I hope you’re all doing well. I’m reaching out for some advice on a couple of audio recording issues I’m facing:
Is there a straightforward method to eliminate the high hum in this audio recording and address any other undesirable noises?
Can you help identify what’s causing this hum, and what adjustments we should make at the sound board to fix it?
Bonus Points: I’d also appreciate any tips on enhancing the audio’s overall quality, such as adding a touch of reverb, creating a sense of ambiance, or any other techniques to make the recording sound its best.
I need to wait until daytime before I can fire up the office sound system, but if it’s what I think it might be, it’s a USB error. You can get this if there is a mismatch between the digitizer from the mixer board and the computer recorder input. We’ll see.
As far as “enhancements,” the things you mentioned separate the performer from the listener. That’s one of the reasons the audiobook people hate “room sounds” and echos. The goal is someone telling you a fascinating story over cups of tea.
Also, the more ambience you add, the harder it is to understand the words. And good luck if you change your mind later. Those kinds of changes are super difficult to remove.
One other note. Do you have a clip with more room tones in it? The existing clip has almost constant speaking and it’s rough to get noise by itself for analysis.
If it is USB mosquito whine, we have a pre-burned filter for it.
I’m currently unable to provide a detailed flowchart of the sound recording setup because one of my colleagues manages the recordings. However, I can tell you that they use a sound system and an Apple MacBook, and they either use Audacity or GarageBand for the recording process.
I have noticed some unusual sounds at specific time stamps in the recording.
[ie: 32:00, 33:00]
Based on my research, low, constant hums are usually caused by ground loops or unbalanced sound cables.
It looks like mains hum, notching out the worst offenders helps, (but notches cause collateral damage to speech).
Newfangled AI does a better job, as the hum slowly changes timbre.
That man never takes a breath. Do you know if this is a copy of the raw recording? There is a current fashion of editing out breath pauses in post production. I think it’s distracting.
It is mains hum or power line in the US. 60Hz, 120Hz, etc.
But it’s not ordinary hum. It’s “dirty.” That’s what gives you the high pitch whine, screechy sounds. My money is interference from the theatrical lights.
You can’t take that out in post production. There is significant interference with the tones that make your voice intelligible. Repair efforts are a good way to turn your voice into wine glass honking.
There is a forum problem, too. Have you ever played “Telephone?” That’s where you sit in a line and the first person is presented with a message. They whisper the message to the next person and so on down the line. The message the last person has is completely different from the original.
I’m up for advanced troubleshooting, but we need to be closer to the actual audio operators. "I told 777 to tell the production people to tell the audio engineer to touch the microphone while the system was hot … Etc.
Is it a metal microphone such as a Shure SM58? If it’s a wireless microphone, fixing the sound damage could be a career move.
It’s possible you may need facility access including lighting and sound setup to cause the problem so you know when you have it licked. If you have to wait for once a week, see: career move.
Run the system (see: lights and noisy sound system) and unplug the MacBook wall power. Make it run from its internal batteries. You can do this with the Mac doing its job. It should make no difference to the recording.
If you can’t run the MacBook on batteries, we may have identified one very serious problem.
Here’s the Facebook Live feed that’s been published online:
Skip to the 00:27:50 mark to get to the relevant part.
If you need the raw footage in file format, I can probably get that for you this Sunday.
We’ll start with some basic troubleshooting by checking the power cables on the speakers and other equipment. Research shows that it’s best to plug all cables into the same power source, like one circuit or power strip.
Does anyone have a simple suggestion for how to do this, especially if the room speakers are 50 feet away from the sound system? Would using extension cords be a good, cost-effective solution, and if so, what gauge should they be?
The room doesn’t have stage lights, but there are can lights and some old fluorescent tube lights. One set of these lights flickers and suddenly changes brightness.
Most of the microphones used are wireless, but in this case, the speaker is using a wireless lapel mic. I can find out the make and model if that helps.
Got it! I want to clean up the sound without losing the natural feel. I like how you got rid of the hums but kept some white noise. I just don’t want it to sound too sterile.
That can cause the periodic change in hum level, bit it’s not causing the problem. That could, however start a fire, so put that on the building maintenance list.
So they’re powered speakers. That could cause trouble, but I’m much more interested in keeping the wireless receivers, mixing desk and Mac on one single power.
Can you hear this buzz on mixing desk headphones?
Let us know if the Mac internal batteries are OK. We had one production manager at work that had no end of troubles with their Mac. I pulled the wall power and the Mac immediately dropped dead. Replace the battery pack and all the problems vanished.
We call that “Clean.” There was a collection of fresh, new production people that made a terrific-looking news set. Good lighting, backdrops, desk, etc. Things went OK until one of them said something. Instant kids recording in the garage.
You got the final solution from Trebor’s filters? We should remember nobody wrote that electrical damage can’t change over time. It’s good to know what’s causing this.
OK, just so I have the solution properly understood:
Plug the wireless receivers, mixing desk, and Mac into a single power source.
So you’re saying they should all be plugged into a power strip (surge protector) that is then plugged into a single wall outlet?
Should I also consider other nearby devices like compressors, amplifiers, etc.?
Should they also be plugged into the same outlet, or at least on the same breaker circuit, to ensure the right amount of power for the devices?
Does it make a difference to keep the powered speakers connected and plugged into one outlet?
Clarification: Their notch suggestion will help with audio that has already been recorded and will need post-production editing.
More importantly, the long-term solution is addressing what is causing all of the interference and potential electrical ceiling fire. If I do this correctly, I could be a hero in the literal sense. I will of course give you the appropriate public recognition.
ie: key to the city, a moment of clean recorded silence, etc.
I see people trying to sell computerized, steam driven, hot and cold running beer socket testers. Thanks, no. Three lights will do it.
It makes my teeth hurt that you’re doing troubleshooting blind (or deaf). Listening to the sound mixer on headphones and turning down the microphones one after the other could go a million miles toward quickly solving the problem.
If you can’t hear the problem there, then it almost has to be the connection between the sound mixer and the Mac. Also See: Mac Batteries.
Just to be crystal clear about this. The shield or case of your electronics is connected to the third prong on the electrical plug. The round one in the US. Ideally that goes to a metal stake shoved into the ground outside the building.
If you have a wiring error, your protective electronic shields (and the case on the mixer) could be connected to that power transformer on the service pole.
Watch the Mac’s adorable little battery health indicator in the upper right. It should be 100% all the time the machine is plugged into the wall. If it drops to a lower number quickly after unplugging the wall, then attention must be paid.
Unless someone went out of their way to buy odd or damaged cables, this should be OK as it is. Electrical Code in the US is pretty strict. You are looking for Dog Chewing The Cable damage.
There could be Old Age Damage. Unplug everything and plug it back in at least once. You can have corrosion between the plug and the socket which can build up over time.
In high-octane trouble servicing, you will be listening to the mixer on headphones when you unplug one of the wireless microphones. The sound will pop once and the buzz with vanish.
