Hissing/White Noise

O

Orson

Well-known member
Using a Zoom H5 and a Rode NT2 shotgun mic in a blimp...........All good.

Trying to record some nature sounds for a project so the subject is not close or in front of the microphone. Remedy .....increase the gain.

Problem is anything above 5 or 6 really introduces a lot of hiss/white noise.

Does anybody know of settings within the Zoom H5 which could limit this or some other method?
 
The hiss most likely comes from the preamp in the Zoom.

What I would do is record at a level that doesn't introduce the hiss, even if it is very quiet, then boost it afterwards in the hope that any preamp noise at that very low level won't be as disastrous as when you record beyond 5.
 
Remedy is not more gain but to reduce the distance if you have to use the zoom. The built in mic preamps are matched quite well so you may get better results with the stereo mics. Other than that you're stuck really. It's not designed with low input in mind, just a design compromise.
 
Thanks both I had reluctantly come to than conclusion but was hoping for a ray of light.

So do you know of another recorder that has better pre-amps which could be used or is it sell both and start again with a major set up?
 
You might be able to treat your noise floor with an FFT filter, but ultimately high gain and distant subject is going to give you a garbage in/garbage out situation regardless
 
A couple of things to consider:

You say the sound you want to record may not be in front of the mic. That's a bad thing for a shotgun mic which is designed to reject off axis sounds. If you are trying to record ambient sounds, a less directional mic might be better, even consider an omni. What do you get with the H5's internal X/Y mics in terms of noise?

What VHS said is good. If you can record a short bit of the hiss before adding the outside sounds, an FFT noise reduction plugin can reduce the apparent noise. While you mentioned the NT2, I'm guessing you mean NTG2 which is the shotgun mic. It doesn't have the lowest selfnoise at 18dbA. Luckily this type of noise is something that a FFT noise reduction algorithm does very well. If you don't have such a plugin, you might posts a sample of a recording with a bit of only the hiss to start with, followed by your outdoor recording. We could try processing it to see if it meets your needs.

My H4n doesn't have particularly noisy preamps, but that's for normal sound levels. You might be pushing the envelope.
 
I'm not so sure that its a matter of preamp hiss that you are hearing. I've got an H4n, so I conducted a little experiment. I used both the internal mics, and a pair of Rode M5 externals. The first thing I did was start recording inside in a quiet room. I ran that for about 5 seconds, then I paused the recorder and moved the whole setup outside on the back steps and let things run about 5 minutes. I had all record levels set at 75%. No compressor or limiter set.

All I had for windscreens were the little foam covers, so there's a moderately strong wind blast at around 2 minutes.

Bringing the files into Reaper, the first section is very quiet, and you can immediately hear the outside noise level at about 5 seconds into the recording. So the system noise itself is quite low.

Finally I threw ReaFIR onto the track using about 2 seconds of the initial sound for the noise profile. That removed the remaining hiss, but you still have a "noisy" recording because that's the actual background noise outside from traffic, construction, wind rustling the leaves and birds chirping.

Try setting your Rode inside a closed closet, where you won't have any noise or airflow, and try recording about 10 seconds of that signal. That should tell you the inherent system noise.

Audio files are attached.
 

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  • H4N External Mics w NR.mp3
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  • H4N Internal Mics Unprocessed.mp3
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  • H4N Internal Mics w NR.mp3
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There is noise from I think the pre-amps and more from one than other. I plugged in my Neumann 103 into the Zoom and it does register some activity in the sound booth. Where as when the Neumann is in my Audient 14 there is zero. But then that is on the PC. So I am assuming this minor activity on the Zoom H5 screen is from the pre-amps?

I don't know that is all a wild guess. But I was trying to record some early morning bird chorus for a project.

One thing though with the Rode mic i could hear people talking hundreds of yards away clearly when banging up the gain to max. So perhaps the sensitivity of the mic is adding to the problem as the hiss may also be garbled background noise far away?
 
TalismanRich you also have a lot of background noise. Mine is a very different noise though as I am out in the sticks and it was about 5 am.
 
DId you think that the first 5-7 seconds of the recording were noisy? That was the recorder + mics inside a quiet room. Everything after that point was outside. Unfortunately, I'm not in the sticks. I'm about 3-500 yards from an interstate hiway, it was 3 in the afternoon, and a construction crew is redoing all the gas lines at the end of the block. It won't be quiet.

Have you tried putting the TM103 out to see what it picks up? The Neumann is about 10dBA lower in noise than the Rode, plus it puts out a stronger signal, 23mv/Pa vs 15mv/Pa for the Rode. That means you can keep the preamp on the H5 lower with the same output. With the Neumann being just a cardioid vs a supercardioid, it should pick up a wider sound field for off axis birds.
 
The 103 would pick everything up as it does in the studio. The problem with an un-directional mic as well is that there are streams in the area which the rode picks up if pointing in that direction.

I think my only chance without spending more money is a spot I know in some woods and leaving my gear there and picking it up an hour later and hoping the birds have been there. That way I could have the gain below 5.

Thanks for your help all.
 
Just to check - have you tried the unplugging the mic experiment? Put it outside, set the gain press record and then 30 seconds in pull the mic plug out. Reviewing the clip will show either a constant low level noise, which comes from the preamps, or a hiss that reduces or disappears when you pull the plug out - and this of course comes from the mic. Probably the recorder, but a worthwhile conformation.
 
rob aylestone said:
Just to check - have you tried the unplugging the mic experiment? Put it outside, set the gain press record and then 30 seconds in pull the mic plug out. Reviewing the clip will show either a constant low level noise, which comes from the preamps, or a hiss that reduces or disappears when you pull the plug out - and this of course comes from the mic. Probably the recorder, but a worthwhile conformation.
Click to expand...

Will try tomorrow morning Rob. Sunday morning no early morning activity from humans. Well outside I mean.
 
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I did what you said Rob and pulled out the mic lead and there is noise even with the mic out. Also one port is hotter than the other and one port is noisier than the other as well.

Not very impressive really is it, or I am I just used to studio stuff like the Audient? That's my experience of all this really, just the gear I have.

I will try recording with the 'XY' mics tomorrow morning.
 
That's at least removed the microphone noise possibility hasn't it. I've got a couple of different zooms and I've never noticed the noise being a problem. If I get a chance, I'll get one out and experiment with them. I guess it could be faulty?
 
Convert that file down to an MP3, maybe at 192K or so. Then go to Go Advanced when you are doing the post. In the lower section, there is a selection for Manage Attachements. There you can browse for and upload the file and it will attach to your message.

Hit Submit Reply as usual and you're done.

I"m curious to hear the file as well. I would expect that the H5 might be a bit noisier than the Audient, but it should be anything that would be unusable. Most all digital recorders are generally pretty quiet unless there is a problem.
 
Is the noise mostly just background noise? There was zero wind and zero human activity. No planes. It was 6am in the morning and countryside. Gain was set on 5 which is midway on Zoom and phantom power to NTG2 mic. I couldn't go any higher with the gain as that background/white noise sounds like you are next to a motorway.
 

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