I usually set my projects to 44100 sample rate with 24-bit resolution.
A few days ago I imported some WAVs sent to me by a client for mastering, they were recorded at 88200 sample rate, 24-bit resolution.
Cubase made the automatic conversion fine, but there’s some crackly noises in the tracks, which become more noticeable when I compress them. At first I assumed it was just flaws in the original recording (lip & string noises - it’s an acoustic guitar/vocal project), but it just occurred to me - is it possible that I could have introduced (or exaggerated) some of this by converting the sample rate? Is there something like “dithering” that I should have done instead (like when changing from 24-bit to 16-bit resolution)?
Should I have set my project to the higher sample rate to start with? How important is this (especially since I’d have to convert it to 44100 anyway before burning the master)?
Changing sample rate won’t make any difference to noises in the recording.
check this out:
this does apply to other conversions, too. it is NOT like just loose or interpolate every second sample, when you convert from 88.2 to 44.1 and vice versa. In fact, sample rate conversion is a rather complex process that includes some lowpass filtering and other things. So it is quiet obvious, that a sample rate conversion DOES effect the sound quality. However, those effects took place at -90 - -140 db (depending on the bit deph), so it isn’t quiet obvious in the first place. I would recomend to use a dedicated sample rate converter, like r8brain from voxengo or similar. These tools are specialized and minimize the ‘bad’ effects from sample rate conversion.
It’s highly unlikely that actually noises and/or crackling would be caused by resampling.
To rule it out, I’d make a new project at 88.2, and import those original files into it. Do they now have the crackling?
Thanks Tomess & enjneer, I’ll try both of those suggestions.
In the sample editor, expand one of those noises and see if, when you get to start seeing individual samples, whether there are abrupt changes in level. If so, it could be from digital drop-ins.
Analog drop-in on tape had a bit of ‘soft landing’ where there wouldn’t be such abrupt changes. Digital is far more ‘accurate’, stopping one signal, and instantly using the other.
I first noticed it when we were doing our CD 10 years ago. We used a couple of musicians, one of which was using keyboards, so his were rendered MIDI, but the other did all his as recorded audio. I just thought the latter was a bit sloppy with minimising recording noises, until I noticed the clicks in the sample editor, and realised the noises occurred before AND after some notes.
I now use iZotope’s RX to do digital drop-ins, as it has a configurable cross-fade time, as low as 1 ms, so I can choose the amount of smoothness of change.
Off Topic - Re clicks when chopping, I use the Auto-Fade/Crossfade settings which adds a configurable fade/crossfade to starts and ends of every audio part.
On Topic - I once got some exports (ProTools ) from from a studio and they had occasional glitches, it was only for guide tracks but still a bit of a nuisance at the time. But these things happen so I asked for them to be redone and all was OK again.