I'm using iTunes-LAME-2.0.9-34 on Intel G5 and having problems getting Highpass Filtering to work.

Using the command line -V8 --vbr-new --highpass .5 works fine, but not the frequencies I want to filter out.
Dropping to --highpass .4 nothing is filtered.

Ideally I'd like to filter below 110 Hz, is there a command line that work for this or this a bug in the setup.

Cheers

I tested your command line with lame.exe v3.97. With -V8 setting it allows to use highpass freq >= 349 Hz ("Using polyphase highpass filter, transition band: 0 Hz - 387 Hz"). For frequencies 348 Hz or less LAME writes: "Warning: highpass filter disabled. highpass frequency too small"

So if you really need such filtering (btw, why?) you have to do this in some other program.

i.e. SoX piped into Lame.

Wow, I'm really surprised by this.

lvqcl I too saw that warning message come up when I tested on a PC while trying to isolate what was happening.

We are producing Audiobooks and nothing much happens under 100Hz with narration. I could filter out before encoding, but I was hoping using the available bits spread over 100Hz to the Lowpass roll off would give a better quality than from say 20Hz.

Who would ever want to cut below 349Hz? 80 and 100 is usually more common to rid background rumble from recordings.

Podcasters must be faced with similar issues.
Any tips on how to make best use filters would be greatly appreciated. -V8 has been settled on here as our starting point for quality vs file size.

Cheers

LAME cannot apply arbitrary low- and highpass cutoff values. So... just filter these frequencies out in any audio editor before encoding.

Is this just in -V8, or does it apply to all Lame encoding?