Lowering the input gain to remove background hiss

[Doug Young]

There should be no hum in a zoom recording I could imagine self noise from the electronics or the mic but that would be hiss. Hum is probably coming from something in your environment.

[TBman]

Originally Posted by Doug Young

There should be no hum in a zoom recording I could imagine self noise from the electronics or the mic but that would be hiss. Hum is probably coming from something in your environment.

I'm humming where I should be hissing.

I'm going to go into my garage and do a recording and see what I get. There's nothing in there that would create room noise.

[Rudy4]

Originally Posted by TBman

I'm humming where I should be hissing.

I'm going to go into my garage and do a recording and see what I get. There's nothing in there that would create room noise.

"Room" noise is just that. It's the sound picked up by the mics from reflections of sound within the room.

ALL rooms (other than an anechoic chamber...) have it, and it's one of those things that we work diligently to negate or minimize.

[Doug Young]

Originally Posted by Rudy4

"Room" noise is just that. It's the sound picked up by the mics from reflections of sound within the room.

ALL rooms (other than an anechoic chamber...) have it, and it's one of those things that we work diligently to negate or minimize.

I'd say that's different from noise. You could have a totally silent isolated room, with no "noise" in it. Then when you play the guitar, it reflects off the walls and so on. That's "room sound", ambience, like reverb. But if there's a sound when no one's even in the room, let alone playing guitar, then that's "noise".

Noise, especially hum, can come from all kinds of places. Electricity, lights, traffic, airplanes overhead. When I throw my breakers, as discussed earlier, you hear the whole sound go down, and you realize the whole house has a sort of "hum", "rumble" whatever you want to call it, that we don't even notice. But mics do...

[sdelsolray]

Some mic preamps generate more noise (in a relative sense) when using high gain than when using a lower gain setting. Some do not have this issue, and they are generally the high quality and higher priced mic preamps.

[TBman]

Originally Posted by Doug Young

There should be no hum in a zoom recording I could imagine self noise from the electronics or the mic but that would be hiss. Hum is probably coming from something in your environment.

You're right Doug. I went out to my garage. It is attached to the house (nothing over the top of it though). The only slight noise I could hear was my son's a/c from the second floor.

That is the only hum the Zoom picked up. Much quieter than my house, even at 1:00am in the morning with everyone asleep.

Problem solved, thanks.

[ljguitar]

Originally Posted by Doug Young

…you realize the whole house has a sort of "hum", "rumble" whatever you want to call it, that we don't even notice. But mics do...

Hi Doug

Doing photography/video and making audio recordings, I always emphasize that unless we are intentional, we don't actually see with our eyes, nor hear with our ears.

Our eyes and ears are receptors and the brain assembles what we thought we saw and heard. But cameras and recorders see and hear exactly what we 'feed' them. I've done professional portraiture for families and individuals for almost 50 years, and it's tricky to shoot pictures of what people think they look like.

[Chipotle]

Originally Posted by ljguitar

Doing photography/video and making audio recordings, I always emphasize that unless we are intentional, we don't actually see with our eyes, nor hear with our ears.

Absolutely true, and you don't understand this until you have some experience with it.

How many times have you taken a picture or video, and not realized until afterwards that awful stuff cluttering the background? Or made a recording, and not heard the background noise until you listen back later? Our brains are pretty good at filtering out that stuff, unbeknownst to us.

That's why the suggestion to flip your circuit breaker. So much background stuff going on--electrical buzzes, running appliances, fans, moving air--that we simply don't notice any more.

[Rudy4]

Originally Posted by Doug Young

I'd say that's different from noise. You could have a totally silent isolated room, with no "noise" in it. Then when you play the guitar, it reflects off the walls and so on. That's "room sound", ambience, like reverb. But if there's a sound when no one's even in the room, let alone playing guitar, then that's "noise".

Noise, especially hum, can come from all kinds of places. Electricity, lights, traffic, airplanes overhead. When I throw my breakers, as discussed earlier, you hear the whole sound go down, and you realize the whole house has a sort of "hum", "rumble" whatever you want to call it, that we don't even notice. But mics do...

I'd agree with that.

"Noise" can be the result of all sorts of things that we normally simply "tune out". An example that's often cited is the low rumble that results from air moving through duct work into our otherwise quiet recording area. Coupled into sensitive microphones it becomes very apparent that we have noise sources that we don't normally even notice.

[Bob Womack]

Originally Posted by Doug Young

...That's "room sound", ambience, like reverb. But if there's a sound when no one's even in the room, let alone playing guitar, then that's "noise".

Noise, especially hum, can come from all kinds of places. Electricity, lights, traffic, airplanes overhead. When I throw my breakers, as discussed earlier, you hear the whole sound go down, and you realize the whole house has a sort of "hum", "rumble" whatever you want to call it...

