Digital Audio and Amplifier Noise Floor Comparison - Is 16bit/44.1kHz All We Need ???

[fas42]

Yes.

 

Over 3 decades ago it was possible to get SQ as good as one could want from CDs, using well done amplifiers  of the day - the "noise floors" of the latest systems, meaning taking everything into account, beyond just the amplifier, are much better than they used to be - but still fall well short of 'testing' the limits of Redbook.

[fas42]

What is important is to have a electronics chain where the gain can be varied by a large amount with no deleterious effects, such as starting to hear hum or conventional circuit noise - albums have a huge range of average recording levels, and you don't want to be caught with not having enough gain to reproduce at a satisfying level, for the occasion.

 

Talking of breathing, there can be an issue with the how the miking of things like string quartets are done - I don't want to become more aware of the body movements of the player, than of the instrument ...

[fas42]

23 minutes ago, sandyk said:

 

 Assuming that your hearing isn't too aged, if you can hear hiss or hum from a Speaker with your ears close to it, then it WILL degrade low level material a little .

 

Which ties in with what I'm looking for in system replay capability - with one's ears very close to a speaker driver, only inches away, do I detect the presence of a driver, or clues that it's a reproduction chain I'm listening to? The obvious giveaway is hum or hiss, but tweeter 'spit' is just as meaningful, in fact more so.

 

The presence of detectable levels of unwanted 'extra' does degrade low level material in the recording - and the close listening reveals it, very easily. It is possible to completely eliminate those artifacts, and then it's very clear that the 16/44.1 format is as good as necessary; play a full symphonic track that's been attenuated by 60dB, as the actual recording, at maximum gain of the rig. You will barely be able to hear it, with your ear hard up against the speaker surface ... yet, the music will still all be there, the full structure will be clear, with no obvious problems.

[fas42]

It's straightforward to assess whether the system can go "quiet enough" - usually most problems arise as one attempts to go closer to live listening levels - can one keep increasing the volume, and the SQ retain its integrity? This is where highly efficient speakers, horns, win bigtime - they have no trouble passing ambitious SPL tests, because no particular stress is being placed on the electronics. Most conventional rigs start to degrade, and lose the ability to create realistic sound levels as the gain is increased; they just end up sounding like another "hifi".

[fas42]

15 hours ago, esldude said:

My next question would be are there recordings with this kind of dynamic range?  Theoretically it would be possible to get close.  I think in practice much of the processing and microphone limitations will mean you can't get to 120 db in most recordings.  I think you'll struggle to actually get more than 80 db in recordings honestly.  

 

Where getting clean behaviour over a wide range is beneficial are recordings like this,

 

 

The intro may not start at a true 80dB or so down, but the impact of the opening is that much greater if the full range of the start is realised.

[fas42]

The theoretical reasons for why a wider range, bigger numbers is "nicer" all seem reasonable enough - however, in the real world of listening to music it's remarkable how well the human hearing system can adjust to what it hears, if all the "right things" are in place ... as someone who has heard the most 'technically brilliant' setups  and recordings come across as being banal, uninteresting; and the most unlikely, "rough at the edges" captures of a musical event take my breath away - I know where I would place my priorities, .

[fas42]

But, 16/44.1 can handle both rough at the edges, and very well recorded - as a means of storage of "all that matters" - the noise floor of 16/44.1 I have never found to be a limit; poor judgement, mistakes in mastering have always been the causes of something that seemed not quite right that in what I've come across.

 

Things like needing dither ... one has to create an extreme listening situation, to clearly hear the effects of not applying dither to CD tracks - a situation which would never happen in any listening to a music CD.

[fas42]

2 hours ago, semente said:

 

Have you tried these audibility tests?

 

https://www.audiocheck.net/audiotests_dithering.php

 

Over the years I've examined what dithering does to the signal ... there's nothing like reducing 16 bit music to 8 bits, and then applying every variant of dithering to that, listening to what the subjective result is, . You then understand why the precise nature of dithering is critical - just applying some arbitrary dither may in fact make the situation worse.

 

Also having a test CD, with music passages attentuated by up to 60dB, with no dithering, is very instructive - it demonstrates that one can hear 16 bit digital artifacts, but they are buried so low down in level that only an extreme listening setup can make them obvious.

 

Only recordings which have faulty mastering on them have shown to be a problem - dithering is one of the last issue to have relevance if one is after convincing sound ...

 

So, no, I haven't bothered listening to those tests ...

[fas42]

Trouble is, anomalies in the sound don't always present themselves as nice, neat, "measurable whenever you want to" behaviours. As a scenario, consider a power amplifier that uses a transformer which is barely good enough to ensure that the specs that look good on the glossy brochure are met - in real world use, the core of the transformer overheats, saturates as one tries for "big sound", and the power supply characteristics change quite significantly - and the subjective SQ suffers. Switch off, giving the circuitry time to restabilise, and then do some 'proper measuring' ... "Nope, the amplifier's working perfectly - all the number's look good!' ... The real problem is never caught ...

 

So many issues in substandard audio are like that - they don't sit obediently on the test bench, waiting to be 'trapped' in a "Ah- hah!" moment ... sometimes, lots of just thinking and idle fiddling with aspects of the whole give one clues as to where focused attention is worthwhile - and good movement forward then occurs ...

[fas42]

A rule of thumb I use is that an amp design has to be capable of intrinsically doing 200KHz; that is, I would look at what the waveform at a reasonable voltage swing was like at that frequency - if it was a complete mess, skip that one; a very decent looking sine wave tells one that the circuitry is "fast enough", and is likely to do well in "real life".

[fas42]

The preamp is not the problem - it's pretty trivial to get RF performance at low currents, a cheap as chips opamp can do that. The fun starts when you want push out amps, into a speaker - you either use something which also serves to keep your house warm in winter, or, start to have battles getting a class AB output stage to behave itself - or use class D.