Noise floor too high (ACX) no matter what. Please help.

I’m on Mac OS X v. 10.13.6
Audacity 2.3.1

I am tearing my hair out to find a solution to this problem. So eager to record but can’t get past this hurdle. I have an isolated recording space that seems very quiet. No motors, electric appliances, etc. I have my gain knob set to record my voice within the ACX recording spec (knob is at about 8), but when I stop speaking, the silence does not go below -45 db. I’m wondering if Audacity with my interface and Rode NT1A are not a good ensemble. Perhaps mic is too sensitive??

Here’s my equipment:
Focusrite Scarlett Sono interface
Rode NT1A mic with pop filter and shock absorber

Both have recently been bought. Is this mic perhaps too sensitive for my interface? I’ve heard someone mentioning about using a bass cut filter on their mic. I wouldn’t even know where such a thing is as I don’t have any controls on my mic.

Thank you in advance to anyone who can fix this…

NT1-A requires phantom-power to deliver a full-strength signal.
There should be a (48V) switch on your audio-interface to deliver that power to the mic.

NT1-A has cardioid polar pattern: it’s possible to have it the wrong way round.

Post some of your work.

Many noises have signatures and sometimes we can just tell you where the noise is coming from.

USB connections can have data scrambling noise. Microphone preamplifiers always make noise and sometimes it’s excessive, one poster has a bad cable and the system is picking up noise from his house wiring, etc.

Everybody fails noise and it can be a serious problem. It’s the reason the noise part of Audiobook Mastering is its own long chapter.

Focusrite Scarlett Sono interface

We assume that’s the “Solo.”


Thanks for the comments. (I didn’t know there were any until now so sorry for the late response.) I was able to get the floor noise to spec by replacing the blankets in my makeshift studio with duvets and moving my chair and mic to a different configuration. My engineer, however, discovered static clicking in the quiet spaces. I can’t hear it until the output volume is way up. I think copy/pasting may be doing it. I will send a clip of it next time I’m aware of it. Thanks, again.

I can’t hear it until the output volume is way up.

Diving for noise doesn’t count. If it’s not audible at normal listening levels, chances are good it’s OK. There are some noises where that doesn’t work, but that’s a rule of thumb.

Clicking during recording can be very difficult to fix, and no, it’s not always editing mismatches.

There’s a fuzzy rule that if you go longer than two weeks trying to solve computer noise problems, stop using the computer.


Even though I need to turn my volume up to hear them, my engineer can hear them very well and as a result, I had to re-do my recording because of them, editing each space. Attached are two samples of them. Thanks, Koz, for volunteering to have them analyzed for determining their source. I noticed, one way they seem to appear, is at the point where two clips are merged. This is not the only instance, though.

This is not the only instance, though.

Nobody wrote you can’t have two problems. Those are really entertaining.

I need to wait until I get to a noise-free environment to listen.

It’s good to have as many observations as possible. It’s good you noticed clicks at edit points. That can be cause by two or three different things (you knew even that wasn’t going to be easy, right?)

The most common problem is trying to cut sound in the middle. You should try to match the electrical character of out-going and the in-coming edit. If you catch it exactly wrong, you may get a tick there.

The top edit in this case may cause a tick.

There is an Audacity tool that can help spot those problems.

A much more evil problem is DC Offset. You can have a broken microphone that when you stop talking, the signal does not settle to zero like it’s supposed to. In this case, you can cut your voice to your own voice all day along and it won’t tick until you try to attach the intro or outro which didn’t go through your microphone.

I can check for some of that when I get back.


just to cover it. Janet Sample 1 has a tick at 2.93 seconds.

I amplified it greatly and that (in my opinion) is the signature of a bad edit or an edit between two sound files that either one or both aren’t technically correct.

Screen Shot 2019-05-23 at 17.27.27.png

All three ticks are cousins of each other.

Screen Shot 2019-05-23 at 17.31.29.png
Screen Shot 2019-05-23 at 17.31.59.png

To be clear, I’m amplifying them greatly so I can see them. They’re practically invisible in real life.

After you announce but before you edit anything, run Effect > Normalize with Remove DC the only option like this:

Screen Shot 2019-05-23 at 17.34.33.png
Do some edits and see if the clicks vanish. Janet Click 2 has a pop at about 2.15 and again at about 2.8. I’m calling that someone inserted a chunk of technically correct silence and the system had trouble before and after. Treat the before and after sound segments to that Normalize trick and redo the edit. I bet the noise goes away.

Effect > Normalize adjusted to those instructions will not affect the sound quality. Let’s see if I’m correct.

The bad news is you can’t fix it in post—after the edit. After the edit you have to zoom into each one and solve them one at a time.

Again in my opinion, your microphone or system is broken, but not so broken that it causes the fire brigade to arrive. Just enough to affect fine quality.

Nice voice if I didn’t say that earlier.


Did that come out English? Sometimes I’m not sure.

The object is do a test where everything you announce goes through that Remove DC filter. You can cut back and forth between you and generated effects like silence, and cut back and forth between you and anything that didn’t go through your microphone. There should be no ticks or pops at the transitions.

Oh, and I don’t think your NT1A is at fault. Jury’s out on your Focusrite Scarlett Solo. That’s a very home recording product.

If it gets that far, Rode makes a terrific interface, the AI-1. That’s not an “L.” It’s Audio Interface One


Thanks, Koz. That’s a lot of information and I really appreciate your taking the time to address the click problems. I do audio recording and do it with punch and roll so dealing with continually having to pull up the Normalize box would slow me down too much. (But I will do that until I am done with my current project. I’ve been wondering if the NT1A was too statically sensitive and if the Solo had a defect since it has had another problem of going off by itself. I was going to return but must replace first. Thanks, too, for addressing that and your recommendation. So appreciated when you’re new in the recording field. Thanks for the complement, too…always nice to hear.

dealing with continually having to pull up the Normalize box would slow me down too much.

We’re not solving your problem. We’re identifying it so you don’t have to go through that exercise in the future.

I will do that until I am done with my current project.

Did it work?

I’ve been wondering if the NT1A was too statically sensitive

Probably not. The NT1A is a fully qualified broadcast microphone with balanced output (3-pin XLR), and from a respected maker.

I’ve been wondering … if the Solo had a defect since it has had another problem of going off by itself.

It would be good to know that earlier. Doctors have a “Doorknob Moment.” A general physical exam goes perfectly and the doctor can find nothing wrong. The patient is leaving and has his hand on the doorknob. He turns and says, “I throw up blood every night before going to bed. That’s OK, right?”

The Solo, in general has a good track record. Interfaces at that level are mostly immune to odd connection and sound problems. However. I bet I can bring this home to your computer. The Solo, unless it’s badly broken only goes off when the computer’s USB service shuts down. Problems with this service can also cause ticking and clicking in the sound as sharing between the different Mac services switches.

There’s a publication about this. Looking.


I’m violating somebody’s rule there. Go for simple, first.

problem of going off by itself

How long have you been plugging and unplugging the USB cable into your Mac? They do wear out. A ratty connection in the wrong place may cause the Solo to temporarily dump at any time. Once it goes down, the computer may not see it any more even if it does come back by itself.

Can you try a different USB connection? My Air has two, one left and one right.