Korg Forums Forum Index Korg Forums
A forum for Korg product users and musicians around the world.
Moderated Independently.
Owned by Irish Acts Recording Studio & hosted by KORG USA
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Noise Removal Questions

 
Post new topic   Reply to topic    Korg Forums Forum Index -> Mastering & Mixing
View previous topic :: View next topic  
Author Message
Yoa
Senior Member


Joined: 03 Feb 2012
Posts: 345
Location: Exeter, NH

PostPosted: Tue Jan 15, 2013 2:58 am    Post subject: Noise Removal Questions Reply with quote

Hi all,

As we all know, one of the main keys to perfect audio is noiseless audio. Sadly, I have a solid noise floor of about -50dB, more or less, and it is incredibly obvious. I do have many problems, such as unshielded audio cables, power lines and transformers running around everywhere, and the fact that a lot of instruments (such as my guitars) act as GREAT antennas. I'm also thinking I don't have the cleanest power and ground.

So, my question to you is: how are YOU suppressing any noise you may have? Obviously there's better cables and noise suppression pedals, but what about, say, power conditioners, or connection materials?

I can probably easily get a better audio main cable (from my mixer to my computer) and a power conditioner (I'm thinking about either the Monster Power PRO 1000 or the Furman M-8X2), any other suggestions?

Thanks!
_________________
Cheers! Yoa

Current electronic equipment: Korg Kaossilator, miniKP, microKORG, nanoKEY, nanoPAD, nanoKONTROL, monotron, Pandora PX5D, AX1000G, M-Audio Keystation 88es, Casio VL Tone, Soundcraft 102 mixer, laptop (which, among other things, has the KORG Legacy Collection and various NI stuffs), Acer Iconia a100 (has many music apps), Stylophone, Yamaha DX7
Back to top
View user's profile Send private message Visit poster's website
Sparker
Senior Member


Joined: 26 Feb 2009
Posts: 483
Location: Wales UK

PostPosted: Wed Jan 16, 2013 3:01 am    Post subject: Reply with quote

I reduced my ground noise by; a) using balanced cables for connecting all my audio components; b) running everything from off of the same electrical wiring feed (via a double wall socket).

I saw in another of your posts that you use a laptop. When I connect my laptop into my system that is run from a desktop PC I get an electrical buzz which is caused by the laptops external power adapter. If I run the laptop just on battery, without the PSU plugged in, then the buzz disappears. However I don't get the same interference from any other external PSUs. I don't know what causes this to happen but suspect there's some artifact happening between the Laptop's PSU and the audio processing. What happens if you run your setup with the laptop on battery power?

At one point I considered getting a Behringer HD400 Hum Destroyer to get rid of the ground noise in my normal setup, however, using balanced cables sorted the problem out to my satisfaction.
_________________
Kronos 61 & KK KARMA / Triton Ex c/w MOSS and TR KARMA / MS2000 / Radias / Kaossilator Pro & Kaossilator / Korg Kontrol 49 / Nanopad / Novation Nova / Waldorf Blofeld

Line 6 Flextone XL / Line 6 POD XT / Roland V Bass / Ampeg Portabass & Cab / Assorted Guitars (no whammy bar) ... and a Fender Champ ...
Back to top
View user's profile Send private message
Yoa
Senior Member


Joined: 03 Feb 2012
Posts: 345
Location: Exeter, NH

PostPosted: Wed Jan 16, 2013 5:06 am    Post subject: Reply with quote

I can't use balanced for everything Sad Especially not my vintage and handmade equipment. Not sure I'd want to though, I'd have to replace all my cables with those. I would use the same feed, but then I'd need more outlets. A lot more. I'm currently using all wall 10 outlets in my studio, most of which using power strips, and I still have problems plugging stuff in. I have the same problem with USB :\

In all honesty, my laptop dies. I can't go but a few minutes on battery. I use it like a desktop computer, only advantage being I can take my whole computer places with ease. Oh, and less cables. However, on that subject, I do have a LOT of PSU's running about (wall-mount, transformers, black boxes, etc), probably creating interference, so is there much of a way to shield them or contain that interference? Basically trying to rule out Part 15 of the FCC rules Smile
_________________
Cheers! Yoa

Current electronic equipment: Korg Kaossilator, miniKP, microKORG, nanoKEY, nanoPAD, nanoKONTROL, monotron, Pandora PX5D, AX1000G, M-Audio Keystation 88es, Casio VL Tone, Soundcraft 102 mixer, laptop (which, among other things, has the KORG Legacy Collection and various NI stuffs), Acer Iconia a100 (has many music apps), Stylophone, Yamaha DX7
Back to top
View user's profile Send private message Visit poster's website
Sparker
Senior Member


Joined: 26 Feb 2009
Posts: 483
Location: Wales UK

PostPosted: Wed Jan 16, 2013 10:17 am    Post subject: Reply with quote

Quote:
I have the same problem with USB


I use a powered hub. My hardware devices are recognised (though not the external the USB IDE Hard Drive). I now have 10 USB ports (7 in the powered USB hub and 3 more on the PC or Laptop)

Quote:
so is there much of a way to shield them or contain that interference?


