MP3 Advantage

[robinhood1701]

Hi,
am new to Audacity and audio, and liking Audacity alot,
have been using it to convert mp2's from my DAB radio and internet streams of old radio to mp3's,
all of which are mono,
would i be gaining anything converting them @ higher bitrates loke 320kbps than lower bitrates, like 192kbps?
which would save space?

Any help would be great,
Thanks

[Trebor]

You can't technically improve on the original recording by making a copy with a higher Kbps
converting from 192Kbs to 320kbs would sound the same but the files would be significantly bigger.

It is possible to make fake stereo (pseudstereo) from a mono track which can sound subjectively better than the original.

If you attach a bit (10 seconds) of your mono music to your next post I will have a go at making it pseudstereo in Audacity.

[robinhood1701]

Hi Trebor, thanks for that, had a feeling that 320kbps would not make a difference,
Have been looking into Audacity more, and learning,
and it seems that i have a stereo recording from the streaming audio

Streaming stereo file

the shiek.JPG (96.35 KiB) Viewed 2104 times

yet when i load the mp2 recordings from my DAB radio, they are mono,
as you can see, i have "mono mix" selected when recording and encoding mp3's
do not totally understand that, will it make a stereo track mono?

03201230.mp3

mono grab

(299.96 KiB) Downloaded 459 times

this is a ten second selection from a mono mp2, its just speech, i record old radio comedy,
if i could convert it to stereo, that would be great.

[kozikowski]

The rule with MP3 compression is you should only do it once, and that's a problem with Audacity. Audacity will not edit an MP3 file. It will open it, convert it to an internal sound format (hidden from you) and then Export a New MP3 when you're done processing, filtering, cutting, etc.

This results in the postings from people complaining that the new MP3 is significantly bigger than the old one was. Probably. There is no standard relationship between the two MP3 files. The bitrate (file size) that Audacity uses for the new MP3 is set in the export step in Audacity 1.3.12.

If you're using Audacity 1.2, stop that.

http://audacityteam.org/download/

MP3 always creates sound damage. Always. Each step of compression builds damage on the steps that came before. So, for example, if you pulled an MP3 from the internet and it used 32 for a compression (barely enough), the show would be garbage if you used it for production and re-exported it at 32. Two 32 compressions back to back will produce trash. Literally, you wouldn't be able to listen to it. You would need to export the finished work at some really high number like 128 or 256 just to stay where you are in quality. That, if you're following along in the hymnal, will produce a very large sound file partially destroying the reason you're in MP3 in the first place.

So print this in large letters and post it over your desk -- Never Do Production In MP3 --.

There are editors which will edit (in a limited way) directly in MP3. No additional damage, but you're still in MP3. I would convert the work to WAV format and do all the production in that loss-less format particularly if you want to save the work for later.

<<<will it make a stereo track mono?>>>

If the original work is in mono, then you should probably set the Audacity production preferences for mono and do all your production like that. Converting in and out of stereo (or two-track mono in this case -- same thing on right and left) is confusing and wasteful.

If you feel like having a go at "stereo" conversion, then yes, you should convert the work to two tracks and apply different effects to each side. If you listen to that enough, the effect can be really annoying because you keep expecting the sound field to change and it never does.

How old is the recorder that it uses MP2? That dates back to when dinosaurs roamed Waxie Maxie Records.

Koz

[Trebor]

it seems that i have a stereo recording from the streaming audio

I think what you've got is "dual mono": the two tracks are absolutely identical, so not really stereo.
You can just discard one of these two tracks: split to mono and click on the"x" in the top left of one of the tracks to delete it.
It will save memory to get rid of one of these identical tracks and will make no difference to the sound quality.

if i could convert it to stereo, that would be great.

I’ve had a go. I’m not sure its worth the trouble of converting the comedy show to pseudo-stereo, the laughter of the crowd does sound more realistic as it sounds like it surrounds, (see the before-after example attached), but the pseudo-stereo version is less intimate.

Dads Army, Original then ReverbedPseudostereo.mp3

(907.88 KiB) Downloaded 361 times

BTW your comedy show is all below 12KHz, so a sample rate of 32KHz is more than sufficient, (you were using 48KHz which can record up to 24KHz, so a waste of memory for a 12KHz show).

[robinhood1701]

kozikowski,
thanks for your insight,
I started with Audacity ® 1.3.12-beta,
now, will not edit in mp3 after your insight,
your explanation made sense,

Am printing "Never Do Production In MP3 "
each letter on a sheet of A4, as i type this!

editing in a copy of the .aup original seems OK to me?,
I found the bitrate button in the Audacity export window,

"How old is the recorder that it uses MP2? That dates back to when dinosaurs roamed Waxie Maxie Records."

errr... its a three year old Pure Evoke 3 DAB Radio koz, (Waxie Maxie Records?)

Trebor,
now you mention it, they both do seem identical, and thinking about it, would have expected it to be recorded in mono, as it was recorded in about 1975? i think,
will try getting rid of one of the tracks and encoding it,

a sample rate of 32KHz i assume you mean the Project rate (khz) box on the selection toolbar?
I read somewhere that 4100 is good? but will try 32khz,
how did you know it was 12khz?,
am still a newbie on a learning curve?
can you do the stereo effect with Audacity?

[robinhood1701]

so, when recording, say a streamed track, which is originally mono, is it best to have Mono Mix selected in the Mixer Toolbar?
But if you are recording a stereo music track to export as a mp3, select Stereo Mix?

[Trebor]

how did you know it was 12khz?

Audacity has “Analyze” options, click on “Analyze” then “plot spectrum” and you get this on your original “03201230” track

Dads_Army_'[email protected]_48000Hz.png.png (13.72 KiB) Viewed 2081 times

The audio only reaches 12KHz, but as you used a 48000Hz sample rate capable of recording ultrasonic frequencies of 24KHz half the frequency response graph is empty. More modern comedy shows may use the whole audio range and may require 41000Hz sample rate. Using 32000Hz rather than 48000 on dads Army will reduce the file size and will not affect the sound quality, (32000Hz can capture sounds up to 16KHz). Getting rid of the duplicate “dual mono” will halve the file size, again without affecting sound quality of a mono show.

can you do the stereo effect with Audacity?

My improvised pseudo-stereo technique uses a comb filter plug-in, (attached).
If you have, or make, dual mono version of you mono show then apply the comb filter individually to each track with different frequency settings the result does sound like stereo(ish). In the example I provided above I used 83Hz with comb decay on 0.07 on one track , and 73Hz @ 0.07 on the other, (if you use a lower value for the comb decay the stereo effect is reduced). The fiddly bit is the tracks go out of sync after the comb filter is applied in this way so have to be realigned, otherwise the sound will apparently come from one side. Once you have aligned the combed “dual mono” tracks , (to within +/- 1 sample), then select “Make Stereo Track” and you’re done.

If you do produce pseudo-stereo versions you will have to save them as stereo: if you discard one of the tracks you will lose the pseudo-stereo effect.

[robinhood1701]

Trebor,
thanks for that,
had a look at the graph earlier, but after studying it for the past few hours on my phone,
it now makes sense, can see where the 12000hz is,

Thanks for the plug-in will give it a try and get back,
Cheers

[kozikowski]

<<<(Waxie Maxie Records?)>>>

A chain store back when music came on plastic disks.

Koz