Hello. I am using Audacity 2.3.2 with Windows 10 and a Focusrite 2i2 USB interface. When the interface is at its clipping point, Audacity shows an input level of -6dBfs. With other software (Sony Sound Forge) an input level of 0dBfs is shown. Any idea why this discrepancy is occurring? Thanks.
First, trust the clipping indicators on your interface. It’s the analog-to-digital converter inside the interface that clips (distorts).
You can Amplify after recording, and since it’s common to leave some headroom you’d probably be doing that anyway.
Here’s what’s happening:
You are recording in mono with a stereo (2-channel) interface but you’re only using one input. Both channels combined can reach 0dB. As long as neither channel clips you are safe and the combined signal won’t clip or go over 0dB.
If you record in stereo that won’t happen, but then you’ll have to deal with the silent channel.
Digital recording differs from anlog recording. As in former times we tried to reach the maximum of volume when recording it is now not longer necessary, but harmful.
The correct way is nowadays to keep a minmum headroom of 10dB in each track. This means no peak in your recording should not reach the 50% height of the track windows (-0.5 to +0.5 on the left ruler)
The avarage signal level should be -20dB. This means the avarage sample graphics of your recording should not reach the 25% height of the track windows (-0.25 to +0.25 on the left ruler).
Do I lose quality?
No! doing like this means not using all 24bit, but “only” 22bit of the Interface. you will keep the full dynamic, but stored with a resolution of “only” 4.000.000 steps. This is more than you can hear and differentiate. But reaching the 0dB mark always will cause losing dynamic, because every signal above 0dB is cutted off. There is no chance of recording +10dB signal peaks in digital recording. Cuts always sound like a dist. guitar. Also if you later reduce the track volume it will stay a cut and it will sound quiter , but still like a quiter dist. guitar.
Also consider of summary effects if you record a lot of single tracks/instruments. Even when there is no distortion in each single track ,the sum volume can exceed the 0dB limit. so, if you plan to record 15 track, you can keep a headroom of -15dB on each track. Not until the end if you have mixed all together in the the final stereo track, you will normalize this track to the CD-level of -3dB.
Thanks for the replies. I understand the concepts of leaving headroom and recording conservatively. My question is why would two different programs display different levels for the same input signal?
Because they are not getting the same input signal.
Sound Forge is probably using ASIO drivers.
Audacity is probably using WDM drivers.
The -6dB level in Audacity is probably indicating a problem in the Windows Sound settings. Check in the Windows Sound control panel and ensure that in the “Recording” tab, the Focusrite is set to record “stereo” (not “mono”).
Thank you Steve - yes, ASIO versus Windows DirectSound. I didn’t realize that could make a difference.