Balanced outputs - how to find out?

[ʝɵʝɵ]

Okay, so I had time for one short quick test to confirm something I experienced during an earlier recording.
Here's a sine sweep at three different input levels, the last one being slightly above 0dB on the mixer output:

https://sagagames.de/stuff/with_behringer.flac
https://sagagames.de/stuff/without_behringer.flac

A direct comparison shows that the first of the three sweeps sounds pretty much the same in both files. However, at the beginning of the second and third sweep, there is definitely some distortion happening in the very low frequencies. I figured out that this can be a problem with fast attacks, but lowering the volume fixes that.

[madtheory]

Very interesting. This would not go down well on Gearslutz

[ʝɵʝɵ]

Yeah, it's definitely not optimal, but at reasonable (TM) levels it doesn't really seem to be an issue. Eventually I may replace those Behringers with more expensive units - now that I know that they do solve my issue, it's a no-brainer to spend more money on those boxes. But for their price, the Behringers do their job quite well, I'd say, and they do look nice, too (not that it matters, they are hidden in the rack ).

[ʝɵʝɵ]

Small update: I also a threw a new ART CleanBOX II into the mix for comparison. It performs very similar to the ART DTI. That is, both of them handle high output levels and fast attacks better than the Behringer with no annoying distortions, but both ART devices seem to filter out less of the HF noise and have more 50 Hz hum in the signal than the Behringer (as a result the noise floor is also slightly higher and less uniform). Gotta choose your poison, I guess...

[madtheory]

Interesting. Are the ART boxes in exactly the same location as the Behringers? I am wondering if there is a PSU near them with EM radiation.

[ʝɵʝɵ]

Yep, I place them just in the back of my rack. PSUs are nearby but there should be enough clearance really (considering that Behringer's cheapo HD400 can do it...).
I think I will be returning the CleanBox II which I just bought brand-new last week. I found out that apparently there is a new version of the Behringer RX1602 mixer that I use, and from my understanding the new version has balanced outputs. This might solve my problem much better than any passive DI box can do. I have researched several other mixers, but sadly none of the more reputable brands have what I want - rack-mounted (1HU), 8 stereo inputs (TS/TRS, not RCA), mute buttons for individual channels, fx output, balanced outputs. I considered the Tascam LM-8ST and ART MX822 but both seem to miss mute buttons, and I want to handle channel volume and channel muting individually.

[madtheory]

Thank you for the info. That Behringer looks really good alright. Very neat with good specs. I dropped the mixer a long time ago, using a patchbay instead since I don't have a lot of hardware. This might change, I might be rescuing a Yamaha CP70B this week...

[ʝɵʝɵ]

Yeah, it's definitely a good mixer for the price. Even more so now that the outputs are balanced... We'll find out more in a few days

[ʝɵʝɵ]

Small update after the new RX1602 V2s arrived: Okay, this is it. This finally solved my problem in the best way possible. The noise floor is now as perfect as it can probably get (just a tiny little bit of 50 Hz hum, to very small spikes around 11-12kHz). No more DI boxes required. Behringer did a great job there, making the RX1602 an even better mixer than it was for this price. The only annoyance is that they changed the color of the green LEDs, so they no longer fit the other green LEDs in my rack.

[madtheory]

Nice! Post studio pics

[ʝɵʝɵ]

lol... incidentally I just took a picture because it just feels completely crazy having 4 of those mixers in the same room - of which two will be sold, of course.

[madtheory]

Looks great. How did you get the labelling so small? My Dymo printer won't go that small (I think). It's very tidy and clear!

[ʝɵʝɵ]

I'm using a Dymo label printer too, set to 10pt font size (the second-smallet setting on mine) and cutting off all the extra padding.

[ʝɵʝɵ]

One more interesting thing has become obvious after playing a bit more with the new mixers: The Kurzweil K2500 is still picking up EMI from the computer, and it doesn't even need to be turned on. Just having the power cable plugged in and the audio outputs connected to the mixer is enough for that to happen. Curiously, the power cable is plugged into a multi-socket outlet and it doesn't matter if that outlet's power switch is turned on or off.
Edit: Something changed. Even when the power cable is completely disconnected, I get the EMI now.

As the DI boxes were unused now, I plugged them between the K2500 and the mixer and lo and behold, the EMI is gone again. And once again the ART DTI doesn't manage to eliminate the noise and the 50 Hz hum is louder. So I guess my solution here will be to use the Behringer HD400 now for the K2500's outputs and get rid of that noise - unless there's a better way. I tried putting a ferrite core on the power cable of the K2500 but that didn't filter any EMI.

[madtheory]

Mysterious. I can't even picture where the issue might be coming from in the system. have you tried unscrewing a lifting the K2500 out of the rack? The loop might be through the casing and rack rails?