Low level, constant, background hiss noise on all my recordings. Help.

O

Optiplex

New member
I've been recording my vocal/acoustic guitar for 15 years now. Always played live from beginning to end into the recorder, never any multi tracking, overdubbing or recording 'tricks'. My recording is always done at home. Sometimes I use 1 mic, sometimes 2 mics.... always plugged straight into whatever recording device I'm using.

No matter what system of recording used, be it stand alone digital recorders, computers, or digital recordings transferred to computer, I ALWAYS get low level, constant background hissing noise from the beginning of the recording to the end. Normally this noise is in the background and can't be readily heard due to the recording's volume. However, in "quiet spots" or pauses in a recording, and also at the end of recordings during the few seconds where the final strum or notes fade away, the noise becomes readily audible.

Over the years I have used good quality condenser mics, with good connector cords, into good quality recorders ... and the noise remains no matter what techniques tried. My recordings are quite good quality that satisfy me 100%, except for this continuing problem.

Often when I listen to other good amateur recordings on the internet, I don't hear this background noise during quiet spots or pauses in the songs. I wonder what the 'trick" is to remove, or not get in the first place, this constant low level background hiss noise? Does anyone have any informed suggestions?
 
If it is indeed a "hiss" and not simple room noise, then the two places to look are the microphones or the pre amps on you gear, with the pre amps being a strong favourite for the culprit. Even pretty good pre amps introduce noise (i.e. "hiss") if you have to turn up the gain anywhere near the highest level.

So...more details please. What microphones are you using and what are you plugging them into?

Also, how are you arranging your system gain? Are the inputs turned up fairly high? If so, can you re-arrange things (perhaps miking closer or whatever) so you can reduce the pre amp gain?
 
I usually go through and select and delete out all the parts that have little or no sound, then use RX4 Izotope to profile the hum and it removes it like a charm. Of course, it costs a little, but you'll never hear it again. Removes all kinds of unwanted noises, hums, buzzing. Here is a link to RX4, you don't need the advanced version, just the regular. https://www.izotope.com/en/products/audio-repair/rx/
 
Please post a clip of the background noise.
IIRC correctly the last test I did with an AKG P150 SDC and the NI KA6 gave me a noise floor, "in the room" of about -70dBFS. Not startling but adequate and the system noise, i.e. sans room, was better than -80dB.

Peeps have been recording acoustic guitar, spinets and other quiet instruments for decades and although tape/vinyl is barely good enough it is just about!

A common mistake is to listen back at too high a level, either on monitors or cans?

Dave.
 
It will be one of three things:

1. Gain staging
2. Noisy equipment
3. Your noise expectations aren't realistic

If you have the mics a couple feet away and the guitar is relatively quiet, you will have the gain turned up quite high. That will bring up the noise of the room and the noise floor of the mic preamp.

If you are using any pro-sumer gear, it will probably be noisier than top quality stuff, especially if it is turned way up.

The noise might not be gear related at all. It might be part of the ambient noise in the room you are recording in.
 
ecc83 said:
A common mistake is to listen back at too high a level, either on monitors or cans?

Dave.
Click to expand...

There's truth in that. I just tried a few things to test that out. I find if I record at a medium to low volume only, then the background hiss is far less problematic, but the problem with that is the overall recorded volume is also too low, which means that to hear it at normal to high volume on playback I have to turn up the volume on the speakers so much that the noise returns. And on speakers that don't have a volume control, then the playback volume is just too low to hear at normal volume. I also did the opposite of that and tried recording at very high volume, so that I'd not have to turn up the playback volume as much, but because of the higher recorded hiss it didn't work out.

The noise is just the usual continuous ssssssssssss type hiss that you get on any recording, even more so on tapes. It's only a problem for me at quiet spots in a song, or at the end of a song as the final notes fade out.

It doesn't matter what mics I use (I use only decent quality mics). It doesn't matter what type of recorder I use, I currently use a Fostex VF160 which is a fantastic sounding mid range recorder, I've used better recorders, and I've used worse recorders, and the hiss background noise is always present.

A lot of people wouldn't even hear this type of background hiss noise in their recordings, but because my music is so quiet and sparse and fully acoustic with lots of gentle quiet spots the background hissing noise can sometimes interfere too much. By the way, the hissing noise is not caused by the noise the recorder makes. I close mic both guitar and vocal. The room is small, quiet and 100% noiseless (even the recorders I've always used are 100% soundproofed .... I solved recorder noise problems years ago).
 
Just as a reference, my last recording was done just a few days ago. I just went back to the recording and picked a silent section between verses. I had to bump the gain by 36db before I could start to hear "hiss". I was starting to hear headphone bleed (which was very low) before I could hear hiss, so that's how little there was. Putting that into perspective, the mic is a Neumann TLM107, the preamp is a Universal Audio 6176 and the audio interface is an RME Fireface 802. The vocals were peaking around -6db while recording, but only on some syllables. Would love to hear your recording to better understand your problem, even if it was just a silent section.
 
Also checked a recent acoustic guitar recording that I did through an AKG C414 xls into the RME Fireface. Bumped up a silent section (just before playing the guitar) by 36db (any more and the sound of my breathing and light handling of the guitar would be clipping... but no hiss.
 
