ambient sound not repeating

[youngti]

Hi All,

So I have two AP16 that just run ambient sound to these speaker are transducers (basically little drivers that don't make sound until you attach them to a surface.) and they are connected to tombstones and they have been working fine but this year when I hook them up and turn them on the ap16 plays the sound once and does not repeat.  I have the option switch set to repeat on and the sound file is named ambient.  it will play once then just stop.  Status light is green and each light by the heat sinks are red.  I have felt the heat sinks and one does definitely get hotter than the other but not too hot to leave my finger on it for a while. 

My question is would the speakers going bad create a situation where it would only play once?  I would think that if the speaks are bad they wouldn't play at all.  each tombstone has two off these traducers connected in series and then each pair is connected to the next tombstone in parallel eventually connected to the AP16.  I have 7 tombstones on one channel and 6 on the other.

Any suggestions?  I have been thinking that I would pull the SD cards format it and recreate the sound file to see it that helps.

[JackMan]

I would start by disconnecting all of the transducers and test the AP-16 with a single "normal" speaker. When things screw up that we're working previously, you have to systematically remove elements one at a time to find the problem.

[youngti]

Yeah I forgot to include that I did try that.  I used an two old car stereo speakers and hooked them up one to left channel and one to right.  Same issue.

Thanks for your response.

[JonnyMac]

I'm with Jack: look to what changed, not what didn't change.

If you're going to reformat your SD card and clean-up the audio files, let me remind you that we always suggest

1) Use Audacity; it's free, easy, and allows you to save canonical WAV files (i.e., free of metadata)
2) Encode to 32kHz
3) If the file doesn't have to be stereo, make it mono

Why 32kHz instead of "CD quality" 44kHz? The idea is that you need twice the sample rate of the highest frequency you wish to reproduce, so 44kHz lets us reproduce a 22kHz signal. Cool -- except that only dogs (with really great hearing) can hear those frequencies. At 32kHz you can theoretically reproduce a 16kHz signal which is still well above normal human hearing. Changing the sample rate down to 32kHz reduces the file size by about 28% -- this can be helpful with some SD cards.

FTR... it takes VERY EXPENSIVE SPEAKERS to reproduce 20kHz. We're talking 10s of thousands of dollars.

Changing from stereo to mono where possible reduces the file size by 50%; again, this minimizes the data that has to be stream off the SD card. If a file is mono, it plays through both speakers.

Finally... you may want to update to the beta code that is posted here: http://www.efx-tek.com/php/smf/index.php?topic=2298.0

This uses an entirely new architecture underneath which we're using in both the AP-8+ and AP-16+.

[youngti]

I hear what you saying and yeah as far as I can tell nothing has changed with the set-up in two or three years.  I will try the new code too. I would like to leave it at stereo because there are two tracks and  with that separated it sounds pretty cool in the grave yard.

But I will take a look at this, maybe it more important to have it work than be in stereo.

Thanks.

[JonnyMac]

Make your files 32kHz stereo. And change the SD card. They do in fact wear out, despite having "wear leveling" algorithms.

[youngti]

cool thanks

[youngti]

Well that was it. Turns out the SD card was corrupt.  Didn't even think that it would happen when it is just sitting there only being read once a year.