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Unity Gain Structure vs. Default MIDI Velocity vs. Sample Volumes vs. Audio Tracks

manysoundsmanysounds The GunksPosts: 18
edited October 2019 in Deluge Software Suggestions

With the addition of the new amazing audio clips function I've come across a roadblock to my workflow.
The default velocity of clips should be "unity gain structure" and it isn't.
What I did:
I set up my audio interface with a loopback, line out to line in.
In a DAW I sent a -12db 1k sine wave out of an extra set of outputs and made certain that I had a -12db sine wave coming back in, assuring us that the output and input were at unity.
I then put the Deluge into the loop to make certain the line in was the same as the line out.
I created a stereo audio clip on my Deluge with monitoring enabled and set the output dial so the levels matched, again.
It turns out this set's the Deluge's volume control at just a wee bit past vertical, 12 o'clock.
OK, so far, so good. Having all that extra output on hand is fine and has no bearing on the this experiment.

I played a beat from my computer through the interface instead of the 1k sine wave.
On my computer attached to the audio interface I set the volume of virtual drum machine (Microtonic so good) so that it's kick/snare hit peaked at -10db. Of course, the out and in levels still matched, GOOD.
I made a synth track on the Deluge. The volume was too low to compete. I tried a range of sounds.
I increased the volume of the synths tracks. Still low. Adding saturation obviously brought the volume up, of course.
THEN I plugged in an external MIDI controller, Alesis QX25. WHAM plenty of volume.
To double test I plugged another one from a different manufacturer in. Plenty of volume.
I was not smashing keys, playing normally. Recording a synth clip would show that I only hit above 110 velocity a few times.

OK, this is the big one for me.
I bounced out the drum loop I was using for the above test. It was a 2 bar loop, as is the Deluge default. It peaked at -10db.
I loaded that loop into a Drum Clip on the Deluge, setting it as default play once for the 2 default bars.
(The DAW and Deluge are MIDI Synced as well, no bearing on the test but obviously easier to deal with)
What "should" have happened is the -10db loop that I played through the Audio I/O loop should play back at the same metered -10db. Instead the reading is ~-20db. Raising the Velocity all the way to 127 got the levels nearly matched to unity. The default velocity being near unity gain is extremely important from a pro-engineer standpoint.

PART 4, Audio Track Unity:
Next I made a new Audio Clip and loaded the drum loop in. The defult playback volume should, again, be unity on the meter but was not. I needed to raise the track volume to bring the level up to match the input-output level unity gain I had set up. What this means is that a sampled source file playing from an external source through the Deluge at unity line level will be at a lower volume if imported onto the Deluge's memory card. That can't be right.

PART 5, Live Sampling.
The volume of a monitored track is louder than the recording played back.
This is obviously very bad. My engineer brain hurts.

These are not insurmountable problems and can be fixed without changing anybody's previously written projects.
1-Raise the default output volume AND default velocity of samplers and synths. 64 is too low. Even when raised to 127 it's still not "unity" so we must raise the default volume of the tracks as well. General MIDI speaking: Fortissimo is 96, FFF being 127. 64 is mezzopiano. Starting out with room to grow is nice BUT unity gain is more important, and more import of a starting point for samples.
2-raise the default volume of audio tracks so they are closer to unity.

Starting with a unity gain structure will save us all a lot of time re-mixing our samples and live inputs AND remembering to add one higher velocity when recording midi/synth tracks.
These issues is most glaring when:
Using an outboard controller and the industry wide standard velocity curve is WAY hotter than the Deluge's default velocity.
Importing self-produced samples from another platform and the default volume is far lower.
Live sampling volume drops.

Please please please please please consider this.