You could try the Hum Destroyer. I believe it changes the unbalanced signal to balanced as well as destroying hum.
_________________
Kronos 61 & KK KARMA / Triton Ex c/w MOSS and TR KARMA / MS2000 / Radias / Kaossilator Pro & Kaossilator / Korg Kontrol 49 / Nanopad / Novation Nova / Waldorf Blofeld

Line 6 Flextone XL / Line 6 POD XT / Roland V Bass / Ampeg Portabass & Cab / Assorted Guitars (no whammy bar) ... and a Fender Champ ...
Back to top
View user's profile Send private message
Yoa
Senior Member


Joined: 03 Feb 2012
Posts: 345
Location: Exeter, NH

PostPosted: Thu Jan 17, 2013 12:10 pm    Post subject: Reply with quote

I'm still trying to find the right hub. Every time I find one that seems okay the reviews are pretty half and half, not including those who didn't read the manual and description Smile Which do you use? I would ned a slightly larger one (at least 12), but they tend to come in different sizes.

I'll look into it. Thanks!
_________________
Cheers! Yoa

Current electronic equipment: Korg Kaossilator, miniKP, microKORG, nanoKEY, nanoPAD, nanoKONTROL, monotron, Pandora PX5D, AX1000G, M-Audio Keystation 88es, Casio VL Tone, Soundcraft 102 mixer, laptop (which, among other things, has the KORG Legacy Collection and various NI stuffs), Acer Iconia a100 (has many music apps), Stylophone, Yamaha DX7
Back to top
View user's profile Send private message Visit poster's website
synthjoe
Platinum Member


Joined: 21 Apr 2010
Posts: 1007

PostPosted: Thu Jan 17, 2013 11:30 pm    Post subject: Reply with quote

-50 dB is a lot. I'd start by unplugging/muting sources on the main mixer to find the main contributors.

Also, the type of noise is a tell-tale: buzz, hum, whine, white (broadband) noise are all due to different causes.

Also, if the noise floor is really -50 dB I'd suspect ground loop and gain structure problems - look for input stages where gain is set at a high level. If preceeded by long cable runs, on these inputs you should really try to go for balanced cables and perhaps have a preamp close to the source (i.e. active guitar pick-up, powered DI box and the like), before injecting signal into the long cable run. As a result of this you should be able to turn the gain down on the input stage and avoid amplifying the noise picked up by the cable, which can be quite significant if unbalanced and longer than a meter or two. Ground loops can also be checked for by disconnecting all cables of a device under test, and if found, a 1:1 DI box (or hum destroyer) can bring massive improvements.

Hope this helps.
Back to top
View user's profile Send private message
Yoa
Senior Member


Joined: 03 Feb 2012
Posts: 345
Location: Exeter, NH

PostPosted: Fri Jan 18, 2013 3:49 am    Post subject: Reply with quote

-50 is with my computer mic turned down, too. Max volume, it's at -36dB.

Well, then, going by what you're saying, I have a really bad studio. Let me break it down:

I did that, and actually the buzz continued. I suspect the cable running from my mixer to the computer myself. It's a cheap 1/8" Belkin balanced cable with gold tips and shielded - not the best choice, I know, but it seemed fair at the time.

As for the type of noise, it's both white noise and a 60Hz hum (as measured by my computer's oscilloscope and spectrometer) with a bit of whine, but oddly enough it seems to be following a saw-like waveform. It differs each time I measure it, though. I can upload audio and pics if need be.

Ok, so high-gain, do you mean high-volume? All my synths are turned up all the way going into the mixer (except sometimes I have to turn down the DX7). My electronic drums are up about 50% but have a 20' unbalanced cable going to the mixer and around all of my guitar pedals and amp. I mic my amps, and turn up the mics to about 50% on the mixer (direct input with 48V phantom power and gain turned up to about 60%).

After reading a bit, it seems that grounds loops occur when grounds are connected and thus sharing any signal passing through, which can add up to destructive noise, right? I'll have to test for that tomorrow as I just came back from the hospital today (messed up knee, nothing major).

