Matching Audacity to USB device's native sample depth & bitrate

Help for Audacity on macOS.
Forum rules
ImageThis forum is for Audacity on macOS 10.4 and later.
Please state which version of macOS you are using,
and the exact three-section version number of Audacity from "Audacity menu > About Audacity".


Audacity 1.2.x and 1.3.x are obsolete and no longer supported. If you still have those versions, please upgrade at https://www.audacityteam.org/download/.
The old forums for those versions are now closed, but you can still read the archives of the 1.2.x and 1.3.x forums.
Post Reply
NewOldVinyl
Posts: 4
Joined: Wed Mar 27, 2019 8:17 pm
Operating System: macOS 10.15 Catalina or later

Matching Audacity to USB device's native sample depth & bitrate

Post by NewOldVinyl » Wed Mar 27, 2019 8:31 pm

OS X Mojave
Audacity 2.3.1
Music Hall pa2.2 Phono Preamp with 24/96 A-to-D convertor and USB output

The Music Hall preamp's "native" A-D conversion is 24/96.

I want Audacity to make the master recording exactly as the pa2.2 provides it via USB: 24/96. I don't want Audacity doing any data manipulation or re-sampling or conversion.

If I set Audacity to 24/96, will it record the signal exactly as the preamp sends it out?

What happens if I set Audacity to 16/44.1? Does it negotiate with the preamp to tell it to use 16/44.1? Or does Audacity do a software conversion on the 24/96 stream it receives from the preamp?

Appreciate any help you can provide on this!

DVDdoug
Forum Crew
Posts: 9468
Joined: Fri Sep 10, 2010 11:30 pm
Operating System: Windows 10

Re: Matching Audacity to USB device's native sample depth & bitrate

Post by DVDdoug » Wed Mar 27, 2019 10:16 pm

I'm a Windows guy...

By default, Audacity captures and works internally at 32-bit floating point. The up-conversion is lossless. Most audio programs work in floating-point and there are good reasons for that. When you export you can convert-back to 24-bits (or whatever you want).

I assume there will be no conversion if you set your Audacity project rate at 96kHz. Audacity won't do any resampling while recording, but the drivers might. (On Windows the drivers make everything "work together" no matter what settings you use, so you can't be sure what the hardware is doing.)


--------------------------------------------------
24/96 is the pro studio standard and there's no harm in using it (other than larger files). But as practical matter it's not that important.... Re-sampling is usually transparent as long as you stay at "CD quality" or better (although it's "bad practice" to re-sample unnecessarily). And, 16/44.1 has been shown to be better than human hearing by the guys how do scientific-blind ABX tests (i.e. comparing a high-resolution original to a downsampled copy).

And with vinyl (obviously worse than human hearing) the resolution and dynamic range are limited by surface noise so you don't need "high resolution".

NewOldVinyl
Posts: 4
Joined: Wed Mar 27, 2019 8:17 pm
Operating System: macOS 10.15 Catalina or later

Re: Matching Audacity to USB device's native sample depth & bitrate

Post by NewOldVinyl » Wed Mar 27, 2019 10:32 pm

I actually started this on Windows 10 but moved it to OS X. I’m kind of liking the Windows setup better, might move everything back to Win.

Interestingly, although there’s absolutely no mention of it in the phono preamp documentation, Music Hall says their preamp can be configured via software commands over USB to run as high as 24/192.

Post Reply