Nominal levels: +4dBu vs. –10dBV

[Guust-Fi]

I did a quick search but couldn't find exactly what I was looking for.

My primary question is:
Is it safe to set your output levels of your soundcard (Echo Audiofire 4 in my case) to +4dBu if you connect your soundcard to the club mixer?

What about when connecting to the amplifier directly?
What about connecting your soundcard to consumer level equipment?

[Monika.mhz]

I always set things to -13db. Across the board.
Helps avoid clipping at any scale. If I'm going to push it i'd rather push it on the mixer, where if it clips it sounds softer than software clipping.

[Guust-Fi]

I am actually talking about hardware here.
I do agree with your statement above but this is a different thing...

Let me qoute from the Audiofire 2 manual (which Ean reviewd before btw):

Nominal Levels
The console buttons that are labeled “+4” or “-10” are nominal level buttons. These buttons allow you to change the nominal level settings for the analog inputs and outputs. By default, the levels are set to send a +4dBu signal. You can switch between +4dBu (professional level) and –10dBV (consumer level) for each analog output and input by clicking on the appropriate button. This feature allows you to connect either professional or consumer gear to each input and output

[Monika.mhz]

Aaaaah, misread your statement!

It's 100% ok to connect it at +4db. basically if you connect it at -10db and you find you've got an audio level problem, click it to +4. otherwise, keep it at -10!

[Guust-Fi]

I checked the DJM-800 specifications:

Standard input level/Input impedance
PHONO 2 to 4 .................................................. .......... –52 dBu/47 kΩ
MIC 1, MIC 2 .................................................. ............. –52 dBu/3 kΩ
LINE, LINE/CD 1 to 4 ................................................. –12 dBu/22 kΩ
RETURN .................................................. .................. –12 dBu/22 kΩ
Standard output level/Load impedance/Output impedance
MASTER 1 .............................................. +2 dBu/600 Ω/10 Ω or less
MASTER 2 .................................................. ........ +2 dBu/10 kΩ/1 kΩ
REC .................................................. ................... –8 dBu/10 kΩ/1 kΩ
BOOTH .................................................. ........... +2 dBu/600 Ω/600 Ω
SEND .................................................. .............. –12 dBu/10 kΩ/1 kΩ
PHONES ................................................ +8.5 dBu/32 Ω/22 Ω or less
Rated output level/Load impedance
MASTER 1 .................................................. .............. +22 dBu/600 Ω
MASTER 2 .................................................. ............... +20 dBu/10 kΩ

I don't get it. -12dBu would correspond to about -14dbV?
That doesn't make sense considering both the standards?
How can I tell if I'm overloading the mixer?
Can overloading cause damage at all or does it only manifest itself as sounding worse due to distortion?

Another quote from the head-fi forums:

Of course. +4 setting is the default setting for professional use, where high output is needed to overcome long cable runs, etc. It should be much louder than -10 setting.

Whether one setting will sound better will depend on how that particular soundcard is implemented and the rest of the system. My Lynx 2B soundcard sounds MUCH, much better via +4 over -10 setting.

If simply a resistor is put in circuit to reduce native output from +4 to -10, the latter may sound worse. If the card natively ouputs -10, but an additional opamp is used to bump up the output to +4, that might sound worse, etc.

It also depends on the preamp/amp after the card. A lot of non-pro preamps and amps may not be able to handle the hot output of +4. For example, my Dynahi headamp's input stage overloaded and distorted with the full hot output from Lavry DA10 DAC at max volume setting. A preamp may not be able to handle +4 output and distort; it could even be more subtle if the preamp doesn't outright distort but "strains," which may lead to less refined, harsh sound.

For systems with passive preamps, +4 will probably sound better due to the sledgehammer signal.

If I analyse this correctly I could set my soundcard to +4dBu. That would give me about 12db gain? If I would then set the master output in traktor to -12db I would effectively avoid clipping at any stage while still being able to maintain the same loudness over the speaker system?

Also if the DJM-800 master output is at +2dBu and the club system has been calibrated to a certain audio level, that would mean I could surpass those levels with the audiofire?

[EanGolden]

yes its "technically" fine to use +4DBU into a mixer but the gain stages are expecting -10Db so your levels are going to be much louder than the average cd player/ serato user.

Personally I prefer -10 otherwise my signal is just too hot and I cant use the full gain of each channel.

[Guust-Fi]

Thanks Ean. I don't quite understand what you mean by "using the full gain" though.
Btw, where do you personally leave your master output in Traktor itself?
Can anyone explain the figures for the DJM-800 too?

[DvlsAdvct]

I always use the +4 gain level. If it's that hot, I turn it down, simple as that. I'd rather have more headroom than less.

If the signal is SO hot that when everything is almost off it's too loud than I'll try something different, but that has never happened.