In the audio for film and video industry we call it "room tone." We ask our location crews to record it for us and on really special days they do. Years ago before the digital era we'd make a loop of that room tone and put it up on a channel next to the location dialog. We'd flip the phase on the room tone channel and then bring up the room tone fader slowly until we heard just the background noise from the dialog channel begin to be cancelled out. Too much and you started to hear cancellation in the dialog. That was the original room tone removal technique.

Years later Dolby A frames were being abandoned as we all went to Dolby SR so everyone had thousands of dollars worth of useless Dolby A frames lying around. Some wiseacre came up with the idea of using the four channels of Dolby A expanders to allow engineers to clean up noisy audio. Dolby came up with a plug-in controller called the Cat.43 that let you manually set expanders on four frequency bands and extend the utility and life of those Dolby A frames. For some reason i haven't pitched ours yet...


The Dolby A card is removed from the frame and the connector for the Cat43 is inserted in its place. The card is then plugged into the bottom of the hideous orange remote control and the unit is switched on. Voile'!!! Instant clunkiness and not in anyone's color wheel. But it was a revolution in noise control for its time.

When the plug-in world arrived, the first thing to be cloned was the Cat43, I think by Waves. Soon after, someone cleverly integrated the out-of-phase trick into the process as well. However, the latest toys use artificial intelligence to discern the difference between significant and insignificant sound. Some "learn" a chunk of the insignificant sound and then allow the operator to select the amount of noise reduction to apply. Some give you a "waterfall" display like a modern sonar operator's and allow you to paint out or copy and paste out the noise. You use your taste to make a compromise between lossy and atifact-y reduction and through-sound.

The funny thing is that even though they keep predicting that the systems will eventually be plug and play, "squirt your audio through here and the system automatically cleans things up," actually, the more sophisticated the systems get, the more sophisticated human they need to operate them.

Bob

[lkingston]

On a Zoom recorder you can get an get an idea of how much preamp noise is there at a given setting by turning up the preamp without a mic attached on the mic inputs. On the H5 or H6 you can try it with the XY unplugged. That or you can plug headphones or an unconnected plug into the 1/8” mic input on an H4. The preamp noise is actually quite significant at higher gain numbers. Yes, often it is masked by room noise, but it still adds to the overall noise.

The time this is most noticeable is when you are distance miking with a lot of gain.

With the XLR inputs you can ad a FetHead, a FetHead Phantom, or a Cloudlifter to the mic if you need to add significant gain. That solves the problem.

I just got the SSH-6 mic and it be fine for the way I intend to use it, which is in the video frame but back six or eight inches so that it doesn’t block my face in the shot. I think the preamps are too noisy to do an out of frame shot without some sort of noise reduction in post (which also helps with the ambient room noise).

[lkingston]

Lowering the gain to reduce preamp noise is just silly if you are recording something soft or from a distance. You’ll get even more noise when you bring the level back up in post. You’ll get the best sound if you record at a healthy (but safe from distortion) input level, even with a noisy preamp. If you are using an XLR mic, the only real solution is a phantom powered gain preamp. That or mic from a closer distance.

This is why Sound Devices (or other high end) gear costs more than Zoom.

[rick-slo]

Not what I would call hum. Environmental noise sounding like some fan blowing and something else that warbles a little. Anyway you were able to remove it pretty effectively.

[Doug Young]

Originally Posted by lkingston

Lowering the gain to reduce preamp noise is just silly if you are recording something soft or from a distance. You’ll get even more noise when you bring the level back up in post. You’ll get the best sound if you record at a healthy (but safe from distortion) input level, even with a noisy preamp. If you are using an XLR mic, the only real solution is a phantom powered gain preamp. That or mic from a closer distance.

This is why Sound Devices (or other high end) gear costs more than Zoom.

For sure, there have to be some modest expectations for a unit of this price. The newer Zooms are much quieter than the old models, tho, and for home recording, quite usable. The self-noise is generally far less than the environmental noise, as Barry discovered here.

I don't hear really objectionable noise in the samples I posted, (for a home recording at least) and my house was definitely not quiet when I did those tests.

As best I can recall, every time someone has complained of noise here - not just related to the Zoom, and questioned preamps or mic self-noise, the real culprit was environmental noise.

[lkingston]

Don't get me wrong, I just bought an H6 along with the SSH-6 stereo shotgun mic. It is great so long as you work with it's limitations. In my case, what I want to do is get close to the Tiny Desktop thing where they stereo shotgun mic the vocals from about a foot away so as not to block the faces. The Zoom preamps are plenty good enough for that.

On my guitar, I'll use a preamp. With any low gain mic (like my SM7B) I'll use a FetHead preamp.

I wish the preamps were a bit quieter, but it's still a great recorder! To get quieter preamps you need to spend a heck of a lot of money.