That computer noise thing...

[synkrotron]

19 hours ago, abacab said:

And another possibility I have considered is that the powered monitors are picking up the computer noise via their AC power lines.

I am thinking the same, @abacab

I've found a power conditioner that I fancy trying. Will order tomorrow...

[synkrotron]

24 minutes ago, Chuck E Baby said:

Same here. My position is 60 degrees left or right of the monitor (which is basically almost having my back to the video monitor)

PS- My Fender J-Bass is the same way

Must be a common enough thing then... Once you hit record you have to remember not to move haha

[John Vere]

In the end you have to make sure any guitars or Basses you use for recording have some sort of Hum cancelling Pups. Or just play REAL LOUD! 

My Strat has the Fender custom shop hum cancelling Single coils and it works great. The sound is still 100% Strat. 

My Yamaha bass I swapped the originals for a set of Dimarzio hum cancelling and they are also still a single coil.  

My problem child is my G&L Astat Tribute Tele. It has these oddball large soapbar single coils that I cannot find good replacements for. I cannot record with it unless I leave the room.  

Edited March 10, 2019 by Cactus Music

[Grem]

Hint, Single Coil pickups will pick up electronic noise like a magnet! When at a right angle to electronic source, it will not pick it up as bad, but it's still there.

 

Now synkrotron have you tried to unplug the cables from your audio interface to your speakers and listened to see if the sound is still there. If it is, then it's the speakers themselves. Although I am doubting this to be the case (I mean I can't see both speakers generating the noise, but you never know). It's worth a check.

 

If you try the above and don't get the sound, hook the cables back up to audio interface and unplug everything else from the audio interface. Still hear it? Then I would look at the audio interface. If it is the audio interface, I would suggeswt getting a ground lift plug adapter to try and see if using it will eliminate the noise.

 

The things I am suggesting are efforts to the find noise source. Once you have the source, you can figure out the solution.

Edited March 10, 2019 by Grem
spelling

[synkrotron]

Hi Michael

10 hours ago, Grem said:

Now synkrotron have you tried to unplug the cables from your audio interface to your speakers and listened to see if the sound is still there. If it is, then it's the speakers themselves. Although I am doubting this to be the case (I mean I can't see both speakers generating the noise, but you never know). It's worth a check.

 

I hasten to add that wherever I mention "ground lifted" or "un-grounded" in the following post I only do this in limited and controlled situations in order to test something out. I will never instruct anyone to try this in a permanent situation in order to eliminate noise problems as it is far too dangerous. Electrical equipment is grounded/earthed for safety reasons and failure to use the correct power cabling can result in serious injury or death due to electrocution and loss of life and property due to fire.

 

I tried a number of things. I went right back to basics and only had a single O-C set up with nothing attached but the power lead and the USB cable. No computer noise.

I then brought O-C #2 online and still no noise.

I then decided to bring in my outboard effects and the MPX 500 introduced that noise. If I used a power lead with the ground lifted the noise went away. I therefore assumed that I had found the culprit. But after leaving my studio for a bit, to have some tea, and then went back to continue my testing, the MPX 500 no longer created noise, event though I had reinstated a grounded power lead.

The speakers are a different problem, I think. Right now, with grounded power leads all round, if I use my active monitors, the computer noise is present in the monitors, but NOT in my DAW, where as before the noise was already present in my DAW.

If I use un-grounded power leads with the active monitors the computer noise goes away.

 

I am assuming that the computer noise is entering the system via its grounded power lead. And sensitive pieces of equipment that are grounded are then being affected by that.

I am now looking at buying a small power extension lead that has a RFI and power conditioner built in, as well as some balanced audio cables to run between my O-C and the active monitors and the MPX 500, as they are the only units that have balanced connections.

 

cheers, and thanks,

andy

 

[msmcleod]

Seriously, try a ground loop isolator between your audio interface and your powered monitors.

It totally solved this for me, and it's only £6

https://www.amazon.co.uk/AV-Link-Ground-Loop-Isolator/dp/B000NVWB9O/ref=sr_1_4?ie=UTF8&qid=1552292358&sr=8-4&keywords=ground+loop+isolator

 

[synkrotron]

2 minutes ago, msmcleod said:

Seriously, try a ground loop isolator between your audio interface and your powered monitors.

It totally solved this for me, and it's only £6

https://www.amazon.co.uk/AV-Link-Ground-Loop-Isolator/dp/B000NVWB9O/ref=sr_1_4?ie=UTF8&qid=1552292358&sr=8-4&keywords=ground+loop+isolator

 

But how can I use balanced cables with this thing? Are you saying to use this instead of balanced cables?

In the product description it says, "Prevents unwanted hum on an audio system" but I don't have hum. So I am not even convinced that this will work.

Plus, I have now tried using ferrite chokes, which I am assuming is what this thing is, and they do not eliminate that computer noise.

 

I know what you are saying, it is only six quid so it may well be worth a try... I'll keep you posted on this one...

[synkrotron]

@msmcleod Okay, I just watched this:-

He suggests one of those things that you have so, like you say, might be worth a try...

