Driving a 5057 Orbit Summing Mixer

[prodbyogchiboi]

Hello guys,

I bought a 5057 Orbit summing mixer by RND and I am trying to drive it as demonstrated in this video at 9:40 https://www.youtube.com/watch?v=pVea3h9 ... ceLikeAPro..

However, I run into digital distortion before I can get anywhere near getting the summing box to start clipping...

In the video, he achieves this with 0 digital distortion and is nowhere near hitting the digital ceiling, yet the device is clipping?

[Hugh Robjohns]

... I run into digital distortion before I can get anywhere near getting the summing box to start clipping...

It's called basic gain staging... and yours is badly wrong!

You obviously need an interface or A-D converter with sufficient headroom to cope with the full output level of a heavly saturated 5057. The main outputs of that unit can generate +26dBu... and there aren't many A-D converters that can handle that much.

However, the 5057 has alternate outputs which are 6dB lower so max out at +20dBu.... which is comfortably within the range of good pro-standard converters (which typically clip st +24dBu). The chap in your video mentions using the alternate (-6dB) outputs from the 5057.

So, use the alternate outputs and a converter with +24dBu clipping level and all will be well...

Unfortunately, most European converters clip at +18dBu, and so if your interface or converter clips at +18dBu, say, you're never going to get the saturation you seek because the digital converter will always clip first.

In that case, what you clearly need to do is attenuate the signal coming out of the RND 5057 even more before it reaches your converter.

Use the alternate outputs on the 5057 to benefit from being 6dB quieter than the main outputs. To lower the level more you can either get inline XLR attenuators, maje your own balanced attenuators (if you're into DIY), or do what I usually do for this kind of situation and route the signal through a passive monitor volume control! I use a JBL nanopatch+... but any balanced passive volume control will do.

Note, although the Trim control on the 5057 will also turn down the mix level, it does so before the output transformer so will prevent you obtaining the saturated transformer effect you seek.

Out of interest, what is your 5057 connected to interface/converter wise?

[Wonks]

It's going to be down to the output levels on the line outs from your audio interface. What interface are you using?

The maximum input level for the 5057 is +26dBU, which very few Audio Interfaces line outs are capable of.

The maximum output level is also +26dBu, which is why the -6dB outputs are going to be a necessity if you do run really hot signals to it.

I notice Hugh in his review fed it through a Yamaha DM1000 console, probably to help get the extra output levels required.

Obviously the more channels of audio you feed, the hotter the combined signal levels will be on the summing bus. 16 identical signals

To avoid digital clipping you really need to keep your channel output signals below a true peak value of say -1dBFS, but you need an interface where that's generating a line out level of over +14dBu if you want 16 identical signals at that level to overdrive the summing mixer, and a hotter signal than that with fewer signals. or else you use the boost features on the

I have no idea how hot you have to drive it to get the onset of some distortion, but obviously the hotter your line outputs go, the greater the choice you have as to how hard you push it.

So the secret is in having the right interface. E.g. a Focusrite Clarett+ Pre has line outs that can go to +16dBu, so you can push it reasonably hard with a few signals but you'll need a lot, all at maximum value, to get it to properly distort (which I doubt is the real reason it exists) and the +26dBu level is to ensure headroom so it doesn't distort.

[prodbyogchiboi]

Wow.... I want to seriously thank you both. I truly appreciate this. Thank you for the free education lol. To answer your questions, I am going out from an Antelope Audio Orion Studio Synergy Core using the 2 DSub25 line outs (capable of +20dbU) into the 5057. The 5057 then goes out into a pair of RND 542 Tape Emulators, then into a WES Audio Rhea, then finally into an SSL Fusion before coming back into line inputs on the Orion Studio so I do have plenty of places where I can trim the audio back before letting hit those inputs.

... I run into digital distortion before I can get anywhere near getting the summing box to start clipping...

It's called basic gain staging... and yours is badly wrong!

You obviously need an interface or A-D converter with sufficient headroom to cope with the full output level of a heavly saturated 5057. The main outputs of that unit can generate +26dBu... and there aren't many A-D converters that can handle that much.

However, the 5057 has alternate outputs which are 6dB lower so max out at +20dBu.... which is comfortably within the range of good pro-standard converters (which typically clip st +24dBu). The chap in your video mentions using the alternate (-6dB) outputs from the 5057.

