3 questions re: Mp3 & editing recordings

[pmcwillie]

Hope it's OK to put all 3 in 1 post.

1. Do u lose quality if u edit a Mp3 in Audacity & then save that Mp3 file?...... ie... I have several purchased Amazon Mp3 downloads that I would like to preform small edits on (adjust output volume, lower Bass, etc). They come w/ 256-Constant encoding. If after editing, I save them in the Extreme or Insane preset, is there a loss in audio quality? I've tried listening tests but it's too subjective for me to make a determination.

2. One of these downloads is a country song from the 50s. The soloists voice volume is too low compared w/ the instruments. I would like to raise his volume w/o changing his voice characteristics. I've experimented w/ Equalization settings but end up changing other aspects of his voice or the instruments also. Would someone please recommend some initial settings to try.

3. Several of my 50s & 60s titles have "muddled" background voices or instruments. I've had some success in improving the clarity by cutting the bass via the Equalization. Is this the proper technique, or is there a better method?

As always..... many thanks for the software & u'r assistence.

[steve]

1. Do u lose quality if u edit a Mp3 in Audacity & then save that Mp3 file?

Yes. Encoding to MP3 "throws away" some of the audio information. The effect is cumulative and irreparable.
Using a high bit rate (for example "Extreme" or "Insane") will minimise the damage.


Questions 2 and 3.
Please start new topic for each of these questions. There is no simple answer, so there may be some discussion. Posting short samples (4 or 5 seconds) in WAV format would be useful (See the "Upload Attachment" option below the message composing box).

[pmcwillie]

1. Do u lose quality if u edit a Mp3 in Audacity & then save that Mp3 file?

Yes. Encoding to MP3 "throws away" some of the audio information. The effect is cumulative and irreparable.
Using a high bit rate (for example "Extreme" or "Insane") will minimise the damage.
.......snip.......

I had that suspicion...I'm experienced in computer graphics & if u edit a JPEG & then save it, more pixels are lost forever. Learning to use Audacity, I find lot's of similar concepts to Bitmap & Vector editing. As I said, my listening tests where too subjective to determine if the loss was audible. It would probably require some blind testing to find out.

[steve]

if u edit a JPEG & then save it, more pixels are lost forever.

That's a good analogy.
PCM WAV format would be more like an uncompressed bit-map - huge, but can be reproduced exactly with no data loss.