[azslow3]

I want just describe my experience with situations (and partially found reasons) with something I call "e-noise" (similar to what you describe):

• all build-in interfaces (Realtek, SB), reacted on (wired) mouse, HDD, load. I could (can) not eliminate that. The level is low, but annoying. In monitors and headphones.
• Kawai DP (2 wire power cable).  Problematic when there is any connection to/from it (any combination of USB/MIDI/Audio). MIDI was cured by cutting ground at the receiving end. By MIDI standard it should not be connected, but most MIDI cables are symmetric (so it is soldered in both connectors). It sounds like my TC voice processor is badly designed, so with DP->TC connected by MIDI, TC XLR outputs start producing the noise. Audio connection is way better with HD 400. No solution for USB yet.
• Behringer small USB mixer (2 wire power cable). Generate "e-noise" as soon as there is more then just one input and output in use. F.e. USB+(balanced)output = No noise. (one Unbalanced/balanced)input+output=No noise. But USB+Input+Output=Noise. Several inputs + Outputs = Low/no noise, connected equipment dependent. HD 400 helps. But I ended putting second hand audio interface (8x8, Phonic) as a mixer.
• Roland TD (unbalanced outputs, 2 wire power cable). Was prone to generate noise with Behringer mixer, HD 400 helps.
• Monitors connected with unbalances (TS) AND balanced (XLR) cables at the same time. Activity on the other cable end (connected/disconnected/connected to different equipment) make no difference. When just one cable is connected, there is no noise.

And now some crazy staff I had "pleasure" to observe during my life...

• mixed "ground" and "zero" in house power net. So at some place(s) they was connected (!). Sometimes indirectly, when "ground" was wired as "zero". That is really dangerous....
• some (not music) devices create distortions on some or all power wires
• UPS/"power conditioners" can smoke and even explode (one has exploded in my hands... I was really lucky, there was no consequences for me). Thinking about it, there was more times such devices coursed fire/troubles then any other equipment. They are also getting crazy when something is wrong with the power line (start switching to battery and back continuously, etc.).

[synkrotron]

Thanks for that @azslow3

Makes me wonder if I should have updated my laptop instead of getting a desktop. No need for UPS for starters...

[msmcleod]

2 hours ago, synkrotron said:

But how can I use balanced cables with this thing? Are you saying to use this instead of balanced cables?

In the product description it says, "Prevents unwanted hum on an audio system" but I don't have hum. So I am not even convinced that this will work.

Plus, I have now tried using ferrite chokes, which I am assuming is what this thing is, and they do not eliminate that computer noise.

 

I know what you are saying, it is only six quid so it may well be worth a try... I'll keep you posted on this one...

Personally, I find no significant advantage in using of balanced cables for output signals, unless your cables are significantly long.

It makes much more of a difference for input signals, and an absolute must for low input signals such as mics.

There was a link to an article on a related thread explaining the difference/advantages between balanced & unbalanced cables, and it basically said the same thing.

[msmcleod]

41 minutes ago, synkrotron said:

Thanks for that @azslow3

Makes me wonder if I should have updated my laptop instead of getting a desktop. No need for UPS for starters...

FWIW, most of the "computer noise" problems I've had have been on laptops. It's only a very minor problem for me on my desktop - i.e. it's very quiet, but audible enough during silent sections to annoy me.

I don't use my UPS in any way as a backup power source. With the amount of gear its powering, it only provides around 5 mins backup power in any case.

The main reason for getting the UPS over a power conditioner, is that it generates its own clean 240V supply from a battery (which is constantly charging in the background). This means regardless of how "dirty" your power source is, it's guaranteed to supply a clean 240V signal, or no signal at all.

A power conditioner may clean up a power signal, but it's still physically connected to the mains, and it won't protect you against brown-outs (i.e. the voltage drops down to 50V or so), which will kill HD's.

 

[msmcleod]

2 hours ago, azslow3 said:

• UPS/"power conditioners" can smoke and even explode (one has exploded in my hands... I was really lucky, there was no consequences for me). Thinking about it, there was more times such devices coursed fire/troubles then any other equipment. They are also getting crazy when something is wrong with the power line (start switching to battery and back continuously, etc.).

The switching issue is something that is more likely to occur on offline UPS's, or less so on line interactive UPS's. 

There's three types of UPS's:

• Offline UPS (cheapest) - power comes straight from the mains until it detects a power drop, then switches to battery. The time taken to switch can  cause power glitches in connected equipment, or as you say major damage in some cases.
• Line Interactive (a bit more expensive) - basically the same as the offline, but the switching mechanism is much more complex. Some will generate their own clean sine wave when connected to the mains, but they still have a small switch-over window from mains to battery.
• Inline (most expensive) - This type of UPS always runs off the battery, so no switching occurs. It generates its own clean sine wave. A separate circuit charges the battery in the background when the mains is providing power. If the power goes up and down, all it's doing is switching the battery charger on and off, and won't affect the power coming from the battery powering your equipment.

[chuckebaby]

32 minutes ago, msmcleod said:

Personally, I find no significant advantage in using of balanced cables for output signals, unless your cables are significantly long.

I may have misunderstood, but close range monitors should always be balanced cables.