Thanks for the help!
_________________
Cheers! Yoa

Current electronic equipment: Korg Kaossilator, miniKP, microKORG, nanoKEY, nanoPAD, nanoKONTROL, monotron, Pandora PX5D, AX1000G, M-Audio Keystation 88es, Casio VL Tone, Soundcraft 102 mixer, laptop (which, among other things, has the KORG Legacy Collection and various NI stuffs), Acer Iconia a100 (has many music apps), Stylophone, Yamaha DX7
Back to top
View user's profile Send private message Visit poster's website
synthjoe
Platinum Member


Joined: 21 Apr 2010
Posts: 1007

PostPosted: Sat Jan 19, 2013 12:37 am    Post subject: Reply with quote

Uh, your setup seems quite complex. Perhaps a drawing would help more than the picture of the noise. What is connected to what, where it is powered from, any other cables (USB, etc.)?

High gain means high input amplification. Outputs being set high (70% or so) is a good thing. you should set input gain (on the mixer, for example) as low as reasonable. Outputs should be about 70-80% as many gear distort if pushed to 100%.

I'd also be suspicious of the cable going to your laptop. Is it a long one? Laptop input is unbalanced and can pick-up noise easily. What is the noise level if you short-circuit the cable going to the laptop input? Do you have a line input as well, or a mic input, only? Mic inputs on computers tend to be a lot noisier than line inputs.

Hope your knee is going to be fine, soon!
Back to top
View user's profile Send private message
Yoa
Senior Member


Joined: 03 Feb 2012
Posts: 345
Location: Exeter, NH

PostPosted: Sat Jan 19, 2013 2:36 am    Post subject: Reply with quote

Oh, boy, drawing it all out would be a challenge, especially to point out interferences. Instead, I put a few pics of my studio together and labelled stuff as well as I could.
http://img89.imageshack.us/img89/3349/imag0114va.jpg
Believe me, this is much better to understand interferences and how things are placed. I know it's not the best, but I've been thinking about rearranging recently. Note though that even with everything turned down on the mixer there is noise (and hum, etc.). Even disconnect the mains interconnect and there's noise.

As for brands (to get an idea), most guitar cables are Monster, 20' is Planet Waves, DX7 is Monster (with splitter), KORG setup is wired with Radioshack and Livewire cables, and main mixer output is a 1/8" Belkin gold plated cable (both parts). All but Radioshack and some patch cables are advertised as being shielded.

I didn't include much in the way of USB, but you can see the KORG nano series, there's also a wireless keyboard, , Numark DJIO, M-Audio Keystation 88es, printer lead, and a general-use USB cable mainly used for that DJ mixer you see.
__________________________________________________
My dad was an audio engineer (as I kinda am now) and engrained a max volume of 80% on most things into my brain, so I kinda stick around that except where it seems too quiet/loud. You can generally see what my mixer is usually set to, but in case it's a bit off I normally have the mics off or 50% (gain at 60%), drums off or 100%, MK+miniKP at around 50%, 70% for the Kaossilator, and DX7 at 50%. Main output volume at 80%, mains cable out at 50%.

It's two put together (as you can see) to equal about 12'. Shorting that actually leads to more noise (very audible hum, however my meters say about the same volume/floor. THe input is supposed to be both mic and line, digitally controlled. Not really sure how that works, but I'd assume it's really just mic only and you can put line signals into it.

Thank you. 4-6 weeks, they say.
_________________
Cheers! Yoa

Current electronic equipment: Korg Kaossilator, miniKP, microKORG, nanoKEY, nanoPAD, nanoKONTROL, monotron, Pandora PX5D, AX1000G, M-Audio Keystation 88es, Casio VL Tone, Soundcraft 102 mixer, laptop (which, among other things, has the KORG Legacy Collection and various NI stuffs), Acer Iconia a100 (has many music apps), Stylophone, Yamaha DX7
Back to top
View user's profile Send private message Visit poster's website
synthjoe
Platinum Member


Joined: 21 Apr 2010
Posts: 1007

PostPosted: Sat Jan 19, 2013 5:05 pm    Post subject: Reply with quote

4-6 weeks? Good, so you have some time to sort this noise issue, then... Smile Always look at the bright side!

