John Curl's Blowtorch preamplifier part II

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#98,801
Markw4 said:
Anyone with a computer can record, it has become widely democratized. And lots of people do. My daughter makes part of her living writing music for TV commercials and whatever else comes up. $500 for 30 seconds. No recording studio needed. Sometimes I help her out with some editing, or mastering. Help out a few friends too. Since I don't need the money I do it for fun.
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Fair enough! I'm still okay saying that the SNR on this topic is pretty poor (but maybe better than the regular comings and goings?) given almost all of us participating will play whatever we get rather than make the music ourselves.

But should I sound too conflicting, I do want to wish everyone the happiest of holidays.
 
#98,804
IMHO of course ---- the main reason music from high hi speakers don't sound like real instruments being played in the room and never will is that the speaker dispersion pattern doesn't match any musical instruments' Each instrument has a radiated pattern... drum, violin, horn, etc... all produce different acoustic radiated into the room patterns. The speaker has one fixed radiated pattern for all instruments.



THx-RNMarsh
 
#98,805

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#98,806
RNMarsh said:
IMHO of course ---- the main reason music from high hi speakers don't sound like real instruments being played in the room and never will is that the speaker dispersion pattern doesn't match any musical instruments' Each instrument has a radiated pattern... drum, violin, horn, etc... all produce different acoustic radiated into the room patterns. The speaker has one fixed radiated pattern for all instruments.
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Too, the real instruments are all in a different place in the space. So, they excite the room's resonances differently.
I think "stereo imaging". With real instruments it is a complex mix of relative levels, phase and different room resonances. Mostly levels only in most of Rock and Pop recordings mixs.
Last, speakers bring their own colorations (membranes), resonances ( See the waterfalls), distortions ....
Well, is that not good enough to had brought-us so much pleasure during all our (long) lifes ? ;-)

May I add that most of the good records just sound ... better ... than any live performance ....

And, how this can be possible, they are not really based on meter's measurements, but on the listening and personal taste of the producers/sound engineers, very subjective, and not blind at all.
Art is subjective ;-)
 
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#98,809
It is but it's wonderful to find a venue that is not enhanced electronically. I also find the presentation of orchestral recordings to be false. No one sits 10 ft above the conductors head.

Also you cannot replicate the experience of going to a concert at home. It's simply impossible.

And as I have noted before, most classical recordings roll off the LF. A few labels (such as Chandos) who issue 5.1 hybrid SACD have moved away from this and the red book layer maintains the full LF extension. Without that the venue is sucked out of the recording, which is very noticable.

So for me, and for the music I prefer I have to say that records, however good are a very poor facsimile for being there. This will not stop me enjoying 1930s Furtwangler performances 🙂.
 
#98,810
billshurv said:
This doesn't fit with my experience across the thousands of CDs and LPs I have. Looking at the waveforms I posted the RMS level looks well below -18dBFS and the DR plugin concurs measuring -24dBFS RMS.
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As per my previous post...
The main passage peaks are averaging around -18, with the transient peaks approaching clip.
I am talking peak levels so of course the RMS level indication will be different.
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In this discussion of levels and VU metering, the point and importance of Wikipedia - Alignment level has been omitted.
The alignment level in an audio signal chain or on an audio recording is a defined anchor point that represents a reasonable or typical level. It does not represent a particular sound level or signal level or digital representation, but it can be defined as corresponding to particular levels in each of these domains.
For example, alignment level is commonly 0 dBu (Equal to 0.775 Volts RMS) in broadcast chains and in professional audio what is commonly known as "0VU", which is +4dBu (Equal to 1.227 Volts RMS) in places where the signal exists as analogue voltage. Under normal situations the "0VU" reference allowed for a headroom of 18dB or more above the reference level without significant distortion. This is largely due to the use of slow responding VU meters in almost all analog professional audio equipment which, by their design, and by specification responded to an average level, not peak levels. It most commonly is at −18 dB FS (18 dB below full scale digital) on digital recordings for programme exchange, in accordance with EBU recommendations.

The reason for alignment level - Using alignment level rather than maximum permitted level as the reference point allows more sensible headroom management throughout the audio chain, so that quality is only sacrificed through compression as late as possible.
Digital audio players such as the iPod, demonstrate the need for a common alignment level. While tracks taken from recent CDs sound loud enough, many older recordings (such as Pink Floyd albums which notably allowed lots of headroom for stunning dynamic range and rarely reach peak digital level) are far too quiet, even at full volume setting. Older audio systems typically incorporated 12dB of 'overvolume', meaning that it was possible to turn up the loudness on a quiet recording to make maximum use of amplifier output even if peak level was never reached on the recording. Modern devices, however, tend to produce maximum output at full volume only on recordings that reach full-scale digital level. If extra gain is added, then playing a modern CD after listening to a well recorded older one is likely to deafen, requiring the volume control to be turned down by a huge amount. Again, the adoption of a common alignment level (early CDs allowed around 18dB of headroom by common consent) would make sense, improving quality and usability and ending the loudness war.
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I would appreciate any examples you have for comparison as I would hate to think this is an outlier. Now if you believe the DRM plugin this RLJ track has a higher 'DR' than any of the sheffield lab DD recordings that John likes.
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Maybe it is an outlier within the context of modern recordings with usual over usage of peak limiting and multiband compression etc, ie loudness war.
The above quoted article describes exactly the volume control knob problem that you describe and the solution too.
Broadcast signal chain standard operating levels are set with the reasonable assumption that 18dB of headroom above 0VU (average not rms sensing) is adequate to keep 'out of trouble' with prerecorded and 'trained announcer' program content.
Downstream from content creation, there is always at least one limiter stage to protect the transmission system from peak overloads in the case of studio misoperation.
This same 18dB headroom assumption has historically also applied to 'polite' music recording, and provided reasonably uniform perceived playback levels.

