John Curl's Blowtorch preamplifier part II

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#62,302
With regard to current recordings, it's the production values that are killing the stuff - this morning they had on TV the Fall Out Boys, a current American rock band, on a morning show - and was it dire! Sounding like it was emerging from a shoebox, squashed into a tight ball, with every spare scrap of possible empty room filled with something going on - the overall impression was that this was tiny, tiny music - instantly disposable when finished, if one was possibly interested in waiting that long. How someone could possibly be inspired to buy the stuff, I find hard to fathom ...
 
#62,303
fas42 said:
With regard to current recordings, it's the production values that are killing the stuff - this morning they had on TV the Fall Out Boys, a current American rock band, on a morning show - and was it dire! Sounding like it was emerging from a shoebox, squashed into a tight ball, with every spare scrap of possible empty room filled with something going on - the overall impression was that this was tiny, tiny music - instantly disposable when finished, if one was possibly interested in waiting that long. How someone could possibly be inspired to buy the stuff, I find hard to fathom ...
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You quite nicely summarized most current 21'st century media.
I can't watch cable - garbage , I won't buy a CD (why should I - I can DL it?)
All this stuff we are made to believe we must have .... not worth squat!

PS - I can't watch "morning shows" - get a headache after the first ad !
Edit - many decades of low value material .... the public now has low expectations.
OS
 
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#62,305
Hi Richard,

You could look at dynamic range required another way, the threshold of hearing is actually below the noise floor of the air on your eardrum at about -6dBA (young adults), the threshold of pain is variously reported at 120-140 dBA, the 140 figure seems high to me, and likely permamently raise the lower number, so any more than 126-136 dBA is wasted, and might only be usable as a one time event.
22 bits more than covers most reasonable use, I cant see 32 being needed at playback any time soon, even if you tried to get near that the dissipation issues in the D/A converter would be significant. Mind you I can see marketing people jumping on it already.

If you try to lower the hearing threshold by dropping the ambient temp there is a phase change of the membrane at 10% reduction in the temperature ;-)

Wrinkle
 
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#62,306
wrinkle said:
You could look at dynamic range required another way, the threshold of hearing is actually below the noise floor of the air on your eardrum at about -6dBA (young adults), the threshold of pain is variously reported at 120-140 dBA, the 140 figure seems high to me, and likely permamently raise the lower number, so any more than 126-136 dBA is wasted, and might only be usable as a one time event.
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You can also look at it yet another way. We can't hear down to -6dB and up to 120dB AT THE SAME TIME. The INSTANTANEOUS dynamic rage of our hearing (such as when we're ACTUALLY LISTENING TO MUSIC which is what all this is about in the first place) is only about 60-70dB.

se
 
#62,307
john curl said:
I want to say something 'professional' about Richard Marsh: I have known him for about 35 years, and first learned from him, the importance of dielectric distortion in capacitors relative to audio applications. I had IGNORED it, previously. This led to all servoed gain modules that I use today, in order to remove the coupling caps. I have no qualms about removing potentially troublesome caps. Richard also was the first person to clue me in to using extensive ground planes for audio. I thank him for that. Richard Marsh has designed a number of audio products, and he even had his own company at one time. This includes: amps, preamps, powerline filters, and who knows what else? He got a patent on a 'revolutionary' high quality film cap that is still made today. I never used it, but it is PERFECT for switching power supplies and such, and potentially valuable for linear applications as well. This is someone who has paid his dues, and he deserves, like everyone else to be addressed in a courteous manner.
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At the end of the day we are discussing audio on an open forum in open debate, everyone should be addressed in a courteous manner... This does not mean we cannot disagree with peoples comments...
 
#62,308
john curl said:
I agree with Dave (Max) and Richard Marsh that we never use the total bits allowed, except on an occasional peak. So, most CD is recorded like 8-12bits, not 16bits. Now what does this mean? Well, dither WILL cover up harmonic distortion as defined mathematically from a series of 'snapshots' that could be taken from an 8 bit digitized sine wave. Now, EVERY 'snapshot' will have a certain amount of NONLINEARITY, or departure from the original audio signal, that is for sure. How to know if this 'nonlinearity' is still audible after dithering, depends on how the human ear responds to it. For me, the nonlinearity is still there, even if my test equipment can't directly measure it.
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If this was my problem I would look inside my head.... for the solution.🙂
 
#62,310
fas42 said:
With regard to current recordings, it's the production values that are killing the stuff - this morning they had on TV the Fall Out Boys, a current American rock band, on a morning show - and was it dire! Sounding like it was emerging from a shoebox, squashed into a tight ball, with every spare scrap of possible empty room filled with something going on - the overall impression was that this was tiny, tiny music - instantly disposable when finished, if one was possibly interested in waiting that long. How someone could possibly be inspired to buy the stuff, I find hard to fathom ...
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I have Fall Out Boy CDs as well as Panic at the Disco and others of that genre.... Of course you were listening on TV it is not the same as a good system.......
But each to their own Heh! lets move on now to criticising peoples taste as well as replay systems....
 