Ok, the picture is indeed better than a drawing - I can tell right away that you should keep a good distance between audio and mains (power) cables. Give it at least a foot or two, even more, if you can. You can bundle audio cables together, but never put it near the power cables, strips, wall-warts, transformers, high power electrical equipment (like the heater in the background), etc. Hang the bundle on the wall, or something. Once you're done with that, you can move to the next level.
Yoa wrote:
Note though that even with everything turned down on the mixer there is noise (and hum, etc.).
...
Shorting that actually leads to more noise (very audible hum, however my meters say about the same volume/floor. THe input is supposed to be both mic and line, digitally controlled.

OK, hold it right there! So, if you pull down the master fader completely on your Soundcraft Notepad (and I assume its output goes directly into the laptop's input), then you still have noise? Then it is a clear case of ground loop. To eliminate, unplug inputs to the mixer one-by-one to find the offending input. Mic, amp mic, long cable (drumkit?), DX7, Microkorg, Kaoscillator. Remember: one-by-one. Probably the noise is going to decrease gradually, but most likely there will be one that will be the worst of all. You'll need to tackle that, first. If you still have the noise after unplugging everything (except the audio cable between the mixer and the laptop), then you have the noise source right there: ground loop between the mixer and the laptop.

First thought: the audio cable between the mixer and the laptop shold be a much thicker, quality one. Make sure you use an excellent quality cable here, this is your most important connection.

OK, so I'll assume that the cable between the mixer output and the laptop input is a 2x1/4 jack to a 1/8 stereo jack. Did i understand you correctly that if you unplug the 2x1/4 jack end from the output of the mixer and on each plug you short the tip to the sleeve, then the noise becomes worse?

If such is the case, then your laptop needs an external soundcard. Anyways, I could not make out the brand of your laptop, what make/model is it? Based on your description the built-in soundcard is probably a mediocre one, aimed at multimedia input purposes (skype, voice recognition, etc.) and most likely not for audio purists... This means that you might have very little means to control the noise there.

Hope tis helps, let me know if anything improved, at all.
Back to top
View user's profile Send private message
Yoa
Senior Member


Joined: 03 Feb 2012
Posts: 345
Location: Exeter, NH

PostPosted: Sat Jan 19, 2013 5:36 pm    Post subject: Reply with quote

Eh, yeah, but not without a job! Pretty much have to use what I have around me. Apparently you get terminated when you get injured on the job.

It seems as if that would be a great idea, but given the lengths of things I don't have much of an option. That 20' cable is stretched yet too short to go around the other way, the DX7 cable is as far from mains as I can get it (so about 6"), and given the small space I can't move anything very far (unless I do in fact rearrange everything). The amp mic cable could move a little, but it would still be close to mains lines.

I tried unplugging everything one-by-one, and the only problem I had was the DX7 audio gave me quite the shock when I unplugged it from the mixer. I unplugged the right side first, then unplugging the left side (which my hand holding onto the right side plug) gave a nice shock. No noise difference during the shock, though (yes, I let myself get shocked for a while while looking at the meters. I did it for the gear). The DX7 is grounded to the chassis, which sometimes shocks me, so I'm assuming that's not good, but not the problem.

So assuming it is a loop between the mixer and laptop, it seems to me that a ground lifting DI box would help, right? I'd make the cable better anyway, when I can. Quality cables aren't cheap, especially not stereo ones.

Actually, this mixer has a headphone output, so I'm using a 1/4" TRS-1/8" TRS adaptor, then going into the 1/8" TRS cable which runs to the laptop. I used what I had on hand :/ But you are correct, when I shorted the tip to the sleeve the noise did increase considerably.

It's a Gateway NV53A, which is currently the cheapest laptop in BestBuy. When I got it it was about $500 I think. It is a very poor soundcard for recording, but the audio out of it (minus the noise) is really good. I was actually thinking of getting an Akai EIE for the massive I/O, the meters, the look, and of course the very fair price for what it is. I've heard great things about it, at the very least.
_________________
Cheers! Yoa

Current electronic equipment: Korg Kaossilator, miniKP, microKORG, nanoKEY, nanoPAD, nanoKONTROL, monotron, Pandora PX5D, AX1000G, M-Audio Keystation 88es, Casio VL Tone, Soundcraft 102 mixer, laptop (which, among other things, has the KORG Legacy Collection and various NI stuffs), Acer Iconia a100 (has many music apps), Stylophone, Yamaha DX7
Back to top
View user's profile Send private message Visit poster's website
synthjoe
Platinum Member


