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Old 19th November 2013, 10:47 AM   #1
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Default Volume (level) ... the bottom line

Some quick truisms (with the disclaimer: all things held equal) ...

(1) When digital came in (PCM recording, CD, etc.), it gave "the industry" about 20dB more in headroom (over prev. generation analog/vinyl). Some say media companies abused this extra headroom by making albums louder (e.g., the loudness war, etc.). (See Bob Katz video links below)

(2) Less resistance in volume control (pot), means better SQ. (all things held equal)

.... ok, so knowing and accepting these two points ... does the audio signal stay more pure if the FULL range of, e.g., a rotary volume is used (because at the higher end, there is less resistance)? Again, all else held equal (so, ignoring ultimate impedance matching, etc.).

I'm asking this question in the context of the "loudness war" (see Refs) ... that some of the added clarity of a lower-level signal (vinyl, or loudness-free CD), is "simply" because listeners are using their volume control in its more-linear (= higher) range?

Refs:
Loudness war - Wikipedia, the free encyclopedia
The Loudness War - YouTube
Bob Katz about the "loudness war" part 1 - YouTube
Bob Katz about the "loudness war" part 2 - YouTube
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Old 19th November 2013, 11:12 AM   #2
DF96 is offline DF96  England
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Your point 2 is false. Too little resistance increases distortion because it adds load to the previous stage.

You also may misunderstand how pots work. Assuming the usual log pot, then at the higher end (but not quite maximum) the impedance seen by the next stage is maximised. This is worst at -6dB attentuation (x0.5 in voltage). So at the higher end there is more resistance, not less.

Do some reading on potential dividers. Using the full range of a pot can reduce noise, as you are not putting the signal through successive stages of gain and attenuation. Apart from that there is nothing to worry about.
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Old 19th November 2013, 01:42 PM   #3
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Originally Posted by hollowman View Post
Some quick truisms (with the disclaimer: all things held equal) ...

(1) When digital came in (PCM recording, CD, etc.), it gave "the industry" about 20dB more in headroom (over prev. generation analog/vinyl)...
I suspect this didn't happen because of the greater dynamic range offered by the CD format over vinyl. I doubt it's even so much an issue of maximum possible playback loudness, as that can be set as desired at home (within the physical limits of a given playback system) simply by adjusting the volume control knob.

It seems to me, that what CD may have done to contribute to the 'loudness war' was to establish a de facto standardized maximum playback signal voltage level of 2VRMS from CD source components. If the volume level is not changed somewhere after the 2VRMS CD source component level, then music content having an average level (ironically, by compressing the dynamic range) nudging up closest to the peak digital full-scale level will sound subjectively louder than music content registering that same peak level but having a lower average level (due to having an uncompressed dynamic range).

It's a music marketing issue, I suppose. For causal music listeners, which means everyone besides we few audiophiles, the louder perceived music will more readily grab the listeners attention, particularly in the bass.
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Last edited by Ken Newton; 19th November 2013 at 01:46 PM.
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Old 19th November 2013, 03:24 PM   #4
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Is an acausal music listener someone who hears music unintentionally?
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Old 19th November 2013, 03:25 PM   #5
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Originally Posted by DF96 View Post
Your point 2 is false. Too little resistance increases distortion because it adds load to the previous stage.

You also may misunderstand how pots work. Assuming the usual log pot, then at the higher end (but not quite maximum) the impedance seen by the next stage is maximised. This is worst at -6dB attentuation (x0.5 in voltage). So at the higher end there is more resistance, not less.
I'm not sure I fully understand the FULL interactive picture ... even DIY Tangent claims he never "got" volume controls -- but if the following stage is high impedance (ideal?), then shouldn't the vol. be low Z (or R)? Also, WRT to my orig. remark on lowest resistance and better SQ, I meant less stuff for the signal to go thru (ergo less noise) ... most pots (audio or not) are not boutique metal-film resistance-grade.

Just to clarify ...a question... for a typical log (audio) pot at max vol., what is a typical resistance that the audio signal (current) feels as it goes thru it?
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Last edited by hollowman; 19th November 2013 at 03:41 PM.
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Old 19th November 2013, 03:54 PM   #6
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A low value resistor is not "less stuff" for the signal to go through. Circuits don't work like that.

A volume pot is an adjustable potential divider. Understand potential dividers and you are well on your way to understanding volume pots. They are actually quite simple; one of the simplest parts of any audio circuit.

A pot at max may present a few ohms in series with the signal and the full pot resistance in shunt to ground. A little below max (-6dB - a very small volume reduction) the source resistance seen by the following circuit (and any cable capacitance) is equal to a quarter of the pot resistance; all other volumes give smaller source resistance.
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Old 19th November 2013, 04:07 PM   #7
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E.g., Note in the this video how much more blue (resistive) area the current (signal) has to travel thru.
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Old 19th November 2013, 04:24 PM   #8
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A low value resistor is not "less stuff" for the signal to go through. Circuits don't work like that.
Then why do most preamps not include bass/treble? Why do better receivers and integrated amps have a bypass for tone controls?
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Old 19th November 2013, 05:06 PM   #9
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Is an acausal music listener someone who hears music unintentionally?
Most certainly. We are inundated with unintentional music listening everywhere in the public sphere. At the shopping mall, in the office elevator, riding in a car, walking on the street, in public rest rooms. We are almost constantly exposed to background music it seems. So much so, that Gilberto's 'Girl from Ipanema' has become a background music cliche'.

I sometimes wonder whether the general apathy which younger generations show toward the focused and intentional listening activity that appreciation of an audiophile stereo system requires may partially stem from this constant exposure.

...And, here, you were thinking it was merely a humorous typo.
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Old 19th November 2013, 05:32 PM   #10
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Quote:
Originally Posted by Ken Newton
Most certainly.
I agree. I have walked out of shops because the task of being an acausal listener was too unpleasant.

Quote:
Originally Posted by hollowman
Then why do most preamps not include bass/treble? Why do better receivers and integrated amps have a bypass for tone controls?
A different issue. The problem (a quite tiny problem in most cases) is the accompanying active circuits, not the physical control with the knob on the end. All circuits add a little noise and distortion so if you don't need them omit them. The fashion for omitting tone controls has led some people to try to achieve tone control in a less convenient way by changing speakers, cables, preamps etc. A volume control cannot be omitted.

Quote:
Note in the this video how much more blue (resistive) area the current (signal) has to travel thru.
The physical size of a resistor tells us little. To the extent that it matters at all, a bigger resistor is likely to degrade the signal less. Don't learn your circuit theory from YouTube!

Learn how volume controls work (as I keep saying). Once you have got that, you could then look at tone controls - but they are more complicated.
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