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PostPosted: Fri Dec 06, 2019 12:33 am 

Joined: Mon Dec 02, 2019 6:23 pm
Posts: 7
So - I am having tons o' fun with Stereo Tool, but right now I am in a bit of a jam - I hope someone can set me straight, because I am expected to install a working transmitter TODAY. (I have a workaround for now, but I need a permanent solution)

I am trying to find a way to print an audio file of the FM MPX output from ST - I of course tried Watchcat, but can't get it to work quite right. There are two problems. The main problem is that the files I am generating are not sounding right at the decoder. No stereo. I am playing them out of VLC to an Apogee Duet - the same card that I am using to push out live MPX, which is working brilliantly with the exact same settings.
I checked and rechecked my settings, but I think that WC not allowing me to set a custom bitrate is the problem, since I am using MP3's as the source.

The second problem is that Watchcat still watermarks all the files despite putting in my license and ensuring that I am not using any premium features. Just
make my file according to my preset (also, no fancy features) I wonder what I am doing wrong?

This probably seems like a nutty setup, but this is for a remote transmitter on a 30 minute loop that has to be stupid simple to operate. I want it all to turn on and off with one switch- I am thinking a HiRes player would be the most reliable, glitch-free approach.Up until now, we've used an iPod shuffle that just stays powered and playing even when the transmitter is off - has worked great for ~20 years. I hope I can keep this arrangement.

I've been pecking away at this for days, and I think I'm out of tricks. Your thoughts and suggestions would be deeply appreciated.

Thanks!

RG


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PostPosted: Fri Dec 06, 2019 3:49 pm 
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Joined: Wed Nov 08, 2017 3:16 pm
Posts: 191
Quote:
So - I am having tons o' fun with Stereo Tool, but right now I am in a bit of a jam - I hope someone can set me straight, because I am expected to install a working transmitter TODAY. (I have a workaround for now, but I need a permanent solution)

I am trying to find a way to print an audio file of the FM MPX output from ST - I of course tried Watchcat, but can't get it to work quite right. There are two problems. The main problem is that the files I am generating are not sounding right at the decoder. No stereo. I am playing them out of VLC to an Apogee Duet - the same card that I am using to push out live MPX, which is working brilliantly with the exact same settings.
I checked and rechecked my settings, but I think that WC not allowing me to set a custom bitrate is the problem, since I am using MP3's as the source.

The second problem is that Watchcat still watermarks all the files despite putting in my license and ensuring that I am not using any premium features. Just
make my file according to my preset (also, no fancy features) I wonder what I am doing wrong?

This probably seems like a nutty setup, but this is for a remote transmitter on a 30 minute loop that has to be stupid simple to operate. I want it all to turn on and off with one switch- I am thinking a HiRes player would be the most reliable, glitch-free approach.Up until now, we've used an iPod shuffle that just stays powered and playing even when the transmitter is off - has worked great for ~20 years. I hope I can keep this arrangement.

I've been pecking away at this for days, and I think I'm out of tricks. Your thoughts and suggestions would be deeply appreciated.

Thanks!

RG
if i am understanding correctly what you are trying to do...
you are trying to save the live FM MPX output from ST to a file for later playback ?
if that is indeed the case, you will need to be sure the sample rate and audio encoding to the output file, is at 192Khz in RIFF (WAV) format respectively, in order to support the MPX pilot (i do not believe any type of audio compression will preserve the MPX).
i am not sure but i believe VLC will play the file without issue as long as the output of VLC is directed to your Apogee Duet and the output level of VLC matches your MPX live output from ST.
this is similar behavior to recording the baseband (I/Q) of a slice of RF spectrum for playback on the demodulating device.


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PostPosted: Fri Dec 06, 2019 9:23 pm 

Joined: Mon Dec 02, 2019 6:23 pm
Posts: 7
Quote:
192Khz in RIFF (WAV) format respectively, in order to support the MPX pilot (i do not believe any type of audio compression will preserve the MPX).
Yes! Thank you! This is precisely what I am attempting the problem I am describing is that I am not seeing the predicted result so far.

I'm thinking that Watchcat might be the culprit as one cannot specify the output bitrate when using the MPX option - The only setting it will allow is "follow source bitrate." I would think that since 192khz is required so the codec doesn't muddle the MPX, that WC would force a 192khz Wav. I might have to get really crazy and experiment with an analog recording just for sh!ts and giggles.

By the way, if I get over this hump, the next fool's errand I will be undertaking is finding a cheap player. I have a couple of Ideas ranging from a Blu-Ray player that takes USB/Flash drives to a portable MP# player, or - my favorite - a Raspberry Pi with a HifiBerry hat.

