give'em a few years to temper his 'tude and he'll be OK...
I've been thinking of expanding it and
somewhere, have to do a bit more "research" ("I'll have the
roast duck and mango salsa..."); get some screenshots off of my lab
equipment. It's part of my theory that audio "pro's" that carry the
title "engineer" have a long way to go. I remember about 15 years ago
AES papers were actual studies with actual peer-reviewed dissertations
math in them. I was hoping that a consumer protection unit would take
on some of the wildass claims these consumer audio companies make. "He
who waits for
legislation waits for no one" I guess...
I was speaking with Rupert Neve a few years
ago, we were
trying to get him to do a DSP card that would emulate his
and with a real nice front end. I asked him how he liked Texas vs
and his wife recently got US citizenship). He was still encumbered with
whole AMEK- Harmon thing and IC's were about the only thing he could do.
So I asked him what he was doing and mentioned
like, " ... so I guess you spend a lot of time fixing the old modules
people pull from your old consoles and are so enamored with..." and his
response was that he couldn't understand why audio "engineers" were
so into those things..."they sound God-awful..." was his response. He
mentioned something on the order of, " Wayne, you know how far along
and passive technology has come? Why would anyone use that stuff?"
And it wasn't a marketing ploy to sell Harmon
(believe me - I got the impression that he was about fed up with that
affair). It's true; 'cause right after I spoke with him, I benched a
few of his
old micpre/EQ's some studio ripped from an old NYC studio's console.
sucked. Massive noise, pure sine waves turned into funky waveforms well
the audible range, THD out the ass. I blamed it (reason for my question
on the dried-out coupling caps and aging transformers (delamination is
primary cause of transformers sounding weird after a while).
But hey, that's what sells - pure hype... shame
doesn't make any $$$$ from the old stuff. I wonder how well his new
(he's free from Harmon) stuff is selling?
And in the long run, I've never heard a 14yr
"did you hear all the transient intermodulation distortion in that last
Black Eyed Peas single? I'm not downloading it!!"
"I don't have much of an appetite..."
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