John Curl's Blowtorch preamplifier part II - Page 1738 - diyAudio
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Old 2nd November 2011, 03:23 PM   #17371
hhoyt is offline hhoyt  United States
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Default CMOS ET Presentation

Quote:
Originally Posted by Bonsai View Post
http://www.cmoset.com/uploads/6A.4-08.pdf

Fascinating presentation Scott. Thanks for sharing.
Seconded! Very innovative thinking!
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Old 2nd November 2011, 03:32 PM   #17372
Previously: Kuei Yang Wang
 
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Scott,

Quote:
Originally Posted by scott wurcer View Post
AD1862 & PDM100, NOT AD1855 (I heard that part, I'd take cirrus logic instead any day, which is about the same as saying I'd rather eat at MickeyD). It is not the manufacturer, it is the specific chip.

My personal list for 16/44 goes (either Non-Os or PDM100 for HDCD):

#1 TDA1541AS2
#2 TDA1541AS1
#3 TDA1541A
#4 AD1862
#5 PCM56
#6 PCM63
#7 and on - the rest of multibitdom

Listening to TDA1541AS2 with JAN GE 6072A ***** as analogue stage ATM...

Ciao T
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Old 2nd November 2011, 03:38 PM   #17373
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Quote:
Originally Posted by PMA View Post
Even 10 us (microseconds) of time DIFFERENCE between left and right ear is audible.
Yes. 1.5 uSec has been discerned, lateralization.

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Originally Posted by SY View Post
Do you position your speakers to 0.3mm?
Why? This is a non-sequitur. (this unit must survive)

Quote:
Originally Posted by rsdio View Post
Even if he has positioned his speakers to within an accuracy of 0.3 mm, I wonder if he keeps his head in the perfect sweet spot when listening, without moving more than 0.3 mm.
It is not necessary. Once the listener is in what is considered the sweetspot based on virtual imaging of centrally derived images, then 10 uSec R-L delay of other signals will cause the other signals to be positioned laterally off center.

Quote:
Originally Posted by scott wurcer View Post
On headphones yes, still looking for the same result in an ambient space without a headvice.
See previous explanation.

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Originally Posted by scott wurcer View Post
I should post a pic, the voice coil has experienced serious liquifaction.
In excess of 660 C? Or, 1062 C? Or, did it exceed glass transition?
cmon scott...need pics..

Cheers, jn
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Old 2nd November 2011, 03:41 PM   #17374
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T

No close mic'ing needed, the band is loud enough you can mic sections and get a decent blend.

I really don't care what analog's range is, I want the best! So 22 real bits with 8 x oversampling should meet requirements for the recording system not to be the limiting factor.

Flat is really not good on an SLM as there are a lot of infrasonic noise sources that are very very loud, some LF roll off is required.

Finally Apples are computers and Oranges are American football players, no comparison at all!
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Old 2nd November 2011, 03:48 PM   #17375
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Quote:
Originally Posted by hhoyt View Post
Also, can one of you who has a handle of the intricasies of digital sampling theory speak to the issue of narrow-band distortion at sub-harmonics of the sampling rate? I noticed this phenomena myself during testing of the aforementioned system.

Howard Hoyt
CE - WXYC-FM
UNC Chapel Hill, NC
www.wxyc.org
1st on the internet
Howard,

My guess would be that this is an example of the alias frequency of a midband signal being the same as the correct signal. So I would expect a 6 db rise in garbage at the midband.

There might be some spreading due to clock jitter.

ES
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Old 2nd November 2011, 03:49 PM   #17376
SY is offline SY  United States
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Quote:
Originally Posted by jneutron View Post
It is not necessary. Once the listener is in what is considered the sweetspot based on virtual imaging of centrally derived images, then 10 uSec R-L delay of other signals will cause the other signals to be positioned laterally off center.
I can't position myself within 0.3mm. Yet my speakers image just fine, and moving imperceptibly does not shift the image.
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Old 2nd November 2011, 03:58 PM   #17377
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Quote:
Originally Posted by SY View Post
I can't position myself within 0.3mm. Yet my speakers image just fine, and moving imperceptibly does not shift the image.
SY

There was a fellow who taught that coaxial speakers were the solution to the path length difference issue and frequency notches that resulted at crossover.

So when I place my high frequency horn 24" away from the center of the midrange horn, what is the path length difference to a close listener at say 200 feet? (Hint the cancellation notch would occur at 56 khz if both drivers had similar outputs.)

As you indicated before there are lots of room reflections in the absolute timing issue to be wary off. But that Pythagoras cat did some really cool math way back even before John was born.
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Old 2nd November 2011, 03:59 PM   #17378
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Quote:
Originally Posted by SY View Post
I can't position myself within 0.3mm. Yet my speakers image just fine, and moving imperceptibly does not shift the image.
Your response is again, non sequitur.

I am speaking of a differential positioning between a central image with ITD and IID of zero, and an imaged voice shifted as a result of a 10 uSec ITD with respect to the image with none.

You are mistakenly attempting to introduce absolutes into a referenced discussion.

Cheers, jn
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Old 2nd November 2011, 04:01 PM   #17379
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But that Pythagoras cat did some really cool math way back even before John was born.
I hope you are referring to John Curl.

cheers, jn
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Old 2nd November 2011, 04:01 PM   #17380
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Hi,

Quote:
Originally Posted by simon7000 View Post
No close mic'ing needed, the band is loud enough you can mic sections and get a decent blend.
So, ahead of the conductors rostrum...

Quote:
Originally Posted by simon7000 View Post
I really don't care what analog's range is, I want the best! So 22 real bits with 8 x oversampling should meet requirements for the recording system not to be the limiting factor.
Do not get me wrong, I would love a 22 Bit SAR or Flash ADC sampling at 384KHz for recordings and I would love to store the masters in this format.

I am pragmatic though, CD can be made very good (but rarely is) and I'd rather have the mainstream recording industry use 16/44 to it's limits than two or three audiophile labels issuing superb recordings in 22/384 of mediocre performances.

Quote:
Originally Posted by simon7000 View Post
Flat is really not good on an SLM as there are a lot of infrasonic noise sources that are very very loud, some LF roll off is required.
Not flat to DC, not sure where precisely the LF rolloff ended up, I normally aim for 8 Hz per stage, if I remember right it had around six rolloffs. So there was an infrasonic rolloff.

My definition of "Flat" is "without weighting" but "suitably bandwidth limited".

Quote:
Originally Posted by simon7000 View Post
Finally Apples are computers and Oranges are American football players, no comparison at all!
My point precisely.

Ciao T
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