Recording- WAV, MP3, file compression and quality loss
Posted: Wed Mar 26, 2008 2:22 pm
In a recent song post some thoughts on recording and loss came up. Instead of using the songwriter's thread, I thought I would post here, and let everyone add their comments.
In my experience I have found certain aspects to be pretty consistent. So here goes:
Anytime you go from digital to analog or vice versa you will get some loss of quality. This means if you go analog from the back of your keyboard (D/A) into an analog input on a mixing board (usually A/A) and out to your computer (A/A to A/D) then into WAV file (D/D) you have at least two to three times where your signal will get diminished. However if you went Digital out of your keyboard to Digital in on your computer there would be NO diminished signal.
Additionally, staying totally in the analog realm will diminish your signal. Every time you lower the volume you will diminish the signal for example.
Once you have a signal going to your computer, you generally should not get any degrading of it unless somehow it is processed differently. Going back and forth between two high rate formats (i.e. WAV and OGG or FLAC) will result in some loss. Anytime you go from ANY format to MP3 you WILL lose some quality. That is because WAV is a raw file and MP3 is a compressed file. That compression for size has to "steal" ticks from your file to compress it. The result is a loss of quality (usually in the lowest and highest registers).
I have a small recommendation to anyone who has this option.
Always record with 32 bit floating point on, and always save files as 24 bit audio wav. If you mixdown save it initially as a 24 bit file. As long as the khz are 44.1 or greater you are ok. A 24 bit file allows a LOT of room for mastering your song, especially if you only take up 90% or so headroom (volume) before the track peaks. This means DO NOT NORMALIZE your tracks prior to mastering.
When you master, always master in two directions: a 16/44.1 track (which is CD audio standard) and 24/48 or 24/192 track (which is DVD audio standard). When you compress to an MP3 file, it seems best to work from the CD Audio track and compress it no greater (technically LESSER) than a rate of 256bits (meaning 128bits is not going to cut it unless you have to upload to Soundclick who is going to mess with your file anyway).
I know this was long winded, and maybe there are some tricks or tips that some of you may have come across to help us out here. Please feel free to add or correct as necessary.
Jon
In my experience I have found certain aspects to be pretty consistent. So here goes:
Anytime you go from digital to analog or vice versa you will get some loss of quality. This means if you go analog from the back of your keyboard (D/A) into an analog input on a mixing board (usually A/A) and out to your computer (A/A to A/D) then into WAV file (D/D) you have at least two to three times where your signal will get diminished. However if you went Digital out of your keyboard to Digital in on your computer there would be NO diminished signal.
Additionally, staying totally in the analog realm will diminish your signal. Every time you lower the volume you will diminish the signal for example.
Once you have a signal going to your computer, you generally should not get any degrading of it unless somehow it is processed differently. Going back and forth between two high rate formats (i.e. WAV and OGG or FLAC) will result in some loss. Anytime you go from ANY format to MP3 you WILL lose some quality. That is because WAV is a raw file and MP3 is a compressed file. That compression for size has to "steal" ticks from your file to compress it. The result is a loss of quality (usually in the lowest and highest registers).
I have a small recommendation to anyone who has this option.
Always record with 32 bit floating point on, and always save files as 24 bit audio wav. If you mixdown save it initially as a 24 bit file. As long as the khz are 44.1 or greater you are ok. A 24 bit file allows a LOT of room for mastering your song, especially if you only take up 90% or so headroom (volume) before the track peaks. This means DO NOT NORMALIZE your tracks prior to mastering.
When you master, always master in two directions: a 16/44.1 track (which is CD audio standard) and 24/48 or 24/192 track (which is DVD audio standard). When you compress to an MP3 file, it seems best to work from the CD Audio track and compress it no greater (technically LESSER) than a rate of 256bits (meaning 128bits is not going to cut it unless you have to upload to Soundclick who is going to mess with your file anyway).
I know this was long winded, and maybe there are some tricks or tips that some of you may have come across to help us out here. Please feel free to add or correct as necessary.
Jon