If you want to play...VK7DB wrote:Interesting comments Owen..
I have two test sets, so I think I will just use one of those to set levels I have only set it by ear at this stage, but it sounds good.. I did have a look on the deviation scope, and it looked pretty good there too.. It wont take a lot to generate the 1k tone and set it up your way, so I might try that and see what the results are..
Dion.
I have dropped the level 4dB in a test tone file I made back then to suit the defaut normalisation by mp3gain. The file is at owenduffy.net/pub/tt2.mp3 .
The description follows:
Test files
A digitally synthesised test tone file is useful in setup of the FM side, it should be played from the same source as the broadcast sound file. The test tone file contains the following:
- 1kHz sine wave at -16.4dBfs (peak) for adjustment of the tx level using Bessel first carrier null (2.4kHz dev);
- 500Hz, 1kHz and 2kHz sine waves at -24dBfs for testing for gross slope across the passband; and
- silence between tones for observing the background noise level.
For operators with access to a deviation meter, the 1kHz test tone at -20dB should be used to set 1kHz peak deviation. Having set the audio level, the passband flatness can be checked using the other tones, the 500 Hz -20dB tone should cause 500 Hz deviation and the 2kHz tone should cause 2kHz deviation.