Gain aGain

Elektron Gear Octatrack
#77

I have sometimes put 64 one shots as a chain onto a flex machine (chain made using Octachainer). Then using the editor you can highlight slices and adjust gain by ear, monitoring on speakers. Then save the adjusted file

When I’ve done this it’s been with a selection of bought in samples which already sound good. I wouldn’t want to change their internal dynamics,/envelope so I’m just using gain adjustments to match their subjective ‘force’ by ear.

You can use the crossfader to jump around the chain for comparison, so not just comparing each hit with its neighbour

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#78

Pro tips!

#79

If one seeks a simple solution i can recommend wavosaur:

Its very lightweight, and can do vst batch processing.

2 Likes
#80

(Wavosaur can also be used for transient detection. Export samples > Octachainer)

1 Like
#81

Since I had some things that drove me crazy and I did not find a final solution or answer to them here in any thread I also sat down with some sine waves and did some testing.
First of all, I have an issue which seems inconsistent with what other people are experiencing: any audio that goes through a THRU track will be 12db lower than audio that goes through a FLEX track, though that is likely due to the +12db boost that samples get by default, and that the THRU track does not make up for the -12db pad applied to the inputs.

My aim was to understand how to get somewhat consistent levels among THRU and FLEX machines and with direct and imported samples.

I did use a cheap Presonus Firebox interface and Reaper, sending a pure sinwave from the DAW out into the OT and then back into it.

So far it seems to me that anything that goes out from Reaper with more than 8dbFS distorts the inputs. But I do not have an absolute value of how much Vpp that is, since I have no way to measure it. The actual level going out from the analogue outputs varies from interface to interface I guess.

Sending a -12dbFS sine from Reaper, sampling that in a recorder and then importing the sampled file into Reaper again was showing a 4db level, which means that the 8dbFS totally make sense, since that would equate to 0dBFS when I import back in (but I am just speculating).
What is totally consistent with everybody else’s findings is that red does not mean overdriven. I was way into red with -12dbFS and it recorded a clean sine.

When importing samples directly into the OT I noticed that they play lower. If I import a 0dbFS sine I have to add 8db in the sample settings to make it play at the same level as the 12dbFS sine coming from the DAW and being sampled into a FLEX via the AB inputs. Which is kind of weird.

My conclusions are more or less these:

  • I don’t see why I should not keep everything at their defaults. It makes it less prone to doing something wrong.
  • use the GAIN and VOL controls mostly for attenuating, not boosting, except for the following thing:
  • crank AMP VOL up to +63 for THRU machines to have unity gain with the FLEX and PU machines
  • crank master volume in the mixer page up if the overall level from the OT is too low.
  • send audio at -12dbFS or less (from the DAW) to the OT, or at a comparable level from other piece of kit, so there’s a bit of headroom.
  • no problem normalizing samples at 0db, but anything between 6db and 0db will work

Let me know if I’m making any big mistakes in my thinking here!

6 Likes
#82

Not a mistake but I’d set THRU Playback page VOL to +63 instead.
VOL +63 seems to be equivalent to +12 db.

I made some tests here :

With a 0db sample, 0db Attributes, Level 127, Amp Vol = +63, Main Level = 0, you should be at 0db. Correct me if I’m wrong!

I prefer Main Level set to 0 because it changes Main recording level.

3 Likes
#83

Tried that, but it distorts the audio, while cranking up VOL on the AMP page doesn’t. I agree that it would make more sense to use the one on the playback page though.

I need to try that, but won’t VOL=+63 add +12db?
When I raise the volume of the sample in the sample editor by +8db I get that is plays at the same level as the -12dbFS sine wave coming from the DAW.
It has to be noted that I have no idea what the inputs on my audio interface do to the audio, so it’s hard to talk in absolute terms here.

1 Like
#84

Surprising. I have to check.

Yes, but apparently default 0 value is equivalent to - 12db.

#85

Something to consider is that every audio interface has a different rated output level. 0dbFS on the DAW will output the max level for the specific interface being used, and usually there’s a toggle to set for +4dBu or -10dBV reference which will each yield a different output voltage…

On my apogee 0dbFS at +4dBu will output +20dBu, OTmkI’s inputs are rated at +8dBu so will definitely clip. At -10dBV the apogee will output +6dBV which is very close to +8dBu (http://www.sengpielaudio.com/calculator-db-volt.htm) so much more OT friendly…

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#86

Yes exactly. So it’s a bit hard to do scientific tests without first making some measurements… but it can still be some sort of reference I guess.
One thing I didn’t think of, but which I will test, to complete the picture is recording the output from the audio interface back into the interface itself, without nothing inbetweeen, so I can see if there’s some attenuation going on.

