Noob question about sample rates and dithering...

[AdamWathan]

This is something I've been wondering for a while, normally when I bounce a track down to burn to CD, I just hit "Render" in Reaper and set it to 44.1 and 16 bit and sit back until it's done. But I hear people talking about plugins for dithering down to different sample rates and stuff and I'm wondering if I am doing this wrong and there is a "proper" way for converting from say a 48khz 24bit session down to 44.1khz 16bit CD ready WAV files?

 

[wishtheend]

Any time you bounce down to 16-bit from 24, dithering takes place. The algorhythms built into software are decent, but I'm sure stuff like IDR is better. I'll usually render out the mix in my DAW and load up a 2-track editor like Sound Forge where I'll run the mastering chain and render that still in 24-bit. Then i apply the Waves IDR 16-bit on it's own and save that as the 16-bit CD-ready track.

 

[Ermz]

You dither for bit-rate conversions, not sample-rate conversions. I let the mastering house do the dithering.

 

[AdamWathan]

So what's the cleanest method to convert sample rates? I'm just trying to learn a bit more about the whole process here so any help would be appreciated... Leaving it up to the mastering house doesn't really teach me anything :\

 

[LSD-Studio]

So what's the cleanest method to convert sample rates? I'm just trying to learn a bit more about the whole process here so any help would be appreciated... Leaving it up to the mastering house doesn't really teach me anything :

don't record in 48k in the first place.
unless you wanna put it on a dvd it doesn't make any sense.

 

[AdamWathan]

Yeah I record at 44.1khz so it doesn't matter, I'm still curious as to what you are actually SUPPOSED to do though. Lots of people record at 96khz so they must be getting back down to 44.1 somehow? Even if it's something I never have to deal with I'm still the sort of person who wants to know how/why to do things, it's a lot more satisfying than just ignoring it and avoiding it...

 

[Metaltastic]

I'll +1 to the general curiosity...

 

[beyond dead]

i would opt to record at 88.2 rather than 96... the conversion is supposedly better. i recorded at 88.2 and liked results, but my spdif pre cant record at 88.2

 

[AdamWathan]

The other question is why do we record at 24 bit if we are going to dither down to 16 anyways? Doesn't that just create more opportunities for bad conversion and audible errors in the audio? Isn't it sort of the same logic we use for justifying recording at 44.1 vs. any other sample rate?

 

[26]

I export from cubase in 32 bit float, stereo split, load the two tracks in wav lab and create a new project.
Which option to save as 24 bit (for mastering) is supposed to be most correct?

 

[Ermz]

You don't need to do anything when you downsample audio. Your DAW will handle the conversion as best it can. Some people claim even divisions sound better, but I've heard in other circles that it's bollocks (if I may take a phrase from the home nation of our gracious host). It's bit-rate conversions that dithering is needed for. Dithering adds minute noise to a signal (shaped and specific noise with better dithering plug-ins) to reduce the occurrence and audible effects of quantization error. If you want a more in-depth explanation I'm sure you can google digital audio theory and get some nice hits.

The reason we record a 24-bit is that there is less degradation of the audio material with all the signal processes it goes through during mixing. You have a higher resolution and the build up of artefacts is less noticeable. Then when you go down to 16-bit you've got a cleaner signal than you would have had staying in 16-bit throughout the process.

 

[PostMortem1666]

i usually record at 88.2 khz and 24 bit. then when i get to mastering i dither down to 16 bit and use pro tools conversion on the highest setting to go down to 44.1 khz. to me 88.2 khz is good because all it takes is just halving it to reach 44.1 rather than going from 48 khz or 96 khz which would be a decimal (which i have heard degrades audio quality) and supposedly it decreases conversion errors and still lets you record at a higher quality. im still a noob at mastering though and all these rates and stuff but im learning.

 

[Zuranthus]

The other question is why do we record at 24 bit if we are going to dither down to 16 anyways? Doesn't that just create more opportunities for bad conversion and audible errors in the audio? Isn't it sort of the same logic we use for justifying recording at 44.1 vs. any other sample rate?

you don't have to dither down to 44.1/16
not for something you are going to put on the net...the whole reason for that is CD's only support 44.1/16
the higher sample/bit rates sound a lot better though, if you don't believe me just open up your amp sim & set it to 44.1 & then try 96 (or higher) you will hear a world of difference

the higher sample/bit rate stores more information, you should try to find a middle ground for quality & file size. your interface may also not support all formats

 

[beyond dead]

you will get much better results processing audio at a higher sample rate and bit rate because you have more detailed representation of the audio at a higher rate. also are the algorithms of plug ins more detailed at higher sample rates?

 

[fistula]

think of it like a headroom...
more bitdepth gives you more detail - quieter details
the sample rate - gives you smoothness of the sound

is like when you're doing your mix on -6db. why? because it gives you headroom for eq and other stuff - the same thing here

 

[fistula]

you will get much better results processing audio at a higher sample rate and bit rate because you have more detailed representation of the audio at a higher rate. also are the algorithms of plug ins more detailed at higher sample rates?

almost all of the DSP stuff (HD, UAD, Duende etc) do like that. they convert audio to high bitrates and then process them that way and then back to your bitrate

 

[Ermz]

I thought almost all DAW operations worked in this fashion? Your signal gets oversampled, processed, then downsampled again?

 

[fistula]

maybe) dont know about DAWs

but plugs do that stuff - Metric Halo CS 100% do that way...

 

[smy1]

Very interesting read from Steve Massey: http://www.smassey.com/blog.html

Second one from the top is about dithering. I liked it!

 

[LSD-Studio]

there is NO reason to record with a higher samplerate then you'll be using on the final medium!

for CD it's 44.1k, for DVD it's 48k


downsampling won't give you any advantages .... the opposite is the case, depending on th e quality of the lp-filter of your software you'll be introducing artefacts etc...

lemme repeat:

there is NO advantage in recording with a higher samplerate than you final media will be able to provide

period