Background/static Noise occurring when recording an electronic keyboard

[ecc83]

I am reading these thread comments (which I appreciate everyone's input by the way) and my lack of audio knowledge just hits the walls constantly. I am unsure what you guys would like to see me try. I did buy a new Audio Interface (100$ value) that actually has line inputs and was goign to try with that (it will probably arrive Monday, tomorrow). But if there is anything you guys want me to try, please let me know. I know [MENTION=89697]ecc83[/MENTION] asked me to record different configurations, but could you specify what "unplug JACK plugs" mean and by "pull XLRs out" did you mean pull them out while also the "JACK plugs" are plugged out? I also know you talked about everything being earthed, which I really didn't know what it meant (but i assume its something bad..?)

I shall review what I said and draw you some pictures. Regarding the "earthing" (aka 'grounding') this applies to your electricity supply. I assume (hope!) you have 3 pin wall sockets? It is possible the earth connection is poor or absent a good test would be a guitar and amplifier. If it is unusually 'hummy' suspect an earth fault somewhere.

Dave.

 

[witzendoz]

We are now talking about the mains power supply earthing, if you know someone who is an electrician they can check the earthing of the mains sockets for you. You can buy a mains tester that just plugs in and shows you if the power socket is wired correctly and if an earth is present.

As there is no indication of which country you live in I don't know what wiring you might have or the voltage.

Alan.

 

[mixsit]

Holly cow. I see some real problems here.
First mine.
I came into this late.
Rather than listening at the 1st two samples, I began at later ones.

Which I now see.. are all way worse -thanks to our help' are both higher in distortion and worse S/N! than the originals!

To top that off- Tensyume originally... simply inquired if this (-60dB!) noise floor.. was 'normal.

Tensyume I'd like to apologize for my part in this. Perhaps you can understand my 'what noise? 'which noise?' confusion.

The first two tracks sound fine. That would be, 'clean, 'open, not 'clipped (yeah the 1st one clipped a few times), no hum' to speak of ..and no distortion' as on the later ones..!

'D/I's, 'ground loops 'mismatches Oh my! WTF? Cue 'rolleyes and grin

I couldn't find squat from Nord on S/N. One forum mention of 'it depends on quality of samples. Great.

Tensyume, you obviously got the first two tracks nicely.
Was that perhaps by putting the Presonus all the way down and further 'trimming as needed at the keyboard?

I ask as sometimes, circuits can adjust the signal level, w/o effecting the general output stage noise level.

A quick test would be arm the record inputs, without playing anything, watch the noise levels on the record meters (in Logic was it?), while turning the Nord's 'level knob up or down.

This is a heck of a lot of speculation here. But the best S/N here could be with the keyboard at 'full out.
If this pans out..? All you need is a pair of in-line pads -or D/I's w/pads into the mic XLR's. And in which case, you would be at the best case s/n from keyboard, with the pads attenuating both the keyboard's 'level -and it's noise floor-

 

[ecc83]

I mentioned the possible use of a simple resistive attenuator in my answer #32.

I have attached a drawing that I hope makes the noise test I outlined in #52. My apologies for the 'rough' picture. Not too well atmo and could not be arsed to sort out the scanner. My wee Fuji A180 was used instead.

I know it seems easy for ME to say but understanding the basics of audio electronics is really not that hard. Get a good grounding in Ohms Law then get to understand simple DC (lamp, battery, switch) circuits. The fact that audio signals are 'Alternating Current' really matters little in most instances.

Dave.

 

[rob aylestone]

Unless I have missed something - why are we continuing to talk about hum, and lifting grounds when the problem he has is a small amount of hiss that is probably just the normal background level for this keyboard. We have no way of knowing how hard he was playing - I can make my piano sound noisy, if the MIDI input or the playing style is gentle in terms of velocity. With what we heard, if the MIDI data for the loudest note was only half scale, then that noise is perfectly normal. With the actual note data approaching full, how low is the noise floor then? Please - lets forget the earth loops and hum reduction techniques, because there isn't any hum!

