I read somewhere that at 128kbps cbr, lame alphas are having some low freq distortion. what does that mean? does it mean that bass sound will be distorted?

was it present in 3.96.1?

is this problem persistent with 160-320 kbps? as in lame alpha 11 160-320kbps cbr/abr code has been changed.
is it better than alpha 10?

lame developers help me plz

There are some warbling/rumbling artefacts with 3.97 since alpha 5. It occurs especially with tonal samples. CBR/ABR are both affected, up to 159 kbps (it disappears at 160 kbps). VBR preset don't have this problem. alpha 11 isn't better than alpha 10 IMO.

There also were some high frequency problems with CBR/ABR in 3.96.1 at these bitrates. Those have been fixed though.

Last night, I tried playing around with various cbr settings for a cranky old mp3 clock radio, and found that the LF rumbling/warbling on tonal samples can sometimes be heard at 160kbps CBR. The one sample where I really noticed this was after the 6:32 mark on the last track of Pink Floyd's Wish You Were Here, which features sustained notes on a Fender Rhodes electric piano.

The LF rumbling is very pronounced at 128kbps, which I especially noticed on opening guitar chords in a Tom Petty track ("Here Comes My Girl" from Damn The Torpedoes). For that particular song, adding --ns-bass -8 and dropping the lowpass to 16kHz seemed to make a significant difference in the LF stability. I wonder if this will improve other samples as well, without leading to too many additional HF degredations?

IMHO 16khz is a pretty sensible lowpass for 128kbps.
Using 3.90.3 I've always perceived ff123's recommendation a little more pleasing than --alt-preset 128.

The rumbling issue still seems to be present in a12, though I haven't ABX'ed the a11 and 12 encodes to see if the issue has improved. That being said, I'm still very surprised at how much better --preset cbr 128 has gotten since I first tried LAME at 3.83. The HF's are much more crisp and stable, and pre-echo handling is much better than it was in the past. For space-limited devices that cough up VBR encodings (such as my clock radio), it really is becoming a viable option.

It seems to me that the rumbling is still present in 3.97b1.

I noticed such in an encode I did of "Dancing Mad #4.2", from the Final Fantasy VI soundtrack (you can download it from SNESmusic.org to test for yourself).

It is easily noticeable with some pipe organ passages. I don't even have to ABX this; it stands out so much from the original.

Actually I wonder... with such an obvious, annoying problem, how did LAME 3.96 ever become stable? In fact how did we even let 3.97 go beta?

Probably because the problem was reported AFTER 3.96 was released (in fact: much later...).

It's probably a reason explaining why it's precisely called beta and not stable. And what do you mean by "we"? Are you developer?

Nope. Good point. I guess we test LAME for no reason other than for fun.

Let's not feed the troll, please.

Yeah, I think I overdid it there.

How about, why's it the HA recommended version here if it's so "broken" at 128kbps?

Now as a matter more of temporarily fixing the problem, rather than questionning the community and the dev team...
Will using --ns-bass -8 adversely and noticeably affect the quality of the MP3's, do you think?

How high above 128kbps do you think it may be warranted to use --ns-bass -8?

If the solution to the rumbling problem is not close in sight, should the dev team maybe add the --ns-bass -8 switch into the presets, for the time being? imho this would be better than advocating everybody to use it, since an important concept with 3.97 is for the user rely less on presets and long commandlines...

> How about, why's it the HA recommended version here if it's so "broken" at 128kbps?
Because it's better than previous versions with a vast majority of samples. 128 kbps is not "so" broken and is simply not "broken" at all. There's a real problem, but also several progress.

> Will using --ns-bass -8 adversely and noticeably affect the quality of the MP3's, do you think?
Answer is here.

Hi Cygnus, I would like to know which version of Lame you tried the --ns-bss -8 and lowpass of 16kHz command with. I remember ff128's recommendation for Lame 3.92. I also remember that he did not recommend it for other versions. Thanks in advance.

3.97b, I believe.

It was 3.97a11, I believe. Just be aware that using the ns-bass switch will steal some bits away from HF content, which could cause additional problems. I'd only use 128kbps CBR if you absolutely have to, e.g. for a non-compliant hardware device. Otherwise, -V5 or --abr 134 are much better options for this bitrate range.