Best method for sample rate conversion

Ora · Post by **Ora** » Wed Jun 05, 2002 7:37 am

I know that there is a lot of talk about what is best for dither & hardware for d/a a/d conversions....but what is best for sample rate conversions? I'm sure there are some good hardware pieces of gear out there that do it professionaly but what is the best method for the more 'budget-minded' studio.....

Currently I use Cubase's mixdown function & I was using the dither as well (which I don't know if its a rumor but I heard that the uv22 in cubase is not the 'real' thing...)
Anyways, I choose the samplerate in a cubase mixdown & bam! its done...easy yes, but is it the best quality?

Ora

snoopy4ever · Post by **snoopy4ever** » Wed Jun 05, 2002 7:55 am

Hi there!

I'm kind of confused about your question. Because I don't know if you want to do sample rate conversion on the hardware side, or just a sample rate conversion using software.

On the hardware side there are some interesting devices for that on the M-audio website : http://www.m-audio.com , these boxes can do sample rate and format conversion between optical,spdif and tdif.

If you only want to use software, you could consider getting steinberg's wavelab.

snoopy

Ora · Post by **Ora** » Wed Jun 05, 2002 8:38 am

Sorry about that - it would be software - would you say that wavlab's samplerate conversion is better than cubase or are they somewhat the same?
I'll check those hardware ones too - thanx!

jupiter8 · Post by **jupiter8** » Wed Jun 05, 2002 10:28 am

The best thing is to avoid sample rate conversion at all cost.
And if you have to and have a choice, a conversion to exactly half the freq. is to prefer.
For ex. 96 kHz to 48 or 88.2 to 44.1.

Why do you need to convert?

Ora · Post by **Ora** » Wed Jun 05, 2002 11:28 am

...I record everything in 24bit 48k.
Do I really need to avoid the conversions at all costs - is it that noticeable when you sample down? ....and if I don't have the option to sample down exactly halfway - what program / method do you suggest?

kensuguro · Post by **kensuguro** » Wed Jun 05, 2002 11:49 am

hmm.. there may be several ways to view this, but I'd think recording in 48khz is questionable if you weigh it against the loss you get when you convert samplerate. (as discussed before) Are you doing something with DV or DVCAM? I'd say either shift up the sampling rate, or just stick with plain 44.1 if that's an option.

From what I know by ear, samplerate conversion seems to be a lossy operation, so a 48khz converted to 44.1 sounds worse than something originally recorded 44.1. But maybe that's just my opinion so you don't have to take it too seriously. Haven't done any specific measurements really. Also, I use cooledit which I think is supposed to have one of the best samplerate conversion and dithering algos.

snoopy4ever · Post by **snoopy4ever** » Wed Jun 05, 2002 11:54 am

Yes Ora..

Jupiter8 said it..

It's better to avoid sampling down until the last point of the process.

When you sample down you loose information from you files, so it's better to sample down (say 44.1 khz ) when you are going to put your music on CD. In other words you should record, mix, process your music at your recording sample rate and resolution, when you have mastered your music and/or you think it's good enough to deliver on CD media, then you should change the sample rate to 44.1 khz and the resolution to 16 bits.

I think there are lots of tools for sample rate conversion on the software side, I think Wavelabe is a good choice over Cubase because wavelab is a mastering oriented software, but to be honest I have not noticed any difference between both programs when it comes to judge the results.

Hopes this helps.

Snoopy

<font size=-1>[ This Message was edited by: snoopy4ever on 2002-06-05 12:55 ]</font>

Ora · Post by **Ora** » Wed Jun 05, 2002 12:29 pm

......I think I have been on the right track then. Generally, I will track everything 24bit 48k then mix it down to 16 44 in cubase.....now, I guess I will mix it down 24 48 & do all the conversions and processing in wavlab.....

jupiter8 · Post by **jupiter8** » Wed Jun 05, 2002 12:42 pm

Just curios to why you choose to record at 48 kHz?

Ora · Post by **Ora** » Wed Jun 05, 2002 4:44 pm

I guess that question brings into question....Is it true that recording all individual tracks at a higher sample rate and then sampling down for the master gives better quality to the overall mix/project then doing everything in 44khz?

Sunshine · Post by **Sunshine** » Thu Jun 06, 2002 1:27 am

I know that rumor does exist... And there is evidence that certain plugs work a little better at higher samplerates (reverbs), but the main question will still remain whether the higher resolution is worth the sr-conversion (same whith 96k)... But of course your converters will work better at higher SR.

