Hallo Terry
Op 31 Aug 97 16:41 had jij het over *system balancing*...
TS> It is more of a theoretical engineering and manufacturing technology 
topic,
TS> out of reach of end user-technicians,
We will see about that 
TS> other than as to learning some clue as to how it affects various
TS> products.
TK>> I'm very interested in these 'white papers'...do you
TK>> happen to have a copy of it ? Preferably in an ASCII-
TK>> text file ? =)
TS> Sorry, nope.
well.....never mind, I will run into it sooner or later...
TS> I haven't run across anyone
TS> else in audio promoting the same type of physics applicable to RF, light
TS> refraction, water, and audio wave theory by similar coupling as I. M. 
Fried
TS> (consider jokes people have played on his name as he listed it on public
TS> documents and speaker labels).

TS> Irving goes back to the era when it was
TS> popular to build a large horn into the architectural corner of a living
TS> room, and worked on design ideas to collapse such efficient coupled front
TS> loading into boxes not much larger than mid sized sealed acoustic springs
TS> (of terribly low low end efficiency, but cheap to control
TS> distortion).
Are you referring to small & heavy pressure compartment cabinets ?
TS> Hmmmm....  thinking back, he even mailed me some of his less
TS> well known white papers after that discussion, which I also have buried
TS> upstairs somewhere.  I'm not sure if he's even alive any more though, but
TS> was a less known serious audio contributor for decades.
What a pity you don't have those papers at hand... :(
TS> Some of the most interesting as I recall date to the time JBL changed
TS> from swirl to symmetrical diamond pattern surrounds
Sorry, you've lost me there.....What do you mean ?
TS> in 24xx series 1 and 2 inch throat compression drivers, and went into
TS> extensive detail as to design compromises in such drivers.
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TS>> Thiele and Small certainly have considered such things,
TK>> As far as I know, those guys were the inventors of the
TK>> standard parameters we use nowadays to design acoustic
TK>> solutions.
TS> Although their work is used more often it seems designing 3rd order
TS> harmonic compromises against box size in tuned port bass bin design....
What about it then ?
TS>>> Of course, I was thinking about bone conduction
TS>>> of sound to influence brain waves,
TK>> I do not quite agree with you:
TK>> Low frequencies are a sensation to the whole body, and
TK>> furthermore headphones can't give the acoustic
TK>> sensation of a room or hall due to the lack of
TK>> reflections.....a mostly underestimated fact
TS> In reproducing sound the room is usually a problem, and not a controlled
TS> hall optimized for specific performance types.
My room is OK....and it's nothing special...I got enough damping from the 
furniture and the resonances are resonably equally spread over the spectrum 
due to the dimensional ratio's of the room.........just lucky with this 
e...
Anyway....the problem with a room: You can't do without it....
TS> Sure, a few people have decent rooms.  For most headphones are of higher
TS> relative quality than crappy speakers and acoustically uncontrolled
TS> space.
With a little effort a crappy room can be tuned to a good one.....if you know 
how.....always remember that if you buy some speakers you only buy HALF A 
SYSTEM....the other half is the room you want to place them in....those two 
halfs GOT to match otherwise you find yourself buried in a lot of troublesome 
work to get it right...IF you can get it right...
nevertheless: You have to spend a large amount of money to beat a good set of 
headphones.....
TS> We can process audio to simulate a desired space into a known 
eproduction
TS> system, such as headphones, as to almost all factors involving amplitude,
TS> balance, and timing, including simulated reverberation and decay.  Low 
nd
TS> bone conduction is the one factor we simply can't include in that 
otherwise
TS> cost/quality effective balance.
Some manufacturers ar experimanting with a very small but powerful vibration 
device which you can place under the seat of you chair.....seems to work 
perfectly....and silent..
TS> Another analogy would be broadcast processing.  For AM, what bandwidth
TS> and distortion level radio will be used?
You don't wanna know. 
TS> For AM or FM, or TV, what kind of speaker system and room will be used?
All diffrent kinds of sets and rooms....that is the core-problem...
TS> There is no answer as specific as what can be expected with midrange to
TS> good headphones and any but the worst line level equipment.
Yeah...you just eliminate the room......what a pity....what a shame.. ;)
TS> Any clearer as to the attempted implied comment I didn't spell out in
TS> detail before?
Yes....it's more about acoustics....I love that... :)
TS>> Of course, the NASA lauch pad where they use unusually high bias TS>
TS>> voltages on B&K condenser mics so as to not overload at 180 dBspl's 
ould
TS>> be another real world example,
TK>> Huh ?!? Example of what ?
TS> High energy level real world challenges to accurate transducer 
echnology.
TS> The raw power for reproduction would be more of a challenge than the 
mall
TS> diaphragm high precision $3,000 mics which are readily available.  B&K 
does
TS> some super high bias voltage mods to standard product line 
nstrumentation
TS> mics for that NASA application, which allows low distortion monitoring of
TS> rocket liftoffs from various elevations right at the lauch pad and tower,
TS> as opposed to the old days of distorted audio from mics spaced back a 
ays
TS> and less useful at helping document takeoffs and analyze
TS> time-vibration-stress issues.
Those mikes really need aa anti-logaritmic-sensitivity...no way to achieve 
that in a lineair way.
TS>> not to mention my old high school classmate who tests solid rocket TS>
TS>> boosters fired sideways at ground level out in the SW US deserts, 
orking
TS>> for Morton-Thiokol.
TK>> I always wanted to use a J-1 or F-2 liquid fuel
TK>> rocketmotor as a subwoofer 
TS> Just make sure you've got plenty of cooling water, or a couple miles of
TS> flame resistant materials you don't mind melting downrange.  
I don't care...but what about my 'speaker' cabinets blowing themselves away ? 

TS>> Of course, I was suggesting how sound can trigger subconscious alpha,TS>
TS>> beta, delta, and other brain wave patterns, pleasurably or with
TS>> possible pain stimuli that aren't directly sensed as well as possibly 
with
TS>> others that are.
Ah...the chapter of "brain-machines" :)
TS> How many artist types who are good at creative sides of audio understand
TS> how any of the above relates to their product?
Only the real artist can 'feel' if it's right or wrong....more ore less.
TS> balance of low duration high end.  That NIN sample helped me understand 
why
TS> a nightclub popular with certain college crowds always sound like shit
TS> despite plenty of JBL biradial monitors and loads of clean power amps.
A DJ who's turning his gain and master pots into saturation is often an 
underestimated factor.... :)
TS> Are you familiar with how certain disco strobe flash rates can trigger
TS> psychotic or psycho-physical disabling responses in some people?
Yep.....epileptics are sensitive to strobes...
TS>  Swept audio at mildly but not damagingly painful frequncies and levels
TS> can be used for similar effect.
Thanks for the tip...
TK>> You definitely should contact your local university about neurology.
TS> I was having trouble finding the Marquis DeSade or some old Viet Cong
TS> Colonels in the local Yellow Pages.  
they don't like Yellow ? 
Groetenzenzovoorts, Thom
*----*
... Van twee kwaden de beste kiezen.
--- GEcho 1.00
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