A\D and D\A converter in octatrack

Elektron Gear Octatrack
#1

Hi,

In a setup where a analog signal is inserted in the input a/b/c or d input, is this signal always converted to a digital one on the octatrack?

I have an analog mono jomox mbrane and mbase which is plugged into a mackie analog mixer. The main stereo outs of the mackie are inserted to the a/b inputs of the Octatrack.

The Octatrack sequences the jomox synths through midi.

The octatrack main outs are plugged to the amplifier. Is this main output signal of the octatrack analog or digital?

The original signal from the Mackie is analog.

If the signal is digital in what sample and bit rate is this audio processed?

Thanx in advance,

Rudy

The Octatrack's sound, really?
#2

Yes, it’s always converted to digital. 24 bit and 44.1khz.

Personally, I notice a coloring of the signal when I monitor external sources through the OT. A flattening, for lack of a better word. I found it took some of the punch off of external drum machines, for example. Not sure if that’s the converters themselves, or something to do with the gain staging of the OT.

It’s enough that I don’t monitor things through the OT in the studio, but it’s probably fine live? YMMV.

Why not just plug both of the Jomox boxes into the Mackie? (And the OT too, if you’re using it for more than just sequencing.)

#3

I believe if you’re using OT to mix your input signals (thus DIR = 127 in the mixer) then it’s directly routed to Main/phone Out. In all other scenarios it’s going thru AD/DA, obviously.

#4

hi, ver interested in this… is it in the manual?
When attempting to use the OT as a mixer, if inputs a&b are hardwired to the respective outputs via the digitally controlled mixer then that would help to explain why there is no way to use two monophonic sources into the ot via DIR level without them being hard panned.
Not ideal since using thru machines wastes two tracks if u want to have the monosynths output to main L&R simultaneously…
sounds like there’s no hope for a software upgrade solution for this mixer routing limitation then?

#5

I experience significant (to my ears) audio degradation on both the input and AD/DA stages. I think the poor DA is due to a cheap or strangely configured output chip and summing stage, and equally poor output hardware, but I could be wrong.

It is a little heartbreaking, but now I can spot who uses an OT in their releases a lot of the time :slight_smile:

I’ve always believed that the flatness of the OT can be worked with and I find that audio really responds to severe EQ in DAW.

I’d be interested to know more about it. My older samplers are heads above it in punch and dynamic but lose out in high frequency information, in some regards.

#6

I´ve asked exactly the same question to the support a few months ago, and the answer was, unfortunately:

Yes, the A/D and D/A conversion takes place anytime, even if you use the DIR directly to the Output. Sad but true.

Still, for Live use, it´s good enough, I think (I route my Xoxbox and Mono Lancet thru the OT), but kind of makes me (as analog lover) think: why then use analog synths? If the signal gets chopped up anyway, I could use digital synths right away !?!?

Octatrack Through Machine and FX usage (AD/DA ?)
#7

I forgot something:

I think the OT is very sensitive for Gain Volumes, if you play around with the Output Volumes of the synths and the different Level options in the OT (Input gain; track volume; track AMP) the sound quality varies quite a lot.

#8

a little compression and eq after the OT does wonders. I basically have my amp level half way up, & the track level used as a type of limiter to adjust the absolute maximum volume I want my track, and overall gain at 0.

#9

Plugged out of OT directly into soundcard. Fuck.

#10

OT basically squashes high frequency content quite drastically. Fuck again.

#11

Y’all are trippin’

#12

I have unfortunately noticed the same when doing an A/B comparison of the direct AR main outputs vs feeding the AR main outs through the OT. Interestingly when I record the AR direct to my DAW it has a lot more perceivable volume than when routing it through the OT and matching up the gains to be identical as seen on the meters. I would say that the audible effect on (stereo) audio running through the OT’s A/D is reminiscent of the audio being slightly out of phase. Perhaps worth further investigation…

#13

I would imagine the quality of the preamps on the OT aren’t quite as good as, say, an Apogee or RME unit so there’s likely to be some difference in how audio sounds after sampling it into the OT.

Could the OT be modded to have the preamps changed out for higher quality ones?

#14

My experience is that matching the peak levels of identical audio running from a DAW and OT, will result in a slightly lower RMS level on the OT as compared with i.e. Ableton. But this might be due to the analog signal path from OT to my RME, whereas the measurement of ableton happened purely in the digital domain. I noticed the RMS dicrepancy while checking levels on digicheck/RME FF400.

So in theory, this means OT has more crest factor, but less RMS than you’d expect. It’s possible to mistake this for “flattening”, because the audio sounds a little less in your face (at identical peak levels), but it’s actually physically the opposite of “flattening”!
Kind of reminds me of the sound that results from the crest factor minimum limitation on vinyl, where you can have short peaks at very high levels, but not a very high average level.

I did not notice a different emphasis of frequencies, as suggested by the people calling it “coloring”.

Intriguing.

1 Like
#15

Thanx a lot sofar.

Pluggin in Jomox mono synths in the octatrack does not produces a stereo signal in my experience. I believe the octatrack mixer isn’t a stereo summer for mono signals. That’s why i route the analog jomo mono synths first through the analog Mackie mixer, which sums a stereo signal which is routed to the Octatrack.

If it’s converted to a digital signal at the octatrack i will consider a different setup because i believe the continuous analog sound sounds better. I must have midi controller and a seqeuncer although.

Probably i will also contact Elektron support and post their answer in this topic.

#16

Rudy, you can use a THRU machine to “make stereo out of a mono signal”. Use the input settings to select a mono input.

#17

No. It doesn’t.

#18

It sure does. I’ll render out the A/B comparison

#19

thanks, please do.

but keep in mind you are doing one AD conversion in addition, and introducing unknown variables:
OT to soundcard (what model, direct or via mixer, cables, etc.?)

so you’d need to compare an external recording of OT’s analog output with an external recording of the soundcards analog output.

#20

Don’t forget that the OT halves (12 dB reduction) the volume by the time it is captured, try to use 24bit to keep some of the resolution

edit - not quite accurate