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#62,311
RNMarsh said:
I hope others didnt see the 50 without the point (.) in front of the 50. It is 1/2 percent.
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Oh! I am sorry Richard, I didn't notice the dot.
0.5% THD is something that I wouldn't worry about.
Then again if you mean that there is a causal relationship between the 8 bits (cause) and the 0.5% THD (effect), I don’t support it.

I was thinking of preparing something for to show Kindhornman that he wouldn't have to worry too much for the effects of digital attenuation. That would be readily applicable to the 8 remaining bits=0.5% THD assumption.🙂

George
 
#62,312
marce, I'm sorry that I happened to target a personal choice of yours. However, the conversation at that moment was about what was "wrong" with current recordings, and I'm afraid what I heard ticked all the boxes. I come from an era when most music had light and shade to it, even on a lowly kitchen radio - and hearing music lacking such does nothing to endear it to me, especially when it appears to be mimicking what "everyone else does".

It also doesn't help when they pretend to play the piece live, the obviously heavily manipulated studio production makes the performance on the set come across as being quite ludicrous ...
 
#62,313
🙂
Wot us young uns listen to Heh! cant understand the lyrics, all noise... When I was a lad etc. etc.
As to live, have you never watched Top of the Pops...........................
Agree regarding a lot of current recordings, add TV transmission and you have basically white noise....
 
#62,314
davym said:
Seems to me that the record industry's lack of interest in producing decent quality recordings will soon make our best efforts seem pointless. Crap in = crap out.
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With so many master pieces in my record collection, including "Bop till you drop" of Ry Cooder, one of the first albums recorded in digital (probably 16 bits 48KHz) i wonder how you can say this.
This is an insult to all those musicians, producers, sound engineers, whose passion and talent are extreme.
Right now, i'm listening to "On solid ground" of Don Pullen, with tears in my eyes. He is in Heaven, but his piano is in my room, as real than the one of my mother when i was a young child...
 
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#62,316
jan.didden said:
Yes sometimes we are too smart for our own good. Reminds me of the Lipshitz/Tiefenbrunn experiment where L scored 100% because he locked onto the difference in back ground noise but not the fact whether there was /was not an AD/DA in the chain.

jan
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The Lipshitz example is a bit different, because he was able to detect an additional noise usable for identification.
In our example it was a real difference in the audio information, which nevertheless could slip through in a controlled test, due to the conditions of the test.

As posted before, i have done quite a lot controlled tests and conducted tests with other listeners as well. The problem that listeners had to get used to the conditions of the controlled tests was obvious whenever i tried it.

Or, to cite JJ:

Do I have to have controls?
YES
Well, unless you don’t want to know how good your test is, of course.
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#62,317
RNMarsh said:
This wont solve anything perhaps...... there is a Mastering School which tells how you ought to record etc.

Listen and decide for your self: Dither versus truncation distortion ? Hear it for yourself
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I'm glad your link correctly stated quantization distortion and not the inherent non-linearity of the A/D, this is an important distinction. A perfect 24 bit A/D still has it. It is not feasible at this time to even make a perfect 24bit A/D, although we are far from the Heisenberg limit (yes their is one) I don't see a financial return from doing better. Another 8 bits of pure noise is no different than the dither.

Dither was not a band-aid it was a massive engineering oversight by a lot of smart people who simply blew it.
EDIT Sorry, or of course the marketing folks that could not deal with -93db rather than -96dB
 
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#62,318
RNMarsh said:
No measurements. so far.

THx-RNMarsh
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They will likely disappoint re: -118dB 🙂. We managed to get -110dB from a cell phone and had the same issues with 300 vs 32 Ohm headphones, but of course I couldn't hear it just measure it.
We played some HDtracks downloads of opera through the reference design and Sennheiser HD650's I could't tell the difference.

I forgot to mention, you should check it out when you are there. In Asia there is a whole program for streaming HD audio over the cell phone network (at least in China). I listened to a prototype phone
while there, pretty nice.
 
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#62,320
For the curious, IEEE 1964

In this paper, the conditions a dither signal must meet so that the quantizer noise can be considered independent of the signal are derived for a quantizer having a finite number of levels. An infinite class of dither signals which satisfy these conditions is given. It is seen that the most useful member of this class is one whose probability density function is uniformly distributed over a quantizing interval. It is also shown that a necessary and sufficient condition for the noise n(t) to be independent of the signal x(t) is that a measurable quantity, called the "D" factor, be zero.
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