Blackmagic Forum

Digital COAX!

I have a Logitech 5.1 audio system that was used via TOSLink from my iMac 27” 2015 computer which I replaced with a Mac Pro. I’d like to find a BMD PCIe card or other solution that will integrate with DaVinci Resolve that will allow me to continue to use the 5.1 speakers I have.

Here’s the connections the Logitech supports with my TOSLink plugged in:



Any suggestions for a BMD card or a cable?

The Mac Pro has HDMI Out, but I can’t find a simple HDMI cable that will connect to any of the ports but I’d prefer to use the Digital options (either COAX or TOSLink Optical Audio). The Digiral COAX port is to the left of the TOSLink cable.

Thanks for any assistance.

Have you looked at or tried any cheapish internal or external 5.1 USB cards with spdif output?
There are a lot of them that sells from $30-70.
Some of them are from decent brands as well.

Or a HDMI to audio splitter/extractor?
There are some with optical out and HDMI through.

No idea about the delay though.

Thanks, that would be inexpensive, and might not have a significant delay.

Username wrote:Have you looked at or tried any cheapish internal or external 5.1 USB cards with spdif output?
There are a lot of them that sells from $30-70.
Some of them are from decent brands as well.

Or a HDMI to audio splitter/extractor?
There are some with optical out and HDMI through.

No idea about the delay though.

Are there any brands you trust for this? I’ve got prices from $10 and up for HDMI splitters to TOSLink.

The description of this seems fine for supporting HDMI 2 and TOSLink 5.1.
https://www.walmart.ca/en/ip/Fosmon-4Kx ... VI2J8PMK9G

I’ve only used some to extract 2.0 from HDMI and/or usb.
But the Fosmon you linked to looks exactly like the DeLock branded one and they keep a decent quality.

For that price it begs to be tested.
Please get back to us with the results.

rick.lang wrote:

Username wrote:Have you looked at or tried any cheapish internal or external 5.1 USB cards with spdif output?
There are a lot of them that sells from $30-70.
Some of them are from decent brands as well.

Or a HDMI to audio splitter/extractor?
There are some with optical out and HDMI through.

No idea about the delay though.

Are there any brands you trust for this? I’ve got prices from $10 and up for HDMI splitters to TOSLink.

The description of this seems fine for supporting HDMI 2 and TOSLink 5.1.
https://www.walmart.ca/en/ip/Fosmon-4Kx ... VI2J8PMK9G

I believe I saw the DeLock in my search as well. Thanks for the feedback. I was thinking I needed a card from BMD, but taking the feed from my HDMI port is a better idea if it works for now.

Ordered the Fosmon 4Kx2K HDMI to TOSLInk but supposedly will deliver April 21st-30th.

Received the Fosmon HDMI Splitter/TOSLink from the previous post. It arrived after five or six weeks today May 14. Comes with a power cable and little power supply like an iPhone and that worked.

The purpose of this was to support my TOSLink speaker system. I am positive I ordered the TOSLink Mini connector according to the webpage but they sent the regular TOSLink connector; not a big deal as I can order another regular cable.

However I don’t know if that’s really working because I don’t know for sure it’s sending optical audio. When used on my iMac, via the TOSLink Mini connector, the end of the link should be showing a red light and I don’t see any light at the end of the cable.

Okay well what about the HDMI functionality, eh? Well I have two HDMI HD monitors and they both work with the Fosmon... for six seconds. The signal consistently drops after six seconds no matter how much I play with the device. The monitors display well without the Fosmon connection.

You might try it with only one monitor attached, and see if you get better results, but splitters are pretty finicky to begin with, some assign a new ID and some don't. The 6-second thing sounds like an ID or HDCP issue (or both?).

Your first idea may be best: a sound card.

I’m going to try without the XDR Display. But could a copyright protection be due to the device being made in China without proper protection for Canada? It isn’t playing video. It’s doing nothing when it fails six seconds after boot completes but I do get the sense it might be software. It also fails after six when connected to the BMVA12G7.

John, I tried booting up to my HDMI display without the Pro Display XDR connected and identical behaviour: works fine until 6-8 seconds and signal dropped.

I’m going to look into getting a more costly item from a Canadian supplier.

After more investigation, the Fosmon HDMI Splitter with TOSLink is not at fault here. I was able to get optical audio playing from my speaker set when the splitter was taking the HDMI feed from the BMPCC4K playing back clips in camera. I also could get good results when using the BMVA12G7 monitor.

Everything worked well when no Apple equipment was in the loop. It appears Apple is not happy with something, but not sure what it is expecting. My very old Apple Cinema HD Display shows nothing on the monitor but the monitor’s power light has a regular pattern of flashing as it’s detected some error condition. Even the XDR Display doesn’t work properly until I remove the Fosmon splitter.

Nice to know the BMD equipment works with clips using optical audio, but might not be very useful in a workflow.

How is the splitter power fed?
I know some splitters I have can be powered over hdmi and for some functionality they work while for other they tend to drop out or behave irrational due to brown outs. Those I have to feed 5v into and then they do not cause any problems at all.

Thanks for the reply. In all my tests the splitter is powered from its supplied power connector from mains power. I’ve never tried using it with only HDMI.

Wouldn't some USB to TOSlink device help?
I used to have one (sorry, forgot the name) and it worked flawlessly on a Mac. As soon as the Mac was seeing it as an audio output, I could send the sound from DR too.
That would separate the video issues from the audio issues.

Thanks, Uli; I’ll look into that for the Mac Pro. Currently rebuilding my old iMac to Snow Leopard to get my optical audio working again there too among a few other failings. The 2009 iMac seems to be dying of old age with different organs failing now. It was doing well running High Sierra in December for a couple of weeks but it’s on life support now.

iMacs were actually laptops in disguise, easily dying from heat. Looking nice, but being fragile.
The old 'cheesegrater' can last considerably longer, if you replace the power supply when needed.