GLP Impression X4 Profile: Can adjust PWM Frequency


In the GLP Impression X4 and X4-S fixture profiles, I can’t adjust the PWM frequency.

According to the manual, the fixture has a parameter called “Special” that allows you to select the pixel control libraries (aka “Pattern Blocks”), adjust PWM Frequency, or reset the motors. In the Eos profile, this parameter is called “Mode.” Setting the DMX value on this parameter to 100-200 adjusts the frequency. 

In the Eos profile, there is a mode on the “Mode” parameter called PWM frequency, but when I select that and move the encoder, it doesn’t affect the “Mode” channel, it changes the Effect Macro parameter instead.

This is an issue in all versions of the X4 and X4-S profiles, the Normal, Hi Res, and Compressed modes. 

Thanks a lot.


Eos v3.0.2

  • Hello Ethan, We seem to be looking at two different DMX layouts for the GLP Impression X4.  The one I found online for v1.0 DMX for "Compress-Mode", 14 DMX channels is this: Impression_X4_v1_0_from_V1_18-18-12-10n_EN   (Page 3-4).


    It does seem like we need to add a third "Mode" option to DMX Channel 14 for Compress-Mode, like this:

    So, I've attached a sample showfile with that fixture patched.  Could you try it out and see if you agree that this fixes the issue?  You may want to edit the PWM Lower and Higher ranges to make Home the lower or upper limit, as opposed to "in the middle" as I've done.

    If my edits don't fix the issue, could you please attach the latest full User Manual so that we can get the fixture updated correctly?

    GLP Impression X4 Compress edited 2021-07-06 10-03-57.esf2

  • Thanks Matt, I will take a look at this when I'm back on that show.  I'm currently on a different gig which is running Impression X4 fixtures on High Res mode.  If you make me a profile for High Res mode, I can test it here.

    It seems you are looking at a more recent, more detailed version of the user manual than the one I was keeping locally on my laptop. But the software version on the fixture is the same.

    While we're at it, please note that I've also submitted a separate update to the profiles for the smaller Impression X4-S fixture, as the pan/tilt ranges are incorrect on the current fixture library profiles:



  • Just looking at it though... Does it that mode really need to have 3 different ranges for Lower, Default, and Higher? Seems like it could just be one range from 100-200 where the Home value is 150.  That way you can scroll continuously through the frequency range from low to high until the on-camera flicker goes away.

    Also, shouldn't the user values be 582 Hz to 618 Hz?

  • I split into the three ranges to match what's in the manual, but I agree you could make just a single range - but then you don't have the option to click on a tile that says "Default" or "58" or "600Hz" and get that exact value.  

    Yes, it would make sense to make the User Ranges be 582 Hz to 618 Hz regardless if it's one range or three.  That was an oversight on my part.

  • Thanks.  I'll test it out first chance I get.

  • Hi Matt,

    So I’m back on the show today and I tested the new profile.  There is still a problem, where the PWM adjustment is in the “Effect Macros” parameter (#14) and not the “Mode” parameter (#13).  I don’t even see the “Mode” parameter on my encoder pages.