Electrical wiring schemes to lower noise floor?

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Orpheus

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hi.

i dunno how the big studios deal with hum problems and other electrical related problems..... i heard of "star-grounding." can anyone explain?

currently, i have a furman ar-1220 voltage regulator going into the wall. then a furman it-1220 balancing transformer going into the voltage regulator. then all the equipment is hooked up to various power strips that are connected to the it-1220.

yet, much of my equipment still hums when i turn up the monitors. spectrum analysis of all my recordings reveal a high amount of 60hz hum, along with gradually lower amounts of its harmonics (120hz, 180hz,... etc.).

for unbalanced cables, i only tie the shield at the output end. for the balanced cables, i tie ground the shield at both ends.

so........ any practical advice to get rid of this noise? it's bugging the hell out of me.
 
yeah... it's a house.... and all the lights here have dimmers. however, even with all the lights off i still have the same problems. could dimmers still cause problems even when the light itself is off?
 
Doesn't seem too likely that dimmers would cause a problem when turned off.

Take a look at the link I posted (at equitech.com), and also poke around the rest of their support section a bit. They have some procedures for troubleshooting hum problems.
 
Are the dimmers off or merely turned down all the way?

Computer monitors are large sources of 60hz hum too, and computer power supplies.

Your noise may well be coming from something after the furmans
 
c7sus,

that sounds like a good idea.... however, i'm not an electrician, and i haven't ever even looked at my breaker box! i don't want to do anything stupid.... so.... i'd have to do this as a last resort. last thing i want to do is fry something or get myself hurt. and it's an old house too..... has some REALLY weird buttons around the house that no one figured out how to use. some things here are really really really strange. it's better not to fool with this house......... my friend swears it's haunted. ;)

innovations,

the dimmers are turned all the way down, so assume they were off, but i guess the only way to make sure is to disconnect all the lights. yeah, i tried to keep all the non-audio stuff off the power from the furmans... and i plug all the lights and monitors and computers and stuff into a separate conditioner off the wall. however, i wonder.... perhaps this causes more problems, since the monitor still connects to the computer, which still ends up connected via firewire to my audio interfaces, which of course are grounded to the mixing board.... etc...... so eventually everything has a electrical path to everything else...................

i dunno.

but you know what?--i also spectrum analyzed many of the downloadable samples on the mp3 mixing page, and they also show the same anomalies. did you ever look at them?--same thing.... the graph usually looks like 2/3 of a mountain in that at 20hz (where there should be little energy)... there is quite a bit of sound. then the curve rises to the 500hz region, then gradually decreases to under 12khz. almost all amateur music looks like this in the spectrum analyzer. now, if you look even closer under a higher-resolution analyzer, you can see that the peaks are at 60hz and its harmonics. so, this suggests to me these problems are caused by electrical problems. so......... i think almost all amateur studios have this problem....

your solutions would help many on this board.
 
Power to my control room is supplied by 3 circuits, all on the same phase.

These 3 circuits run to 3 Furman IT1210 balanced transformers (one on each)... all gear in the control room is supplied via those transformers.

There's not a HINT of noise anywhere -- it's dead quiet!
 
how 'bout computers and stuff?--you keep them on the balanced lines?--or separate? how 'bout networking stuff like switches/routers? ......is everything running off the studio power?
 
eeeeeeeeeeeeeehhhhhhhhhhhh Furman...........
glorified power strips.
I'm sorry to say that I've never experienced those things to actually do a good job.

real power conditioners are extremely heavy pieces of gear. Good ones are made by companies like Powervar and ADC.
These things will reduce your noisefloor substantially.
They are expensive new, but the good thing is that they are indistructable, so you might as well buy second hand.
My friend Mr. Patchbay always seems to be able to find them
http://www.flash.net/~motodata/patchbays/power.html

Of cause, regardless of the kind of gear you use, a good earth is a primary requirement. Sometimes it helps to find out which gear makes noise, isolate the ground of that gear and run it on a seperate, dedicated ground. Over here we have a seperate ground for the most sensitive gear, the 'normal' ground, as well as another seperate ground connection in the tracking room.
 
the link didn't work.

not heavy?--the it-1220 is 65 lbs. i wouldn't call that light. that's twice as heavy as my 1000 watt amp. the ar-1220 is 35lbs..... so that's 100lbs in just power "conditioning."

......well, if i ever get to build a new studio from scratch, it'll definately be grounded correctly. but for now.... still trying to figure out what to plug where. if blue bear reports no hum.... then he must be doing it right.
 
ok, thanks.....

what would i look for then while using these breakers?--what electrical problems would cause high hum? cause like i said... it seems to be in everyone's recordings on this board.
 
Orpheus said:
...the peaks are at 60hz and its harmonics. so, this suggests to me these problems are caused by electrical problems. ...
Click to expand...
Did you happen to look at any recordings made by Europeans? If so, were the peaks in those recordings at 50Hz and its harmonics?

Just curious.
 
you know... that's a good question. got links to the european music on this mp3 mixing forum?--i dunno who's european.

but you know, stangely i did a recording yesterday, and the peaks shifted to 100hz and their harmonics....... so i'm totally confused now. but the graph is still odd shaped--there really shouldn't be much energy at 20hz or lower if the music was properly recorded.
 
If I get a chance I'll look at some myself later on. There are several Europeans who are regular contributors here. Pedullist is one who comes immediately to mind.
 
k.... i just checked out tinnitus blues by wfaraoni in texas:

has peaks at 55, 109, 164, 220hz .... etc...

i tried to find trojka's music, but he doesn't seem to have anything downloadable at the time...

just looked at boogab's, and i couldn't find any real peaks in the low-end. though his spectrum analysis graph is also skewed awkwardly.

so, for now i would say my findings are in-conclusive. i'll have to do more research later. i'll let you know.

next i need to rip a pro CD and see what it looks like....
 
Orpheus said:
i tried to find trojka's music, but he doesn't seem to have anything downloadable at the time...
Click to expand...
All downloadable for me. But I'm a NoWhereRadio member. Each artist can decide whether to allow downloads by non-members. Evidently Pedullist (aka Trojka) has this turned off. Sorry!
 
i appreciate it.

but i don't think the problem is line noise. various components here hum more than others. stuff plugged straight into the wall in another room in the house, without any conditioning, sounds totally silent. it's just when it's plugged into my studio system everything starts to hum. i have more than 50 pieces of equipment here..... so it probably has to do more with grounding and stuff. but someday when i have time i might try your suggestion.
 
c7sus said:

DON'T BECOME PART OF THE PATH TO GROUND ON A LIVE CIRCUIT.

As long as you NEVER LET THAT HAPPEN, you will be fine.

ALWAYS TURN OFF A CIRCUIT BEFORE WORKING ON IT.

NEVER TAKE ANYBODY ELSE'S WORD THAT A CIRCUIT IS DEAD.
Click to expand...

Amen to that!
 
One final question: Are you running balanced connections?
 
where i can. of course, most synths aren't balanced... i might buy some line transformers later.... but all the good ones are kinda expensive. but if the unit has balanced in/outs, that's what i used.
 
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