John Curl's Blowtorch preamplifier part II

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Interesting, since I listen to it in clubs and my living room routinely.

I think he has a point though, depending on what you call a "real" environment. In some cars at highway speeds some compression is appreciated. Same thing for portable if you don't have IEMs or headphones with a lot of ambient noise isolation. Unfortunately it seems like almost every pop/rock recording just sits at full-scale.
 
I think Pano is correct, mostly.

My setup right now with my polished amplifier I've been making isn't enough to drive past 102db, and that's if it was a perfect increase not accounting for driver compression or anything, because I've been using inefficient speakers. Thing is you'd never really think dynamics are low, but admittedly on a friend's system the occasionally high crest factor on few records will be startling by comparrison. Ironically it doesn't sound more real because we NEVER get truly high dynamics in concert like we can by placing microphones near instruments where we'd never put our heads. Now which is louder... well depends on the concert.

The perception of dynamics I think has more to do with technique in recording, and the post work, than SPL level alone. Part of making good dynamics is frequency compression (limits) so your SNR doesn't plummet so far that the captured sound requires a dynamic range so large that compared to the rest of the song it's quiet until it peeks, and by then it's not even that loud especially since it sounds like white noise in the way that it's half room noise.
 
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Here you go, Its all done and ready: https://media.uaudio.com/assetlibrary/l/a/la-2a_manual.pdf

its the earliest use of electrolumenescent panels I have seen by 20+ years. since they are pretty much instantaneous it may work quite well. You could also implemnent a digital version but with no tubes glowing or hard to source/fabricate parts it could not possibly be any good. . .
 
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The perception of dynamics I think has more to do with technique in recording, and the post work, than SPL level alone. Part of making good dynamics is frequency compression (limits) so your SNR doesn't plummet so far that the captured sound requires a dynamic range so large that compared to the rest of the song it's quiet until it peeks, and by then it's not even that loud especially since it sounds like white noise in the way that it's half room noise.

These people have a great interest in and a lot of experience/expertise with dynamics and loudness. Some technical material:
https://tech.ebu.ch/docs/r/r128-2014.pdf
https://tech.ebu.ch/docs/tech/tech3343.pdf
https://tech.ebu.ch/docs/tech/tech3342.pdf
https://tech.ebu.ch/publications/ebu_loudness_test_set
The radio stations which are EBU members regurarly transmit and share among each other a lot of live takes or recordings from music vestivals, live performances and concerts, good examples of proper compression and dynamics handling (most of these radio stations are streaming their program as e-radio, accessible wordwide)
EBU - Members

George
 
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Michael I agree with this:)

Here George, it was >25yr. ago and I scratched this out for the folks at The Naval Labs in Maryland. I "think" I built it but can't recall exactly. The bias stuff on the left is non-critical, you just want a cascode voltage that also gets the right drain currents for the FET's.

Thank you Scott for that. What you’ve drawn up seems deceptively simple but it isn’t. I will redraw it with all the internals of the pins 2,15 and 5,12. We will have a talk on this.
But now a simple question. Was the intent of the modification to lower the (already very low) noise?
If yes, does it worth for our head-pre application and considering the noisy vinyl groves to put in risk of worsening (due to external components matching) the all important CMRR?

George
 
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I had a read thru of the EBU material, thanks again for posting it. Also downloaded tge test tracks. I've read some of the info before, but in other documents. I had forgotten about the loudness meta-data that can be embedded. It' takes what RN Marsh want's a step further.

I liked the EBU method of gating and of long/-medium-short-sample times. These seem like common sense when evaluating dynamic range. I was doing something similar, but with out codified guidelines.
Mostly described on page 43here:
https://tech.ebu.ch/docs/tech/tech3343.pdf

and also here:
https://tech.ebu.ch/docs/tech/tech3342.pdf
 
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Piezoelectric hydrophone sensor requires high impedance load (or charge amp)

That’s correct Dimitri but AD625 inputs are already 1GΩ/4pF. How high does the input impedance goes with the FETs?
Now I’m thinking that Scott might have meant to squeeze out some more HF bandwidth needed for medium-short range SONARS by having part of the 40dB gain outside of the IC.

George
 
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The advantage of doing your own recordings is that you know what it is supposed to sound like and can accurately correct/improve your system.



THx-RNMarsh


Yes, or tuning your stereo to your recording device...

Of course you need the best in mics, use of them and mic preamps and recorder (digital has taken over in most places as the medium to record to.... very flat response et al..... much less to make sound grossly different from original).

And that keeps getting better and so it is a long term iterative process.


THx-RNM
 
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The perception of dynamics I think has more to do with technique in recording, and the post work, than SPL level alone
Agreed. There are simple ways to look at dynamics, and more complex ways. Just how complex is needed? And what defines "dynamic sounding" as opposed to simple measurements of dynamic range? How much does spectral content matter?
 
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