An XLR - TRS cable, short length used for Speakers will run you about 20 bucks for 2 of them.

[Grem]

4 hours ago, synkrotron said:

The speakers are a different problem, I think. Right now, with grounded power leads all round, if I use my active monitors, the computer noise is present in the monitors, but NOT in my DAW, where as before the noise was already present in my DAW.

 

This is what I am not understanding. Your DAW should have nothing to do with the noise. Only if it's present on the inputs. 

 

So with just the Active monitors plugged in to the electrical wall socket, and not to the audio interface, they still make noise?

[msmcleod]

1 hour ago, Chuck E Baby said:

I may have misunderstood, but close range monitors should always be balanced cables.

An XLR - TRS cable, short length used for Speakers will run you about 20 bucks for 2 of them.

Balanced cables are generally used for either longer cables, or cables carrying a weaker signal.

The are designed for preventing noise that enters the cable after it has left your audio output. The longer the cable, the more chance of noise being introduced along the way. For weaker signals (such as a mic), any introduced noise will be much more noticeable due to the high gain of your preamp. 

The balanced cable holds two copies of the signal, one in reverse phase. As any noise introduced will affect both signals with an equal phase, reversing the "reversed phase" signal and summing it with the original will mean that the noise is now reversed in the 2nd signal and will cancel out.

So the question is, how likely are you to get noise introduced into your cable if it's a short run between your audio interface & your monitors? I guess this largely depends on your environment.

Obviously it's better to use balanced cables if you can, as it will cancel out any introduced noise, but unless you've got a lot of RF being produced around your cables it shouldn't really be necessary.

If the computer noise has been introduced before the signal leaves the cable, then balanced cables won't help.

[azslow3]

3 hours ago, msmcleod said:

The switching issue is something that is more likely to occur on offline UPS's, or less so on line interactive UPS's.

It is more about logic inside UPS, so how long it waits the power is fine again and which instructions in produce.

My best real live example is 20 years old. "Smart" colleagues have connected (relatively) big particle accelerator  to the office power network. Normally it was powered from a separate major line (many megawatts power consumption). As the result, there was "tiny" pikes of like ~500V every several seconds. Typical measure devices was still showing constant 220V, only oscilloscopes could observe real picture.

That was a good test for many devices. Interesting that most computers, switches and other electronic have continued working normally. At the end we have "lost" just several devices (from thousands). But UPS (and alike) equipment  went crazy. Best UPSes have indicated continuous failure, after a while have switched off powered equipment gracefully  and went offline. Many UPSes was switching on/off, some of them eventually was completely discharged and a part of them have not even triggered graceful shutdown. The best observation was with big power system, which had diesel generators as the second level backup. The electronic was starting/stopping engines 🤣

[synkrotron]

1 hour ago, Grem said:

So with just the Active monitors plugged in to the electrical wall socket, and not to the audio interface, they still make noise?

Good question Grem, so as soon as I read this I turned everything off and did some rearranging of my stuff.

Just to explain, although I have some active nearfield monitors I am using them more to just monitor my hardware synths and modular system. I had therefore positioned the monitors to the left and right of those pieces of hardware so that I could play around, especially with the modular, without having to put my headphones on.

A waste of nearfield monitors, perhaps, but I am not a professional studio and I am simply using what I have gathered over the years, without seeking much advice (not much on the interwebs back then, or forums). So I have all sorts of stuff, these monitors, cables, my audio interfaces and what have you and I haven't put in as much thought into that. Whereas if I had started from scratch then I would probably have done some proper research before building up my system, and the outlay, in one big go, would have probably put me off doing this sort of thing altogether.

 

Anyway... Here I am, sat at my computer having moved my active monitors to either side of my video monitor. And as I am typing this, my computer is on, as are my audio monitors. But I have not plugged in the audio cables to my audio monitors yet. All is quiet, well, apart from a very, very low mains hum and I am not really bothered about that.

Okay, plugged the audio cables into my audio monitors but not into my audio interface. All is still quiet.

If I now plug in the other ends of the audio cables into the outputs of my audio interface, which is still not powered up, the computer noise starts. There is a constant noise but if I move my mouse around then I get additional noises. And if I open another web page or open windows explorer I get more noises. The noise isn't particularly loud, but loud enough to get annoying over time, especially when monitoring at low levels.

At this time all the other cables, power, USB and other audio inputs and outputs are all connected, so I will disconnect everything until the computer noise stops.

Okay, so the noise only stopped once I removed the USB cable which is connected to the computer. So it is something to do with being connected to the computer with the USB cable. I have some ferrite chokes available and when I stick these in place it does not affect the computer noise at all.

I should also note that at this moment in time the audio interface and all the instrument hardware is not attached to the mains at all.

Mains is now on and I have powered up #1 OCTA-CAPTURE.

The computer noise level has gone up quite a bit, regardless of what I set the volume to on the O-C. I can have that on full blast and the computer noise stays the same.

The only thing I cannot try at the moment is balanced cables or the ground loop isolator thing.

It is a shame that you have to throw money at problems like this when the issue, in my opinion, should be resolved at the source. Perhaps I should have checked with my PC builder first...