I’m trying to drive my Rupert Neve Designs 5057 Orbit summing mixer for some transformer saturation warmth, as I saw demonstrated in a YouTube video. The signal goes from my Antelope Audio Orion Studio Synergy Core interface, to the Orbit, and then to a stereo bus chain of RND 542 tape emulators, a Wes Audio Rhea and an SSL Fusion. The YouTube presenter achieved saturation with zero digital distortion (he’s nowhere near the digital ceiling and can even get his Orbit to clip) but I run into digital distortion before the levels are anywhere near to clipping the Orbit. What am I getting wrong?
SOS Forum post
SOS Technical Editor Hugh Robjohns replies: I’m afraid this is a basic gain structure issue imposed by your interface, though there are other factors. The Antelope’s maximum output level per channel is +20dBu whereas the Orbit’s maximum input level is +26dBu, so with one signal even when your interface output is hitting the 0dBFS end‑stops, you’re still 6dB below the Orbit’s maximum. That said, as the Orbit is a summing mixer, all the input channels are added together and the sum of multiple channels will be greater than any single channel: typically, each time you double the number of channels the mixed level rises by about 3dB. I say ‘about’ because it’s dependent on the nature of the signals on each input channel: if identical, the level would rise by 6dB; if very different it may not rise at all (and in some cases it could even reduce!).
To push the Orbit harder, you need either an interface that provides more output level per channel, or you need to introduce some additional amplification.
Clearly, if you want to push the Orbit harder, you need an interface that provides more output level or to introduce some amplification between the interface and the Orbit. 16 channels of high‑quality standalone amplification wouldn’t come cheap, but replacing the Antelope for something that can send the SMPTE standard output level of +24dBu for a 0dBFS source would probably get you the saturation you’re looking for. (There are many interfaces that can do that, but very few can deliver more.)
Having said that, my feeling is that the Orbit was designed with such a high headroom specifically to avoid the risk of unwanted overload saturation, even though it happens to distort in a musically pleasing way. For coloration, there’s the onboard Silk facility, of course, which will have some effect even on low‑level signals but this is pretty subtle in the grand scheme of your signal chain — if you want to introduce controllable analogue warmth in your current setup, you already have your RND 542s, the Wes Audio Rhea, and the SSL Fusion, and any or all of them could be easily persuaded to add a variety of saturation effects. In your situation, I’d suggest you focus on exploiting those!