The Noise-Free Studio: 10 tips to battle electrical noise



Your favorite hype man might be in the business of "making noise" but in the studio or live in concert, that's the last thing you want to hear. Noise comes unexpectedly, ruins a clean signal and reduces the dynamic range of records amongst other vices. So no, noise is not your friend.

This post is is going to take a look at how using the right cables and devices can help ensure the cleanest signal and mitigate against noise.

Common sources of  Electrical Noise
Electromagnetic Induction: Cables can pick up noise from nearby devices with varying magnetic fields like a computer monitor (screen) via electromagnetic induction. That's why studio speakers which are usually placed close to computer screens/monitors are usually magnetically shielded.

Radio Frequency Interference RFI: Ever hear a particular noise from your speakers when your phone is close to it and there's an incoming call? That's RFI, it basically occurs when cables or electrical devices act like an antenna and receive radio signals.

Ground Loops: Ground loops are created when two devices (e.g a guitar amp and a mixer) that receive power from two different grounded power outlets (e.g. wall sockets) are connected together usually using a cable. Any change in potential or induction from nearby devices can make current flow in the in the earth wire and cause unwanted noise.

Audio Cables and D.I boxes
Unbalanced Cables: Unbalanced cables consist of two wires, one for signal and the other for ground which also doubles as a shield to the signal wire from electrical interference. They usually come with TS (Tip Sleeve) connectors or as phono/RCA cables.

RCA/Phono cables (unbalanced)
In lengths of no more than 18ft they can be used for a variety of studio applications.

Balanced cables: Usually seen with XLR or TRS (Tip Ring and Sleeve) connectors, balanced cables consists of two signal wires and a third ground wire that serves as an interference shield too. The two signal wires (hot and cold) carry identical copies of the signal however one (cold) has its polarity reversed by the gear sending the signal. In transit, the same noise is picked up by both signal wires and are identical too. On reaching the receiving gear, the polarity of the 'cold' signal is reversed back to the original and summed with the 'hot' and in so doing the picked up noise is cancelled by a phenomenon called 'phase cancellation' and the original signal (now doubled) is halved to it's initial level.

TRS cables (balanced)

A bit complex but an ingenious way of ensuring noiseless signals. I sincerely hope your respect for balanced cables has been buffed up.


DI Box (Direct injection): A DI box converts unbalanced signals to balanced copies. It's used for converting high impedance signals (high voltage, low current) like those from a passive guitar or keyboard to a low impedance one (low voltage, high current) like those from a microphone that can be fed into a mixer.

DI boxes usually also have a 'ground lift' switch to isolate the equipment from ground loops.


10 Tips to Reduce Electrical Noise In the Studio

1. Make sure all your audio cables are quality shielded cables. Get quality audio cables from Shmproaudio.com

2. To avoid ground loops, connect ALL studio devices to one power extension, which is then plugged into a wall socket.

3. For even better results, all studio devices should be connected to a power conditioner like Furman M-8X2 and Samson Powerbrite series  which filters AC power for RF/EMI noise and protects connected devices too from voltage spikes.

4. To ensure clean monitoring, use balanced cables (with XLR or TRS connectors) to connect your monitors to your sound card and if you have to use unbalanced cables make sure they don't exceed 5 metres in length.

5. Most modern monitor speakers are magnetically shielded, but if you're still using a tube computer screen it's best your speakers are at least 2 feet away from your computer screen on both sides (left and right).

6. Radio frequencies sometimes can be a bit of a hassle to combat especially when your studio is near a transmission mast or broadcast station, but over time some monitor brands have been more prone to RF interference like the KRK VXT monitors. As a rule of thumb avoid them and worse case scenario, wrapping your monitors in aluminum foil does help attenuate RF interference.

7. Use a D.I. box for guitars and keyboards to ensure a cleaner take and more dynamics without clipping, especially for basses.

8. Read the documentation for your gear to know it's input and output formats, whether balanced or unbalanced.

9. If you must connect you guitar to an Amp and mixer simultaneously using the DI box'es "thru" feature, make sure the "ground lift" feature is on to mitigate against ground loops if the Amp is connected to a different wall socket from the mixer.

10. Make sure the studio is acoustically treated so you can detect any electrical noise easily.


Written by
Chidi 'Tite' Nnadi

Location: Nigeria

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