I use 44.1 for music projects. 48k was always the standard for movie scoring, so 48k is the standard for "film" audio. It should be mentioned that "Sony" did their "Starwars" Episode-I recording of the London philharmonics at 44.1 for the CD version, avoiding the SRC.

I once attended a SR-algo test, where "Cool Edit" and "Samplitude" seemed to have the best algos. Whith Cool Edit 2000 you get the longest processing times of all...which yielded the best results but it seemed as there is a certain amount of filter-ripple or "ringing" in very impulsive material, though. Third best was "Waves" whith their stand-alone program, as far as I remember. Nuendo/Cubase was fast, but midfield at best, amongst SoundForge and others. Wavelab had changed the frequency content in a too abvious way IMO, but the dithering options aren´t so bad. For the ones who are interested, there is another software solution... called Audio Magic Ring (AMR) working as a samplingrate-, wordlength, normalize- & format- (Wave, AIFF, BWF, OMF, PMF, etc) converter....to be found under http://www.merging.com. It´s a demo which works for a month, I think.

Regards,
Sunshine

Mr Arkadin · Post by **Mr Arkadin** » Thu Jun 06, 2002 2:30 am

I always record at 24 bits, 44.1kHz. If most of your work will end up on CD then dithering 24 bits to 16 is cool (if you track carefully then recording 24 bits will give you a better dynamic range for your master 16 bit version) but I would try and avoid 48 to 44.1 conversion if possible. Honestly, I think that recording at 24 bits you'd be hard pushed to notice the difference between 44.1 & 48.

jupiter8 · Post by **jupiter8** » Thu Jun 06, 2002 6:07 am

If you are recording for a project ending up on cd there is NO reason whatsoever to choose another SR then 44.1
Au contraire.
The resampling process will mess up your sound.

All of the information above the nyquist freq. (half the sample rate) will be lost.
ALL of it.
I can't stress this enough.

Ora · Post by **Ora** » Thu Jun 06, 2002 6:42 am

wow.....
so even if I were to take the final mix of 24bit 48k to a pro mastering house they would get the same results too?

kensuguro · Post by **kensuguro** » Thu Jun 06, 2002 6:58 am

I would certainly doubt that 4hz would make too much of a difference if the material is mastered very well. There not too much of a boost in quality as opposed to the amount of effort needed to downsample the mere 4 hz without too much artifact.

The only time I've used 48hz in the past is for stuff to go with things filmed in DVCAM, and as stated before, everything in motion pictures go at 48.

Why not just go 96 next time?

Ora · Post by **Ora** » Thu Jun 06, 2002 7:37 am

...that kinda sux - I have started an album of mine and another artists @ 24/48 and I'm trying to keep everything consistent.......hmmmm
So 24/96 would actually make a difference then or is it just better to stick w/ the ole 44k?

jupiter8 · Post by **jupiter8** » Thu Jun 06, 2002 8:00 am

I don't like repeating myself but.....

If your recording for CD there is NO reason whatsoever to choose another samplerate then 44.1.

Can i be more clear ?

subhuman · Post by **subhuman** » Thu Jun 06, 2002 9:16 am

jupiter8 is completely correct. I won't bother repeating what he has said already a few times here...

kensuguro · Post by **kensuguro** » Thu Jun 06, 2002 9:22 am

Nestor · Post by **Nestor** » Thu Jun 06, 2002 10:05 am

I’ve asked this question to a real expert on the topic, one of the most famous guys in the UK who does all the mix to everybody there, he said that raising the bit rate results always in a better sounding material at the end. For instance: 24 bits is better than 16 bits, and 32 better than 24 bits. But, that sample rate is just a commercial issue to sell soundcards cos, despite the fact that it’s true that you get a more compact wave file by the end, it is not worth the trouble cos the difference is imperceptible.

So he said: To record at 96kHz it’s not worth the trouble, it’s better to record always at 41.1kHz, even if you go 32 bits recording.

Honestly, I would just pay attention to what this guy has said, cos it’s a 50 years old man that has being in business since 15 years old and knows all about analogue and all about digital, it’s a real genius.

So again, Jupiter8, Ken and Sub are completely right, all you need to do is to start recording that way. Good luck.