Low level hum in background of recordings

[kozikowski]

It's intermittent.

Isn't that just the very best? Nobody wrote you can't have two or more problems, either.

The first ACX Mastering tool, Filter Curve, is a rumble filter. It's job is to get rid of everything lower pitch than about 100Hz. Many home microphones produce rumble, thunder, and low pitch trash (because they're home microphones) and basic wall power hum is 60Hz. All gone. That's what saved the sound file I analyzed. It had a lot of low pitch stuff going on, but much of it is more or less normal and it all vanished in the Filter Curve correction.

90Hz is right on the edge. Some of that gets quieter, but a lot of it survives the mastering corrections. There was no 90Hz trash in the second sound file I checked. That's why it worked so well.

I would so start waving the microphone around the room and see if you can figure out where this is all coming from. At least the 90Hz tone. That one is not normal and may represent something broken.

How are you reading the work? Not paper, right? You're reading from something electronic?

I use a paper script, record on a stand-alone sound recorder, and leave my phone in the garage. I don't have any of these problems.



Koz

[kozikowski]

Nowhere in the messages do you tell us why you're doing this. Are you producing training exercises for a school?

Stand-alone training classes or is the goal to submit for audiobooks?

Fair warning that there are two relatively new restrictions for new audiobook readers. I have to be able to buy your book in paper or eBook on Amazon. No fair trying to submit both at once. One forum poster tried that. It wasn't pretty.

There is a list of book types they're not interested in.

Scroll down.

https://www.acx.com/help/200878270

The fuzzy rule is your book should have plot, characters, and setting. There was a forum poster who was going to try to read her cookbook. Probably not.

Koz

[bbrady32]

Ok, so I'll turn off the lights, record. Take my phone out, record. I don't have anything else electronic in the room. What else should I try? It is totally crazy-making. Especially when I record a big long thing and then it's ruined. Could it be the mic itself? It's only a year old, I wouldn't think so but...

[bbrady32]

I record curriculum for an online education company. I do typically read text off my phone to record, so that could most definitely be it. I'll try taking it out and see.

Could you explain a little more how to do the wave around test? What am I looking for in the playback that indicates a problem? I don't have access to my space right now, but will double check my mastering set up. I set it up on a shortcut and don't actually remember how to see the steps!

Thanks for all your help. This extra work has been really important this year and I'd like to make sure my quality doesn't go in the toilet!

B

[kozikowski]

Ok, so I'll turn off the lights, record.

I know you're waiting for me to trot out a magic formula for solving this, but sometimes step-by-step scut work is the answer.

If you're making actual recordings, slate them. "I turned the lights off," "I'm turning my phone off," "Turning my tablet off." Hold your breath for a second or two after you do that so we don't have to compete with your lungs for the analysis.

Could it be the mic itself?

I don't think so, either. I really liked the G-Track before this one.



I told the owner if he wasn't paying strict attention after this photo shoot, I was going to take it home with me.

Koz

[kozikowski]

I need to step away for a bit.

Koz

[kozikowski]

The G-Track can be set for Cardioid (directional) and it probably should be. That means the sensitive spot is the side grill just up from the company name. You can pick up the microphone and aim it to different parts of the room and it will "prefer" that direction over others. I expect if you aimed it to the room heater or air-conditioner, the wind or rumble noises will increase.

This is how I found my bad sound cabinet. I aimed my microphone to the cabinet (which was supposed to be off), and it said, "mmmmmmmmmmm." So I got closer and it said, "MMMMMMMMMMM."

So I pulled the power plug and it said, "______________"

A bit ago I was recording a simple voice track on a messy desk and I laid the microphone on top of the mixer power cables.

PowerSupplyHumTest-Edited.mp3

(800.82 KiB) Downloaded 10 times

Surprise.

You can do all this live by plugging your headphones into the G-Track, set Monitor On (on the rear) and listen as you go. It's perfectly "legal" to jam the microphone close to the source of noise just to make sure of what's happening. You can also yell into a microphone. That's OK, but never blow into one. That can reduce some microphones to expensive trash.

Let us know how it goes.

Koz

[bbrady32]

Ok, I will try that. I also played around with some different conditions -- I think I hear more hum in the file with my bluetooth on and the lights off than the one with my phone put away and the lights off. I expected the opposite.

[bbrady32]

Also, here are the mastering specs I use.

[kozikowski]

It counts if you can make it worse. That won't do you any immediate good, but it will tell us more about the problem.

Nobody wrote it can't be a monitoring problem. Are you on wireless headphones or earphones? Wireless means you can't live monitor yourself for real time quality control. Wireless also greatly increases the possibility of listening damage.

Can you post the actual Macro text? I've been avoiding publication because of the wonky way Loudness Normalization behaves.

Koz