Eddie Runner wrote:

Nousaine wrote:

case you have forgotten and since you obviously need to read it again
http://www.installer.com/tech/aiming.html

Actually your cartoons have no scaling to them.

Well the pictures may not be EXACTLY to scale, but the article does clearly
point out the scale, in the first picture the woofer box rear is 3 ft from
the
reflecting wall.... What is it about THAT SCALE you dont understand???
Similar distances in cars for car sub woofer boxes ARE QUITE COMMON!

Scale seems believable to me....!!

The frequencies would have to
be referent to some room dimensions so you can't just 'claim' they are 60
Hz.
Without a distance scale it can't be determined.

Not true!
we dont have to HAVE A ROOM for a standing wave to occur!

Actually you don't seem to understand that
a standing wave requires 2 opposing surfaces to form. If you have a single wall
there will be no standing wave.So where is the listener in your cartoon? And
how does that fit with an enclosed space? You're attempting to describe the
Allison effect with a single wall, and yes there may be some interdriver
interference but in your example that would be occuring at much higher
frequencies around 200 Hz.


A standing wave can occur WHENEVER two (or more) waves combine to make a
result
(node or antinode (cencelation or reinforcment)) that is ALWAYS there..!!

A standing wave will ONLY occur when you have two opposing walls or surfaces.
Otherwise its a propagating wave.

In other words, if a reflector causes a peak at 60Hz ALWAYS it is a standing
wave...
Or if a reflector causes a DIP at 60Hz ALWAYS it is a standing wave!

Only when there's an opposing surface.


Your schooling on this matter seems to just include the rudimentry facts
normally
shown in the most elementry physics books that mention standing waves...

My paper must be confusing you because I show ONLY ONE reflector, breaking
the standing wave problem down to its simplest form, which doesnt make sense
to you cause THERE IS NO ROOM!

And there's no standing wave either, is there?


ha ha

2nd.... A self proclaimed AUDIO GURU such as yourself should know that
a 20 or 30 ft wave as you suggest above would be about 37Hz to 55Hz if
your here on planet earth with the rest of us, but you keep rfering to
60Hz
which is only about 18ft.....

60 Hz is where the the lowest axial mode occurs in many small cars.

Like your little CORVETTE.... Yes, there are MANY corvettes out there!
You carefully worded that so that YOUR statement may be correct!

Oh it's correct alright not only for this Corvette but the 2 C4s I used prior.
It was also true for my Z28 and Integra. The CRX had a slightly higher turnover
frequency.


But its sad that YOUR WORDS have little to do with mst of the folks out
there!

Why hide behind these carefully choosen words?????
Why not speak the truth with as many words as you can??

I'm hiding behind nothing Eddie. But I wonder why you are so sensitive about
this? Too much initial shouting and blather does that to people I guess.


3rd... And this is where I would guess your off track in your
theories...For
a standing wave to occur the whole wave (18ft at 60Hz) doesnt need to be
stretched out to a full 18 ft like you seem to be saying... A reflection
can
come back on itself and create a standing wave in as little as 1/4
wavelength
(4.7ft)....

OK, what's the frequency of the that standing wave? (Hint:, the 2nd of 60
hz is
120 Hz, the 4th is 240 Hz.)

MORE IMPORTANTLY where are the nodes and antinodes!!!

And what are the frequencies involved? In a 22 x 12 x 8 foot room the primary
axial modes occur at 26,45 and 70 Hz with 2nds at 52,90 and 140. In the car
shift everything up by a little more than an octave.


I think you missed that part in physics class! Were yu sick that day???

So while your spouting the HUGE 20-30ft wavelengths (as you
did above) trying to justify your position, your ignoring (or just dont
know)
about the facts that standing waves occur in as little as 1/4 wavelength
(and
even shorter is possible in complex reflective situations like A CAR).....

As I said, the standing wave region in a small car is between roughly 60
and
600 Hz.

So your just saying 60Hz and 600Hz??
Am I hearing you correctly??

I think your mistaking RESONANCES with STANDING WAVES!!!

Resonances of what? Inter-driver cancellation effects? That's not a resonance
condition. Standing waves often help form resonances in walls or car bodies
that affects the wear-down of standing waves but standing waves are a direct
function of opposing surfaces of which there are 3 sets in an enclosed
rectangular structure. In the car, a much smaller but still an enclosed space,
there are still a set of three axial standing wave sets which are a function of
the volume and dimensions of the space. These will ALL occur at 60 Hz and above
in a car the size of a Corvette.


Tom, I hate to dissapoint you but I was an AES member back in 1982...
So what happened?

I guess you were dissapointed by the facts that you mention AES in the
attempt to make your self look like a bigshot and I already been there and
done that..... ha ha ha

Done what? Given a Convention Paper? I'm guessing that you're no longer a
member, why not?


Yes I have the LMS system, and I have been around audio test equipment
for well over 30years.....

OK then why not publish some response graphs at the listeners head position
with the enclosure in different directions or locations? That's what I did.

Cause Im lazy, its raining today and I would rather watch these kiddos call
you names here on the internet..... ha ha ha

Eddie Runner
http://www.installer.com/tech/.

Well I guess that may well be. I'm also guessing that you don't know how to do
a transfer function meaurement in the car.