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rec-tec



Joined: 04/03/09
Posts: 117
stopping guitar hum for recording
      #1107696 - 13/06/14 06:18 AM
hi all

whenever i try to recording electric guitar i notice when i solo the guitar track there is always a little hum which ranges from alot (unusable) to just a little (annoying)

is there a gizmo that i can plug the guitar into that sits in between the guitar and the recording device - would a DI box help - or is it just something inherent in guitar circuits?

help/advice (as always) appreciated

cheers

RT


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Hugh RobjohnsAdministrator
SOS Technical Editor


Joined: 25/07/03
Posts: 22131
Loc: Worcestershire
Re: stopping guitar hum for recording new [Re: rec-tec]
      #1107713 - 13/06/14 09:10 AM
This is usually caused by the natural sensitivity of single-coil guitar pickups to ambient electro-magnetic fields.

You'll probably find that if you orientate the guitar in different directions you'll get different levels of hum. You might also find that if you turn some things off in the room you'll reduce the levels of hum.

H

--------------------
Technical Editor, Sound On Sound


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rec-tec



Joined: 04/03/09
Posts: 117
Re: stopping guitar hum for recording new [Re: Hugh Robjohns]
      #1107738 - 13/06/14 10:48 AM
thanks for that hugh

i did notice one time - if i put my bare foot on the jack that stuck out of the fx unit i was using that the hum significantly reduced (groundloop? - not really sure what that is, but...)

i will try your suggestion

cheers

RT


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ef37a



Joined: 29/05/06
Posts: 6891
Loc: northampton uk
Re: stopping guitar hum for recording new [Re: rec-tec]
      #1107758 - 13/06/14 12:57 PM
Quote rec-tec:

thanks for that hugh

i did notice one time - if i put my bare foot on the jack that stuck out of the fx unit i was using that the hum significantly reduced (groundloop? - not really sure what that is, but...)

i will try your suggestion

cheers

RT


AARRRRGH!!!! That sounds as though you have no earth on the system (you cannot, by definition have an earth "loop" with just a guitar and an interface unless said interface is separately powered perhaps.)

What country are you in RT? If UK get an electrician in to check the mains wiring. In the meantime, do not "experimentally" touch bare metal objects! Actually peeps,NEVER do that!

On the wider point of guitar hum. Been a while since I tried it but if you set a Strat for -20dBFS on a modest strum, you will be lucky to get the noise below -70dBFS. But I shall have another look.

Dave.


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Jack Ruston



Joined: 21/12/05
Posts: 4557
Re: stopping guitar hum for recording new [Re: rec-tec]
      #1107763 - 13/06/14 01:26 PM
Yeah just turn yourself and the guitar, and keep turning until you find a quiet (er) angle. DON'T do that thing with putting your bare foot on some metalwork to get rid of the noise. That's how people get fried!

J

--------------------
www.jackruston.com


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ef37a



Joined: 29/05/06
Posts: 6891
Loc: northampton uk
Re: stopping guitar hum for recording new [Re: Jack Ruston]
      #1107764 - 13/06/14 01:30 PM
Quote Jack Ruston:

Yeah just turn yourself and the guitar, and keep turning until you find a quiet (er) angle. DON'T do that thing with putting your bare foot on some metalwork to get rid of the noise. That's how people get fried!

J




Yeah! The BEST one is when they say "If I hold THIS and then touch THA........!"

Dave.


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Hugh RobjohnsAdministrator
SOS Technical Editor


Joined: 25/07/03
Posts: 22131
Loc: Worcestershire
Re: stopping guitar hum for recording new [Re: rec-tec]
      #1107781 - 13/06/14 02:51 PM
Quote rec-tec:

if i put my bare foot on the jack that stuck out of the fx unit i was using that the hum significantly reduced




It would help to know what your entire recording system comprises.

The grounding with the foot thing suggests to me that your recording system has no ground reference. This is common when using battery-operated units and standalone recorders.

If all your mains-powered equipment is 'double insulated' (it will have a box-within-a-box symbol on the power unit) or battery-powered, it has no connection to the mains safety earth. In that situation everything 'floats' and the cable screens essentially act as aerials to pickup any stray interference going.

The solution in such cases is to engineer a deliberate ground connection to the mains safety earth from the sleeve of one of the signal jack connections. If this sounds like the case for you, let me know and I'll explain how to achieve this safely.

H

--------------------
Technical Editor, Sound On Sound


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rec-tec



Joined: 04/03/09
Posts: 117
Re: stopping guitar hum for recording new [Re: Hugh Robjohns]
      #1107789 - 13/06/14 03:35 PM
thanks hugh

my guitar goes into a (jack) strymon timeline (mains powered) then into a (jack) us144 (usb powered) or motu 828mk3 (mains)then (usb) computer - etc

cheers

RT


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Hugh RobjohnsAdministrator
SOS Technical Editor


Joined: 25/07/03
Posts: 22131
Loc: Worcestershire
Re: stopping guitar hum for recording new [Re: rec-tec]
      #1107794 - 13/06/14 03:50 PM
If the computer is a desktop model it will be class 1 with a mains earth connection, and the whiole system should be grounded through that. But if it's a laptop it's probably class II (double insulated) and so the whole system will be earthless -- which is what it sounds like you have.

You can get a safe grounding plug here:

http://www.groundology.co.uk/earthing/earth-connection-plug-uk

You'll then need to make up a lead -- single wire -- with a 4mm plug to go into the mains adapter plug, and wired to the sleeve of a suitable plug to connect with an unused audio socket on your interface.

You could use an ordinary mains plug, but you should take GREAT care to insulate the live and neutral pins inside the plug, just in case the earth wire comes loose and starts floating about in there!

