Subject:What is the right type of sound file?

Posted by: wbtczn

Date:12/20/2005 6:55:31 PM

Ok, another beginner question here...I recently recorded an orchestra / choral concert at our church on our new flash recorder. It was saved as an MP3 file with attributes of 44,100 Hz, 16 bit, Stereo.

The question is -- is that a good format to be recording in? I've seen some things about MP3 and compression, but don't fully understand them yet. Did I give myself a bad start by recording in MP3 instead of WAV?

Next, what does 44,100 Hz, 16 bit mean? Are they good? Bad? Do they matter?

From an application standpoint, my intent is to add the file to video that was shot, as well as burn it to a CD. Any sage words of advice on how I should be saving the files?

One more question...I've got multiple files from the songs that were recorded. Is it better to splice them together first before doing things like normalizing?

As always -- thanks!

Subject:RE: What is the right type of sound file?

Reply by: Chienworks

Date:12/21/2005 7:33:14 AM

If you can, it's better to record to WAV instead of MP3 since MP3 is a lossy format and not all the original detail of the music is retained. On the other hand, WAV can take up 10 to 20 times as much space as MP3 so you may not be able to record the entire performance if your memory is limited. If you need to stick with MP3 then use the highest bitrate you can. 32Kbps is good enough for dictation but music will sound rather poor. 192Kbps will sound almost indistinguishable from a CD recording, but will take 6 times as much memory as 32Kbps.

44,100 Hz is the sample rate and 16 bit is the sample depth. These are the same parameters used for CD audio. They're pretty good for most circumstances. Depending on the rest of your equipment and signal path these settings can produce a recording every bit as good as a professional CD. Using 22050 Hz would result in a file half the size, but would also lose the top octave of the frequency range from the recording so the sound could be a bit more dull sounding. 8 bit is awful and sounds like an old AM radio.

I would save the files you get as WAV files matching the sample rate and bit depth you get from your recorder. Saving as WAV means you can edit and resave without losing any more quality due to compression.

Yes, please do splice the files together before normalizing. If you didn't do this then you could experience jarring volume jumps from one section to the next. You don't have to join all the songs together into one large file first, but you should at least have each individual song as a single file.

Subject:RE: What is the right type of sound file?

Reply by: rraud

Date:12/21/2005 12:58:16 PM

In addition to Chien's excellent advice.
If your going to lay the audio back to video digitally you may have to re-sample the file to 48,000Hz or record it at that to begin with.

Subject:RE: What is the right type of sound file?

Reply by: wbtczn

Date:12/21/2005 5:23:26 PM

Thanks for the feedback. I could have recorded the performance in WAV, but not knowing better, I had it set to MP3. Lesson learned! If I'm reading chienworks' note correct, as I edit the file now, I should save it as WAV to avoid any more degradation, correct? Or is the deed done already since the source is MP3?

I'm not sure I follow the last paragraph -- "do splice the files together before normalizing...You don't have to join all the songs together into one large file first...". If I splice them together, don't I have them in one file? Or is there a way to logically join them without physically joining them???

rraud -- what does resampling do? Does that affect the playback speed?

As always -- thanks. The more I learn, the more I realize I know nothing!!!! ;)

Subject:RE: What is the right type of sound file?

Reply by: rraud

Date:12/21/2005 6:22:49 PM

Always record and edit a project in an un-compressed file format. (wave of aiff) Anytime you re-save or save an MP3, the file is degraded, If MP3 is going to be a delieved format, "Save as" an MP3 as the absolute last step.

Splice the file together, then nomalize.

Re-sampling does NOT change the speed. Process> Re-sample

Changing just the sample rate does, like speeding up/slowing down an analog R-R or cassette. File> Properties> Format

Subject:RE: What is the right type of sound file?

Reply by: Chienworks

Date:12/21/2005 6:26:22 PM

There has been some loss already because of using MP3. However, you can avoid having any more loss by working with them as WAV.

From the way you asked the question i got the feeling that each song had been split into multiple files. If this is the case then each song should be reassembled into a single file before normalizing. If what you mean is that each song was a separate file then you're fine using them as is.

DV is 48,000Hz. Resampling is the process of converting from one sample rate to another. If you use Vegas for the video editing it will automatically adjust for you while rendering.

Subject:RE: What is the right type of sound file?

Reply by: wbtczn

Date:12/21/2005 9:04:03 PM

Awesome -- thanks again.

Now to start playing!!!

Subject:RE: What is the right type of sound file?

Reply by: wymondham

Date:12/31/2005 11:55:28 AM

Good advice regarding the use of software bit rates etc, however I would suggest the 48kHz at 16 bit format for recording choirs or even 24bit which is becoming the norm now. Choirs may be easy to record but demand a lot from equipment. Using the best mikes for a start makes a lot of differance to the sound.

Good Luck David.H

Subject:RE: What is the right type of sound file?

Reply by: wbtczn

Date:1/3/2006 3:41:55 PM

David - I agree. I just wish I had learned that prior to the performance! The microphones hanging over the choir are 4 freshly installed Audio Technica ES933/MLs.

All of our soloists wore wireless mics w/ headsets. They came through really well. We had problems with the choir mics because we kept trying to turn them up loud enough to boost their in house sound over the orchestra. Thanks to some guidance from folks on this forum I was able to use Wave Hammer (primarily with the medium compression setting to start), and Dynamics/Graphic... to help find some balance.

For a first cut, I'm pretty happy with it. I'm seeing so many things I would have done different (and really wishing I had multi-track recording capabilities!).