 

[witzendoz]

Unless I have missed something - why are we continuing to talk about hum, and lifting grounds when the problem he has is a small amount of hiss that is probably just the normal background level for this keyboard. We have no way of knowing how hard he was playing - I can make my piano sound noisy, if the MIDI input or the playing style is gentle in terms of velocity. With what we heard, if the MIDI data for the loudest note was only half scale, then that noise is perfectly normal. With the actual note data approaching full, how low is the noise floor then? Please - lets forget the earth loops and hum reduction techniques, because there isn't any hum!

The reason I mentioned earth lift in the audio is that the word static was talked about. If there is an earth loop using digital gear, for example computers and interfaces, the earth loop can show up as digital static. The word hum has also been mentioned along the way.

Some here are also saying that my suggestion that using a line into an instrument input can be a problem is rubbish, well the best introduction of audio noise, hiss, in a signal is having an impedance or level mismatch. If none of my suggestions fixed the problem then yes it is something else, but you have to start on the problem somewhere and not being next to the equipment with the problem makes it hard to know exactly whats going on.

Alan.

 

[ecc83]

The reason I mentioned earth lift in the audio is that the word static was talked about. If there is an earth loop using digital gear, for example computers and interfaces, the earth loop can show up as digital static. The word hum has also been mentioned along the way.

Some here are also saying that my suggestion that using a line into an instrument input can be a problem is rubbish, well the best introduction of audio noise, hiss, in a signal is having an impedance or level mismatch. If none of my suggestions fixed the problem then yes it is something else, but you have to start on the problem somewhere and not being next to the equipment with the problem makes it hard to know exactly whats going on.

Alan.

Alan, I disagreed to an extent that a 'line out' and an instrument input were NECESSARILY incompatible but I certainly did not use the word "rubbish" and would not in reference to any HR contributor (except T-in C, where my "wit" has sometimes caused trouble!) so if it was MY comment that caused you hurt, I apologise unreservedly.

Ref the 'hum' thing? Yes, whenever there is a noise issue with multiple devices and COMPUTERS, there can always be a hiss/hash/hum issue. Makes sense to try all solutions.

"Static" has little meaning in this context this side of The Pond and is of course an oxymoron since electrons have to MOVE to generate noise!
Dave.

 

[witzendoz]

Alan, I disagreed to an extent that a 'line out' and an instrument input were NECESSARILY incompatible but I certainly did not use the word "rubbish" and would not in reference to any HR contributor (except T-in C, where my "wit" has sometimes caused trouble!) so if it was MY comment that caused you hurt, I apologise unreservedly.
Dave.

Its fine I was not taking it as any kind of direct insult, I was however trying to point out to newcomers here that you do really have to watch out for incompatibility with signal levels.

Alan.

 

[ecc83]

Its fine I was not taking it as any kind of direct insult, I was however trying to point out to newcomers here that you do really have to watch out for incompatibility with signal levels.

Alan.

Ok Al' cheers! Yes! Signal levels and noooobs! This just bloody annoys me, not the newbs, the bloody kit makers! As I mentioned earlier, there is no technical reason why an unbalanced high Z input should be any nosier than a 10k-10k balanced line input' The HZ in could also have a similar level of headroom, it should certainly no be bothered by a +4dBu line out even if +22dBu is beyond its capabilities.

I am happy to say the amp company I worked for fit a +4/neg 10 switch to their FX loops.

Dave.

 

[rob aylestone]

We always have trouble describing audio problems in words. Static is often misused when they really mean hiss - as in white or pink noise. Hum tends to be used for any of the common data style noise which isn't remotely low in pitch, and in my mind, hum is low - 50 or 60Hz, and possibly first harmonic at 100/120. It then falls apart with 'buzz' which I know in my head, but somebody else might thin k of something totally different. I tend to think static is intermittent single or repeated crackles and short spikes and clicks. The common ground/earth loops are very distinctive and once heard can be identified very simply. As far as I am concerned line is .775V and above, instrument somewhere below that, and mic levels a longer way down.Background hiss in synths and keyboards really does vary. I have two Rolands - one is to all intents and purposes silent - no special care required when setting levels. The other is noisy when set to electric piano mellow sounds where you're likely to play quite gently, meaning the gain gets turned up. It's stabby brass sounds and synth bass sounds are powerful and quite loud, meaning you turn the gain down and the noise goes down with it. I still have an ancient Korg M1 which hisses like a snake! None of the Nords I have come across ever made me think they were noisy, but maybe I wasn't listening? I don't know.