So, use the alternate outputs and a converter with +24dBu clipping level and all will be well...

Unfortunately, most European converters clip at +18dBu, and so if your interface or converter clips at +18dBu, say, you're never going to get the saturation you seek because the digital converter will always clip first.

In that case, what you clearly need to do is attenuate the signal coming out of the RND 5057 even more before it reaches your converter.

Use the alternate outputs on the 5057 to benefit from being 6dB quieter than the main outputs. To lower the level more you can either get inline XLR attenuators, maje your own balanced attenuators (if you're into DIY), or do what I usually do for this kind of situation and route the signal through a passive monitor volume control! I use a JBL nanopatch+... but any balanced passive volume control will do.

Note, although the Trim control on the 5057 will also turn down the mix level, it does so before the output transformer so will prevent you obtaining the saturated transformer effect you seek.

Out of interest, what is your 5057 connected to interface/converter wise?

I wasn't worried about the levels going out of the 5057 causing distortion, I was referring to the levels going out into it. I find that I boost so much and don't get the saturation but then you may have just answered that question as to why that is the case. But how did you know that the trim level on the 5057 is before the transformer? Doesn't it make more sense that they would make that post transformer? I am not an electrician so what do I know...

[prodbyogchiboi]

I just put into practice what you guys said, and clearly it would seem that my audio interface outputs are not generating enough juice to drive the 5057. The start distorting (the outputs) because I am hitting the digital ceiling before I get a chance to drive the 5057...

[Wonks]

There wouldn’t be much point having a trim level after the transformer. With it before the transformer you can control the amount of distortion the transformer gives to the signal. If it was after, you’d just get a louder or quieter version of the same signal.

This is also easy to work out from monitoring the output signal.

[James Perrett]

Something like this could bump the level up

https://www.sonifex.co.uk/redbox/rbul2_ld.shtml

I have a similar issue with a hardware Dolby unit which expects to be connected to gear that can work at up to +24dBu so I use it with a Sonifex Red Box AD-DA which can use those levels.

[Wonks]

You’d need quite a few of those for 16 outputs!

[James Perrett]

The problem is that quite a few alternatives run out of steam at +24 or +25dBu. There's the old Fostex 5030 which would give you 8 channels but the maximum output is specified as +25dBm into 600 ohms. You may get very slightly more into a higher impedance but it could be marginal. I'd guess that there were similar units from Teac/Tascam but I can't remember the details (and Google wasn't being very helpful).

This one gives 8 channels (4 stereo) with a maximum output of +28dBu.

https://www.sonifex.co.uk/redbox/rbul4_ld.shtml

Sonifex gear tends to do what it is supposed to do without any fuss.

Edit to add: there's one for £100 on Ebay at the moment...

[prodbyogchiboi]

You’d need quite a few of those for 16 outputs!

Lol I was thinking exactly the same thing... doesn't seem very realistic. At this point, the only way to get close to saturating a +26dBu input is to buy a new interface capable of at least +24dBu line level outputs.

[prodbyogchiboi]

I just wanted to make sure I wasn't crazy lol. Watching the video, then not being able to replicate the same on my system was driving me crazy. He must have been feeding the 5057 using some sort of device capable of higher level outputs.

The RND website does state that the red light starts to come on at about +2dBu below the ceiling which comes out to +24dBu. Even at that, in the video, he was nowhere near the digital ceiling so I don't know...

[Hugh Robjohns]

You don't need to overdrive the individual inputs. It's the output transformer that adds the character, so you just need a healthy signal level on all the inputs. Signals add together and the mix is louder than each individual source. Every time you double the number of inputs, the mix signal will be roughly 3dB louder.

But yes, it's going to be easier to get there with 16 tracks peaking +24dBu than +20.

[prodbyogchiboi]

You don't need to overdrive the individual inputs. It's the output transformer that adds the character, so you just need a healthy signal level on all the inputs. Signals add together and the mix is louder than each individual source. Every time you double the number of inputs, the mix signal will be roughly 3dB louder.

But yes, it's going to be easier to get there with 16 tracks peaking +24dBu than +20.

Thank you sir and everyone for your help. I now understand my gear more than I did before lol.