how to get the lower bitrates? Options

[amppa]

So, I would like to have mp3 files close to 192 kbps. I listen mostly metal (various types - heavy, power, black, ...) and --alt-preset standard seems to create mostly bitrates of 200-250 (tested with several albums). I consider this to be too high, how should I create the files to get lower rates? Should I use ABR with --alt-preset [rate] or maybe some VBR command line (for example, edited -r3mix), using -V[n] to adjust the bitrates? Any suggestions?

[Dibrom]

My stance on this:

Lowering the lowpass is by far, the most graceful way of lowering the bitrate. If you can't hear beyond 16khz in real music (not on a test tone.. maybe you should try this to know for yourself), then the best solution of all would be to add the -Y switch. If you do this, frequencies over 16khz will not be encoded if they require a significant jump in bitrate... meaning that probably 80% of the stuff over 16khz won't get encoded, and you'll save a very large amount of bits.. probably on the order of 40kbps or maybe more, depending on the file.

The other solution, which is much less graceful and much more dangerous, increasing the possibility of ugly noise based artifacts creeping in, is to lower the ath. This is part of the approach that --r3mix uses, and is one of the reasons that I don't recommend it (--r3mix, or this approach) at all. However, even with a lower ath, you'd still get some of the benefits of alt-preset standard, but it would be very non-ideal. Most of the other settings in this preset are all based around a very fined tuned threshold, so lowering the ath significantly could very well "break" most of that.

Lowering the -V switch puts you in nearly the same boat as the ath (everything being tuned right to the threshold). You might be able to get away with -V3, but I wouldn't go much lower than that.

The lowpass really is your best bet.

Slightly OT:

In between the experiments I've been running on and off lately in trying to modify the abr stuff for higher quality, I've also gotten some possible ideas (no promises) for ways to maybe reduce the bitrate some more.. either in aps or in another new vbr preset. Chances are that if this happens, there will be something sacrificed elsewhere... like employing an adaptive lowpass, with a lower nominal cutoff, but increasing it beyond 19khz in critical moments. A more agressive adaptive ath might help here also. Neither of these things would increase quality, but might allow again for a tighter quality/size ratio.