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Inpulse 500 generates a whine when HDMI extension monitor is plugged in

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I am working on extending my gear to include karaoke. Each of the three USB ports is used for lighting, music, and the Inpulse 500.

When I go as far as adding any external monitor via HDMI, a high pitched whine is generated. I've noticed that when I've reset the connection on the controller, the whine changes pitch during the start-up light show.

When I set up a secondary laptop to handle the karaoke portion and feed the audio from my mini-mixer to the aux input of the controller, there is no issues at all. This isn't my preferred means to handle it, but it is quieter.

Any known fixes with the HDMI-USB on my DJ computer?

1 Answer

Hello ScottbryantDJ,

The most likely explanation in my opinion is a limit of bus power with HDMI port and USB ports sharing the same power in the computer.
To check it, you may place a USB hub powered by a power adapter (not powered by the computer) between the computer USB port and Inpulse 500: if it fixes the noise, it probably means the issue was the limit of bus power.

Another possible explanation may be an electric grounding conflict: if the ground of the HDMI monitor is different of the ground of the speakers connected to the DJ controller, you get a bad sound quality in the speakers if the USB port of the DJ controller partly gets the ground of monitor via the USB host chipset while the audio output of the DJ controller gets the ground of the speakers. But in that case, I would rather expect a low frequency noise than a high pitch noise, so my favourite explanation is the limited power on the USB+HDMI circuit (output of southbridge).