How do i get rid of electrical hum in my recording set-up?

I will check the balanced cables to see if the ground wire is connected if so i will disconnect it on one side (that should help right?)

Edit: Disconnecting the lift pin (at the end of the connector which connects to the monitor) on the balanced cables didn't work

You need to disconnect both left and right speaker cables, disconnecting on won't work.

Alan.
 
Here is a short 20 second recording i made of the hum: vocaroo (.) com/i/s0wXNblTWjFI

I put the monitors on max volume so the hum would be clearly audible in the recording.

- How did you make the recording? Mic in front of monitor?
- Any 'hum' heard in headphones plugged into the interface?
- How are the levels set between the interface and monitors? If the interface is set say around 3 o'clock on the Master Level output control and the monitor input level is set for normal listening volume, can the noise be heard?
 
Not simply basic 'hum', but some other crap in there as well. Downloaded sikes wav file, loaded up in Audacity and normalized to bring it up to listening level. New mp3 file as an attachment.

What else do you have on the desk/table where the gear is located? Florescent lighting/CFL bulbs, device with a transformer nearby to cables or the gear or anything else that could possibly create electrical noise?

Mark, what did you do to get that link to play please? I pasted it into Fire fox but just got the Voccara website, no sign of OP's audio.

Dropbox I can handle (sort of, it grabs everything, runs all the time and I don't like that so I don't have it installed) but now there are SO many obscure bloody sites!!

Jus' paste a freeking MP3 for 20 second tests chaps! I don't then have to record it again, just stuff it into Samplitude and convert it to 16 bit 44.1kHz .wav for Right Mark anny. (cos, if 16 bit wavs wos allowed for short tests???)

Dave.
 
Here's a wetransfer link with a 320 mp3 file for everyone who wasn't able to open the last link. I'm apparently too new to the forum to post links or attached files hence the weird way of posting the link (just type the . without parentheses): we (.) tl/t-xAua4Tx8MB
 
- How did you make the recording? Mic in front of monitor?
- Any 'hum' heard in headphones plugged into the interface?
- How are the levels set between the interface and monitors? If the interface is set say around 3 o'clock on the Master Level output control and the monitor input level is set for normal listening volume, can the noise be heard?

-Recorded using an okatva mk 012 pointed to the speaker (about 10cm away). I recorded it with the connected audio interface. The hum does not appear on recordings done with the interface, it's purely on the speakers.

-The hum can not be heard on headphones, only the speakers.

-The output volume of the interface does not seem to affect the loudness of the hum, increasing the volume of the speakers does make the hum louder.
 
Mark, what did you do to get that link to play please? I pasted it into Fire fox but just got the Voccara website, no sign of OP's audio.

Dropbox I can handle (sort of, it grabs everything, runs all the time and I don't like that so I don't have it installed) but now there are SO many obscure bloody sites!!

Jus' paste a freeking MP3 for 20 second tests chaps! I don't then have to record it again, just stuff it into Samplitude and convert it to 16 bit 44.1kHz .wav for Right Mark anny. (cos, if 16 bit wavs wos allowed for short tests???)

Dave.

I had to look a bit as well.....
 

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Yes, that is horrible. Rightmark give another view. The strong 3rd harmonic suggests to me a mains transformer being run very close to its VA limit. Could indeed be a choke in a lamp.

The level at 50Hz shows it is induced hum and not the 100Hz you get from poorly filtered power supplies.

Dave.

The main light in the room i have this gear set up uses a dimmer switch that actually emits a weird buzzing noise when turned on. You think that could have something to do with it? Because i too am starting to suspect it has more to do with the electricity here than with audio wiring and the equipment.
 
The main light in the room i have this gear set up uses a dimmer switch that actually emits a weird buzzing noise when turned on. You think that could have something to do with it? Because i too am starting to suspect it has more to do with the electricity here than with audio wiring and the equipment.

Dimmers can be particularly 'noisy'. They work by 'chopping' a clean sine wave into smaller chunks which deliver less power/voltage to a lamp. The chopped up chunks tend to have sharp rise and fall edges which can create harmonics. Kill the lights that are fed off the dimmers and see if there is a difference. I had mentioned in an earlier post florescent/CFL lighting. Some of these can put out noise if they use electronic ballasts. LED lights also have electronics in them which could be suspect.
 