And the other problem is that I am still getting watermarked files out of WC in spit of the fact that I supplied my ST license.

Quote:
I am not sure but i believe VLC will play the file without issue ....


I though so too. I chose VLC because I didn't think there would be any funny business going on under the hood, but I don't know that for sure. I probably should look into that.

Thanks so much for the speedy reply.


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PostPosted: Fri Dec 06, 2019 10:39 pm 
User avatar

Joined: Wed Nov 08, 2017 3:16 pm
Posts: 191
Quote:
Quote:
192Khz in RIFF (WAV) format respectively, in order to support the MPX pilot (i do not believe any type of audio compression will preserve the MPX).
Yes! Thank you! This is precisely what I am attempting the problem I am describing is that I am not seeing the predicted result so far.

I'm thinking that Watchcat might be the culprit as one cannot specify the output bitrate when using the MPX option - The only setting it will allow is "follow source bitrate." I would think that since 192khz is required so the codec doesn't muddle the MPX, that WC would force a 192khz Wav. I might have to get really crazy and experiment with an analog recording just for sh!ts and giggles.

By the way, if I get over this hump, the next fool's errand I will be undertaking is finding a cheap player. I have a couple of Ideas ranging from a Blu-Ray player that takes USB/Flash drives to a portable MP# player, or - my favorite - a Raspberry Pi with a HifiBerry hat.

And the other problem is that I am still getting watermarked files out of WC in spit of the fact that I supplied my ST license.

Quote:
I am not sure but i believe VLC will play the file without issue ....


I though so too. I chose VLC because I didn't think there would be any funny business going on under the hood, but I don't know that for sure. I probably should look into that.

Thanks so much for the speedy reply.
what sample rate do you have ST set to under I/O > Sound Cards > Sample Rate
i assume its 192Khz.


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PostPosted: Sat Dec 07, 2019 9:38 am 

Joined: Mon Dec 02, 2019 6:23 pm
Posts: 7
Yup - the whole chain is 92khz.

It might be helpful to know that I Output live ST with the same settings and the same soundcard, and it works a treat. This is why suspect I have Watchcat not configured properly. After a few pokes at it, I ended up with a folder full of files.
Is there Watchcat guide that will explains these settings? The Still trying to suss out what is supposed to happen with regards to bitrates when I set it to save as MPX output. It seemed straightforward, but I think I am missing something at the Watchcat stage of the process. I don't think I am getting the right type of file, and that is why I am getting an unexpected result when I try to feed it from VLC to the transmitter.

Here is what I THINK (hope) it's supposed to do:

320Kbs MP3 (sorry, I have no control over this) ---> Watchcat(my preset) ----> Save to MPX~~~> 24/192 .WAV

Then at the transmitter: WAV (VLC )-->Apogee-->Xmitter MPX IN---> Receiver---> Loud, punchy, stereo JOY!


The files I am generating are indeed 2116Kbps - 24 bit, no?

Also, the watermarks! What is up with that?

thanks again!


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PostPosted: Sat Dec 07, 2019 11:33 pm 
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Joined: Mon Mar 17, 2008 1:40 am
Posts: 11185
Hi,

Can you check that the output files are indeed 176.4 or 192 kHz and that they contain MPX data? You can use a program like OcenAudio if you need a free program to check them. 2116 seems to be a weird number... (44.1 x 4 x 16 bit = 2822, with 48 it's even higher).

Have you filled in the Stereo Tool license in WatchCat? And does WatchCat show an option in the output to output MPX? (It should, if not something is wrong with the preset).


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PostPosted: Sun Dec 08, 2019 10:41 pm 

Joined: Mon Dec 02, 2019 6:23 pm
Posts: 7
I fixed the issue by installing WC on another computer and starting from scratch. (Scratch... Cat.... See what I did there?)
It's all good in the hood now. For what it's worth, I am (now) certain I had all the settings right, and the license installed. In any case, solved.

Next step - If you were me, what would you use to loop the file at the transmitter site? Client has no budget to speak of (Or I would have gotten the upgraded ST with that delicious de-clipper!) I have been looking at something like this:
https://www.amazon.com/gp/product/B07JD ... KMFW&psc=1
I think as long as I turn off any dynamics processing, etc, this should be fine, yeah? Moving up the quality ladder will get me more precise playback and less chance of spurious overshoots is my guess, but I am planning to be conservative.

Just like the iPod before it, the plan is to keep it looping 24/7 while the transmitter only operates for a few hours each night. I know it's kooky, but I have to make this process either run on one switch (or even better, a timer) as I want to put the transmitter in a hard to reach location. (I do have future plans for remote control) It has to stupid simple to operate and not require any attention on my part.

Thanks again everybody!


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