Octatrack Dj EQ Centre Freqs?

[GhostArchive]

Hi y’all, just wondering if anyone knows what the centre frequencies on the DJ EQ are (or other eq’s for that matter)?
Obviously all i get is 0-127 which doesn’t really help.

[Supercolor_T-120]

I don’t have an answer but a good way to find out would be to patch your OT into a daw, play back a white noise sample through the Dj EQ, and monitor what frequencies it cuts and boosts with a free spectrum analyzer like Voxengo Span.

For the filter, you could turn the resonance all the way up, too, that way you’ll get a really obvious peak at the cutoff frequency and it will be easy to read. Because of the way the filter works (the value of the lowpass is relative to the value of the highpass) I would test just the highpass (resonance on the lowpass turned off in the setup page) across its entire range, and then go back and test just the lowpass across its entire range with the high pass at 0. In practice, the actual lowpass cutoff for any given value would be the sum of the highpass cutoff plus the frequencies you measured for the lowpass cutoff at that value when the highpass was 0 (or the maximum cutoff it can reach, I’m pretty sure there’s a limit on how high you can push the LP cutoff by turning up the HP cutoff but I haven’t really paid close attention to that so if I’m wrong hopefully someone will correct me), unless Elektron are doing something fancier than I realized.

The filter is probably more effort than it’s worth when you could just work by ear, but I could see it being useful to know the actual frequencies (or at least the general range) the Dj EQ was adjusting.

[license]

…and when you do figure it out, please post your findings here

[GhostArchive]

Cheers, i’m onto it…
Watch this space…

[yokermoon]

Interested if you ever did map this out

[sezare56]

@yokermoon

map this out

OT filter and EQ values?

I tired to measure the frequency of the OT equalizer a looong time ago. Im not sure if my measurements are really reliable some values seems strange to me Anyway here is what I found (left column = equalizer value, right = frequency in Hertz) : 6 8.075 10 10.7666 12 10.7666 14 13.4583 16 16.1499 22 21.5332 26 26.9165 28 32.2998 30 34.9915 32 40.3748 34 45.7581 36 51.1414 38 59.2163 40 67.2913 42 80.7495 44 86.1328 46 104.9744 48 118.4326 50 13…

[yokermoon]

Thanks @sezare56 - I now have this thread bookmarked for future reference.
Has any info been shared to suggest that the 0-127 ranges are comparable across the EQ, DJ EQ and Filter?

[sezare56]

@yokermoon

Has any info been shared to suggest that the 0-127 ranges are comparable across the EQ, DJ EQ and Filter?

Possibly, but I’m not sure. I made some tests too long ago. Can’t test right now…

I’d compare DJ EQ with EQ shelves, using a sample with phase opposition.
Easier to compare EQ and Filter with resonant frequency…

[sezare56]

Edit. Checked quickly.
EQ and Filter seems to match.
Can’t tell about DJ EQ yet, it didn’t work with EQ shelve comparison. I’d try with Filter comparison…

[Microtribe]

@yokermoon

Has any info been shared to suggest that the 0-127 ranges are comparable across the EQ, DJ EQ and Filter?

They are.
I did my own tests years ago. 70 = approx 500hz on both filter and EQ.

50 was about 100hz.

[sezare56]

@Microtribe

They are.

Hi !
So you mean that these values correspond to DJ EQ centre frequencies ?

(BTW DJ EQ it’s not neutral with phase opposition test, nor Filter (EQ is neutral), so it’s not easy to test with OT only.)

[Microtribe]

Sorry, no I meant the parametric EQ.

Numerical values equate to same hz value on both filter and parametric eq.

Didnt test the dj eq.

[yokermoon]

Thank you both very much: fantastic info.

Not too worried about absolute neutrality for use case (live performance) but this definitely helps give me a steer in what I’ll use to help isolate elements in the spectrum.

I know not to anticipate Octatrack updates but 0-127 (or -64-64) isn’t intuitive for certain parameters like this and would be a nice wee quality-of-life change. Even if it was fairly coarse, I’d at least know what I was cutting/filtering/shelving/boosting.

Anyway, shall use this info, the other thread linked and my ears - thanks again.

[Microtribe]

You can test yourself by shoving some white noise through the filter with the resonance cranker up and watching a spectrum analyser on a computer (there’s probably apps for it too if you’re into that)

I really only ever care about 2 areas.
500hz = mud zone.
100hz = anything that isnt bass can be cut here, or higher.

My ears do the rest.

Over the years, Ive completely let go of numbers and just do it all by ear now. I dont look at the knobs at all. Octatrack has trained me well.

[yokermoon]

Yeah, these are the principle frequency areas I want to actively manage/go after for this application.

I like how the Octatrack sounds and will often record just the main stereo outs: I’ll try and remember to make a point of doing so with some spectrum analysis of the individual components next time I’m working like this. I can be pretty rough and ready about these things but taking a moment to get things sitting nicely first will save mixing headaches.

Will share any interesting findings of course.