Audio output converted to time & signal?

Special Interest Groups Audio Processing
1

I am trying to get a short WAV file (don’t know the actual audio encoding type), to a simple set of signal level values.

I am a novice with Audacity, but have used it several hours for simple editing and noise reduction.

Example:

1 second of data, mono
11kHz sample rate

Desired output (in a file):
Value1
value2
…
value11000

Or
time1, value1
time2, value2
…
time11000, value11000

The goal is to output this file on a signal generator, so I am trying to get a time vs voltage type of file output.

I appreciate any suggestions or pointer in the right direction.

Thanks,

JP

2

Not sure if you can do that with audacity… but you can open wav audio files in other programs such as matlab or similar. If you have linux you have some free software such as octave or scilab which should be able to import wav files too. Don’t know about windows but there should be some free software available too…

3

not clear what you are trying to do
please try to explain in a different way
and only one way - to avoid apparent contradictions

are you trying to convert freqs to voltage
or have a freq at various levels of SPL out
or have the same output for many different freqs
or something else

you can find these already done on the internet
and in ready made cds

if you want to make your own
pick the freq
amplify to the level you want
repeat until you have all the examples
group them as you need them

be aware that the actual output level will depend on your player the preamp and the amp and their settings as well as the speakers and all subject to possible nonlinearity deviations too

all you can set is the relative levels in audacity

not sure how you output this file on a signal generator
you can make a cd and play it, or you can play it from audacity
but playign the file from a siggen would require a unique capability that my sig gen devices do not have.

4

Thank you bgravato and and whomper for your suggestions.

bgravato

I hadn’t really thought of another utility to tease out the information I need. I will try searching.

whomper

I apologize for my confusing explanation.

Let me try again:

I was looking to output a short segment of audio on a signal generator to drive a speaker to get the attention of students and generate interest.

I have a signal generator that will take 2 arrays of data for a single waveform generator: 1 array of times, 1 array of voltages

This generator does not have any sampling or analog input, so I need a series of voltages to drive it.

I understand that I may need to normalize and/or scale the signal so that it is appropriate for my signal/waveform generator.

Thanks again,

JP

5

Why not simply generate the audio signal in Audacity, your computer can generate any audio that your signal generator can, and more.

You could download test signals, e.g. this sine sweep … http://www.freesound.org/samplesViewSingle.php?id=22714

[ Here is a good example of a indefinitely rising Shepard tone. A minutes worth will either will either grab your students attention or drive them insane ].

6

jakepeters, Here’s a plug-in I made some time ago that may be what you are looking for.
Extract the zip file and put the “sampleprinter.ny” file into your Audacity Plug-ins folder.
I think it’s fairly obvious how to use it, but if it’s not, just ask.
The plug-in prints a list of sample values to an html file in the form:

"1 = 0
2 = 0.0230352
3 = 0.0460512
4 = 0.0690291
5 = 0.0919498
6 = 0.114794
7 = 0.137544
8 = 0.160179
9 = 0.182681
10 = 0.205032
...
...

(plug-in in my next post)

7

I think that zip file is missing :wink:

8

Thanks BG - I was on my Windows partition to check something out for another user, typed the message, then realised the plug-in was on my Linux partition, and of course Windows can’t read Linux partitions. “No problem” I thought - “I’ll just post the message, switch back to Linux and upload the file”.

Vista says: “Do not switch off your machine. Do not pass Go. Do not collect 200… Installing update 1 of 11… Installing update 2 of 11…”

Finally - here’s the plug-in:
sampleprinter.ny.zip (744 Bytes)
BTW, if you go to much over 10000 samples it may start to get very slow. How far you can go will depend on your computer - start small and work up.
To get more than 1000 samples you will need to type in the box rather than using the slider.
To get more samples using the slider, open the “sampleprinter.ny” file in a text editor and change the last number in the line:

;control number-of-samples "Number of samples to measure" int "[integer]" 100 1 1000
9

Not entirely true… :slight_smile: There are some utilities for windows which allow to mount/browse ext2 and ext3 partitions… I have one of those in my windows xp but I don’t remember the name of it but it’s free software. I think it only works in read-only mode, but I wouldn’t be wanting to write on linux partitions from windows anyway… :slight_smile:

I think its name is something like explore2fs…

10

stevethefiddle,

thanks for the plug-in.

I did a quick try, and got an error:

Nyquist did not return audio

And no file was generated. I tried a few different values for Number of Samples to Measure, but always got the same error. I did give it a valid pathname.

Updated Request

I guess what I am really looking for is a WAV to RAW capability.

I saw stevethefiddle’s posting on another forum, so I appreciate your help here also.

Thanks again,

JP

11

Jake,
To help Steve with the plug-in problem, click on the Debug button instead of the OK button. When do this, you will still set the “Did not return audio” message, but when you click OK to dismiss that info box, another debug box will appear with a lot of incomprehensible text. Cut all the text, top to bottom, and paste it into a message to StevetheFiddle. It will help him figure out what is wrong. Since it’s a small plug-in, I may be able to spot the problem it you PM the debug text to me also.
It’s probably a typo of some sort.
Dave

12

It’s for mono tracks only.