Gpi?

[Daniel Ellis]

What are some examples where you guys are using the GPI ins and outs?

I never hear anybody talking about this. And im curious because I don't do anything with them and Im wondering if there is something i could be doing that would help me since i have them..

[trevora]

Short answer: forget GPI, you'll never need it.

Longer answer: google is your friend: http://en.wikipedia.org/wiki/General_Purpose_Interface

It's a way of providing triggers (typically closing a circuit type triggers) that used to be used to fire a separate piece of equipment (or for a separate piece of equipment to fire PT, typically 'play' or 'record').

[noclevername]

I use it to trigger the delayed power up for my amps. It goes to the power supply and then just sends either a power up or power down to the relays. I've got it set to trigger automatically on power up and then have it set up to power down with a function key.
I've been thinking about making something that hooks up to the Soundweb London Logic inputs in order to cut off the Lobby feeds when we are rehearsing. Right now I just have a mechanical switch hooked up to that... boring!

[Sheldon Radford]

Hi Daniel,

Combined with the Events list there are lots of creative uses for the GPI. Here are a few favorites I've heard of...

Extra Set of Hands
The monitor engineer for a popular touring act had his hands full between songs: he had to raise the level of the audience mics (so the band could hear the roar of the crowd), plus turn on some onstage talkback mics so the band members could talk amongst themselves and call out the cue for the next song. Then, once the cue was called out the engineer had to recall the correct snapshot for song about the be played, mute the talkback mics and fade down the audience mics. Lots of moves in a short amount of time.

He set it up so that when he steps on a footswitch (in this case connected to the footswitch input, which is essentially the same as a GPI), it recalls a snapshot that takes care of turning on the audience mics and talkback mics (with a smooth crossfade, too), which allows him focus on getting ready for the next song. Once the band counts in the song he steps off the switch and another snapshot is recalled, fading down the audience mics and turning off the talkback mics.

Similarly, another touring band uses the GPI inputs wired to floor mat sensors placed at the vocal positions to turn the vocal mics on/off automatically. Saves the FOH engineer from having to figure out who's singing when...

System Startup
If your sound system is connected to a power sequencer, you can set up an event that closes a GP output once the console is in its ready state. This then tells the power sequencer to turn on the next components in the chain, usually speaker processors/amps. This saves any embarrassing and/or damaging pops through the system....

Playback Trigger
Use a GP output to close a switch any time a channel is turned on/off or raised above/below a certain volume. This can trigger a remote-controlled playback device to start playing, for example.

Visual Cue
Use a GP output to drive an external light/beacon. This can indicate any number of things: "your mic is live", "Talkback is on", "solo is active" etc.

Sheldon

[Tragic Dog]

I have to say the floormat thing is awesome.

On a side note was kind of wondering how to handle our power sequencer if we decide to go with a profile in our main room. :)

[Mystere1]

I use it to dim the lamps on my custom KVM switch box. I've been meaning to setup another out as a stop all for qlab as well but I haven't gotten around to it yet.

Gpio is great. You can do pretty
much whatever you want with it. I'd be a bit worried about having a power sequencer on it though.

[digidesigner]

I'm looking to replace a bands yamaha monitor mixer with Profile/personalQ setup. Lead vocalist is used to have a midi controller for controlling his vocal level with a foot controller with 5 level preset with this yamah desk. This is a rock band so personalQ controller does not fit the picture for him. Any way to do this with GPI? If so, how long cables can be used for GPI? We are talking about one (foh only) desk system here.

[Mystere1]

Getting ready to put in Profile #2 and designing a muting setup for the horn player.

How far can you run on Cat5e cable Sheldon?

Looking to use one cable to take care of 4 foot switches and one cable to run 4 LEDs. ~300' total length. I'm fairly certain the Footswitches will be OK, not so sure about the outputs.

[Sheldon Radford]

Hi,

There's no formal spec I'm aware of for something like this, given that you're just using the Cat5e for the physical cable, and not carrying actual Ethernet data (which would be limited to 100 metres).

For the GPI ins there's likely no issue - they're use looking for a simple transition between the voltage high reference and ground.

GPI outs driving LEDs may be another matter at long distances, depending on the drop across the cable over distance. Chances are it would be fine, but in the worst case you could use a local power supply at the far end to drive the LEDs, and have the GPI output act as the switch to turn power on/off. This is detailed in the Profile user guide, begin on page 246 (see p250 for the power supply example).

Sheldon