Danny Danzi ... However, when you upload to one of these digital distribution places, that beautiful 320 you created *MAY* get smashed down to something else. It may end up 160 or 192. This is the problem at hand. Imagine an mp3 OF an mp3. LOL! This is why some of that stuff sounds so bad. 

This article: 
 
http://images.apple.com/itunes/mastered-for-itunes/docs/mastered_for_itunes.pdf 

is a good and interesting read and the thing I really got from this is the AAC file stuff. It is a better compressed format for music so therefore it can be assumed that ITunes won't be damaging any aspect of your mix as such and that can only be a good thing. You can make your own AAC files too and listen and compare to the original wave files. They are meant to be very close.

So yes common sense could prevail here and as long as you keep your mixes a bit clear of 0dBFS things should be fine. I tend to go down as far as -1 dB. Maybe that is too low but it ensures you wont be pushing any conversion or converters too much either. 

I find when you mastering you can always print alternate versions that may use a little less limiting for the compressed formats. And yes ITunes is not the be all and end all. There are plenty of MP3 format deliveries and we have to master for them too. Some pre conversion processing for MP3 can make a difference.

batsbrew


jeff,
why do you believe the aac thing is a 'better compressed format'?

Improvements include:
    More sample frequencies (from 8 to 96 kHz) than MP3 (16 to 48 kHz)
    Up to 48 channels (MP3 supports up to two channels in MPEG-1 mode and up to 5.1 channels in MPEG-2 mode)
    Arbitrary bit-rates and variable frame length. Standardized constant bit rate with bit reservoir.
    Higher efficiency and simpler filterbank (rather than MP3's hybrid coding, AAC uses a pure MDCT)
    Higher coding efficiency for stationary signals (AAC uses a blocksize of 1024 or 960 samples, allowing more efficient coding than MP3's 576 sample blocks)
    Higher coding accuracy for transient signals (AAC uses a blocksize of 128 or 120 samples, allowing more accurate coding than MP3's 192 sample blocks)
    Can use Kaiser-Bessel derived window function to eliminate spectral leakage at the expense of widening the main lobe
    Much better handling of audio frequencies above 16 kHz
    More flexible joint stereo (different methods can be used in different frequency ranges)
    Adds additional modules (tools) to increase compression efficiency: TNS, Backwards Prediction, PNS etc... These modules can be combined to constitute different encoding profiles.
 
 
Actually I mistakenly thought AAC was lossless, it isn't. It's a marginal improvement over mp3, which like Danny I can hardly distinguish in listening tests at higher bit rates if at all, but I do think there should have been a lossless standard adopted by now.
 
The fact that AAC (mp4) is so widely adopted now it will again hold back the technology that is already available to distribute compact lossless formats.  Even Microsoft have a lossless version of WMA already available and it has been for some time.
It's mass appeal that drives standards though so we'll have to live with lossy formats for some time to come even if they have improved somewhat.

Thanks Jonbouy for that. I was going to say that there seems to be an all round consensus after doing the research that the AAC file is quite interesting and very good. If anything this discussion has brought myself and maybe some others to the attention of the AAC file in general.

thanks for that info guys.


so...


this is what i think:


that between all of the possible ways you can LOSE fidelity due to delivery methods alone....


the issue of CAPTURING THE MOST PRISTINE TRACKS POSSIBLE...
within your budget...


becomes GOAL #1.

AAC doesn't offer a practical benefit to consumers of 2 track music...  mp3 handles it fine albeit at relatively higher bit rates.

Ultra lo bit rate 2 track music files don't seem to be a big priority for consumers these days.


AAC's chief benefit is for companies that own the data bottlenecks. It's more attractive to stream 3 96kbs AAC streams to 3 end users than it is to waste the bandwidth on a single user listening to a 320kbs mp3. The communications companies may charge by the bit but there economy of scale has a sweet spot and after that it get's expensive for them to offer additional bandwidth. They want everyone paying to be connected but they don't want to hog up the line. Indeed the original intent for mp3 was to allow for denser and more profitable multiplexing on phone lines... and then it leaked out to the music culture. 

AAC is also great for DVD and BluRay distribution where finite storage space and a low bandwdith make it desirable to squeeze the audio to the max so that the remainder can be used for picture. I get to see lots of barely compressed video... it looks worse when you go to mpeg 2 or mp4 and any xtra bandwidth you can devote to picture is taken from the audio.

AAC has some terrific potential for installed sound systems where there may be dozens of speaker drivers on a network... the multi channel streams can be used for all sorts of things.



iThink iTunes is promoting AAC music downloading as innovative technology because if it didn't... it probably wouldn't occur to the many consumers that are simply looking to buy a copy of their favorite song that AAC is anything more than an inconvenient format that doesn't play nice with their house and car full of mp3 playing appliances.



best regards,
mike

Mike I think we've all since taken the time and got to the point where we've all worked that much out by now.  There's a list couple of posts up outlining the differences between AAC and mp3.
 
Thing is we have to live with it just now if we want our music to be disseminated over those existing networks as saleable items in that market.
 
I'm not using iTunes as a distribution option nor do I buy music from there, therefore it isn't a concern I have personally.  I encode to flac to save space for my portable players.
 
There is no need for anyone to adopt a lossy codec anymore, like you say nobody is counting the cost in bandwidth terms when it comes to streaming HD video, the amount of extra bandwith required by any lossless audio codec over a lossy one is negligable in comparison.
 
Currently though the reality is AAC for the majority of digital audio downloads do you reckon that you or I are going to be able to change that any time soon?
 
You alluded to the fact you enjoy entering mp3 tags more than writing on a cassette case, thank goodness we're still not having to listen to cassettes.
Many of us have also reported barely discernable differences given a high enough bit-rate with current lossy formats.  Those formats are pretty useless if you want to do any further processing though, maybe that's the reason major corporations like them better. 
 
 
Music consumers on the whole aren't complaing, quite rightly as there is little for a consumer to complain about in actuality with regard to the product, and the politics of corporate business practices is left out of the equation.
 
The guidlines show how content creators can produce the best possible product on the format is all.

Just to further comment on my last post about Tunecore, they responded to me today with this:

Hey Danny,

Conversion is all done on the stores end and we have no idea how or what program they use to convert the wav programs. Each store I would assume is a bit different. There are no choices. The stores have their own conversion ways and bitrates. They have the same for everyone. Usually it's 256 kbps mp3 for all other stores except for iTunes which is a 256 kbps m4a file.

If this is in fact the case, no one in this thread should worry about bad sounding material if they use the guidelines we've all presented in my opinion. A 256 kb mp3 is pretty good even if you use "fast encoding" on my end with "variable bit rate" enabled. It's not quite as good as "slow encoding" and "constant bit rate" but it's good enough to where a well recorded, mixed and mastered file, should be really good quality for all of us. :)

-Danny