Just for fun, I made a little tune for the phone queue of the company where i work.
The original track sounded good in 16bit 44kHz stereo, but as you can imagine…
extremely crappy 
in, i guess, 4bit 11kHz mono (?) when heard though a phone.
Are there any special tips or tutorials specializing on optimizing/mastering music for phones?
Or dou you guys have some tricks for me?
Aunt Google couldn’t help me so far…
what if you in advance convert to 4bit 11khz yourself, in let’s say Wavelab or Audacity (dunno if it supports it)?
then I guess you can take a little control over exactly how it converts, and maybe even tweak it with some EQ or mastering before you save the final file.
i would assume it will give slightly better results (?).
Telephone quality speech has a bandwidth of 200Hz to 3.2kHz, 8Khz sampling rate @ 12bit. Good for speech but poor for music (obviously) I found that info here
I’d forget about all the rest and just look at mixing your music as best as you can between 200-3200Hz ie boost multiples of fundamental frequencies of the bass ie if the bass sits around 120hz, boost at 240 and/or 360 etc; you get the idea
I also would make sure that each sound has it’s own niche in the frequency spectrum as much as possible (moreso than ‘normal’ mixing) - be brutal. Can you monitor over a ‘telephone speaker’ while you are mixing? That’d help a lot
Good luck; I’d like to hear a sample
I read this one at some point, there is mobile part:
I’m not sure that this is really a mastering problem insofar as getting the sounds right in the first place to fit such a narrow frequency range
The article says "Click the “Project rate” option on the bottom left bar of the Audacity screen, and set it to 11Hz. Depending on your phone, you may want to hike this up. However, a higher frequency will mean a larger file size.
I don’t think file size here matters too much (does it?)…and I think they mean 11kHz btw
It also says to remove the bass (30-300Hz)…ok but does not say anything about the higher end of the spectrum; get rid of that to stop wasting headroom.
Also, mono is the key here. I doubt that any mix of a 24bit 192Khz stereo track would sound any good on a telephone speaker unless the mix was tested on a mono system (the crapper the better in this case)
Get the mix right first and then look at ‘mastering’
oh dude so simple
always chek your work in phones if that is the target media
That mastering tutorial isn’t exactly what he is looking for. He said phone queue, not ringtone. That means huge difference in terms of possible formats and speaker quality.
Like hotelsinus said - check with the phone. Unfortunately I have no idea of phone which supports playing audio from the ‘ear speaker’ (or whatever it’s called you use when making a call).
I agree this isn’t so much a mastering issues, moreso a mixing issue. Things need to be neat, and focused on the midrange. A great mix and master should translate well on all sorts of outrageous speaker systems, provided it’s not strange music that is all just sub and ultrasonic highs (I’m looking at you avant garde composers).
Every phone in the [insert chosen deity]-forsaken world supports hearing “stuff”; be it speech or music or bullshit
Mono 300-3000Hz. MIX for that, fuck mastering - you must choose the lowest common denominator ie a tiny speaker
If you want it to sound good on a teeny-weeny mono speaker, you must mix for that (no offence to teh OP)
Thanks for the tips so far!
Btw, file size doesn’t matter at all. It’s a software based PBX, and i just fed it the 16 bit .wav file, so it’s the phone server that does the conversion. What I did so far was: render the file, upload it to the server and then listen to it with my headset (=phone)… I see that this is a quite “cumbersome” way.
Although i said “mastering” (i meant it in a sense of “post production”) , of course it includes mixing too. I should have been more precise, sorry. 
That frenquency range you mentioned seems to be the core of the problem: one issue I have, is that the hihats smash through (or better smash down…) the whole mix. They sit around 3k Hz (at least that what’s left of it)… greetings from fletcher & munson… 
Well, it will play around a bit with the faders and eq’s and inform you how it went…