Line Level Outputs, dBu values???

[GuitarHack]

How do Line Level Outputs relate to dBu values?

I originally posted the following in the "Getting an Audio Interface FAQ" sticky, but wanted a Crash-course on the Levels of Line Level Outputs and dBu levels.

From my other post:

Are the Line Level Outputs HOT enough on the Saffire Pro 24 and 40 for a reamp box?

Reason for my question is an article from: http://audiogeekzine.com/tag/profire-2626/ talking about Profires, but the Output Levels from the Saffire 24 and 40 are similarly low like the Profire 610. The 2626 is HOTTER:

Profire 2626 Line Outputs (Balanced)
Maximum Output Level +20.2dBu balanced, typical
Output Impedance 300 Ohms, balanced

Profire 610 Line Outputs (Balanced)
Maximum Output Level +15.9dBu balanced, typical
Output Impedance 940 ohm balanced


FOCUSRITE
Pro 40
Line level Outputs
Maximum level (A-weighted): 15.7dBu at 0.883%

Pro 24
Line level Outputs
Maximum level (A-weighted): 16.13dBu at 0.885%

Any thoughts/experience before my head explodes?

What level is required for a good output to a Reamp box?

Thanks

 

[C-Martin]

How do Line Level Outputs relate to dBu values?

I originally posted the following in the "Getting an Audio Interface FAQ" sticky, but wanted a Crash-course on the Levels of Line Level Outputs and dBu levels.

From my other post:

Are the Line Level Outputs HOT enough on the Saffire Pro 24 and 40 for a reamp box?

Reason for my question is an article from: http://audiogeekzine.com/tag/profire-2626/ talking about Profires, but the Output Levels from the Saffire 24 and 40 are similarly low like the Profire 610. The 2626 is HOTTER:

Profire 2626 Line Outputs (Balanced)
Maximum Output Level +20.2dBu balanced, typical
Output Impedance 300 Ohms, balanced

Profire 610 Line Outputs (Balanced)
Maximum Output Level +15.9dBu balanced, typical
Output Impedance 940 ohm balanced


FOCUSRITE
Pro 40
Line level Outputs
Maximum level (A-weighted): 15.7dBu at 0.883%

Pro 24
Line level Outputs
Maximum level (A-weighted): 16.13dBu at 0.885%

Any thoughts/experience before my head explodes?

What level is required for a good output to a Reamp box?

Thanks

I generally just try to hit 0dbVU which is +4dBu, and depending on the converters your using will change what that means in dbFS. It depends mostly on how your converters are calibrated. If the maximum output level is 16dBu then that means 0dbVU would be at around -12dbFS. This would basically be your converters sweetspot and it's generally good to stick to the sweetspot of your recording gear, especially if you use outboard.

That said, i really don't think this is that crucial for reamping so long as you have a loud enough signal with low noise and your not clipping.

 

[GuitarHack]

Thanks for the explanation. Much appreciated.


EDIT: Here is another good example I found on another forum, just in case anybody else was as confused by this as I was:

"Here's my easiest answer...

My mixer has a headroom at its output of +18dbu max output... go above that and it clips..

OK...

0dbfs is equal to the maximum digital level... go above that and it clips digitally...

Most of the time full digital level 0dbfs and +18dbu (or whatever your max output is) are calibrated to match up at the factory..

So if I'm hitting 0dbfs digitally in the computer my outputs will be hitting +18dbu analog

Now take the figure 18 (your max output) and subtract it from 0 (full digital scale)... what do you get? -18dbfs (digital)!!!

So.. when I'm at -18dbfs.. I will also be at 0dbu at my analog output..

Now if I was shooting for MY line level I would be aiming for -14dbfs which equals +4dbu. A VU meter can help in these situations... Just calibrate a VU meter to your output where 0VU equals +4dbu or -14dbfs.. then all you ever have to shoot for at your output is 0VU....

Ya see with digital its metering stops at 0.. and with analog and its metering starts at line level either +4dbu(standard) or -10dbv(consumer level also equal to -7.78dbu).. and then goes up from there depending on how good your equipment is (just read the manual).. some gear can get up to +24dbu at the outputs without clipping.. at +24dbu your line level digitally would likely be -24dbfs digital..."

 

[deLuther]

From my experience +20 dbu or so is sufficient for pickup level recreation in case of reamper with unity gain (1 to 1 level transfer). Some passive pickup can be pretty hot, peak level can exceed several volts (same stands for active pickups on 18 V supply). To get the same level something should driven hard enough, maybe interface inputs or something after interface output for gain compensation.

And there is some misconception about input/output ratings, some manufacturers have specification in dbV/dbu from RMS values (as it should be), some specify according to peak level, so difference can be 3 db.

 

[MarcelCSFocusriteNovation]

Dear GuitarHack,

Thanks for your thread.

You should be able to get a great guitar tone with the Pro 40 and 24 without the need of a reamp box as you can see in the following video: