EZ-8 Audio Sync

[DL]

I have an EZ-8 REV-B triggering a Cowlacious CARP300 card via 12v on the audio card's trigger.  My sequence is created in Vixen.  When I run the EZ-8 and audio embedded in Vixen (through a connection), I have no issue with the sound synchronizing to the programming.  But...when I download the sequence to the EZ-8, I have a couple problems.

Problem # 1. I use a push button to start the EZ-8...connected to the switched input.  The EZ-8 then triggers the audio card using one of it's 12v channels.  This won't stay synced.  On one run the audio might match the sequence start point of the EZ-8.  The next time it might not.  It seems to be intermitent.  When I use the EZ-8 start button...it seems to work properly.

Problem # 2.  I couldn't find an easy way to sync up the audio recording on the audio card with the start EZ-8 sequence.  I recorded my sound to the audio card, removed the embedded sound in Vixen, and then changed the frame positioning of the trigger signal (EZ-8 channel #8).  After a bit of testing, I got it lined up with the same start point.

After downloading the code to the device, I triggered the prop from the card's start button and found that the overall timing of the audio no longer matched the EZ-8 sequence.  Even if the start was at the same place, the audio seems to mis-match the EZ-8 program.  In an attempt to solve this, I re-recorded the audio to the CARP300 with Vixen (with the cable) playing the sound.  It didn't fix the problem.  Even if the audio starts at the same point, the audio track doesn't seem to stay synced.

Am I doing something wrong?

[JonnyMac]

I don't know if you're doing anything wrong.  What I do know is that the EZ-8 is a pure digital player and doesn't change when outputs go on or off; that always remains the same.

We suggest that you use Channel 8 for audio and always start with that.  Here's what I'd do:

1) Record your sound into the CARP; make sure you can manually start it (with a button input)
2) Connect the V+ and OUT8 terminals of the EZ-8 to the voltage input trigger of the CARP -- use the 12v setting
3) Create a blank Vixen program
4) Put a 1-second pulse output on Channel 8 where you want the audio to start
5) Play the sequence live through the EZ-8 to ensure that the audio starts every time you play the sequence

Once you have these steps going, then you can build up your animation.  It's best to get the audio start sorted out before you attempt to add any motions, as the motions can be distracting and prevent you from getting an accurate handle on what's happening.

[DL]

I'm triggering audio (singing pumpkins/This Is Halloween) using channel 8. 

I believe Vixen is not accurately recording the sequence timing to the EZ-8.  (It set timing to 33ms.)  When I play it via the computer...allowing the sound card to trigger from the EZ-8 and play along with embedded sound in the Vixen application...it runs beautifully...with the sound card echoing the computer note for note (both play through the same speakers).  If I push the button to turn off the sound card it never misses a beat.  Same in reverse, if I unplug the computers plug with the sound card still playing...its all in sequence.

When I turn the code over to the board...downloading the sequence to the EZ-8, and then play it from the EZ-8 without a computer and vixen running...the sequence is slightly out of whack.  There's a noticeable delay along the way.  Lights that should flash in sync to the turn aren't in sync to the song.  I've reattempted this over and over...reprogramming the sequence several times from start to finish.  I think Vixen needs to be adjusted in how it is timing the recording to the EZ-8.

[JonnyMac]

I'm confused (easily done), how is it that you have the CARP and Vixen playing through the same speakers?   Did you start your new Vixen sequence at 33ms?  If you allow Vixen to change a sequence to 33ms then some events will change due to rounding errors in math.  Sorry, I should have told you earlier -- start you sequence with a 33ms event timing so that Vixen doesn't have to modify that before downloading.

[DL]

I started the Vixen sequence at 33ms.  (I've tried it multiple ways.)   Using a clean file, I reprogrammed it from scratch.  It's definitely in how it downloads to the card.  I can send you the file and you can see for yourself.  If you play it via the PC, it works just fine.

Playing the audio through the same speakers was unexpected...but helpful. 

My computer has an output plug for audio, which I ran as an input to the carp300.  (Even though I have already stored the audio track onto the carp300.)  The carp300 has an output, which I ran to my speakers.   When played in computer mode....the sequence will trigger the audio card (so long as that wire is connected).  The computer is playing into the input of the carp300, and surprisingly, the carp300 added it's recorded track to the sound layer.   In essence I heard a harmonious echo of both tracks layered on top of each other....one slightly quieter than the other.

This was very helpful because it confirm was I was trying to prove...that the audio card wasn't distorting the track.  The computer sound played exactly in sync with the recorded track on the carp300.  That allowed me to eliminate the audio card as an issue.  The EZ-8 always triggered it exactly on the same timing.  It's the overall speed of the EZ-8 recording that is off.

[JonnyMac]

Well, I will do some measurements and see if we can find a difference between Vixen and the EZ-8.   The timing in the EZ-8 is fixed; we may need to tweak the timing for Vixen.  I got your files; will have a look.

[DL]

I hope the show (TransWorld Halloween 2010) went well for ya'll.  Any chance that you've had an opportunity to find a fix to the EZ-8 timing sync problem?

[JonnyMac]

The "problem" is two separate clock sources.  When you're running live out of the PC you're using the PC's clock; when running out of the EZ-8 you're using the EZ-8's clock; two [non-atomic] clock sources, no matter how good, will not stay in perfect sync over a very long show with short events like you're using.

I have a solution in mind that I think will help.  Any chance you have an SX-Key or Blitz?  I can post code for you to try without having to return the board to us.  That said, I need to talk with KC as well because the Vixen interface will need to support the changes.

The solution also helps us with a few customers that have asked, believe it or not) for even LONGER shows -- though none of them are doing very short, very precise events like you.  Here's what I intend to do:

1) Change the timing resolution from 33 to 50ms
    -- this will lengthen the show from ~36 minutes to ~54 minutes

2) Reduce the baud rate to 9600
    -- this will ensure good downloads over bad wires and be compatible with the timing change

You are the only person that has experienced the sync issue, but I believe that's because you have really pressed the EZ-8 further than anyone else -- so we'll make an update to help you and, perhaps, others that do long shows and may start to use short, precise events in the stream.

Thanks for your patience with Transworld.  Yes, it was a great show for us and a new company called Ethereal FX for which we designed/manufactured a new low-voltage, DMX-compatible lighting product.

[DL]

No, sorry....I don't have an SX-Key or Blitz.

[JonnyMac]

Okay, then, you'll have to return the unit to us for the program update.  We're not ready to do that yet as we need to get the Vixen side updated as well (I've made the changes to the EZ-8 code).

[DL]

Any update on the Vixen side?

[JonnyMac]

Just recently received and update but have been focusing on the AP-16+; will test the new Vixen code (which has to work with old EZ-8 code) and the new EZ-8 next week.

[DL]

Shall I return these cards for a refund?