Audacity Forum

Hi, my name is Martina. I'm a new user of Audacity and I need to create a tick noise of 440Hz, 20 milli seconds duration, and 1 beat per second. I need all that in 6 different amplitudes or dB readings. Now my questions:
1. When I generate a tick noise with 20 milli seconds duration and 60 beats per minute, how do I select the frequency?
2. When I play the .wav file via loudspeaker, how do I know the dB output?
3. How do I adjust the dB for the 6 different files I need to create?
Cheers,
Martina

The easiest way to do this is to use Generate > Click Track.

Use these settings:
MIDI Pitch of 69 is 440 Hz
You can change the number of bars to whatever you want.

The amplitude of the generated signal is -2.5dB. You can use Effect > Amplify to change it.
However, the actual Sound Pressure Level (SPL) you will get when you play the sound through your loudspeaker will depend completely on your system, and how loud you turn it up. Short of measuring it with an SPL meter (which is a science in itself) there is no way to know how loud it is.

PO'L

Hi Irish,
thank you so much, that was very helpful. I didn't quite get the MIDI Pitch thing. Why is it 69 at 440Hz?
So if I use the Effect>Amplify to change it, I would get different tracks that I could play through a speaker and one would be louder than the other (if I don't change the speaker settings themselves), right? I am just asking as I will probably be coupling the speaker coil with gearfor my experiment and I will be measuring it with accelerometers. The problem is that I am a bit short of time and need to start the experiment now even though the accelerometers will not arrive for a few weeks, yet. If I can leave my speaker at one setting and just play different .wav files, I should be able to replicate the exact vibrations once the gear has arrived.
Cheers,
Martina

MIDI isn't a sound program. MIDI is a music management program, so it's not concerned with sounds so low they only show up on a CalTech Seismometer or so high only dogs can hear them. The fact that Audacity can do these things is, in my opinion, an Audacity shortcoming.

So for MIDI to deal with it, it has to be an actual audible musical note played on a musical instrument.

http://www.phys.unsw.edu.au/jw/notes.html

Oboe note at the start of the orchestra is A440 or MIDI 69.

As suspected at the top of the discussion, you really want to measure SPL or Sound Pressure Level, not just dB worth of digital sound on a wire.

The easiest and cheapest way to do this is one of the Radio Shack sound level meters.

http://www.radioshack.com/search/index. ... meter&sr=1

Also as pointed out, once you turn loose sound in a room, everything about the room can cause changes in the sound. Many books have been written about measuring actual sound.

But yes, if you're just intent on measuring one physical property of a device moving under stimulation of sound, then you actually have a fighting chance. You understand that's not trivial, either. People have been designing speaker voice coils for hundreds of years. I think the last great advance was "Magnetic Fluid Cooling." You will always get the inertia and mass built-into the device and missing from the applied signal.

Koz