Calibrating Input Level for Plugins

[laxu]

So what you need to do is:

- put a signal generator on track 1, route it to output 3. (probably want to turn your monitors off just to be safe), set the level of the sine wave so it is at 0dBFS.

- run a line level cable from output 3 to your Lehle, as you are doing.

- rather than plugging your Lehle to the amp, plug this cable straight to your audient instrument input.

- follow my steps above

This is to determine the level hitting the amp, it’s the one that matters. The level coming from the loadbox isn’t really important for capturing an amp, if you’re doing a pedal capture and want to retain accurate output level modelling then you’d consider it.

Once you know the level hitting your amp, you can determine how much you (or anyone else) needs to adjust to reach unity.

For the level coming from the loadbox, just avoid clipping

I tried this, but skipped the Lehle as it doesn't really matter here.

Output 3 -> Instrument Input 1.

With the signal generator (Logic Test Oscillator plugin) set to output at 0 dB through Output 3, the input I see on the Instrument Input 1 is -38 dB in Logic. To get this track to unity, I need to turn up the preamp by 38 dB. Logic reports it a bit weirdly as a scale of -8 (audio interface gain on zero) to 50 dB. Specs say the gain range is 58 dB.

With the sine generators default -12 dB level, Input 1 sees predictably -50 dB.

 

[bikescene]

I tried this, but skipped the Lehle as it doesn't really matter here.

Output 3 -> Instrument Input 1.

With the signal generator (Logic Test Oscillator plugin) set to output at 0 dB through Output 3, the input I see on the Instrument Input 1 is -38 dB in Logic. To get this track to unity, I need to turn up the preamp by 38 dB. Logic reports it a bit weirdly as a scale of -8 (audio interface gain on zero) to 50 dB. Specs say the gain range is 58 dB.

With the sine generators default -12 dB level, Input 1 sees predictably -50 dB.

Is your Volume 2 on the interface maxed out? The online manual seems to indicate that Volume 2 is linked to Output 3+4 and/or the 2nd headphone out.

 

[MirrorProfiles]

I tried this, but skipped the Lehle as it doesn't really matter here.

Output 3 -> Instrument Input 1.

With the signal generator (Logic Test Oscillator plugin) set to output at 0 dB through Output 3, the input I see on the Instrument Input 1 is -38 dB in Logic. To get this track to unity, I need to turn up the preamp by 38 dB. Logic reports it a bit weirdly as a scale of -8 (audio interface gain on zero) to 50 dB. Specs say the gain range is 58 dB.

With the sine generators default -12 dB level, Input 1 sees predictably -50 dB.

Is your Volume 2 on the interface maxed out? The online manual seems to indicate that Volume 2 is linked to Output 3+4 and/or the 2nd headphone out.

Yeah, check you HW output levels are fully maxed out. Sometimes they are linked to speaker output controls, or have software controlled levels. Also check if they have a switch to go between -10dbV and +4dBu etc.

I’d test with the Lehle and correct cables just to factor it all in.

 

[laxu]

Is your Volume 2 on the interface maxed out? The online manual seems to indicate that Volume 2 is linked to Output 3+4 and/or the 2nd headphone out.

I had it left where I usually set my headphones level...

Thanks! With the volume maxed, Input 1 sees -11.4 dB.

 

[MirrorProfiles]

I had it left where I usually set my headphones level...

Thanks! With the volume maxed, Input 1 sees -11.4 dB.

Looks like the headphone outputs are a lot weaker than the speaker outs.

If you use the speaker outs (1+2) you should get about 11dBu out of the Lehle (you can verify by running a sine wave back into input 1 and there should be a 1dB difference).

Making captures at 11dBu is pretty ideal and should be easy (aside from having to unplug your monitors!).

 

[laxu]

Looks like the headphone outputs are a lot weaker than the speaker outs.

If you use the speaker outs (1+2) you should get about 11dBu out of the Lehle (you can verify by running a sine wave back into input 1 and there should be a 1dB difference).

Making captures at 11dBu is pretty ideal and should be easy (aside from having to unplug your monitors!).

There is no difference between the line outs.

Basically the interface works like this:

• If headphones are connected to headphone out 1, then line outs 1/2 on the back are disconnected and audio is routed to hp out 1.
• If headphones are connected to headphone out 2, then line outs 3/4 on the back are disconnected and audio is routed to hp out 2.
• If instrument input in front is connected, mic/line input 1 on the back is disconnected.

I tried swapping it around so that it goes Output 1 -> Input 1, and the result is the same. With a 1 KHz sine generator at 0 dB out, I get -11.4 dB on Instrument input 1.

If I connect Output 1 -> Input 4 (mic/line, these are all identical), with Input 4 gain on zero, then I see -15.1 dB on that input.

 

[MirrorProfiles]

There is no difference between the line outs.

Basically the interface works like this:

• If headphones are connected to headphone out 1, then line outs 1/2 on the back are disconnected and audio is routed to hp out 1.
• If headphones are connected to headphone out 2, then line outs 3/4 on the back are disconnected and audio is routed to hp out 2.
• If instrument input in front is connected, mic/line input 1 on the back is disconnected.

I tried swapping it around so that it goes Output 1 -> Input 1, and the result is the same. With a 1 KHz sine generator at 0 dB out, I get -11.4 dB on Instrument input 1.

If I connect Output 1 -> Input 4 (mic/line, these are all identical), with Input 4 gain on zero, then I see -15.1 dB on that input.

Ah got it. It still seems like some level is getting lost somewhere, if you were sending -12dBFS out and getting approx -11dBFS back in it would make sense. the Lehle stuff tends to be 1:1 on the transformer ratio so it SHOULD be 11dBu on your output (i.e. 1dB louder than the maximum the DI input can take).

 

[laxu]

I tried the whole chain again with the Gigrig Wetter Box, and now the gains are pretty much identical. I'll see if I can get a capture made.

The key was maxing Volume 2, and maxing output 3 volume from the EVO Control app.

 

[laxu]

Thanks for all your help! I got a capture made and comparing it with the Wetter Box going to audio interface vs direct to amp, the tones are very close.