Some science.....digital of course

[Welder]

I got directed to this by a gaming mate of mine who is interested in audio for games (thanks GeneralDisarray :))
Games were at the forefront of developing quality computer based audio long before the audiophile community dragged their sorry arses away from their valves and needles and brought all their mystic wisdom and golden ears into the debates :doh:
It’s a fairly weighty bit of writty and not much oil for the true subjectivist to slide around on…..oh well, never mind ;)

http://www.dspguide.com/

[Vincent Kars]

Hi John

This one I do think is a good introduction to DSP too: http://www.bores.com//index_dsp.htm

[Welder]

Hey Vincent :)
Thanks for the link. I’ll work my through it slowly.
One area I’m interested in atm is how replay gain works and what effect if any it has on perceived sound.
Exactly how the differing players retrieve and process data seems to be quite hard to get information on.

[Vincent Kars]

Hi John

In principle they should adhere to the standard: http://replaygain.org/
There is a technical description on this site.
The result is a single number applied to the track so DSP wise this is digital volume control.

[Welder]

Since transferring to file based audio I’ve become interested in how digital audio works and the often contentious debates that surround the benefits of higher resolution audio.
I have my own view concerning these issues based not only on the theories that underpin digital audio but also my own experiences of the audiophile industry and what I have heard, or not, with my own ears over the years.
This is one of the more informative discussions I have found on the net.
It’s a fairly lengthy debate and the links need to be read to grasp the reasoning behind parts of the debate.

http://www.head-fi.org/forum/thread/415361/24bit-vs-16bit-the-myth-exploded

There have been changes in both recording technology and digital to analogue processing that some might say add substance to the view put forward by those who contest the original post. I’ll leave you to decide if these changes are a) in common use in the industry and b) given the limitations of the vast majority of the HI Fi we are likely to own, likely to have a major impact on the basic principles.

Unfortunately we are as humans pretty gullible and a great many of us either haven’t bothered to investigate the workings and limitations inherent in the technology that surrounds us, or don’t have sufficient grasp of the maths and physics that underpins them to adequately counter some of the more fanciful claims concerning the components and media the audiophile industry is interested in selling us.

Also, unfortunately, there is no counter argument to those who say “I can hear this” unless one is able to test their assertions in a controlled environment. Failing such tests which are often also contentious within the audiophile community I tend to rely on what is probable, a pragmatic approach that most of us live by when all is said and done.

[WAD62]

Hi John

In principle they should adhere to the standard: http://replaygain.org/
There is a technical description on this site.
The result is a single number applied to the track so DSP wise this is digital volume control.
Some very interesting stuff, I use native 16bit/44.1 Flac myself...

Winamp now has an the added feature of 'ReplayGain Pre-Amp' (available on the latest pro version), which I think is documented in the proposed standard on your link. It allows for up to +6db, which dovetails nicely with an average Replaygain (Album not track) figure in my 2k FLAC collection of -6db.

I've tried it at +6db with my 'quietest' ReplayGain albums (the Orb blue room strangely enough) at +6.61, so in my simple head that makes +12.61, and there no clipping at all (I've turned the 'avoid clipping' off).

I just hope people like Squeezebox start picking up on this ReplayGain pre-amp feature, it would reduce ones amplification requirements somewhat...

[Vincent Kars]

This is one of the more informative discussions I have found on the net.
A bit more homework for you

http://www.hydrogenaudio.org/forums/index.php?showtopic=49843

http://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=70002

[Marco]

Also, unfortunately, there is no counter argument to those who say “I can hear this” unless one is able to test their assertions in a controlled environment.


{Yawn} Please let's not go there, John. And I'm not sure I'm entirely cock-a-hoop about the sentiments expressed here either:


Games were at the forefront of developing quality computer based audio long before the audiophile community dragged their sorry arses away from their valves and needles and brought all their mystic wisdom and golden ears into the debates :doh:


Remember that AoS is primarily a subjectivist forum (read Our Ethos) for those who trust their ears and experience implicitly with audio - and for good reason! ;)

I enjoy reading many of your contributions, but not when you go into 'provocative objectivist mode' :)

Marco.

[Welder]

It isn’t my intention to start subjective/objective debate Marco, and yes, I’ve read the ethos and do in general try to respect it when contributing :)

It is however an interesting and informative thread. The main protagonists writes in a coherent and knowledgeable fashion and the subject would seem particularly relevant given the increasing availability of hi res downloads and 24/192 capable Dacs.

My interest is in the theories that underpin the debate which are explained rather well imo. With regard to the debate itself, yes, I would agree with you, not particularly entertaining and not something I wish to rake up yet again :rolleyes:

I have a 24/96 capable Dac and 24/96 files and I can hear a difference using a 20Hz to 20kHz system which makes me wonder if something is being overlooked in the interpretation of the theories.

“Games were at the forefront of developing quality computer based audio long before the audiophile community dragged their sorry arses away from their valves and needles and brought all their mystic wisdom and golden ears into the debates ”

Hmm, okay Marco, possibly not the most endearing statement construction and possibly overly provocative for a subjectivist forum where many are vinyl enthusiasts :(
I wonder though Marco, do you remember the way digital audio was dismissed by some of the most prominent members of the Hi Fi press when CD music replay became an affordable option for the consumer?

Lets face it, we, the over 50’s in my case, and predominantly over 40’s in the audiophile community are not the ideal people to be evaluating audio. Many of us have become accustom to a particular sound and reasonably, enough this is what we have come to consider as “good” sound.
It would seem a great many of the Hi Fi reviewers are in the 40 to 60 age bracket. Apart from the inevitable deterioration in our hearing due to our age many of us have been subjecting our ears to lengthy exposure to music at damaging decibel levels for years. From what I’ve read on the subject of age related hearing loss and the effects of prolonged exposure to listening to music at high volume, it is not just a case of deterioration in the perception of higher frequencies, the ability to hear midrange harmonics is also affected. Strangely one can find some detailed information regarding the technical specs of the reviewed equipment but I have yet to see any technical specs concerning the reviewer.


The audiophile community may indeed have a wealth of experience in Hi Fi related matters but with regard to what an accurate reproduction of music is in any chosen format, our experiences (read established preferences) and hearing abilities don’t recommend us as the ideal candidates for auditioning.
I don’t think many would argue against the statement that as we get older our receptiveness to new experiences and new technologies decreases by and large; that’s my experience of the world anyway; we hit a comfort zone.
When computer based audio came to the attention of some of the established Hi Fi reviewers, their lack of knowledge regarding the theories underpinning digital audio in general and computer audio in particular was imo truly horrifying. While I accept it is not necessary to understand how something works in order to appreciate its usefulness/beauty if one is going to criticize or evaluate compared to something else then some in depth knowledge would seem appropriate.
So, in short, with regard to my above statement at the time when file based audio came to the attention of the Hi Fi press it tended to be evaluated by men over 40 with less than optimal hearing, a bit set in their ways without the knowledge concerning the theories that underpin it.
From some of the reviews I recall, digital audio was approached with suspicion and prejudice and dismissed as inherently inferior. From some of what I’ve read it seems file based audio is getting similar treatment.

I am I have come to realize more of a subjectivists than the rational part of me feels comfortable with so my less considerate outbursts probably reflect the objectivists part of me rebelling when I sit back in appreciation of some tweak or other that the rational would say has absolutely no foundation in theory.
I’ll try to remember to set Sunny on it before my fingers hit the keyboard in future :lol:

[Marco]

Wow - that deserves a proper reply, John. And you'll get it when I have time later :)

Marco.