Question About Exporting

[Astro-Xana]

I have created a remix and exported it as an mp3 at 48000 Hz, 32 bit float and 320 bit rate. But I've decided to open the exported remix itself in Audacity (since I didn't save a project file for it) and to apply some effects on it and export it again. Should I export it as an mp3 again, or would it be better for me to export it as a WAV (Microsoft 32 bit float) at 96000 Hz first and then export it again as an mp3? And also, if I want to export something as an mp3, would it be better to export it first as a wav, then to export it as an mp3 (because I'm assuming that it would give better quality, but not sure).

[steve]

and exported it as an mp3 at 48000 Hz, 32 bit float and 320 bit rate.

No you haven't. Your files in Audacity may have been at 48000 Hz, 32 bit float, but mp3's are always 16 bit, so the audio has been "down sampled" as part of the encoding process.

There is no need to go overboard with the "Quality" settings, especially if the final product that you want is an mp3. For recording and making a few edits then converting to mp3, you will probably find that using 16 bit 44100 Hz produces mp3s that are just as good as if you were using 192 kHz, 32 bit.

For high quality work that requires lots of processing, 48kHz 32 bit is usually a good option, but note that 32 bit files are a lot less standard than 16 bit. 16 bit 44100 Hz is CD standard and will play on anything - this is an excellent choice for exporting your final work, especially since it can be recorded onto an Audio CD without any other format conversion being required.

MP3 is not a good format for backup copies, or master copies. The sound quality of an mp3 is always lower than it would have been if you saved it as a wav. Once that quality has been lost, there is no way of getting it back.

MP3 encoding makes files smaller by throwing away some of the data (lossy compression). WAV format is an uncompressed format - files are larger, but quality is better.

[Astro-Xana]

Actually, I've changed my mind about wanting to export as mp3. Instead, I wish to export as wav since they are obviously better quality. Therefore, would I choose WAV (Microsoft 16 bit PCM) as the uncompressed format? Also, I do have a project file for another remix which consists of 25 mono tracks, and each and every one of them are at 48000 Hz 32 bit float. So after setting the project rate at 44100 Hz, do all the tracks get converted into 16 bit (since the uncompressed format was at 16 bit PCM), or do I have to set the sample format at 16 bit for each and every one of these tracks before exporting? As for the quality settings, if I set the default sample format at 16 bit, does that export everything as 16 bit, or is it only used in making audio that is currently being recorded/imported into 16 bit?

Now would I stick with 44100 Hz for exporting as a wav in this case, or could I go higher (like all the way up to 96000 Hz). And would that play well on other computers? And as for the bit rate, would I stick with 320?

[steve]

Therefore, would I choose WAV (Microsoft 16 bit PCM) as the uncompressed format?

It depends on what you want to do with your recordings. Generally I would say yes, 44.1 kHz 16 bit Microsoft PCM WAV is an excellent choice. It is compatible with nearly everything and is the standard for audio CDs. Higher bit depths and sample rates create larger files, but for there to be any real improvement in sound quality the recording itself must be excellent quality (better than a CD) and your audio system would need to be extremely high quality, and you would need excellent hearing and a highly discerning ear. Unless you are using professional studio equipment it is very unlikely that you will be able to hear any difference.

each and every one of them are at 48000 Hz 32 bit float. So after setting the project rate at 44100 Hz, do all the tracks get converted into 16 bit

In Audacity 1.2.x the audio gets converted to the default sample rate and bit depth (set in Preferences) when you "Export".
In Audacity 1.3.x you select the Export format through the Export dialogue screen.

And as for the bit rate, would I stick with 320?

You are talking about MP3s here - 320kbps CBR is the highest quality MP3 format. 128kbps is generally considered to be the minimum acceptable quality for music, but 180kbps or more is better. I generally use around 160 to 220 if I want a good quality MP3, an the files are a lot smaller than using 320.

[Astro-Xana]

Now since all my recordings are at 48000 Hz, would it be better for me to just export it as a 16 bit Microsoft PCM WAV at 44100 Hz, or to first export it as a Microsoft WAV 32 bit float at 96000 Hz first in order to get everything at 96000 Hz, and then to export it as a 16 bit Microsoft PCM WAV at 44100 Hz?

[steve]

Why do you want to use 96kHz?
If your final show is going to end up on an audio CD, just export as 26 bit 44.1
If your show is going to end up on a DVD (a sound track for a video), export as 16 bit 48 kHz
For general purpose, export as either 16 bit 44.1 kHz or 16 bit 48 kHz. (16 bit 44.1 kHz is more compatible with other applications).

There is no need to convert to a higher resolution first - that will just increase disk usage, take more time, but gain you nothing.

As long as you have a good recording in Audacity (a good strong, clean signal without too much noise and without distortion), then Exporting the final show as 16 bit 44100 Hz will give excellent results.

[Astro-Xana]

Finally, just one more thing. When you said compatible with other applications, are you referring to media players (such as QuickTime Player, Windows Media Player, Real Player, etc.)? Also, if an audio file is not compatible (or not very compatible at all), would that mean that the audio file will not play at all, or that it would actually play, but show some artifacts such as skipping or any other artifacts?

Another question I have is that I do wish to export at WAV (MIcrosoft 16 bit PCM) at 44100 Hz. Therefore, was I a lot better off having my recordings at 44100 Hz from the very beginning? Since all my recordings are at 48000 Hz, wouldn't that have some quality loss when exporting at 44100 Hz? Or would it be the same as having my recordings at 44100 Hz from the beginning and exporting at the same rate (44100 Hz)?

[steve]

When you said compatible with other applications, are you referring to media players

Yes. And any other application that uses audio files (video editors, audio editors, Digital Audio Workstations, CD burners, audio encoders.... Also hardware).

Also, if an audio file is not compatible (or not very compatible at all), would that mean that the audio file will not play at all, or that it would actually play, but show some artifacts such as skipping or any other artifacts?

Unsupported file types will typically either not play at all, play at the wrong speed, or turn into a horrible noise.

Therefore, was I a lot better off having my recordings at 44100 Hz from the very beginning? Since all my recordings are at 48000 Hz, wouldn't that have some quality loss when exporting at 44100 Hz? Or would it be the same as having my recordings at 44100 Hz from the beginning and exporting at the same rate (44100 Hz)?

There may be some theoretical loss in converting from 48kHz to 44.1kHz (compared with starting with 44.1 kHz), but I have been unable to hear, detect or measure any loss. 48kHz has an extended high frequency response, which means that it can reproduce very high (threshold of hearing) frequencies more accurately than 44.1kHz. For practical purposes you would need very high quality equipment, have excellent hearing, and be under 21 to have any chance of hearing any difference, and even then the difference would be minute.