jaddie
Account deactivated by request.
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- Mar 28, 2011
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I'm posting this because square wave testing has come up in a couple of threads recently, and I thought it might be handy to have a couple of examples to play with and audition. The idea is to look at the images files and listen to the audio. The zip file has 4 image files and a 20 second audio file. The audio file is digitally generated, 96KHz, 32bit float .wav, and has 4 different 100Hz wave forms in sequence, 5 seconds each, and with a 50ms gap between them for identification. The first one is a "perfect" 100 Hz square wave, and the following 3 all started out as the first file, then had something done to them that changes their appearance. The .jpg files are named sequentially and match in sequence the signals in the audio file.
The purpose of this group of files is to show that using square waves as test signals may be useful, but is also difficult to correlate to audible results. In particular, look at the 4th example. There are many things you can do to the appearance of a square wave that do not result in an audible change, just as there are things you can do that do result in an audible change.
When we talk about square waves and how "messed up" they look, the real concern is not how they look, but how the cause also changed some audible property. The visual evaluation of a distorted square wave is only useful when knowledge of the cause and it's audible effect is considered.
The examples are playable in any software capable of playing a 96KHz file, and worked fine in Audacity, which also gives you the ability to zoom in and look around for yourself.
Get the zip file here. The file was created with Audition.
If there's interest, I could post more examples.
The purpose of this group of files is to show that using square waves as test signals may be useful, but is also difficult to correlate to audible results. In particular, look at the 4th example. There are many things you can do to the appearance of a square wave that do not result in an audible change, just as there are things you can do that do result in an audible change.
When we talk about square waves and how "messed up" they look, the real concern is not how they look, but how the cause also changed some audible property. The visual evaluation of a distorted square wave is only useful when knowledge of the cause and it's audible effect is considered.
The examples are playable in any software capable of playing a 96KHz file, and worked fine in Audacity, which also gives you the ability to zoom in and look around for yourself.
Get the zip file here. The file was created with Audition.
If there's interest, I could post more examples.