Background hiss frequency?

[Beemer]

I have made a recording with my Zoom H4n using its built-in crossed condenser mics. The recording was done with the rec level at 68% and there was no clipping.

On playback in Audition there is a background hiss and its frequency is between 6 and 8kHz. This makes it difficult to filter out. I checked the frequency by selecting the 30 band equaliser and starting at 25kHz moving each band down to -96db.

Is this a typical hiss frequency?

regards,

Beemer

 

[SouthSIDE Glen]

Not necessarily. It depends upon the source(s) of the hiss.

And the method you used to get those numbers also depends greatly upon the response curves of your ears, your monitors and your room. It's possible that there was more noise than your could hear at other frequencies or that there is a bump in the response of your listening chain at 6-8 kHz. You can't tell for sure by the method you used alone.

Audition has an FFT spectrum analyzer built into it. Take a look at that to see what the actual response curve of the hiss looks like. And then remember that not all hiss is necessarily the same.

G.

 

[Beemer]

Glen,

I selected a 1 second section that has no performance but does have the hiss. I changed to spectral view and see brighter streaks in the 7-12KHz area. I then used the marquee to select around that area and selected the FFT filter (process). I guess I could draw a notch shape but I now understand your comment about my perception of the "hiss".

Removing frequencies in this 7-12kHz area would remove the harmonics of the performance which is a church pipe organ.

I'm new to using the H4n so I will wait awhile to try to build up knowledge of possible preamp noise.

thanks,

Beemer

 

[SouthSIDE Glen]

I've not used AA's FFT filter, but it looks as though it's really a fancy name for a kind of paragraphic EQ. And yeah, trying to attack hiss with EQ can throw out a lot of the baby with the bathwater if you're not careful.

You might want to look up in AA, under "restoration effects", the "Noise reduction" tool. AA also has an "Adaptive noise reduction" tool and a "Hiss reduction" tool in that section, but I've not used them, so I don't know how good they are or are not.

Outside of AA, both Waves and Sony have very good "noiseprint"-style NR plugs, which actually take a sample of the noise itself, analyzes it, and then automatically applies the proper filtering to attack the noise specifically. How well they do that without artifacting the signal depends upon the nature of the noise itself. Sometimes those NR plugs work virtually transparently like magic, other times they can't help but mess up the signal also.

G.

 

[Ethan Winer]

look up in AA, under "restoration effects", the "Noise reduction" tool.

Yes, this is the correct way to remove hiss, rather than using EQ. I often use Sony's noise reduction plug-in, with great results.

I have a Zoom H2, which I love for what it is. But you really have to optimize the recording level adjustments for the lowest noise, and even then the preamps are not what I consider low noise. I have no idea if the same applies to the H4n. This is from some notes I made for myself after testing the Zoom H2's preamps:

I did some test recordings through the Line Input with the H2's internal record level control at various settings. As I suspected, the H2's +/- internal level control is after the input stages. So when it was set low at 60, the recording clipped at -10 when fed a loud input signal. Setting the H2's level to 100 allows full volume recording with no distortion. The manual is typically unclear about using the Line Input, but the sample screen shows the volume set to 100 and says to use the source's output volume control to set the level. So 100 is the magic number, then set the record level from whatever you're recording.

--Ethan