Joined: 21 Apr 2010
Posts: 1007

PostPosted: Sat Jan 19, 2013 6:21 pm    Post subject: Reply with quote

Sorry about your job - hope you'll be out of this soon.
Shock is not good, you should investigate that.
Putting hooks on the wall and hanging cables should not need more length than running on the ground, should it?
Perhaps you want to think about getting into making your own cables. Then you'll have the length and quality you desire at a very reasonable price.
OK, so you've shorted all three contacts on the mixer end of the 1/8 cable only to get more noise? Try to wrap some aluminium foil or stranded wire around (for a good short across all three terminals) and make sure you're not touching it while checking. Do you still get the noise?
If so, then you'll need a better cable or a better laptop (soundcard). From what you wrote about the laptop, I'm afraid you'll not solve this fully without getting an external audio interface.
While waiting for a better cable between the mixer and the laptop, you can take a thick, flexible electrical wire (the ones making up power cables of household equipment or multiplugs) and link the mixer and the laptop with it, by tightly attaching both ends to metal parts (i.e. loosening a screw on the mixer and tightening with the wire placed under it, attach securely to the metal part of the VGA port on the laptop, and the like). Do this while everything is unplugged and switched off, otherwise some damage might occur.
Back to top
View user's profile Send private message
Yoa
Senior Member


Joined: 03 Feb 2012
Posts: 345
Location: Exeter, NH

PostPosted: Sun Jan 20, 2013 1:02 am    Post subject: Reply with quote

No need to worry yourself with my issues, y'know?

I have. The power transformer within the DX7 has a virtual ground which grounds to the chassis. All other grounds also attach to the chassis. There is no actual ground on this thing, which in itself is kinda scary.

You'd think not, but when I tried going on the walls and ceiling (I'm in an attic, so the walls are also the ceiling) when I first set up this place I couldn't get but 3/4 of the way over.

I'll look more into making cables. I've made a few custom George L's and they've lasted forever, but they don't seem to be very high quality.

That's actually what I did! I also tried individual shorts using a wire. Still noise Sad

That seems like quite the hack, but I'll look into it. I'm not sure if I have any such wire, though. I thought about doing a similar thing with my DX7, but it was strongly advised against (DX7 chassis>outlet ground). Not sure why, it seems fairly safe.

Thanks, by the way.
_________________
Cheers! Yoa

Current electronic equipment: Korg Kaossilator, miniKP, microKORG, nanoKEY, nanoPAD, nanoKONTROL, monotron, Pandora PX5D, AX1000G, M-Audio Keystation 88es, Casio VL Tone, Soundcraft 102 mixer, laptop (which, among other things, has the KORG Legacy Collection and various NI stuffs), Acer Iconia a100 (has many music apps), Stylophone, Yamaha DX7
Back to top
View user's profile Send private message Visit poster's website
synthjoe
Platinum Member


Joined: 21 Apr 2010
Posts: 1007

PostPosted: Sun Jan 20, 2013 7:27 pm    Post subject: Reply with quote

Yoa wrote:
I thought about doing a similar thing with my DX7, but it was strongly advised against (DX7 chassis>outlet ground). Not sure why, it seems fairly safe.

Well it should be perfectly safe if the grounding is good (checked by a qualified electrician) and there's a leak current detector/breaker in the house.

Otherwise I'd advise against, too - groundings can sometimes be weak. Anyways, please note that I only suggested to link your laptop's metal part to the mixer's - but not to tie them to the ground on the outlet. This should not increase the risk of electric shock compared to what you might already have present (due to potentially unsafe grounding), but might eliminate your problem. At worst it can kill some delicate electronic eqiupment (e.g. laptop), but not so if you connect them while everything is unpowered (and by this I mean that probably you should unplug everything before doing this).
Back to top
View user's profile Send private message
Yoa
Senior Member


Joined: 03 Feb 2012
Posts: 345
Location: Exeter, NH

PostPosted: Mon Jan 21, 2013 12:34 am    Post subject: Reply with quote

Yeah I don't think we have either of those, to be honest Smile Joking, I'm actually not sure. There are a lot of problems with the wiring (stray hot wires, etc.), so it's totally possible that there's something wrong.

I still need to find a suitable ground on my laptop, but don't worry; I have wire and can ground everything. Thanks again for your help, I'll let you know when I get things hooked together.
_________________
Cheers! Yoa

Current electronic equipment: Korg Kaossilator, miniKP, microKORG, nanoKEY, nanoPAD, nanoKONTROL, monotron, Pandora PX5D, AX1000G, M-Audio Keystation 88es, Casio VL Tone, Soundcraft 102 mixer, laptop (which, among other things, has the KORG Legacy Collection and various NI stuffs), Acer Iconia a100 (has many music apps), Stylophone, Yamaha DX7
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    Korg Forums Forum Index -> Mastering & Mixing All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group