Post edited by manysounds on


  • 2
    manysoundsmanysounds The GunksPosts: 18

    OK so, rather than asking you guys to redo the gain structure of the unit can we simply add the following to the DEFAults menu?
    MVELocity - default MIDI velocity (for all clips)
    AVOL - deafult audio clip volume

    Please consider

  • 0
    manysoundsmanysounds The GunksPosts: 18
    edited October 2019

    Another experiment:
    Generated a sine wave file at 0dBfs
    New synth instrument on Deluge.
    Analyzer running on computer
    At 127 velocity, the master volume of the instrument maxes out at 28 before harmonic saturation begins, regardless of where the output volume is set.
    At 97 velocity, inst master 37
    63 (default), doesn't clip/distort/saturate even at 50
    1- with instrument master volume at 50, maximum velocity is 72 before the full volume sample begins to distort internally, pre-output level knob.
    2- with instrument master at 40 (default and assumed "unity") maximum velocity before 0dBfs sample clips digitally internally is 99.
    "Seems off" to me. If this were old analog tape days then 99 velocity/40 master is the equivalent of 0dbVU. If it's Midas XL4 premap it's like +12.
    I think...
    I think I've worked in too many formats. My brain hurts.
    The only thing I'd really really really like here is the default velocity to be 99. I think that would do us closer to "unity" in this amorphous strangely gain staged environment. -Especially when sampling/looping directly into the mic and line in. The lack of a clip light is whatever to me but it's gonna make a mess out of some people's workflow.
    I guess this should also make the default volume of audio tracks 40 as well. Maybe.

    Post edited by manysounds on
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    manysoundsmanysounds The GunksPosts: 18

    Main issue I'm facing today is recording an audio track while monitoring it results in an audio track at a lower volume on playback.
    SO, the function as an audio looper as a preset is broken. You cannot just open a fresh project and start looping audio without adjusting the volume of the audio track. The playback volume should match automagically, eh?

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    AlamoBlendAlamoBlend WA, USAPosts: 1

    Bumping this thread.

    I LOVE how much effort you put into this, @manysounds ; I've been anecdotally noticing similar issues, but I haven't taken anywhere near this time and effort to scientifically attack the problem. One area that I had noticed it in particular is in a multi-format song (internal synths, sample kit, external synth via audio input), where my kit samples started to distort when I was playing my external synth into the audio input, which I found very odd. FWIW, I had turned up the velocity on my kit steps to 100 (mostly), but yeah, the gain staging just isn't intuitive and getting everything to play nicely together while not feeling hamstrung in the loudness department takes some of the wind out of my sails when I'm jamming.

    Just yesterday I tried using my Deluge as a proxy to my audio interface for my laptop - the Deluge is plugged into my MOTU, so rather than fish out the USB cables from my desktop PC, I figured I could just plug my laptop's headphone output into the Deluge input and monitor it in stereo through my interface. With my laptop's volume at maximum, I could barely turn the Deluge's channel volume above ~30% (guesstimate based on the LEDs), but even if I turned down the laptop volume, I couldn't turn the audio input level up far before it distorted - and everything was fairly quiet at the interface regardless.

    I love the Deluge and if changing the gain structure is harder than it sounds, that's fine, but in lieu of that I would love some sort of visualization of the input/output gains or at minimum a detailed description of "best practices" for gain staging on the Deluge.

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    hexagon5unhexagon5un MunichPosts: 65

    You run into this with the Analog Kid waveforms as well. They're full scale, so if you use them as an "oscillator" in a patch, you can't have the volume up above ~30 before it distorts. (That said, the solution is to just put the "level" down at 25 and get on with it...)

    I'm not sure if this is a firmware change. But I agree that it'd be good to have the gainstaging written down somewhere.

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    RandomAztecRandomAztec IrelandPosts: 98

    It's the only issue I have with device.. I'm not an engineer like the other posters so I cant describe the issues like they can but I adjust the levels for a single note I'm happy with it.. Then play a chord.. It distorts.. Continuously adjust levels make me frustrated

  • 0
    IcoustikIcoustik NorwayModerator Posts: 676
    edited March 19

    @RandomAztec said:
    It's the only issue I have with device.. I'm not an engineer like the other posters so I cant describe the issues like they can but I adjust the levels for a single note I'm happy with it.. Then play a chord.. It distorts.. Continuously adjust levels make me frustrated

    The easiest thing to do is to just turn down the Affect entire song volume, this will give headroom for everything even with max velocity and normal/ high track volumes :) Its way easier and quicker than turning down each clip's volume and/ or OSC levels.
    Save a working template with Affect entire song volume already turned down, and you won't have to do it repeatedly

    Post edited by Icoustik on
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