John Curl's Blowtorch preamplifier part II

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Jan,

Another challenge: six wave files, some have been processed, some not. just use your ears and divide in two groups if you can!
Golden Ear Special

Why should I bother? And why should take your challenge? Do I need to proove anything to you? I don't think so. So forgive for declining.

Ciao T
 
@ simon7000

1st tone sounds more distorted with higher harmonics than 1st one.

@Thorsten

I will now listen to the tones presented by Jan and present my findings, why not?

If there is one thing that -for me- came out of Ed's first test tone was perhaps unintended, but it is that only a minute delay between start up of fundamental sine wave presents a rather audible click. This points into the direction that phase gets locked by the brain, and that sharp discontinuities lead to sharp artifacts. What could have otherwise be the source of that click.

vac
 
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Demian,

I kind of expected the 9K would always be on the tweeter. This was intended as a demonstration not a test!

Ed and all

The above makes me emphasize that I have only listened your original file (as well as Klaus brickwalled and mine gapless) through headphones only (AKG K240, Audio Technica AT-706 and one lesser Sennheiser).
This mention of yours about –separate- tweeter may shed some light about your - up to know- unspoken intentions and different reported aural perceptions.

If you only had answered my question!

Regards
George
 
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Demian,

Here is another tone. Anyone care to comment on what they hear?

I took a listen (10-15 times) on Ed’s second file:

A Mid-upper bass tone, losing some higher pitch past the middle of the file. A click (glitch) at the end of the file.

Listening through headphones, eyes closed. Since an hour ago, 1.5l of a fine micro brewed beer resides in my stomach.:)

Regards
George
 
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I took a listen (10-15 times) on Ed’s second file:

A Mid-upper bass tone, losing some higher pitch past the middle of the file. A click (glitch) at the end of the file.

Regards
George

That's all I heard.

Tweeter vs. headphone; both drivers share more than they differ and both have the same intrinsic asymmetry. The tweeter has a much bigger magnet but the diaphragm is in a similar scale. The voice coil location is actually looser on most headphone drivers. However they measure very low distortion usually. I was getting higher distortion on some samples recently and realized I was using a different fixture. It turns out the small electret mike in the fixture had much more distortion than the headphone.
 
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That's all I heard.

Tweeter vs. headphone; both drivers share more than they differ and both have the same intrinsic asymmetry. The tweeter has a much bigger magnet but the diaphragm is in a similar scale. The voice coil location is actually looser on most headphone drivers. However they measure very low distortion usually. I was getting higher distortion on some samples recently and realized I was using a different fixture. It turns out the small electret mike in the fixture had much more distortion than the headphone.

Demian
I made the note about listening the file only through headphones, because I can not disregard the possibility of different acoustic outcome of that file when heard through a loudspeaker system with a midrange, and a tweeter. Physical separation (distance)of midrange/tweeter and the cross-over filter elements may do something to the sound of this file that single element headphones don’t.
That’s a speculation, I haven’t tested it yet.
You’ve provided some stimulating info here:
http://www.diyaudio.com/forums/analog-line-level/146693-john-curls-blowtorch-preamplifier-part-ii-1524.html#post2681637


Scott
Found it-
Kiryu and Ashihara “Detection of Threshold for tones above 22kHz.” – Convention paper 5401 presented at the 110th Convention, May 12-15 2001, Amsterdam.

Dave's .ppt is a hefty download but might amuse and certainly annoy.

www.davidgriesinger.com/intermod.ppt

Indeed. Thanks


Regards
George

SY
I’m still fiddling with the FFT. I’ll report back.



PS. Demian, your home address ( http://www.element.us.com/demianmartin.htm )doesn’t work for me.
 
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@ simon7000

1st tone sounds more distorted with higher harmonics than 1st one.

@Thorsten

I will now listen to the tones presented by Jan and present my findings, why not?

If there is one thing that -for me- came out of Ed's first test tone was perhaps unintended, but it is that only a minute delay between start up of fundamental sine wave presents a rather audible click. This points into the direction that phase gets locked by the brain, and that sharp discontinuities lead to sharp artifacts. What could have otherwise be the source of that click.

vac

Did the start-up delay cause the sine wave to start at a non-zero value? That would give an audible click.

jan didden
 
Thanks Guys and Gals?

The waveform is generated to start at zero, so any start up clicks are in the transmission and decode process.

This was a test everyone seemed to get. The first half is a 150 hertz tone with 1% ninth harmonic distortion. The second half is the same tone without any deliberately added distortion.

So if you listened you know have an idea how bad naked upper odd harmonic distortion sounds.
 
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I was thinking of a similar situation with one of those digital attenuators like tha PGA2320 series. The swiching is done on a zero crossing of the signal and generally is inaudible. If you switch off the zero xing, you get the click which, with a rapid increasing or decreasing level is known as 'zipper noise'. Sorry Ed, back on topic!

jan didden
 
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