Welcome Guest ( Log In | Register )

missing frequencies/sounds >16kHz using lame 3.99.4-64
post Feb 26 2012, 14:51
Post #1

Group: Members
Posts: 13
Joined: 11-September 11
Member No.: 93636


i recorded some vinyl using Goldwave 5.25 under win 7 pro x64 and saved the files as a 24/96 un-compressed Windows Wave file.

i had a look at the frequency representation in Adobe Soundbooth CS5 and noted that the max. freq. attained was around ~27kHz (which seems acceptable given my sound card, cartridge and phono stage).

i then compressed the file using Foobar2000 1.1.9 to a lame mp3 with the settings:

Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Mode : Joint stereo
Duration : 5mn 51s
Bit rate mode : Variable
Bit rate : 282 Kbps
Minimum bit rate : 32.0 Kbps
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Compression mode : Lossy
Stream size : 11.8 MiB (100%)
Writing library : LAME3.99r
Encoding settings : -m j -V 0 -q 0 -lowpass 24 --vbr-new -b 32

having a look at the frequency representation again in Soundbooth showed a reduction/cutoff above 16kHz for certain sounds (not all).

Why is this and how (if possible) could I retain these upper frequencies ?
I assumed since the mp3 is a 48kHz file each channel should contain up to 24kHz sounds - from the graph it does, but only for certain sounds, and others are removed >16kHz

Also, is it a default setting by either foobar/lame to use lowpass by default ?

i've uploaded some screen grabs for visualisation:

Go to the top of the page
+Quote Post
Start new topic
post Feb 26 2012, 18:27
Post #2

Group: Members
Posts: 1844
Joined: 24-June 02
From: Catalunya(Spain)
Member No.: 2383

Sorry for the confusion about --vbr-new. I thought that it was written in the comment field, and not guessed.

Now, extending on lvqcl's comment, --bitwidth is only necessary for raw audio (foobar sends .wav, so that's not raw) and the format setting should be "lossy".
This one is just a hint for foobar to know what the codec will do (so it is not dangerous, but better to have it to its correct value, which is lossy).

You were given a link for more info about the ATH, i guess that's enough but as a simple explanation, the ear is not equally sensitive to all frequencies and the ATH is the representation of how sensitive we are to them.


Go to the top of the page
+Quote Post

Posts in this topic

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:


RSS Lo-Fi Version Time is now: 5th September 2015 - 16:38