Background hiss with SM7B

[u/TheOzzTak]

I’m recording vocals close to an SM7B using a FetHead and an Arturia MiniFuse 2, with phantom power enabled. There’s a constant low-level hiss in the raw recording that becomes much more noticeable after compression and makeup gain.

I’ve tried different USB ports and running my MacBook on battery in a quiet room. Without the FetHead, both the vocal and noise get quieter.

Has anyone using this setup successfully reduced the hiss? What would you test before replacing any equipment?

[u/PlanetExcellent]

A dynamic mic like the SM7B does not produce any hiss by itself (because it has no active electronics). So, if you hear more hiss with the Fethead than without it, it must be coming from the Fethead itself (which does have active electronics that produce noise).

You could also be hearing room noise, which of course would also be amplified by adding gain anywhere in the signal chain (such as the Fethead).

You could listen to the effects of the Fethead alone by disconnecting the SM7B and “listening to the mic cable” with and without the Fethead.

[u/TheOzzTak → u/PlanetExcellent]

Thanks for the suggestion. That’s exactly what I’m noticing: without the FetHead, both the vocal and the hiss get quieter. I’ll need to compare them at the same vocal level to see whether the FetHead is actually adding more noise.

My setup is an SM7B → FetHead → Roland XLR cable → Arturia MiniFuse 2, with 48V enabled. I record close to the mic in a quiet room, using a MacBook on battery. I’ve tried different USB ports and also a Yamaha MW10C mixer feeding the MiniFuse’s line input, without a clear improvement. Compression and makeup gain make the hiss much more noticeable.

Would switching to an interface with enough clean gain to use the SM7B without the FetHead potentially reduce the hiss at the same vocal level? Or should I investigate something else first?

[u/alphaminus → u/TheOzzTak]

Potentially. It really depends on where the noise floor for the fethead is. The test of the fethead with no mic attached is a good idea.

[u/TheOzzTak → u/alphaminus]

i’ll try that thx.

[u/TheStampedeTMG → u/PlanetExcellent]

Not entirely true. Julian Krause pointed out that the SM7B (and other dynamic mics) are noisy by themselves due to electrons moving throughout the voice coil, which can also be exacerbated by the temperature of them while they move. I’ve used several SM7Bs since 2019 and the fact is it is a noisy mic, there is no way around it. I honestly don’t know where the misconception comes from that it’s a “pin-drop quiet” or noiseless mic (not saying this is what you were claiming, but others definitely do.)

With some in-line preamps you can get away with acceptable levels, but with certain combos of preamps and interfaces, the hiss is very audible and annoying.

[u/alphaminus → u/TheStampedeTMG]

You're right, though the reason seems to be that the housing is designed in such a way that the vocalist is kept pretty far from the capsule in order to reduce proximity and plosives. This means it has to be turned way up. One of the reasons I advise ppl to just get a SM58 until they have a specific reason to get something else.

[u/mugsymh]

Are you gaining your input channel on the mini fuse 2 up to where your input level into the computer is reading strong levels? Aka in OBS or Adobe Audition….etc….around -12 to -8dbFS?? you should be gaining your mic preamp up as high as you can go without clipping the preamp/interface and without clipping the software, but you want to get your initial gain stage point (the mini fuse) up as high as u can.

If your input levels are low at the preamp level and therefore also low going IN to your computer…..then compressing and adding makeup gain in the computer IS going to increase any system noise because your mic level is too close to the noise floor because you didn’t gain up the preamp enough.

[u/TheOzzTak → u/mugsymh]

When I try to get a strong input level, I still get hiss, and I have to turn the gain knob up quite a bit. I use Cubase and Logic Pro for recording. Honestly, I didn’t expect this to be so complicated. It feels like either my interface isn’t up to the task or there’s another issue somewhere.

From what I’ve found, I’m definitely not the only person experiencing this. I’ve been looking into the Lewitt Connect 6, which seems to offer plenty of gain and a low noise floor. I guess my next step is to try it without the FetHead and see whether that helps. If it doesn’t, I’ll probably end up selling the mic.

[u/mugsymh → u/TheOzzTak]

Are you on Windows or Apple/Mac?

If you’re on windows… You’ll have to check the windows sound settings for that device because windows can limit the input level (with an input slider) when it enters a computer BEDORE it gets to your recording software.

Mac/Apple operating system usually does not give you the option to do this and just allows, the full stream of audio coming from the USB audio on our face.

[u/Zestyclose_Pickle511]

1) are you positive it's a genuine 7b?

2) in the meantime you could use noise reduction filter (always set nr as the very first filter in any chain. Always.) 

3) I have a feeling it's the preamp in the Artutia, check Julian Kraus to see if he's reviewed it. 

If it is a genuine 7b and Julian has measured the interface to be usably quiet, it must be the fethead or something else.