When I recently fired my home studio rig up, I noticed a few cracks and pops coming through the right channel. I had not experienced this before and spent a lot of time researching where the problem may be coming from.
So, how do you troubleshoot and remove the crackling noises? Look for visible signs of damage first. Then systematically check devices and power outlets. Finally, go through each item in your signal chain until you isolate the exact cause. About 6 times out of 10, it’s a problem with a cable.
Using unbalanced cables can be an issue in home studios, especially when the mains ground is less than perfect. Finding the exact cause of your unwanted noise can be stressful, so hopefully, the following troubleshooting guide will ease your agony.
The first thing we are going to determine is if the crackling sound is confined to one channel only or if it is coming from both sides. Listen to each monitor separately and figure out if the unwanted noises are coming from one side or from both sides.
If the crackling sound is coming from just one side, you have just halved the amount of troubleshooting you are going to do.
Look for obvious signs of damage to any cables through your system:
If you do find a damaged cable:
Replace the damaged cable with a new one. If you know how to, repair the damaged cable. Most cables can be repaired inexpensively and quickly. If you can't fix it just yet, and wish to keep a hold of it, don't forget to label it “DO NOT USE”.
If you have a second set of monitors attached through your studio controller or audio interface - switch to these and see if the crackling goes away. If it does, it looks like either the connection between the controller and the main monitors, or the power supply to the monitors, are at fault.
These are not necessarily the most common issues, but they take less than a minute each to do - so let's cross them off the lsit.
Switch off your cell phone or move it far away from your studio room - sometimes mobile phone signals can interfere with unshielded monitor cables.
If this fixed the problem, you have a short-term solution until you figure out what is allowing the phone interference to cause crackling on your system.
Turn off any wireless devices on your PC or Mac - bookmark this page so that you can keep troubleshooting if you lose your internet connection - sometimes a wireless transmission signal can cause interference with your CPU or other solid-state devices.
If this fixed the problem, check you have the latest drivers for all of your devices.
One by one turn off devices that are externally connected to your PC or Mac, or to your home studio setup.
Disconnect or switch off the following:
Keep it clean: do not switch on or reconnect anything just yet. It's going to be less complicated to troubleshoot with fewer things connected.
If you have more than one power outlet in your room, plug your gear into that. Just remember - two power outlets on the same plastic housing are not separate outlets - internally they will be wired to the same mains supply. Try each of the following:
|OUTLET A||OUTLET B||OUTLET C|
Table 1: Mains Outlet Troubleshooting Combinations
If you have determined that the problem is confined to one side, go ahead and swap out the monitor’s power supply cable and monitor signal supply cable (XLR cable).
If the crackling has gone away, it’s likely one of the two cables (that you have just swapped out) need replacing. Swap each of the two cables back in separately to see which one is the faulty cable. Be sure to swap them both back in, in the unlikely - but not impossible - scenario, that they are both damaged. Repair the damaged cable if you can, or get online and order a replacement straight away.
Continue to isolate each item of gear in your signal path. Use headphones in your Audio Interface or Studio Controler to work back towards the DAW. This way, you are isolating the monitors, and it is easy to see if the crackling is coming from a particular source.
Figure 2: Home Studio Signal Chain
Keep your XLR cables in pairs. I like to use ‘same brand’, ‘same spec’, ‘same length’ for left and right channels. So, if you do need to replace one - order two! The old one can be repaired later on, and after checking the second good one, you will have two spares you know are in good working order.
Some people recommend putting the bad cable on the good channel to reproduce the problem. DO NOT FOLLOW THEIR ADVICE! Instead, keep broken cables away from your cherished home studio gear! Broken cables can damage the things they are connected to if you are not careful.
If you suspect the cable is damaged, don't use it again until it has been repaired.
If the crackling sound is pulsing this can point to a problem with software such as your iOS, DAW, or device drivers. After you exhaust the other troubleshooting steps reinstall software and ensure you have the latest drivers for all your audio gear. You can also try increasing the buffer size for audio interfaces.
Confirm you are using balanced XLR cables to send audio to your monitors. Balanced cables use three wires, so the male connectors have 3 pins, or use Tip-Ring-Sleeve (TRS) connectors (which kind of look like stereo guitar cables).
Figure 3: Balanced 3 Pin XLR Connectors
Figure 4: Balanced 3 Part TRS Connectors
If you have a multimeter check the continuity between each of the three wires. Wiggle them about to test for dry joints or bad connections. Be on the lookout for cheaper, mass-produced ‘overmolded’ cables and plugs - you will know they are ‘overmolded’ because you won't be able to unscrew the housing - the ‘overmolded’ cable connectors are notorious for lousy quality.
TIP: If you do have these type of overmolded style cables, think about replacing them when your budget allows.
Why do my speakers pop when I first switch them on? The popping sound is caused by an initial signal surge and shouldn't happen with your monitors in isolation (if you have good monitors that is!) - cheap ones, on the other hand, are poorly designed, and there is little you can do without replacing them. If you hear a pop while your monitors are already on, and you are switching something else on, such as your studio controller, there is most likely a problem with the grounding in your room. A temporary fix for this is to switch the controller on first, monitors last - and vice versa when you have finished for the day – monitors off first, then controller, then computer.
What is a balanced cable? A balanced cable has three wires running through it. Two wires carry the signal, and one is for the ground shielding. There is no shielding on an unbalanced cable. The shield, usually a foil mesh, helps to reduce noise. One of the two signals is inverted at the source and reinverted it at the destination resulting in noise canceling. A balanced cable is useful to reduce noise and interference, especially over long distances.
What is RFI? Radio Frequency Interference (RFI) is also known as Electromagnetic Interference (EMI). RFI and EMI are not 100% the same thing but for most purposes can be thought of as one. RFI is the interference from one electrical source to another. RFI can be emitted within the same device or can be transmitted through the air. Long unbalanced cables can produce RFI, especially if tied together in a loom.