H

--------------------
Technical Editor, Sound On Sound


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rec-tec



Joined: 04/03/09
Posts: 117
Re: stopping guitar hum for recording new [Re: Hugh Robjohns]
      #1107804 - 13/06/14 04:18 PM
hi hugh

yes - it is a laptop - so i think you are correct

i am hopeful that this will fix it and am most grateful for your advice (as ever)

i always get great advice on this site

cheers - hugh

RT


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rec-tec



Joined: 04/03/09
Posts: 117
Re: stopping guitar hum for recording new [Re: rec-tec]
      #1107808 - 13/06/14 04:28 PM
just purchased the plug thingy

so will report back with feedback (and hopefully no hum!)

cheers

RT


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10K-DB Music



Joined: 04/01/11
Posts: 16
Loc: Midwest USA
Re: stopping guitar hum for recording new [Re: rec-tec]
      #1108960 - 22/06/14 11:23 AM
I always use a "Noise gate",,,for live or studio. Makes things much less complicated.

--------------------
Indie artist writing/performing multiple styles of music,recording+producing @ home studio on Tascam 24 trk 2488 Neo. Vocals/Guitars/Bass,,using BFD/ECO drum software/Digitech processors.


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The Elf
active member


Joined: 14/08/01
Posts: 9603
Loc: Sheffield, UK
Re: stopping guitar hum for recording new [Re: 10K-DB Music]
      #1108969 - 22/06/14 12:06 PM
Quote 10K-DB Music:

I always use a "Noise gate",,,for live or studio. Makes things much less complicated.



Live, yes. Studio, never.

A gate can ruin an otherwise perfect take. If you need a gate to record then there's something wrong higher in the signal chain, whch should really be fixed it properly at source. If you do still need to gate, then do it AFTER recording, not as you record.

--------------------
An Eagle for an Emperor, A Kestrel for a Knave.


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10K-DB Music



Joined: 04/01/11
Posts: 16
Loc: Midwest USA
Re: stopping guitar hum for recording new [Re: The Elf]
      #1108971 - 22/06/14 12:22 PM
Quote The Elf:

Quote 10K-DB Music:

I always use a "Noise gate",,,for live or studio. Makes things much less complicated.



Live, yes. Studio, never.

A gate can ruin an otherwise perfect take. If you need a gate to record then there's something wrong higher in the signal chain, whch should really be fixed it properly at source. If you do still need to gate, then do it AFTER recording, not as you record.


Ok,,point taken. Thanks

--------------------
Indie artist writing/performing multiple styles of music,recording+producing @ home studio on Tascam 24 trk 2488 Neo. Vocals/Guitars/Bass,,using BFD/ECO drum software/Digitech processors.


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10K-DB Music



Joined: 04/01/11
Posts: 16
Loc: Midwest USA
Re: stopping guitar hum for recording new [Re: rec-tec]
      #1109046 - 23/06/14 12:19 AM
Heres a trk using Noise gate on all trks,,except drums. I guess using a NG in studio is a subjective application,,similar to using your "favorite" mic,,or gtr,,its the end result that we all have to live with that matters,,at least for me anyways. The threshold setting on a NG is critical thats for sure,,just one mans opinion. https://soundcloud.com/scooter261/clouds-10k-db web page soundcloud

--------------------
Indie artist writing/performing multiple styles of music,recording+producing @ home studio on Tascam 24 trk 2488 Neo. Vocals/Guitars/Bass,,using BFD/ECO drum software/Digitech processors.


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The Elf
active member


Joined: 14/08/01
Posts: 9603
Loc: Sheffield, UK
Re: stopping guitar hum for recording new [Re: 10K-DB Music]
      #1109071 - 23/06/14 08:42 AM
A noise gate is a useful tool in many instances - and drums are where I would use them most often!

But modern editing and silence stripping has removed much of the requirement for the humble noise gate in the studio. Putting a gate on a guitar is fine, but if that guitar is going to fade off at the end of the song the gate is going to either cut the fade or begin chattering - not good. Much better to edit the gaps out and fade the guitar off at the end. Why mess around finding exacting threshold settings when you have scissor and fade tools to do the job perfectly and permanently?

Only when editing is onerous (e.g. drums) is a gate maybe a better solution nowadays.

I don't see gates as being particularly fetishistic in the way of mic's and such. A gate is pretty much a gate. They are devoid of character, at least since the days of hardware.

--------------------
An Eagle for an Emperor, A Kestrel for a Knave.


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The Elf
active member


Joined: 14/08/01
Posts: 9603
Loc: Sheffield, UK
Re: stopping guitar hum for recording new [Re: 10K-DB Music]
      #1109079 - 23/06/14 09:24 AM
Like the song, BTW. Great drumming too - heck what a tragic loss...

--------------------
An Eagle for an Emperor, A Kestrel for a Knave.


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grab



Joined: 08/07/07
Posts: 2933
Loc: Cambridge, UK
Re: stopping guitar hum for recording new [Re: rec-tec]
      #1110143 - 30/06/14 06:44 PM
Mains grid frequency (50Hz or 60Hz) is *very* stable. In the UK, supplies are guaranteed to be between 47Hz and 52Hz (at least they were when I was working on national grid stuff about 15 years ago), and generally they'll be a lot closer than that. So if you fire up the parametric EQ on your DAW, you can use pretty aggressive notch filters with stupidly high Q factors (i.e. a really needle-like dip in the curve) so that you only touch that frequency and you're really unlikely to take out any actual notes. This is one time where you really have to be able to type in the frequency - mixing "by ear" doesn't cut it. Generally you'll find that you'll also have some harmonics in there too, so add more sharp notches at 100Hz, 150Hz, etc., until you've killed it off.

Of course it's better if you can stop it happening in the first place...


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