Lavry Blue / Black ADC's
- Thread starter reubenm
- Start date
Help Support GroupDIY Audio Forum:
Sammas
Well-known member
They are different scales for different things.
Digital systems and analogue systems are pretty much exclusive in scales.
0dBFS (Full Scale) is the absolute limit of a digital audio system. Audio can't exist above it.
+4dBu is an RMS voltage reference of 1.23volts.
Now remember that a digital audio system takes voltage and converts it to datasets. There isn't any concrete rules about how an RMS voltage translates to those datasets. There are some common practises for calibration though.
One of the common ones is +4dBu (which is also 0vu) = -18dbFS.
The Lavry probably isn't far off that calibration, so when you feed the converters a +4dBu signal, the meters in your DAW will read -18dbFS.
The idea behind this is headroom. In the analogue realm, signals can exist above "0" on a VU meter. Digital signal can't exist above 0dbFS. By setting +4dBu to -18dbFS, both systems have similar amounts of headroom (though great analogue gear can go all the way towards +30dBu).
Digital systems and analogue systems are pretty much exclusive in scales.
0dBFS (Full Scale) is the absolute limit of a digital audio system. Audio can't exist above it.
+4dBu is an RMS voltage reference of 1.23volts.
Now remember that a digital audio system takes voltage and converts it to datasets. There isn't any concrete rules about how an RMS voltage translates to those datasets. There are some common practises for calibration though.
One of the common ones is +4dBu (which is also 0vu) = -18dbFS.
The Lavry probably isn't far off that calibration, so when you feed the converters a +4dBu signal, the meters in your DAW will read -18dbFS.
The idea behind this is headroom. In the analogue realm, signals can exist above "0" on a VU meter. Digital signal can't exist above 0dbFS. By setting +4dBu to -18dbFS, both systems have similar amounts of headroom (though great analogue gear can go all the way towards +30dBu).
but i see focusrite REDNET and SSL's Alphalink AD/DA coverters are +14dbu and +24dbu clip rated each.therefore a +4dbu input signal is clean. on the lavry, seems 0dbFS was the maximum (distortion/sampling error free - doubtable). so i think i must need to run the +24db converter for the +4db signal.
ruairioflaherty
Well-known member
reubenm said:
Read Sammas post again carefully.
There is a difference between 0dBFS and 0dBu
Every digital converter is limited to 0dBFS, there is no way to make a digital signal above that level.
Every converter is calibrated differently so that different analog levels realize different digital levels.
Sammas
Well-known member
reubenm said:
reubenm said:
reubenm said:
You are getting confused.
dbFS is a digital level. dBu is an analogue level.
They are different things!
All converters clip at 0dbFS. Lavrys, apogees, SSL, benchmark, etc, etc. All of them! That is the limit of digital systems. No signal can exist above 0dbFS. At 0dbFS the signal clips within a digital system.
From the Lavry Blue M-AD824 website (http://www.lavryengineering.com/products/pro-audio/lavryblue-m-ad-824.html):
- 24dBu peak level with no internal gain (front panel pots counter clockwise)
The lavry clips 0dbFS (DIGITAL) when it receives a +24dBu ANALOGUE signal.
The SSL clips 0dbFS (DIGITAL) when it receives a +22dBu ANALOGUE signal.
For the Lavry's: a +4dBu analogue signal equals -20dbFS DIGITAL.
For the SSL's: a +4dBu analogue signal equals -18dbFS DIGITAL.
the Lavry Blues can handle hotter signals than the SSL's.
Sammas
Well-known member
reubenm said:
No sweat. I remember it confusing the f*%k out of me when I first came across it!
