Mini displayport to HDMI adapter not sending audio from iMac to TV

MisterBen

Novice Member
Hi, I'm having problems getting audio to my tv from my iMac via a new hdmi adapter.

Setup is a late-2012 iMac running macOS Catalina 10.15.7, connecting to a Samsung AU7100 4K tv.

I currently have an old mdp to hdmi adapter which is working ok to send both audio and video to the tv from both mdp ports, but I'd like to replace it with a 4K adapter. I think it's also causing some popping noises on the tv speakers when playing audio from the Mac.

Finding a new adapter which works is proving a little difficult.

I've bought an Alogic 4K mini displayport 1.4 to hdmi adapter, but having tried this can only get video to the tv with no audio. I've tested with another hdmi cable and a different tv with the same result. I happen to have two of these adapters and both refuse to send audio.
(The adapter: https://alogic.co/uk/product-soluti...-1-4-to-hdmi-adapter-4k-60hz-active-20cm.html)

When this Alogic adapter is plugged in, video is sent fine, but looking under sound outputs on the iMac, only the internal speakers are listed. Going to sound effects in system preferences, again only the internal speakers are listed in the 'play sound effects through' dropdown. Have also looked in Audio MIDI Setup but the tv/hdmi is not listed. Have reset PRAM but that hasn't done anything.

I also bought a Club 3D 1.2 to hdmi 2.0 adapter (which I've since returned) to see if that would work, but that wouldn't send either video or audio...
(The adapter: Club 3D | Mini DisplayPort 1.2 to HDMI 2.0 Active Adapter)

Hopefully someone can suggest something else I can try. Thanks. :)
 

next010

Distinguished Member
Your Mac might be pre DP 1.2 which supports 4K, maybe the mac forums here or elsewhere know better.

Not sure about your Thunderbolt port and what version it is, if its a v2 then TB2 to HDMI 4K 60hz adapters did exist like this, some should still be out there or on ebay.

If you happen to own an AppleTV or Chromecast connected to the TV you can use Airparrot to stream the macos desktop via your network, not sure such an old Mac might be able to deliver best quality though as its real time video encoding.
 

MisterBen

Novice Member
Your Mac might be pre DP 1.2 which supports 4K, maybe the mac forums here or elsewhere know better.

Not sure about your Thunderbolt port and what version it is, if its a v2 then TB2 to HDMI 4K 60hz adapters did exist like this, some should still be out there or on ebay.

If you happen to own an AppleTV or Chromecast connected to the TV you can use Airparrot to stream the macos desktop via your network, not sure such an old Mac might be able to deliver best quality though as its real time video encoding.
Thanks for the reply

Just checked and I believe the ports are Thunderbolt 1 (up to 10Gb/s speed) so that presumably won't do 4k, but as long as I can get better than 1080p that should be fine. I just need to work out why I can't get audio or find an adapter that does work :)
 

EndlessWaves

Distinguished Member
Looking around it seems to be a common issue on Apple PCs. One of the reported problems is that hotplugging is not very reliable so make sure you restart or start up the PC once you've plugged the adaptor in.
 

The latest video from AVForums

Samsung S95B QD-OLED Review - A Quantum Leap for OLED!
Subscribe to our YouTube channel
Support AVForums with Patreon

Top Bottom