Ok I have uploaded the band limited pink noise and it is level adjusted. Now just note that it is only at -14 db FS. If you want to make a -20 version just subtarct 6dB of gain. It does basically the same thing as the full range pink noise except that because it is band limited any low end issues in your room environment wont influence it in any way.
 
https://soundcloud.com/jeff-evans
 
I am only going to leave those test tones up there for a little while so anyone else interested should download all of them and put them into a folder. They come in handy for various things from time to time.  I find another good thing to do as well is to take a commercial track eg Steely Dan and re adjust it so it just peaks the VU's at your chosen ref level. It is handy sometimes to put music to a very precise ref level onto a track just to see how everything is shaping up in your system. Interesting in that the Steely Dan's CD 'Everything Must Go' was mastered only up to -12 dB rms which is pretty cool. No wonder it sounds so damn nice. I only had to lower it by 2 dB to make it a -14 dB track instead. And then you would take it down another 6 dB to make it a -20 dB track instead.
 
I still would not mind knowing what ref level produces +4 dBu from your audio interface. That is an interesting test. If it turns out to be -18 then you might as well stick to -20 as a chosen K system reference. -18 is very common amongst a lot of pro digital gear too. Interesting that where I teach sound engineeering they bought an SSL AWS948 console and it came set for -20. But it is easily changed in that console. My digital mixer has chosen -14 and so has Harrison Mixbus for some reason too. I can change my mixer but Harrison Mixbus is fixed at -14 for now. I would like to see that variable perhaps in a future update.
 
It has been a pleasure to help you John and others. I am a bit of a level and calibration nut when it comes to all this. I find once it is done it makes such a difference. It means everything you turn out is to a precise level. I really care about helping others make better recordings. I get a lot of satisfaction from it.

Thats great Jeff
I have two RME devices. The Fireface 800 and the Babyface.
The output for the Babyface says 
Maximum Output Level @ 0 dBFS Line: +15 dBu
Maximum Output Level @ 0 dBFS Phones: +8 dBu
The Output for the Fireface 800 says 
Input/Output level for 0 dBFS @ Hi Gain: +19 dBu
Input/Output level for 0 dBFS @ +4 dBu: +13 dBu
Input/Output level for 0 dBFS @ -10 dBV: +2 dBV
I will do a check  on this at the weekend.

So much to take in Jeff. You really know your stuff. Thanks for the education. Hopefully I can put it into practice as well as anyone else who has been reading this thread.

Yes Jeff is great and he has a wealth of knowledge and he explains everything so well. We can learn so much from him. 

Jeff
I still would not mind knowing what ref level produces +4 dBu from your audio interface.

 

fitzj
Thats great Jeff
I have two RME devices. The Fireface 800 and the Babyface.
The output for the Babyface says 
Maximum Output Level @ 0 dBFS Line: +15 dBu
Maximum Output Level @ 0 dBFS Phones: +8 dBu
 
The Output for the Fireface 800 says 
Input/Output level for 0 dBFS @ Hi Gain: +19 dBu
Input/Output level for 0 dBFS @ +4 dBu: +13 dBu
Input/Output level for 0 dBFS @ -10 dBV: +2 dBV
I will do a check  on this at the weekend.

 
The info listed by RME hints at the fact that it is in the ball park. If you want to know the specific details it is easy to take a measurement.
 
If you want to measure your hardware's dBu output to find out what reference level produces +4dBu send a 1kHz sine wave out and measure it with a true RMS Volt-Ohm-Meter set to AC voltage. A dBu level is measured "unterminated" so the super hi impedance of a VOM is appropriate for a direct measurement of the voltage. Play back a 1kHz sine wave through the RME and adjust the level on the RME until the VOM reads 1.227652988 volts (or close to that) and then look at what the meter says on the RME.
 
The reading on the RME meter will indicate what reference level produces +4dBu.
 
Then if you have real analog VU meters you can see if they are calibrated so that the 1.227_vAC (a.k.a. +4dBu) reads as 0VU on their scale.
 
Most top of the range pro gear will be designed so that -20dBFS on the digital meters will equal +4dBu at the outputs.
 
There is a lot of high quality prosumer gear set up where -12dBFS equals +4dBu at the outputs. This usually correlates to the fact that the analog outputs on that gear do not have as much head room as might be encountered on top of the range gear where +24 thru +26dBu output before clipping is common. As transfers to analog tape become less common there is less practical need to have such high output levels and so a lot of high quality gear has lower Max output levels. The extra output capability was primarily used to saturate tape recordings and get a fat sound during the transfer and to maximize the SNR.
 
best regards,
mike