Nord Lead 3 - Digital Aliasing Issues

[Erotic Cabaret]

My Nord Lead 3 often has an annoying digital "aliasing" sound, only noticeable with sounds that have long release times and lots of high frequency content. It sort of sounds like buzzing.

If I compress the sound, the aliasing is much more apparent, which is definitely a problem for recording.

Is this normal? If so, are there any keys to getting rid of it?

[madtheory]

It's not normal. Can you post an audio example?

[Erotic Cabaret]

Yeah, let me record something really quickly.

[Erotic Cabaret]

Alright, here is an example. There is a little bit of compression on this to really show the effect.

http://www.sendspace.com/file/vsmoa1

[madtheory]

There's no aliasing there. There's a tone a perfect octave up, which stops suddenly. There is noise caused by poor grounding, and there is quantising distortion. I would guess that both of those issues are the converter used to record the signal, not the Nord itself. It's truncating which would explain the sound stopping suddenly. And it's not grounded very well, typical of internal soundcards.

What soundcard are you using? How is the Nord connnected? Can you make a 24 bit recording?

[Erotic Cabaret]

Thanks for the quick response.

First of all, this is not an issue with my converter, which is a Fireface 400. The sound is inherent in the synthesizer...I program it using the headphone out. Second of all, this is not an issue of harmonics or a "tone an octave up." Did you not hear the digital buzzing at the end of the sound? Third, this was recorded at 24/88.2 with a 16bit quantizing plug-in on the master track and nothing else.

So, you think this is an issue of how the synthesizer is plugged in? It's plugged into a surge protected power strip.

[madtheory]

There is a low level ground loop which can be caused by poor mains grounding, but it more likely to be caused by cost cutting in the audio circuit.

Although the two types can sometimes be indistingushable, it sounds like quantising distortion to me, not aliasing distortion. Why does the sound end suddenly and not smoothly? That could be explained by a quantising problem too. I don't know what DA the Nord uses, but this is a problem that can easily occur with older chips if there is a bad connection on one or more legs. The simple ladder type of DAC.

There is a smooth tone an octave or two up, it is not enharmonic like aliasing typically is.

[Erotic Cabaret]

I just checked my cousin's Nord Lead 3. His seems to have the same issue, but it is noticably less pronounced. What do you recommend I do for my NL3?

[th0mas]

have you tried recording via line outs instead of headphone out?

[Erotic Cabaret]

I recorded that demo via the line outs. And, yes, it is less pronounced in the line outs than the headphone outs. Still, it is too loud. And if I used compression on a sound in a mix, it would be way too loud.

[madtheory]

I have a Nord Lead 2x here, what patch did you use? I will see if it has the same issue.

Can you record it again and see if you can get the amplifier envelope to to decay gently right into the noise floor? And post as 24 bit without dither, just to eliminate that variable. Is the Nord set to maximum output level?

[Erotic Cabaret]

I'm using patches of my own creation. It's a universal problem...it doesn't matter upon the patch. As long as the sound has high frequency content and a long release, the problem exists.

I just got this response from Clavia tech support, who listened to the clip:

"I can imagine that there can be audible artefacts on almost any digital synthesizer if you listen hard enough. There is nothing serviceable that can be done regarding this as far as I know. This sounds like typical aliasing that occurs at extremely low levels, when the D/A converters are down on their last bits and is normal. Since the Nord Lead 3 has been discontinued from some years, I suggest that you find some way to work around this."

Haha...

[aeon]

yes, a pure recording at near FS level - the current example isn't even close.

as has been previously said, I don't hear aliasing here - but I do hear recording issues including (lack of proper) gain staging, grounding issues, compression use, and potential colorization via dithering.

please provide NL3 -> FF400 -> 24-bit WAV

no compression, no quantizing and/or dithering

from this we can likely provide a proper diagnosis.

(edit) as has also been previously said, aliasing is inharmonic - your sample doesn't demonstrate that.


cheers,
Ian

[Erotic Cabaret]

Alright, I'll provide what you asked, just give me a minute.

[Erotic Cabaret]

Same sound. Recorded at 24 bit/88.2 khz on my Fireface 400. 24 bit/44.1khz at mixdown. No compression. No dithering upon mixdown, obviously.

http://www.sendspace.com/file/r0wfrd