Does Shure Sm7B have high self-noise?

[kofman13]

I have my eyes set on an SM7B for my online teaching and streaming. I love the way it sounds in all the hundreds of reviews ive watched on it. Most people love it. But then i read and watched A FEW reviews that complain that it has a very loud self-noise hissing, more than a crappy $40 USB mic. are they using it wrong or did they get a defective SM7B? its kind of hard to believe 95% people loving the mic but then a few reviews say it has tons of noise and is unusable (they even used a cloud lifter)

( i use a Motu M4)

 

[Blumlein 88]

I've not used one. That mike is notorious for being insensitive. Which means you have to apply lots of gain. Anytime you apply lots of gain, you are also applying lots of gain to any noise. It isn't really noisy itself as much as some preamps will be noisy turned up on it. I think Shure suggests 57 db gain is enough on the SM7B. I think your M4 would be okay with it.

 

[mjwin]

The SM7b is a very low output moving coil microphone. Having eventually found the specs, which are hidden on the Shure website well away from the end user's prying eyes, they're still not entirely clear.

Ok. Since this is ASR, we can do some "back of envelope" calculations...

SM7B sensitivity is quoted at -59dBV @ 1Pa (i.e. -59dB referenced to 1V for an input sound level of 94dB SPL).
Although equivalent input noise is not explicitly stated, they do mention a strange entity: "hum pickup at 60HZ" = 11dB (equivalent spl).
This is actually meaningless as it is quoted, and I suspect that it should have read "equivalent input noise=11dB SPL", but has been corrupted for some reason. Assuming this is the case, then this is a pretty good figure, and much as one would expect from a mic which is simply a coil of wire attached to a diaphragm.

However, due to the mic's low sensitivity, the output level of the noise (hiss) would then be -59-94+11 = -142dBV (=-140dBu).
To realize this low noise level in practice, requires an extremely low noise mic preamp. The best pro-spec mic preamps have an equivalent noise of around - 130dBu. If you want lower than that you need to use a step-up transformer. So the input noise of the preamp is likely to dominate.

Your Motu M4 is specified to have input noise = -129dBu. Given the sensitivity of the SM7B microphone, this will result in audible noise (hiss) at a level equivalent to 22dB SPL. This is perfectly ok for close-miked vocals, but you might notice a slight hiss if used at a distance to record acoustic music. So not the best choice for a lute recital!

I guess that the anecdotal reports of high levels of noise are related more to poor quality preamps than the mic itself.

 

[Longshan]

I have my eyes set on an SM7B for my online teaching and streaming. I love the way it sounds in all the hundreds of reviews ive watched on it. Most people love it. But then i read and watched A FEW reviews that complain that it has a very loud self-noise hissing, more than a crappy $40 USB mic. are they using it wrong or did they get a defective SM7B? its kind of hard to believe 95% people loving the mic but then a few reviews say it has tons of noise and is unusable (they even used a cloud lifter)

( i use a Motu M4)

As long as you're using the mic properly (it's meant to be relatively close to the sound source), you should have no problems with noise. Your Motu has perfectly fine pre-amps for this microphone.

 

[kofman13]

The SM7b is a very low output moving coil microphone. Having eventually found the specs, which are hidden on the Shure website well away from the end user's prying eyes, they're still not entirely clear.

Ok. Since this is ASR, we can do some "back of envelope" calculations...

SM7B sensitivity is quoted at -59dBV @ 1Pa (i.e. -59dB referenced to 1V for an input sound level of 94dB SPL).
Although equivalent input noise is not explicitly stated, they do mention a strange entity: "hum pickup at 60HZ" = 11dB (equivalent spl).
This is actually meaningless as it is quoted, and I suspect that it should have read "equivalent input noise=11dB SPL", but has been corrupted for some reason. Assuming this is the case, then this is a pretty good figure, and much as one would expect from a mic which is simply a coil of wire attached to a diaphragm.

However, due to the mic's low sensitivity, the output level of the noise (hiss) would then be -59-94+11 = -142dBV (=-140dBu).
To realize this low noise level in practice, requires an extremely low noise mic preamp. The best pro-spec mic preamps have an equivalent noise of around - 130dBu. If you want lower than that you need to use a step-up transformer. So the input noise of the preamp is likely to dominate.

Your Motu M4 is specified to have input noise = -129dBu. Given the sensitivity of the SM7B microphone, this will result in audible noise (hiss) at a level equivalent to 22dB SPL. This is perfectly ok for close-miked vocals, but you might notice a slight hiss if used at a distance to record acoustic music. So not the best choice for a lute recital!

I guess that the anecdotal reports of high levels of noise are related more to poor quality preamps than the mic itself.

I could always get a cloud lifter to help even more right?

 

[kofman13]

As long as you're using the mic properly (it's meant to be relatively close to the sound source), you should have no problems with noise. Your Motu has perfectly fine pre-amps for this microphone.

I could always get a cloud lifter to help even more right?

 

[Longshan]

I could always get a cloud lifter to help even more right?

You could, but it won't get you a quieter recording, and isn't necessary.

 

[JohnYang1997]

So basically you have motu m4, wanting to buy sm7b but don't know if it's a good choice due to high self noise complaint in some reviews.

Answer: You'll be fine.

 

[mjwin]

I could always get a cloud lifter to help even more right?

I checked the "cloudlifter" web page and I can find no proper specification anywhere. They do say that the device gives an additional gain of 25dB (which you won't need with your Motu M4), but nowhere do they mention the equivalent input noise! They just wax lyrical about JFET input stages (as if this is supposed to mean anything to the end user). What is it about audio? Just vagueness & mumbo jumbo. ( I'll stop because I can feel a rant emerging...)

My suggestion (fwiw) is for you to stick with your Motu M4. Buy an SM7B if you want to. Don't overthink things, as it will work. See prev posts, too.

 

[Blumlein 88]

I checked the "cloudlifter" web page and I can find no proper specification anywhere. They do say that the device gives an additional gain of 25dB (which you won't need with your Motu M4), but nowhere do they mention the equivalent input noise! They just wax lyrical about JFET input stages (as if this is supposed to mean anything to the end user). What is it about audio? Just vagueness & mumbo jumbo. ( I'll stop because I can feel a rant emerging...)

My suggestion (fwiw) is for you to stick with your Motu M4. Buy an SM7B if you want to. Don't overthink things, as it will work. See prev posts, too.

I've seen a measurement of the Cloudlifter and competitors over at Gearslutz. I forget the exact number, but the EIN of the Cloudlifter was good. Not SOTA good, but good. It also had flatter FR and marginally better specs otherwise than a couple of the more common competitors. If you look this up on GS under postings of Jim Williams for the user you will find it.

 

[jtwrace]

FWIW, I use an SM7B with a Motu M2 with excellent results. I did add an inline amp from Naiant and it's awesome! Jon really gets it. Less money than the cloudlifter and properly done IMO. See his blog here about it.

I use the M2 setup for my daily real job. I use another SM7B/Naiant with a Rodecaster Pro for my podcast.