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Here's a wetransfer link with a 320 mp3 file for everyone who wasn't able to open the last link. I'm apparently too new to the forum to post links or attached files hence the weird way of posting the link (just type the . without parentheses): we (.) tl/t-xAua4Tx8MB

So, can I ask, (cos I ain't too PC bright!) IF there is an exact form for the link why could you not type that and tell me to copy and paste it?

I know I have had more trouble since I had to move to Effing Fox but sometime PEEPS don't help either! (I am going to give Chrome a do but leep resisting. Don't larn fast these days.)

Dave.
 
Have a look too for dodgy filtered switch mode PSU's - the wall wart ones are notorious for generating all kinds of crud and putting it on the ground line - a ferrite filter often reduces it - it's rich in harmonics so disconnecting each one, one at a time might lead you too the culprit. The one on my old Dell laptop was so made I never did get it to be workable.
 
So, can I ask, (cos I ain't too PC bright!) IF there is an exact form for the link why could you not type that and tell me to copy and paste it? ....
OP just inserted some spaces and parens, which we deleted out after copy/pasting into a new tab - at least that's how I did it. No magic. Here's the link (you'll have to peer closely to find the download link buttons as [MENTION=190964]arcaxis[/MENTION] points out).


P.S. Yeah, get rid of that dimmer. I took out the one on the 2nd floor (didn't check to confirm it was on the same circuit) and all CFLs a couple years ago. Quieted my space down noticeably.
 
OP just inserted some spaces and parens, which we deleted out after copy/pasting into a new tab - at least that's how I did it. No magic. Here's the link (you'll have to peer closely to find the download link buttons as [MENTION=190964]arcaxis[/MENTION] points out).


P.S. Yeah, get rid of that dimmer. I took out the one on the 2nd floor (didn't check to confirm it was on the same circuit) and all CFLs a couple years ago. Quieted my space down noticeably.

Ok but WHY put in extra bits? Just say "paste this" ? How am I to know what is needed and not?

Dave.
 
Ok but WHY put in extra bits? Just say "paste this" ? How am I to know what is needed and not?
Because as a noob posting a URL is not allowed.

Well, spaces and special characters can pretty safely be assumed to not be part of the domain name, so start by taking those out. See what happens!
 
Well, not knowing much about Belgium wiring standards, I really can't suggest much. I can only assume there are standards that relate to safety and quality, as there are in the U.S. And in Europe, you guys have a higher voltage system than we do...240 volts, or 230 volts, not to mention it's running on a 50 hertz system, compared to a 60 hertz system in the U.S.

But, even with this said, I'd still suggest having some professional check out the wiring of your house. Things like having the hot and neutral wires reversed, or the earth ground not connected or properly grounded...all can cause a nasty hum here in the U.S. We also have a very cheap device you can get at the neighborhood DIY home market that you plug into your wall outlets that tell you if they are wired correctly.

The thing is, in many cases, analog devices work just fine, even if the hot and neutral wire are reversed. But in the years since digital started being involved in everything, it also became necessary to have the house wired correctly. You can also damage your sensitive digital stuff if it's running on incorrect electrical wiring, not to mention you can also amplify nasty sounding hums and buzzes through your system, as a result of incorrect electrical wiring.

So, your noise might be coming from the output of a particular device in your system, but it might be caused by incorrect wiring. If that's the case, get it fixed as soon as possible. You are ultimately damaging your sensitive digital gear. Also, in the U.S. fluorescent lights and even those pig tail types that were suppose to replace incandescent bulbs (before the more efficient LED versions became popular) will reek havoc on your audio, even if the wiring is perfectly correct.

Compressors on the same line as your audio system will also damage your stuff as well as cause noises. You might hear things that sound like the noise is in some kind of phase system. That means things are out of phase and slowly eating your sensitive digital chips.

Now, I'm not saying your problem isn't something in your audio wiring or in some digital unit that has it's own issues. I'm just saying to deal with first things first. Then, you can cancel out bad electricity and concentrate on spending money on good grounded mic cables, etc.

I've found that a good copper mesh is a very good ground in XLR cables. Some you'll see are wrapped with copper or aluminum, or even is aluminum mesh. Copper mesh is best. And anywhere you can use a balanced cable, you should, be it XLR or TRS.
 
"I've found that a good copper mesh is a very good ground in XLR cables. Some you'll see are wrapped with copper or aluminum, or even is aluminum mesh. Copper mesh is best."