When you have the headphones up really loud to listen to the quietly recorded track, was the hiss still there when you hit stop?

Setting your recording level relative to your monitoring level isn't a good idea. You should have the recording level set such that the sustain of a strummed chord sits about half way up the meter. (as long as it doesn't clip on the strums)

The trick to solving your problem is figuring out where the noise is introduced.

At this point it would probably make sense to post a clip. Also describe the mic placement and what mics you were using for the clip, and how high the preamps needed to be set.
 
"Was the hiss still there when you hit stop?" --- no with either external speakers, computer speakers or headphones.

I have found that if I record at a low enough volume to seemingly get rid of the noise, then the playback volume is way too low. And when I turn up the playback volume to hear the recording comfortably, the background hiss is still there.

Here's a sound sample ---- Playing Test. by Test - picosong for the first 5 seconds or so there's silence as the volume is at zero, then the volume is turned up and the hiss can be heard, then I sing and play for about 20 seconds (during the music the hiss can't be heard until the end during a 1 second pause), as the notes decay on the guitar at the end you can hear the hiss becoming prominent again, then 5 seconds from the end of the sample I turn the volume right down to zero again for silence.

Both mics are about 6 inches away, one for vocal one for guitar. They are Studio projects B1 condenser mics. The recorder, A Fostex VF160, has internal preamps and their volume was set in the middle at 0 --- neither plus, nor minus. The recorder has an internal CD, so I transferred the recording onto a CD, then the CD went into the computer. The noise on the final clip that you hear is exactly the same noise that's on the original recording on the digital recorder.

I can cut the hiss from the beginning by simply editing the recording to start at precisely the point where the music begins, but the problem with pauses throughout songs and the noise interfering with the note decay at the endings still remains.
 
Wow, that is a lot of hiss. Do you have any other mics that you can try? I would hate to think the Fostex is that noisy. Since it's an all-in-one unit, there really isn't any way to mess up the gain staging that badly...
 
That is a lot of hiss. But the way it is pushed to the back during the guitar and the singing, then comes in on the decay of the guitar makes it sound to me lile a compression artifact. Have you got something on the track that is heavily compressing? Or is there some kind of automatic gain control at work?
 
gecko zzed said:
That is a lot of hiss. But the way it is pushed to the back during the guitar and the singing, then comes in on the decay of the guitar makes it sound to me lile a compression artifact. Have you got something on the track that is heavily compressing? Or is there some kind of automatic gain control at work?
Click to expand...

I noticed that too
 
Lorra,lorra noise yeah!

The spectrum "noise 3" is of just the noisiest part of the into but even with the "taps shut" the noise floor is barely better than -60dB. That is poor. The noise shown should be about 30dB bellow indicated.

The noise spectrum also shows the climb from about 1000Hz down? This usually indicates poor pre amp design.

As for a gating effect? the other specc' show that even with the guitar and voice low pass filtered out, the LF noise is still there so IMHO no gating is taking place.

Can you do a 10second run with the mic pre gains as set before but no mic plugged in and another with gains at minimum?

Dave.
 

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As Gecko and Guitar have already said.........I strongly think it's some sort of compression effect...........like an automatic level control. There's no doubt that the hiss drops off with input volume increase and rises as the input level drops. It does not, however, appear in the very beginning of your sample..........and then suddenly appears right before you start playing. What did you do to cause the hiss to appear? That's the action / area of your process that's likely causing the hiss.
 
Mickster said:
As Gecko and Guitar have already said.........I strongly think it's some sort of compression effect...........like an automatic level control. There's no doubt that the hiss drops off with input volume increase and rises as the input level drops. It does not, however, appear in the very beginning of your sample..........and then suddenly appears right before you start playing. What did you do to cause the hiss to appear? That's the action / area of your process that's likely causing the hiss.
Click to expand...

He said that he turned up the level just before he started playing. So that part was not automatic. But yes, once playing starts the hiss drops off and returns when the playing stops.... but it sounds more like sidechain compression. If the hiss was normally there, it would be there all the time. This hiss comes up during quiet parts. That means that gain is being applied to low levels during quiet parts and attenuated during loud parts. Makeup gain during normal compression would be constant, this gain is variable depending on music level. Mickster's comment on automatic level control sounds interesting...
 
This may seem real simple not sure if you've tried this already. Record the guitar at low level that doesn't have any hiss. After it's recorded normalize and or compress the track. Then turn up the volume on your playback. It seems to me you are just recording then cranking your system to hear it back, a low level recording cranked full blast will always produce noisy playback.
 
Philly Duffy said:
This may seem real simple not sure if you've tried this already. Record the guitar at low level that doesn't have any hiss. After it's recorded normalize and or compress the track. Then turn up the volume on your playback. It seems to me you are just recording then cranking your system to hear it back, a low level recording cranked full blast will always produce noisy playback.
Click to expand...

Yep, I've tried that. Whether I record at very high volume, very low volume, or anything in between --- the result is always the same at playback time, hiss. The only way to remove the hiss is to playback at extremely low levels, but when that happens you can hardly hear the music.

I've also tried just about every compression setting available, and the hiss still remains.
 
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