-6db Clipping

[petrula]

Windows 7 Pro 64bit SP1
Audacity 1.3.12-beta (Unicode)
Cakewalk UA-25EX USB audio capture box
CAD E-100 microphone

I have a Cakewalk UA-25EX USB audio capture box.

Using Sound Forge Audio Studio 8.0, I can record to 0db without clipping.

Without changing any settings on the Cakewalk UA-25EX, Audacity 1.3.12-beta clips my voice at -6db for both stereo and mono.
Why?

Thanks in advance.

[kozikowski]

The up side is you have prepared a very clear, accurate description of the problem including numbers and descriptions.

The down side is I have no clue.

If you go into Audacity Preferences > Devices, are you in fact recording from the USB Sound Device, or are you recording from Stereo Mix, a holdover from the last time you tried to capture a YouTube song.

Koz

[petrula]

I believe I found the solution.

Right mouse click on the Windows 7 Sound icon in the tray of the lower right of the screen.
Select "Recording devices"
Select UA-25EX.
Click properties button.
Select Levels tab.
Move the slider to 100%.
Now it clips at 0 db.

Apparently, the Levels slider for the UA-25EX controls the level where the UA-25EX clips.

[DVDdoug]

Yeah, very weird... Usually it has nothing to do with the software... Usually it's the analog-to-digital converter clipping (hitting it's maximum) and that pretty-much 'defines' 0dBFS.

A couple of "dumb questions"...
How do you know it's clipping?
How are you "measuring" -6dB and 0dB?
When you open the file in the 'other' program do you see the same thing? i.e. If you record in Audacity and open the (exported) file in Sound Forge do you see the clipping at -6dB?
.

[kozikowski]

Apparently, the Levels slider for the UA-25EX controls the level where the UA-25EX clips.

Maybe not. If you have a show in the UA-25EX when you change that setting, does the show go up and down, too?

Koz

[steve]

I believe I found the solution.

Right mouse click on the Windows 7 Sound icon in the tray of the lower right of the screen.
Select "Recording devices"
Select UA-25EX.
Click properties button.
Select Levels tab.
Move the slider to 100%.
Now it clips at 0 db.

Thanks very much for getting back with the solution.

Apparently, the Levels slider for the UA-25EX controls the level where the UA-25EX clips.

Yes and no. The slider is not intended to set the clipping level, but it can produce that effect on recent versions of Windows due to the weird way that Windows handles audio. It is usual that the input gain of USB devices cannot be controlled by the computer (this is why there is a physical gain control on the device). However, Recent versions of Windows provide a means to scale the digital data and this gives the appearance of the recording level changing in exactly the same way as using the Amplify effect in Audacity. If the signal is clipping in the USB device, then lowering the record level in Audacity (which uses the Windows recording level control) does not prevent the clipping, it just scales the (clipped) audio to a smaller waveform. Usually you would record with the Audacity recording level set to 100% and use the gain knob on the device to adjust the recording level.

Earlier versions of Windows did not provide scaling of the digital data, so the record level control in Audacity is greyed out and you can only control the recording level by using the gain knob on the USB device. Personally I prefer this way of doing things as it is less confusing.