Can not remove hiss/hum

Question

Okay for quite some time now I have had a problem with hiss, or hum or whatever you want to call it. My father used to record the family in our home studio. Because of this he has many microphones which I have tried using. So when I play my drums in said studio, I record with two microphones. Both afterwards have no hiss/hum/white noise. I use Audacity to record.

But when it comes to filming my skits and gameplay, there is terrible hiss. I have a small Nady phantom power box which I use. But it does not help. So for example, today I tried a multitude of different microphones ranging from RODE to MXL. SO i plugged in the phantom power, then plugged the output from a phantom plug to aux and into my camera. Which worked but there was still terrible hiss. Mic quality was fantastic but the hiss was unbearable. I use the same set up for my computer. I have also tried different post options, such as Audacity (which is not the best I know but I tired it anyways), Sony Vegas (again this is a video editing software not audio but it was also worth a shot since it's what I have) OBS, and even the Adobe Audio restoration software. Which none have come to my help.

I have written this in a fit of rage due to the fact that I have had enough with this hiss. No microphone is clean without hiss. Yes I know the higher the gain the more noise but I can not get rid of it to save my life. Maybe I need a mini mixer, I do not know. But I'm asking everyone and anyone for help.

Can anyone help me Please?

Answer 1

What type of cables are you using to connect your audio interface into your camera? Does it support TRS? TRS cables generally do a great job of eliminating noise. The issue could range from gain staging (input on camera is too high), cable selection or it could be that the camera itself has a high self noise ratio.

Answer 2

Sounds like you could benefit from a pre-amp of some sort to between the microphone and your camera. Your camera most likely takes a line level signal into the Aux jack. Here is an example of one way to handle your issue: The Saramonic SR-AX107 It will take the microphone and provide enough gain to get the signal up to line level. I can't vouch for the quality of this unit as I use a digital 4 track recorder to record the audio separately and sync my audio in post.

Answer 3

Camera microphones and inputs are usually not renowned for good Signal to Noise ratios. The inputs usually have plugin power and expect to drive the FET preamp of an electret condenser mic. The microphone you use instead is a true condenser needing phantom power. Your phantom power box does that, but it does nothing else in the way of adjusting signal levels. As a result, the output levels are way below what the camera expects and you get quite worse results than what the camera is capable of (and that, in turn, is still likely worse than what the microphone is capable of). Instead of the bare phantom power supply, you rather want a preamp (which can be part of a mixer) with phantom power.

That is the kind of stuff you want for making best use of your camera's audio recording capabilities. However, for many consumer-grade cameras, you'll likely be better off doing the audio recording to your computer and then using a video editor for replacing the audio track recorded on the camera (Kdenlive allows synchronizing external audio tracks with existing ones, making the audio replacement reasonably straightforward and accurate).

So now you are back to looking for a nice audio interface to your computer providing phantom power. The good news is that such an audio interface will more often than not have the connectivity allowing you to let it double as a preamp only (assuming you can get it power). Some might even have a purely analog signal path (no "DSP" or "digital" mixer before a "monitor" output, alternatively an "insert" connector carrying the preamp signal). So if you get an interface of the right kind, it will even work conveniently enough for computerless recording on the camera only for the cases where the quality is good enough for your purposes.

Answer 4

Looks like a use case for the "Fethead" kind of preamp (the model powered by and passing on phantom power). Definitely the smallest size of additional equipment discussed here, just not exactly the smallest asking price. But once one of those is part of your toolbox, it might come in handy in other cases of gain staging mismatch.

Answer 5

You are "filming your skits and gameplay"? With audacity?

When I first recorded stuff with a condenser mic, I was annoyed at a ticking sound. It was a wall clock two rooms away behind closed doors. You would not have noticed it in the recording room. But you did in the recording. Humans are great at directional hearing and just blending out whatever is coming from a region/distance of non-interest. Microphones aren't.

What I am getting to: are you sure you are not recording hiss/hum because there is hiss/hum as physical sound? Like computer fans? I have my recording computer in a different room because of that (stage box to the rescue). Can you switch off the fans (and any rotating hard disk) for a short test or put them in another room, putting as much distance between the microphone and your computer as possible if you cannot render your computer noiseless?

Noisy anecdote: when a friend of mine worked as organ tuner, he gave explicit instructions for needing total silence when intoning the registers. He wasted about an hour trying to get some strange sound out of a pipe until he finally realized that the strange component was a vacuum cleaner from a side room. The cleaning lady, instructed about the need for absolute silence, only switched on her vacuum when there was organ noise anyway and waited patiently otherwise.

When recording "gameplay", the graphics card fan might follow a similar strategy and just switch itself on when you are not in a good position to detect it.

Answer 6

The line-level issue mentioned by Mike Rinehart seems likely here. Check your camera for a gain switch on the input (mic/line).

Likewise on your computer, try plugging into the Mic input instead of the line-in.

Alternatively, buying a small mixer might be a good idea; it should output signal at line level.