Electribe output/headphone hiss: Some data points

seebs · Post by **seebs** » Tue Jun 05, 2012 11:55 am

A while back, I was trying to sample some stuff off my NS5R, and I found a problem: It sounded fine at first, but when I turned things up so I could get the best possible resolution, there was hiss! I don't think it's my mixer, because other synths don't do this, and also it happens on the headphone out, too.

Well, long story short, I decided to replace the NS5R, so I started searching around, and one thing led to another, and I got an ESX1.

And I was doing something with it, and turned it up... HISS! And I tried headphones. Same thing!

Well, that's... odd. I have other instruments that don't do this, for one thing. For another, the hiss had a very interesting trait, which is that if I turn the synth's volume ALL the way up, and leave the mixer at 0dB, I can't hear ANY hiss at all. With the ESX1, that applies even if I turn both main volume and tube gain all the way up.

But!

On headphones? Right around 50% volume, hiss.

And on the mixer, even if the ESX1's volume is set pretty low, any gain at all above 0dB produces hiss.

Well, I got to thinking. What if the headphone out is amplified, or at least is amplified when it's set above about 50% volume? And what if the issue here really is that amplification of the signal is Doing Something which I do not understand that causes the hiss?

The reason I bring this up is that I've seen several threads, here and elsewhere, where people complain about the very noticeable hiss, and where other people say they've not seen it. And it occurs to me that not everyone is going to have cause to amplify the signal, rather than merely ceasing to attenuate it.

What I've tried so far:
* Several sets of headphones on both NS5R and ESX1.
* A Mackie LM-3204. There is *no* hiss at all unless I set volume (or one of the EQ) above unity, or headphone outs above about 30%. Also *no* hiss at all on, say, a Kaossilator pro, no matter what I crank up.
* A Yamaha MG-102C desktop mixer.

All have EXACTLY the same behavior -- sound is absolutely crystal clear for other devices, but the NS5R and ESX1 both produce very noticeable hiss as soon as the signal is being amplified (either in the per-channel mix or in headphones). I don't seem to get any hiss if I have a never-more-than-unity signal up through the mixer outs, then send it to amplified speakers; I can have the sound there loud enough that kick drums create a noticeable breeze at the subwoofer and there's no hiss.

Things that mystify me:
1. Happens both on headphones and through mixers.
2. Doesn't happen to any other synths.
3. Doesn't relate to total volume, but to the amount of amplification. I can turn the volume of the instrument down all the way to zero and still hear the hum quite clearly.
4. Sounds staticy, but if it's amplified a bit more, starts sounding like equipment hum of some sort.

The main reason I'm posting this: If you are having this problem, the above should give you the information you need to mitigate it or eliminate it. Specifically: Remove gain from the signal path. Where possible, remove attenuation to make up for it. If your ESX1 volume is set below maximum, and your mixer is amplifying to make up for it, you may well get this hiss. If you crank the ESX1's volume (consider using the tubes; they don't seem to have much effect on this), and reduce the mixer's volume, the hiss may become basically undetectable.

Hope this is of use to someone.

seebs · Post by **seebs** » Wed Jun 13, 2012 3:45 am

Update: Got a chance to try with an EMX1. Same deal. Double-checked that the Kaossilator doesn't do it. So there's something going on here.

chilledbeatz · Post by **chilledbeatz** » Wed Jun 13, 2012 2:14 pm

I notice all of the above on both my ESX and EMX.

What I know for sure, the headphones are slightly amplified hence the loudest "noise" of all outputs. The main stereo outs are slightly quieter and outs 3/4 are quietest but still have noise.

I have previously recorded the noise and can tell you that between 0 and max volume (tube @ zero), there is very little increase in noise, however it becomes harder to hear at lower volumes and you start believing it has gone (it hasn't).

I also noticed that if I set the main output to max but then turn the gain down on my mixer the noise becomes less noticable but is very much still there.

I figured this is either a result of the tube circuit or that korg meant for the electribes not to be a pro production tools and designed the noise in on purpose (who cares if there's a small hiss through the PA, right?).

I have a few workarounds that can remove the hiss completely:

- Record with ESX/EMX set to full volume to get highest signal to noise ratio (tube is optional)
- Set all samples to +12db to get highest SNR (only possible on ESX)
- Use a denoiser on your final recording (Izotope RX works beautifully) if you don't have that then the same RX denoiser is actually built into FL studio too! (see edison).

The outputs on the EMX are actually around 6db hotter than the ESX and you can't do +12db on samples but the denoiser also fixes any problems in your recording afterwards.

If you're playing live, it's likely that nobody will even notice, especially since any audio drowns out the noise.

seebs · Post by **seebs** » Thu Jun 14, 2012 3:49 pm

Yeah. I just thought it was particularly interesting that I get exactly the same noise on the NS5R, which was in a different genre entirely, but not from the Kaossilator Pro or, well, anything else I have.

Olivander12 · Post by **Olivander12** » Fri Jun 15, 2012 4:12 pm

Personally, I lowered noise by setting the EMX main volume to the highest level, and adjust it via my mixer.

I think that digital artifacts and distortion, which may occur if the same frequencies are layered, is more an issue if you want to have a clean sound.