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Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: waltmon on August 07, 2013, 01:07:25 PM
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I've resampled in Soundforge 7.0 in the past, but want to make sure I am doing it correctly.
Thank you.
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resampling or dithering?
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I use r8brain. Works for me. I've heard good things about it. I'm no expert on such things though.
It's free:
http://www.voxengo.com/product/r8brain/
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Soundforge is very good. Not sure about the differences between your version and the newest. In this day of age MBIT+ dithering is the way to go with ultra noise shaping. There's a couple of other important settings, but no need to discuss as each software may do it differently. I use iZotope RX II Advanced personally.
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I've resampled in Soundforge 7.0 in the past, but want to make sure I am doing it correctly.
To clarify, one process by which you may convert from 24-bit to 16-bit is dithering. (You could also truncate.) Resampling is a different animal entirely.
Most of the commonly used editors do a fine job dithering, IMO. What editor do you typically use today?
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I used the Soundforge 7.0...and honestly I was kinda ham and eggin it...just made some great recordings out west and wanted to process correctly. ..so I want to dither as opposed to resample? Correct?
I want to tighten up my processing game as I've been transferring a lot of masters. So from 48 > 44 is resample..?
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Converting from 24 bit to 16 bit is truncation- the least significant 8 bits of each 24 bit sample are lopped off and thrown away. It is always advantageous to dither first before the truncation happens, and most editors and stand-alone programs do that automatically for you in a single step, meaning you don't actually have to tell it to dither first and then truncate. As best practice, dithering/truncation should be the last editing step, other than tracking. If you are planning on doing further editing, you are technically better off using simple triangular dither (you'll probably see that option in whatever you are using) rather than a fancy "noise-shaped psychoacoustic" dither. The noise shaped dithers can lower the perceived noise floor by a few additional dB and might be technically better if no additional processing will be done in the future, but honesty I doubt you'd hear any difference on most any material at playback levels anywhere near appropriate for non-harmful human listening. I've only heard a difference between different types of dither if I really crank up the quietest sections of my most dynamic, pristine recordings made in very quiet environments, and that simply doesn't correlate to real world listening. Doing that convinced me that simple triangular dither is usually the best choice for me unless I'm doing a final CD edit of really pristine stuff for a band to release or something, and even then just because I can, not really because I think it matters.
Resampling recalculates the sample rate, for example changing from 48Khz to 44.1kHz. That is a far more processor intensive task than changing the bit-depth, requiring mathematical calculations which aren't really much of a problem these days, but high quality routines used to be pretty demanding on more limited computer resources. A good quality resampling routine is probably more important than a fancy dither routine partly because of that computational overhead difference (dithering/truncating is computationally easy- just add some engineered noise to the bottom 9 bits and then chop off the lower 8 bits), and partly because low quality resampling artifacts manifest across all volume levels and are "unmusical" information, whereas dither noise effects only the very quietest bit of the wave file noisefloor of the recording and simply sounds like very quiet tape hiss, usually completely buried in the far louder acoustic noisefloor of any live recording. I try to use the best quality resampling algorithm my software offers and don't worry much about fancy dither.
Best practice order-
Do any processing such as fades, EQ, compression and what have you at or above the native bit-depth and sample rate of the recording. Most editors do that for you automatically. When that’s all done and if you need to convert, resample first, then truncate/dither as the final two steps. An exception is tracking, which can be done before or after resampling and dithering depending on what is more convenient for you. That’s because tracking is simple file splitting and doesn’t change any data between splits.
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..so I want to dither as opposed to resample? Correct?
Quite possibly you want to do both, say for example if you recorded at 24/48 and want to convert for CD burning to 16/44.1, then you need to do both processes.
MBIT + iZotope plugin works great. I have Sound Forge 10 Pro and it's included, not sure about version 7.
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Quite possibly you want to do both, say for example if you recorded at 24/48 and want to convert for CD burning to 16/44.1, then you need to do both processes.
Exactly.
MBIT + iZotope plugin works great.
Unless it's a hassle, you're better off doing it in the opposite order.
In your case, resample with iZotope before dithering/truncating with MBIT.
Always best to dither & truncate last.
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Thanks guys that clarifes a lot...is there a best practice for volume level boost? I understand this should happen pre dither.
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Doesn't matter so much, technically after EQ and dynamics, unless your recording levels were really low, then you may want to bring up the signal level first to something easier to work with. Most if not all modern editors do their calculations internally at higher bit-depths than the native file was recorded at so it shouldn't matter that much in terms of sound quality. However, if you are doing any kind of dynamics processing such as compression or limiting, you will want to avoid making upstream level changes once you have the dynamics processing set the way you want. Otherwise their behavior will change when you make a level adjustment, which may require you to readjust the dynamic processor settings. Mostly just a a PITA thing. Doesn't effect them to change the signal level after it passes through.
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sox is another great option for resampling -- it's available as a plugin for foobar2000, which leads to a VERY simple workflow. I currently track everything in 24/96 and add metadata to my 24/96 flacs. Then, I use foobar2000 to resample and dither as necessary. Significantly, since many portable players (e.g. ipod/iphones) can play 24 bit 48k files, I generally find myself resampling directly to 48k and not dithering down to 16 bit files -- reserving 16/44.1 for those luddites that still require cds ;)