Hi,
I record audio using a Fostex MR-8HD. I use it to record conversations and later make transcripts, it works wonders especially when people interupt eachother since I have a mic for each person recording into its own channel. Anyway it produces huge wav files of far more quality than what I need, I only require that the words be understood clearly.
In one of the recording.org forums I recieved some advice, but I’m still stuck. Here is part of my last post there:
“Can’t find how to change it (the wav sttings) in the recording equipment (MR-8HD), and using the Audacity program it changed the size from 376 MB to 1.41 GB, obviously I’m doing something very wrong. This is what I did, open file, set Sample format feom 32-Bit Float to 16-Bit, then Set Rate from 44100 Hz to 11025 Hz.
I think I should be messing with the Bit Rate (705kbps, Is that kilobites per second?, if so WOW), but I don’t see how.”
Thats my reply to this advice from RemyRAD:
“You could make your wave files, much smaller by changing your settings to 22.5kHz or even 11kHz sampling frequency at 16 bit. You don’t need response to 20kHz for spoken word purposes. 22.5kHz will get you out to 10kHz bandpass and 11kHz sampling will get you out to 5.5kHz bandpass. With each change in sample rate, the size will half.”
Sure, you can change the sample rate of a wav file if you need to. If it’s just voice you can probably get away with 8-bit, 11.025KHz. You would change the output format like this:
in 1.2.6, press [ctrl]+p → File Formats → uncompressed output format. change that to Microsoft Wav 8bit. Then, exit that menu and change the sample rate in the bottom left hand corner and Export your file to Wav.
in 1.3.3, change the sample rate in the same place, ten click File → Export. Set the format to Wav, then click Options and change the output format to 8-bit. Then name the file and save it.
But you should probably just go ahead and Export those files as MP3s, they’ll be even smaller and will sound nicer, unless you need the files in wav format for some reason. 96 kbps is fine for voice.
MP3: if it dosen’t matter the format you can use mp3 format which can get down to 10x smaller than WAV files (96 kbps is ok)
WAV: encoding: if it matters you can use any of the ADPCM encoding and GSM 6.10 encoding which can get 6kb per sec. Samples per second: you can make WAV files to 11025SPS if it’s recoded but before you set the SPS to 8000SPS SPS really changes the quality