How to over-ride level control.

[CarvedDuck]

Win8.1, two different devices (i5-laptop (borrowed), Atom-Tablet) both do the same.

I am trying to record a motor running so I can find if it is making harsh noises.

I set the recorder running and on the motor initial start the level is good and plays back clearly but after a few seconds it slowly drops down to barely audible.

Seems like some kind of level control is assuming it is background noise or something and tries to tune it out. Totally worthless since I can't find anywhere to over-ride it.

I tried using my phone and it records correctly and the motor noise level stays the same, but do not want to leave my phone in a pump-house for 6-hours, every day for a week.

How can I stop windows interfering with the recording process?

 

[fireberd]

How are you recording, continuously, for 6 hours? Even my recording studio program won't record continuously for that long a period.

But, the internal mic is probably the issue. Use an external microphone and record.

 

[CarvedDuck]

How are you recording, continuously, for 6 hours?

Thanks for the reply, I'll see if an old headset mic will do it. The problem with the tablet will be battery life as it does not have OTG charging. But if I can find an old headset here that plugs into headphone jack, I can then use the charger. But the headset I am thinking of is a USB one. Will check the junk box though.

Why not record for 6-hours? One useless test file was 3-1/2 hours and only 144MB, so not sure what problems you anticipate with 6-hours.

 

[fireberd]

A USB headset should also work. Just be sure you set it as the default recording device.

You must be using a very low MP3 bitrate. A one minute .wav file is approx. 10Mb and a one minute MP3 (128) is approx. 1 Mb.
If you are listening for "noises" I would think you want a better fidelity audio file?

 

[CarvedDuck]

The noise is generally a steady hum within a small bandwidth. Thinking about it, the music recorder is expecting peaks to 12K+ and lows of 10Hz whereas the motor probably never exceeds a spread of maybe 500Hz at whatever center-frequency the hum is. Also probably explains the levelling windows is doing with the mic, it sees it as constant noise and assumes we don't want that. About right for msoft programmers.

The sound file plays back in a more than a suitable fidelity and sounds exactly like the motor. We can even hear relays clicking in from a control box nearby. File size will not be an issue.