 

[ecc83]

I am obliged for the info Rob. About a year ago I tried to answer a similar question about noise and a synth. I spent quite some time trying to get figures for output levels and source Zs to little avail. To get a S/N specc would be impossible.

The old, med ridden brain has just remembered this! I think we have to treat each case individually.

Dave.

 

[tensyume]

Hello gentlemen. A little update. I am away from keyboard for Thanksgiving (for those who wondered my location, I am in US) until next Wednesday but the new audio interface is here and I will be able to try it next Wednesday.

I will post new updates once I get to try it, along with other things that you guys wanted me to try. Until then, happy turkey day, if it applies to you!

 

[mixsit]

".. then, happy turkey day, if it applies to you!
It does! And same back at'cha!

 

[tensyume]

I think we did it guys. The new audio interface seems to produce the result I am pretty happy with

Just for reference, I will upload the before (when I first wrote this thread) and after (the one I just recorded now at different level outputs from keyboard, low level to high (making sure to not go over -5 and average -13 like someone on this thread said ))

Before: View attachment backgroundnoise_lesslevel.mp3

After: View attachment With new AI.mp3

What do you guys think?

I guess there is still a LITTLE bit of that white noise even with the new Audio interface, but I would say it's a HUGE improvement from before.

Edit: Just listened to them through my monitors instead of headphones, and the new one sounds a bit more muddy than the before one. I'll play with the settings a little and put an update

 

[keith.rogers]

I'd be straining and listening at a level I would not normally listen at to hear noise in the latter mix, but as it's been reduced and compressed, it's hard to say that anything you hear in that is actually due to the AI or keyboard, or even the audio D/A side!

I don't hear any muddiness.

I'm still thinking all of these kinds of discussions would be helped by having a download of the original, non-lossy audio file to listen to. (Related Q - What are your MP3 settings?) I now understand that only MP3s can be attached, but you could post a link to a file in Dropbox, for instance.

 

[witzendoz]

Just out of curiosity, have you still got the DI? If so plug the keyboard into the interface using that and see if it improves even more?

Alan.

 

[Steenamaroo]

Edit: Just listened to them through my monitors instead of headphones, and the new one sounds a bit more muddy than the before one. I'll play with the settings a little and put an update

I don't hear a difference in tone or any hiss worth worrying about, but you've inadvertently reversed stereo when switching AIs.
That'll skew your perception pretty hard when comparing.

 

[tensyume]

I'd be straining and listening at a level I would not normally listen at to hear noise in the latter mix, but as it's been reduced and compressed, it's hard to say that anything you hear in that is actually due to the AI or keyboard, or even the audio D/A side!

I don't hear any muddiness.

I'm still thinking all of these kinds of discussions would be helped by having a download of the original, non-lossy audio file to listen to. (Related Q - What are your MP3 settings?) I now understand that only MP3s can be attached, but you could post a link to a file in Dropbox, for instance.

I didn't quite get your first line. Does that mean the latter mix is too reduced and compressed that it's hard to tell if there are any noise?

And yes, I can upload a wav file instead of mp3 on somewhere else and get back to you on this

 

[tensyume]

Just out of curiosity, have you still got the DI? If so plug the keyboard into the interface using that and see if it improves even more?

Alan.

I do, and it's making a lot more noise. Maybe I have to fiddle with the settings on the AI? (Like Line vs Inst input, Pad, Stere/Mono, etc...)

 

[tensyume]

I don't hear a difference in tone or any hiss worth worrying about, but you've inadvertently reversed stereo when switching AIs.
That'll skew your perception pretty hard when comparing.

OOPS. Wait how did you know that I accidentally switched the stereo. (Audio geniuses over here...) Whoa didn't even realize that was going to be a problem. Also you said you didn't hear a difference in tone or any hiss to worth worrying about, does that mean you didn't hear anything in both recordings or the latter one?