Best Sample Rate and Audio Bit Depth for Recording Projects
Ideally the best sample rate and audio bit depth for recording is as high as possible as your recording software and hardware can handle. Below are common sample rates used in recording:
a.) 44.1 KHz
b.) 48 KHz
c.) 96 KHz
d.) 192 KHz
And below are the common audio bit depths:
c.) 32-bit float
But for most home studio applications, selecting 32-bit float and 192 KHz is not practical. It is because when you are tracking at this bit depth and sample rate; even a 2-second audio sine wave (the simplest form of audio wave) is already 1.46MB in file size. The real audio you are recording; that is the sound of your voice, guitars, etc are complex waveforms that demand VERY large file sizes when recorded at this given sample rate and bit depth.
Advantages of high audio sample rate and bit depth
But what are the advantages of recording at the highest sample rate and bit depth possible? One obvious advantage is that your digital recording captures almost the entire analog sound perfectly. Remember in the analog audio to digital conversion; the music you hear and all the sound that surrounds you are “analog” in nature. When you like to record it to your computer hard drive, it will be digitally converted. A higher bit depth and sample rate during recording will provide a more accurate representation of the analog signal in digital domain. The only downside is that the resulting file size will be very large typically if you are planning to create lots of recording and do a lot of projects. You will be running out of hard drive space very early.
Going at the low end, selecting 8-bit depth and 44.1 KHz (or even lower) does not do any good. Why? It is because the digital representation of your analog recorded sound is far from being accurate. In other words, the recording results have low fidelity.
Best practices in audio bit depth and sample rate
Professional music production has its best practices in sample rate and bit depth. These are the following:
a.) The most common bit depth and sample rate used in commercial audio and broadcasting is 16-bit/44.1Khz (this is the sample rate of CD audio, commercial MP3, etc that you found in recording stores, streamed in Internet radio, everywhere). Most MP3 and audio players are configured to play at this sample rate and bit depth.
b.) The music production bit depth and sample rate SHOULD be higher than the 16-bit/44.1KHz. Why; to get benefits of higher fidelity, more room in the audio, more “content” in the digital audio that results to “true to life” quality.
c.) This music production bit depth should be implemented started at the tracking, mixing and mastering sessions.
d.) The final result of the mastering session which is the production master should be in 16-bit/44.1KHz.
Final Recommendations for Optimal Bit depth and Sample rate
It makes sense that the best sample rate and bit depth for recording SHOULD be above 16-bit/44.1Khz BUT below 192 KHz and 32-bit float. You then have the following recommendations:
a.) 24-bit/48 KHz
24-bit/96Khz is a common standard commonly implemented in most recording projects. Some DAW such as Ardour defaults to 48 KHz sample rate. If your DAW has lots of hard drive space and you are not worried about saving large files, then use 24-bit/96KHz in your recording sessions. If your DAW is limited of hard drive size and you are planning to reduce the file sizes of your recording sessions while retaining reasonable quality, then you can record at 24-bit/48KHz.
This recording bit depth and sample rate is initiated at the recording/tracking session. After recording, all the tracks are forwarded for mixing. Then the audio mixing engineers will work on the “same” sample rate and bit rate used in tracking. Finally when the mix down as created, the sample rate and bit depth is still the same.
At the mastering session, the mastering engineer will be working on the same sample rate/bit depth used in the tracking and mixing. However the final product should be 16-bit/44.1KHz. The audio mastering engineer will apply audio dithering techniques to reduce the bit depth from 24-bit to 16-bit. And also apply audio sample rate conversion to change 96 KHz or 48 KHz to 44.1 KHz. You can visualize it as follows:
What if you have recorded at lower bit depth and sample rate than what is recommended? Of course, you cannot scrap directly the recordings particularly if the artist performance is brilliant. It is indeed very hard to re-record and to have that artist performed at the same level of charisma, etc as before particularly for lead vocals. In this case, you can implement audio upsampling techniques. However bear in mind that tracking at higher bit depth/sample rate is still recommended compared to up-sampling.
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