Ain't necessarily so..Braided screens as we call them here in LimeyLand do not give 100% coverage at RF, rarely a problem but foil screens do. For fairly "static" (I refer to "movement" not the oxymoronic term used for electrical interference) cables such as those going to and from a patch bay or in ducting to wall boxes, Aluminium shielded foil cable with a copper drain wire gives excellent screening, is a dream to strip and terminate and is cheaper! It can also be got in smaller diameters than HD balanced cable, 3-4mm and thus is less bulky en masse.

I too know nothing of OPs electrical system but in general the EU is pretty good for safe practices. Do agree it it worth getting a sparks in for a check especially if it is an old property and not been seen for decades.

Dave.
 
Ain't necessarily so..Braided screens as we call them here in LimeyLand do not give 100% coverage at RF, rarely a problem but foil screens do. For fairly "static" (I refer to "movement" not the oxymoronic term used for electrical interference) cables such as those going to and from a patch bay or in ducting to wall boxes, Aluminium shielded foil cable with a copper drain wire gives excellent screening, is a dream to strip and terminate and is cheaper! It can also be got in smaller diameters than HD balanced cable, 3-4mm and thus is less bulky en masse.

I too know nothing of OPs electrical system but in general the EU is pretty good for safe practices. Do agree it it worth getting a sparks in for a check especially if it is an old property and not been seen for decades.

Dave.
Now isn't that strange? It might have had something to do with why we yanks moved over here. Just kidding. I think even over here, there would be instances when something else would work better, depending on the area involved. That aluminum foil wrap can cut out quite a bit of weirdness.

I would also agree that the UK has pretty good safe practices when it comes to electricity, since you've been at it for a long time. And also rather strangely, I understood who you were talking about, when you said to get a sparks to check his wiring.
 
Now isn't that strange? It might have had something to do with why we yanks moved over here. Just kidding. I think even over here, there would be instances when something else would work better, depending on the area involved. That aluminum foil wrap can cut out quite a bit of weirdness.

I would also agree that the UK has pretty good safe practices when it comes to electricity, since you've been at it for a long time. And also rather strangely, I understood who you were talking about, when you said to get a sparks to check his wiring.

SO! Nice to get a pleasant, well thought out reply. The situation is complex and there are no hard and fast rules. Tracking down hum problems can be time consuming and counter-intuitive.

In addition to a pretty safe, conservatively rated electrical system, EU also has very strong EM regulations governing the ***t kit can chuck out AND the susceptablity othe gear is to such ***t. The latter is very important and often poorly implemented on budget gear. A good deal of the latter is only possible at the low prices because they leave out "hidden" engineering such as RF stoppers and overated components to prevent "collateral damage.

Dave.
 
All right seeing we are looking at all kinds of causes, I had an induced noise from a power pac plugged into the back of a piggy back plug (or double adaptor) the item with the power pac was fine but the other piece of gear, in this case a Yamaha SPX90, suddenly started to hum and have noise problems.

I also had problems in one of my early studios with the telephone exchange across the road, I was getting induced noise into the mains supply cables, this was extremely hard to get rid off and the only way was to use very good quality cables. It caused real problems whenever a single coil guitar turned up as that picked up the airborne stuff.

Just pointed this out as there is sometimes no simple answer and investigation is needed.

Go back to my answer #8 where I asked if the power point had a good earth, don't assume it does, even the house earth may be bad or non-existent. I did move into a house years ago where someone had broken the main earth cable through the roof between the main switchboard and the main earth point, just left it and did not fix it, a deadly trap for some poor person later. Fixed that and put down a better earth stake and all noise including the stereo in the lounge went away. Check the earth resistance in the house!

Alan.
 
YES! We assume too much, when it will either cost us money or it was someone's job to do it right in the past. I think I've already said this in this forum somewhere, but when you buy a house, here in the states (and probably most anywhere), there are safety rules that the builder had to follow. In the trades, it's called following the builder's code. And things are inspected, to make sure these codes are followed. When it was a pre-existing house, everything still has to be inspected, to make sure it's "up to code", in regards to safety, before a sale can be finalized.

But, there are ways around all of this. It's sad, but if you know somebody...who knows somebody else, you can do things out of code or not fully following code. My house was remodeled before I bought it. It looked great. The ceiling was vaulted in the kitchen and a cathedral ceiling in the living room. The ceilings were originally 10 feet high, so they didn't disturb the attic, when they did that. The home owner did all of the work and his uncle was an inspector. See where this is going? Yep, while they didn't do anything themselves that could have been considered that unsafe with the electricity, they connected their wiring to the existing wiring, and that wiring was far below present day code.

