tschlechter
Hello,
I use professional audio equipment (that really deserves the name) on a regular basis. Now I would like to use the digital inputs on recent LabGruppen amplifiers and on some older Digital Field Controllers (crossover and controller) from HK-Audio. This way, I can get rid of the useless D/A - A/D conversion between the DJ-Laptop and the audio amplifiers in order to just use the final and ultimately necessary DA conversion in the amplifiers or crossovers. This works nicely with professional digital mixing consoles (such as A&H GLD-80 f.i.) that respect the EBU alignment level of -18dbFS (http://en.wikipedia.org/wiki/Alignment_level and http://en.wikipedia.org/wiki/DBFS).
Now Virtual DJ outputs 0dbFS. If I connect the digital output of my macbook to the DFC's or Lab Amps, these devices are overloaded: an alignment level of -18dbFS means, that these devices will output their full rated nominal power at -18dbFS.
On windows and without using ASIO-drivers, I can use the windows-mixer to drop the output level to match the input sensitivity of the crossovers or amplifiers. But when I use a professional grade audio digital AES output sound-card with an asio-driver on windows or any digital output on a mac, I cannot influence the level of the digital signal on OS-level. According to one manufacturer (yellowtec puc2), it is the software's responsibility to create the proper digital signal with the proper alignment level.
The range of the Virtual-DJ Master-Out slider is way too small to adjust the output within a useful range. At the lowest setting, it is already near the -18dbFS (that correspond to full power output).
Using zeroDB to achieve the alignment degrades audio quality. I suppose zeroDB is applied on the input side of the processing (the VU-meters confirm this supposition), i.e. the original 16bit audio track is reduced by some bits just to add some more zeros at the output stage again to add up to the 24bits of output.
The alignment should be quite simple to do in most cases, since the typical 16 bit sources already need upscaling to 24 bits, upscaling to fewer bits should be an easy modification.
Of course, this alignment level should be configurable / switchable, since there are quite a lot of D/A-converters (typical Soundcards) that "align" without any headroom at 0dbFS.
Thank you for your attention,
Tun Schlechter
I use professional audio equipment (that really deserves the name) on a regular basis. Now I would like to use the digital inputs on recent LabGruppen amplifiers and on some older Digital Field Controllers (crossover and controller) from HK-Audio. This way, I can get rid of the useless D/A - A/D conversion between the DJ-Laptop and the audio amplifiers in order to just use the final and ultimately necessary DA conversion in the amplifiers or crossovers. This works nicely with professional digital mixing consoles (such as A&H GLD-80 f.i.) that respect the EBU alignment level of -18dbFS (http://en.wikipedia.org/wiki/Alignment_level and http://en.wikipedia.org/wiki/DBFS).
Now Virtual DJ outputs 0dbFS. If I connect the digital output of my macbook to the DFC's or Lab Amps, these devices are overloaded: an alignment level of -18dbFS means, that these devices will output their full rated nominal power at -18dbFS.
On windows and without using ASIO-drivers, I can use the windows-mixer to drop the output level to match the input sensitivity of the crossovers or amplifiers. But when I use a professional grade audio digital AES output sound-card with an asio-driver on windows or any digital output on a mac, I cannot influence the level of the digital signal on OS-level. According to one manufacturer (yellowtec puc2), it is the software's responsibility to create the proper digital signal with the proper alignment level.
The range of the Virtual-DJ Master-Out slider is way too small to adjust the output within a useful range. At the lowest setting, it is already near the -18dbFS (that correspond to full power output).
Using zeroDB to achieve the alignment degrades audio quality. I suppose zeroDB is applied on the input side of the processing (the VU-meters confirm this supposition), i.e. the original 16bit audio track is reduced by some bits just to add some more zeros at the output stage again to add up to the 24bits of output.
The alignment should be quite simple to do in most cases, since the typical 16 bit sources already need upscaling to 24 bits, upscaling to fewer bits should be an easy modification.
Of course, this alignment level should be configurable / switchable, since there are quite a lot of D/A-converters (typical Soundcards) that "align" without any headroom at 0dbFS.
Thank you for your attention,
Tun Schlechter
Inviato Fri 17 Apr 15 @ 7:11 am
Adion
I am not sure why this equipment would want a digital signal at -18dB.
The easiest to achieve this is indeed using the master volume.
At these low levels it can be difficult to control manually, but you could use a custom button to set it to an exact value, in this case you could use
master_volume 0.125893
To set it to exactly -18dB (see here for converting from dB to multiplier for example http://www.sengpielaudio.com/calculator-gainloss.htm )
Keep in mind however that the limiter would still work at full scale however, so while mixing multiple songs, using eq, effects or gain etc... it is still possible for the output to be above -18dBFS.
It depends on the working of your equipment what happens then I guess.
There are probably also limiter/compressor VST's that could be configured as master effect for VirtualDJ and configured for -18dB output.
Using the zeroDB value will not decrease sound quality btw since internal calculations are in 32-bit. The biggest problem using zeroDB for this is that it only affects the individual decks which makes the individual VU meters useless as you noticed, and also has the same problem as mentioned before that the mixed output could still go above -18dB.
The easiest to achieve this is indeed using the master volume.
At these low levels it can be difficult to control manually, but you could use a custom button to set it to an exact value, in this case you could use
master_volume 0.125893
To set it to exactly -18dB (see here for converting from dB to multiplier for example http://www.sengpielaudio.com/calculator-gainloss.htm )
Keep in mind however that the limiter would still work at full scale however, so while mixing multiple songs, using eq, effects or gain etc... it is still possible for the output to be above -18dBFS.
It depends on the working of your equipment what happens then I guess.
There are probably also limiter/compressor VST's that could be configured as master effect for VirtualDJ and configured for -18dB output.
Using the zeroDB value will not decrease sound quality btw since internal calculations are in 32-bit. The biggest problem using zeroDB for this is that it only affects the individual decks which makes the individual VU meters useless as you noticed, and also has the same problem as mentioned before that the mixed output could still go above -18dB.
Inviato Fri 17 Apr 15 @ 8:05 am
vlnjacki
Eventually you can use the Hofa 4 U vst plugin,as Mastereffect in VDJ 8
this works with EBU 128,but have self this not tested on my PA,but in VDJ 8 this works.
Im searching,looking and read more over the EBU 128 Norm,eventually i will do this too.
But all this is Newland for me.
http://www.kvraudio.com/product/hofa-4u-meter-fader-and-ms-pan-by-hofa-plugins
greetings,Dirk
this works with EBU 128,but have self this not tested on my PA,but in VDJ 8 this works.
Im searching,looking and read more over the EBU 128 Norm,eventually i will do this too.
But all this is Newland for me.
http://www.kvraudio.com/product/hofa-4u-meter-fader-and-ms-pan-by-hofa-plugins
greetings,Dirk
Inviato Sun 19 Apr 15 @ 10:22 am
Adion
I haven't tested it, but it doesn't look like it does any limiting, so I think it is either just a -18dB volume (and in this case any volume over 0dB at the input of the plugin will still come out louder than -18dB at the output), or it clips the output at -18dB, in which case you would get clipping artifacts. I would personally prefer a limiter in that case.
Inviato Sun 19 Apr 15 @ 10:45 am