Lengthening an aiff file

Hi, I am a complete noob when it comes to sounds files. I have a sound file (tock.aiff, it is the “tock” sound when you press a key on the iPad) that is playing fine in iTunes, plays fine in Audacity, makes nary a sound when I play it from my program on the iPad. Another similar file (short beep.aiff) plays fine on the iPad, and I am just swapping the file name, everything else is the same. Someone mentioned that the file may be too short. So, in the interests of testing that I would like to lengthen the file with some dead air. Don’t know how to do that (and have no recording equipment). Suggestions on how to do this in Audacity would be appreciated.


PS I can upload the file if anyone want to do the addition to the file.

– Mark

when I play it from my program on the iPad

Don’t gloss over important information. Which program?

(tock.aiff, it is the “tock” sound when you press a key on the iPad) that is playing fine in iTunes.

iTunes where?

You can, if you’re on a MacBook or larger computer, open the file in QuickTime and press Apple-I for the INFO I think that works in Preview, too. Sometimes that can tell you things about what kind of file you actually have. I know of no duration limitation in aiff files.

Import the sound file into Audacity. Press END to put the cursor at the end of the timeline and then Generate > Silence and pick the duration. Then File > Export > AIFF (Apple).


Thanks Koz. I’ll give that a try. Answers to your other questions: my program on the iPad: It is called Perinatal DB and it is a perinatal database I am developing for two Winnipeg area hospitals. Problem: canadian postal codes (format LNL NLN where L=Letter, N=Number requiring 5 shifts of the iPad keyboard to enter a postal code). Solution: a did a screen capture of the numeric keyboard on the iPad, copied the top row of keys (numbers) and when the user enters the postal code field I display the default keyboard and pop my own row of numeric keys above it. (Call it the “expanded iPad keyboard” if you will). I detect where the user touches the screen and if it is a number feed the number into the field. Works great. Problem: no sound on my expanded row of keys. Weird because I use “short beep.aiff” as an error indicator when the user enters an incorrect key into a field. When I swap tock.aiff for shortbeep.aiff I don’t hear the tock sound, I hear nothing.

iTunes where: I load the sound into iTunes on a Mac OSX (MacBook Pro) and use the regular play button to play the sound. This works for both shortbeep.aiff and tock.aiff. Same for Audacity, when I load either sound file I can play it.

QuickTime: didn’t know that trick, thanks for mentioning: short beep: linear cpm, 16 bit, big-endian, signed integer, 2 channels, 44100 Hz, 3Kb. Audacity shows a time graph of from 0 → 0.0140 (I presume seconds, the units are not actually indicated). tock.aiff: exactly the same as short beep except file is 9k and time graph in Audacity is from 0 → 0.025. More weirdness: neither file makes an audible sound in QuickTime (I adjusted all the volume controls I could find to max).

Back to Audacity: your instructions where very clear, thank you. I have added a second and will see if that helps.

– Mark

Hi Koz,

Unfortunately lengthening the file by one second made no difference. I will make up a sample program that demonstrates the problem and send it to RunRev (makers of Livecode, the app development program I am using)… maybe they can figure out what is going on. Thanks again for you help.

– Mark

linear cpm

It’s PCM. Pulse Code Modulation.

I have a sound file

Another hole. Where did you get the sound files from?

Your system may just refuse to play any sound under certain conditions. Audacity converts music to its own internal format and then creates a whole new file on export, so now you know that two totally different AIFF files fail.

Try mono instead of stereo. I would bet that the sound effects inside the Mac are mono. It’s wasteful to use stereo when it’s not required, particularly on a portable device. Apple may be insane, but they’re not stupid.

Past that I got nothin’.