This is an old shot gun house. It was built in 1935. It has actual 2X4 lumber in it and square nails. The main structural frame of this house is still quite strong. Unfortunately, it also had slat and lath walls, too...AND NO INSULATION! Back when it was built, there were no high energy bills. You just turned the heat up a little more.

When the previous owners remodeled the house, they only put insulation in rooms they put new sheet rock on. And they ran new electrical wires in those rooms, too. But, half of the house just had newly painted walls, to resemble the ones that had been remodeled, so we "assumed" the whole house had been remodeled. In fact, those were the very words that were spoken..."the whole house has been remodeled".

The electricity in the part of the house that hadn't actually been remodeled hadn't been updated or even checked for many years. And with the remodeling, that present wiring experienced vibrations and other movement that it hadn't felt...probably ever. So, some of the connections up in the attic were weakened, even if they were good connections in maybe...1950 or 1970?

I wasn't in the house 6 months before half of the electricity in the kitchen just went out, but no breaker blew. How I found it was to plug in a loud blender and then go up into the attic and start moving wires around, until I found the connection that was causing the separation and heard the blender come on. It was one of the existing connections (pre-remodel) and all they did back then was to twist the two ends of a wire together and tape it with electrical tape. There were no wire nuts and the tape was mostly rotted away. Over the years, and with vibrations and movement from the remodel in the room below, that twisted connection got loose.

Thankfully, I saw the way the electricity in the house looked very soon after the purchase. There could have been a fire, if those wires happened to get loose enough to heat up, or even arc. And if not that one, maybe one of the other existing connections. So, I redid all of the wiring in the house, taking out the old wire and putting in new. The wire itself wasn't bad as it was good 12 guage electrical wire. But, I just went with "out with the old and in with the new" thought process.

In the process of doing this, I found that in the part of the house that just had newly painted walls (the ones with slat and lath and no insulation) also had no earth ground wires at all. Oh, they put in new 3 prong outlets, but they didn't have a green wire to ground in any of them. They also didn't do that good a job of putting in the new outlets either as they reversed hot and neutral in several of them.

It really makes me wonder...if the electricity hadn't gone out in the kitchen, or if I hadn't decided to put in a studio, a little later, I might have never found these safety issues. True, they didn't do anything really illegal themselves, but they weren't qualified electricians to do the work, either. A qualified electrician wouldn't have done some of those things or left the existing wiring like that.

I won't even go into how some devices will be perfectly fine when used alone, but if you put two of them in the same system, they don't like each other and a buzz or hum develops. Maybe one of the manufacturers didn't go far enough in filtering out possible EF interference and it now is causing you headaches. But, even if they did leave out some filters to try and save some mass production money, if your electrical wiring is correct as it can by with a good earth ground and the hot and neutral wires where they should be and there are no compressors from a refrigerator or something else on the same circuit, it might not be an issue.

But, even if you have everything correct, you can still hear some strange things. Maybe the sun decided to have a few spots one day or something else totally out of human control happened to find it's way into your life. I've got an Interstate highway about 1/2 mile from my house. There are still days, while fewer and fewer in number, when I'll hear some trucker saying "breaker one nine, anybody out there got their ears on?" or something similar in my speakers. It only lasts for a few seconds, but at just the wrong moment, it could appear on my recordings.

So, don't assume someone did their job, when looking for what could be the cause of a hum or a buzz in your recording system. It's not always true. There are so many ways for someone to get around doing what they should do and what we assume they did. And sadly, even if it's not done correctly, electricity does still work and the lights will go on. But, if you assume that's because someone did it correctly, you could be mistaken.

All right seeing we are looking at all kinds of causes, I had an induced noise from a power pac plugged into the back of a piggy back plug (or double adaptor) the item with the power pac was fine but the other piece of gear, in this case a Yamaha SPX90, suddenly started to hum and have noise problems.

I also had problems in one of my early studios with the telephone exchange across the road, I was getting induced noise into the mains supply cables, this was extremely hard to get rid off and the only way was to use very good quality cables. It caused real problems whenever a single coil guitar turned up as that picked up the airborne stuff.

Just pointed this out as there is sometimes no simple answer and investigation is needed.

Go back to my answer #8 where I asked if the power point had a good earth, don't assume it does, even the house earth may be bad or non-existent. I did move into a house years ago where someone had broken the main earth cable through the roof between the main switchboard and the main earth point, just left it and did not fix it, a deadly trap for some poor person later. Fixed that and put down a better earth stake and all noise including the stereo in the lounge went away. Check the earth resistance in the house!

Alan.
 
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