Of course this levels 'gentleman's agreement' has all gone out the window with modern unlimited 'in the box' processing, new genres and new production values....so be it.

I took a look around the Dynamic Range Database ....reordering by clicking column headers is illuminating and informative.

Dan.
 
#98,811
billshurv said:
It is but it's wonderful to find a venue that is not enhanced electronically. I also find the presentation of orchestral recordings to be false. No one sits 10 ft above the conductors head.
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A most pleasantly memorable service call was in a cathedral whilst the resident organist practiced Toccata 25 times.
Recently via a colleague I have free next season tickets to the local state symphony orchestra - WASO 2018 Season Calendar
Nice way to calibrate my ears.

Dan.
 
#98,812
Max Headroom said:
As per my previous post...
In this discussion of levels and VU metering, the point and importance of Wikipedia - Alignment level has been omitted.
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Why spending time on this subject ? It is not a problem for any professional sound engineer I know.
Getting the highest possible level on a tape (or digital file) without risking any clipping is the basis of the work. Whatever the instrument to record. Trivial. With the help of either VU, peak meters, crest meters, oscilloscopes ... as you prefer. And whatever the way they are tuned in relation to the "reference level" in the studio. (the first thing you verify when you enter in).
Trivial as cooking a boiled egg for a chef.

And, anyway, is a sound engineer not supposed to use his ears, as the ultimate measuring instrument ?
This -18dB digital EBU reference level was not fixed by accident or unwashed people.
 
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#98,813
Tournesol said:
Why spending time on this subject ? It is not a problem for any professional sound engineer I know.
Getting the highest possible level on a tape (or digital file) without risking any clipping is the basis of the work. Whatever the instrument to record. Trivial. With the help of either VU, peak meters, crest meters, oscilloscopes ... as you prefer. And whatever the way they are tuned in relation to the "reference level" in the studio. (the first thing you verify when you enter in).
Trivial as cooking a boiled egg for a chef.
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I brought the subject up as clarification.
Trivial to you and me, not so for some others perhaps.
This -18dB digital EBU reference level was not fixed by accident or unwashed people.
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Yes, that is what I meant by 'gentleman's agreement'.

As part of final mastering for a particular pop record, we calibrated the two track recorder 2dB 'hot' to tape.
This caused 2dB over recording (magnetic levels) whilst maintaining usual upstream operating levels.
This known degree of 'overdrive' produced useful compression and 'fatness' upon playback....early loudness wars technique.
I commented recently that the digital copy of this two track tape sounded distinctly different...loss of sparkle and air and 'fun/groove' factor.

Dan.
 
#98,814
Max Headroom said:
I commented recently that the digital copy of this two track tape sounded distinctly different...loss of sparkle and air and 'fun/groove' factor.
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Was the analog magnetic tape aged ? I ask this, because the things I appreciate with digital recordings are exactly at the opposite: no loss of "sparkle and air.
Anyway, depending of the media people are working on or with, one's mix will be very different. Analog/digital mixing desk, analog/digital recorders etc ...
Each "gear" has his character ... that a good producer will use for his benefit, or chose for what it brings.

Heat, transparency, power, precision, coherence, details, sound stage, air ...
 
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#98,819
Markw4 said:
With respect to audio, I would say I know what less than half of those terms refer to. Let's see, transparency and details seem kind of self-explanatory. Air means HF? What about the others? Can anyone define them?
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Heat, may-be not the right word: warmth ?

Well, magnetic tape when pushed in level, brings in the same time an increase of distortion and a dynamic decrease of HF bandwidth (due to saturation). Both together, that create an artificial feeling of "Loudness", (power) and can increase imaginary "size" of individual instruments.
Coherence ? Let-me try to explain. When some mix two instruments together, that had been recorded separately, sometimes not even in the same place, you can mix them in such a way something sound not realistic between them.

Different reverbs, levels VS response curve, whatever ...

Analog magnetic tapes, may-be because distortion+ hiss+flutter, tend to bring some kind of "coherence" between them where digital does not help to "sweeten the pill" ;-) Just like our room VS headphone ...

This last example about what i called Power. With speakers, pushing the volume can increase the feeling of "power" while, in headphones, it can be just "played at higher level".

Destroyer OS said:
So make a microphone like not having one ear plugged is the answer?
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Why don't try "Couple ORTF" or artificial head ?
Couple stereophonique type ORTF MSTC 64 U - Apercu - SCHOEPS.de
- Welcome home Sennheiser MKE 2002 Dummy Head - Binaural | None |
 
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