At the end of the day I don’t even think that we need to get all scientific, I just need to know two things: what do I do to make levels consistent and how to I prevent overdriving the inputs/outputs.
From there it’s just a matter of adjusting the workflow.

1 Like
#87

Yeah, I guess I just said that to clarify that the results you get will be right for you, but someone using a different interface will get different results as they don’t all have the same output voltage for a given dbFS reading on a DAW…

The inputs of an audio interface would follow the same concept. Whatever max level the inputs are rated for will be what shows 0dbFS in the DAW, and again there will be two different settings… On my apogee they are rated the same, I imagine most are but not really sure…

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#88

Yes absolutely correct, and thanks for mentioning it!

Btw. I have done another test, just to be sure. I patched the outputs of my interface into its own inputs and checked if there was some significant level differences going on. As far as I can see there is just a 0.4dB difference.
In the light of this:
Flex and Thru machines behave as expected, if I send out a sine @ -12dbFS and sample it back in and play the result back I get the same volume. which means that the incoming level is maintained. If I do the same with Thru I get a signal that is 12db lower, which confirms that there is a -12db attenuation and tells us that the Thru machines do nothing to make up for it by default.
So far so good.
Now considering that:

  • the output level of my audio interface (and please note that as @Open_Mike as stated before, this value changes from interface to interface) hits the overdrive mark in the OT at -8dbFS (in the DAW) and
  • that when I import a sinewave at 0dbFS into the OT directly and play that back without any changes of level it will measure 20dBFS in the DAW. 20 - 12 = 8, so you have those 8dbFS again.

So let’s just say that my audio interface has an “offset” of 8dbFS compated to the OT. If we remove those 8db we get how the OT bahaves independently from my audio interface.
For the sake of this explanation let’s just call the -8dbFS in my DAW 0dbFS. so 0bd in the DAW == 0db in the OT

Now, there’s one oddity that emerges if I do the math:

  • If I send out a file @ 0dbFS from the audio interface and sample it I end up with a @ 0db on the OT’s CF card not -12db.
  • When I import a 0dbFS sample and play that back I get a level of -12dB, which is 12db lower than what I was expecting.

So I deduct that the OT will apply the +12db boost that is automatically set in the sample settings for the recording buffers the moment you hit “save to new sample”. I need to see if the same happens if the setting is at 0db.

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#89

My assumption leans to the idea of attenuation. My MK2 has awful signal pathing. When i sample, i need to have ALL levels at maximum just to gather something with a reasonable volume, and then i still have to apply maximum gain while resampling in order to make a usable sample. Did i throw my scratch at a lemon? Maybe start a support ticket?

#90

“Wuld”

#91

It was a while ago, but IIRC what I did to help mitigate the interface itself as a variable was do a direct loopback like described above, but on the return channel I used a gain plugin to match the level of the returned signal to the level the tone generator was nominally putting out. Any analysis plugins went after the level compensation. That way any changes in level that were being introduced by my interface and cables were more or less out of the picture and for the purposes of relative level measurement with that specific test signal I could act like the interface didn’t exist - any change between the signal being output and the signal being measured at the return would be happening in the Octatrack. Still can’t make any meaningful observations about absolute values this way of course, but in terms of RELATIVE values - how the Octatrack CHANGES the level of the test signal passing through it - it seems like a pretty good way to make some meaningful observations.

#92

Never had such issues, MKI…
Maybe this post could help:

Noob questions
#93

Yeah. Digitally controlled, but analog. I assume this too!

#94

So, for people with short attenionspan(/noobs):
What are the key take aways?

My samples are definitely of very low volume when recording in the OT2.
And in all cases, recording in OT2 or dumping samples, I have way too much doubt, as to which setting/knob I should use, for controlling the volume of the samples being played.

Any final bulletpoints on this topic- or is it still work in progress?

Thanks for your effort :slight_smile:

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#95

Hot enough signal? With some signals it’s better to hit the red led. Increase mixer GAIN.

How is the recording waveform?
Picture?

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#96

Thank you, I know about the gain option in the mixer.

I am actually more interested in understanding the theory of your above discussion, than understanding my particular use case. There are a lot of word, terms and numbers I don’t understand, after reading through it all. So I was just wondering, if there was going to be a easy-to-understand conclusion of all your testings, perhaps in bullets :wink:

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