Finally found the solution to get the two x Ferrofish 16 MX units daisy-chained on Mac Pro 2019 running OS X Sequoia v.15.6.1.
I wish someone had told me the info. below, this would have saved me a lot of time and hassle.
The problem turned out to be a faulty fiber optic cable. With metal-core cables it’s easy enough to check for broken wire inside or a badly-connected plug, with fiber optic it’s different. There can be an internal breakage which still allows some of the light to pass. The end of the cable can have been damaged by scratching, which also compromises the cable's ability to carry light with fidelity. Fiber optic cables are very delicate. Don’t bend them, don’t tread on them, don’t allow their ends to touch anything. Be super-gentle when you insert them, without letting the bare end scratch on the side of the socket. It’s possible to get fiber optic cables with angled ends. You want one with a straight-cut end (90º angle).
You must have a multiplex fibre optic cable (these are blue, purple or orange and labelled ‘multiplex’). A ‘duplex’ cable (usually yellow), is not designed to take the amount of data being transferred to and from the Ferrofish and won’t work.
On the Ferrofish, ‘Tx’ means ‘transmit’ or ‘out. ‘Rx’ means ‘receive’ or ‘in’. Connect the two units with 'Out' from RME (MADI optical) to 'Rx' on Ferrofish #1, 'Tx' from Ferrofish #1 to 'Rx' on Ferrofish #2, then 'Tx' from Ferrofish #2 to ‘In’ on the RME (MADI optical).
On the Ferrofish #1’s Routings page, set Analogue Out 1-8 and 9-16 to go to MADI In 1-8 and 9-16 respectively. On the Ferrofish #2’s Routings page, set Analogue Out 17-24 and 25-32 to go to MADI In 17-34 and 25-32 respectively. Here, ‘1-8’, '9-16’, ’17-24’ and ’25-32’ are each represented by ONE moveable white square. All other squares can be put on any unused MADI/Analog inputs and outputs.
On both Ferrofishs’ Setup pages, BNC termination should be ‘on’, MADI 86K frame ‘off’, MADI short frame ‘off’, MIDI control ‘both’. On Ferrofish #1 set Delay Comp. to '1 of 2'. On Ferrofish #2 set Delay Comp. to '2 of 2'. The numbers on the screen are minuscule, so ensure you get these right.
On both Ferrofishes’ Clock page, I find the display a little confusing. Ignore the ‘SMUX/1’, ‘SMUX/2’ & ‘SMUX/3’ for the moment (for which see p9 of the Ferrofish Pulse 16MX manual). At the top of the page here, you have ‘MASTER’, MADI’, ‘ADAT’ and ‘BNC’ as options. The thing is that (i) these are not mutually exclusive and (ii) putting the cursor on ‘MASTER’, MADI’, ‘ADAT’ or ‘BNC’ activates these modes. - If the cursor is on it, then that’s the one that’s active!
If you put the cursor on ‘MASTER’, this makes the Pulse 16MX generate its own wordclock and it will ignore any wordclock coming from the RME. All three of ‘MADI’, ‘ADAT’ and ‘BNC’ put the Ferrofish into slave mode. If you put the cursor on ‘MADI’, ‘ADAT’ or ‘BNC’, it will slave itself to a wordclock source from ‘MADI’, ‘ADAT’ or ‘BNC’ respectively, external to the Ferrofish. Remember: if the cursor’s on it, that’s the one that’s active and there's nothing more to do if the Ferrofish is in one of the three slave modes.
For using two daisy-chained Ferrofishes with the RME, you want the wordclock source to come from the RME, and for both Ferrofishes to be slaved to that. ‘MADI’ stands for 'Multi-channel Audio Digital Interface’. The RME 'owns' the MADI. Thus on both Ferrofishes ‘Clock’ (‘Clock Source’) page, put the cursor on ‘MADI’ to highlight it, and leave it like that. In (MADI) slave mode, both Ferrofishes will look to the MADI signal from the fibre optic cable (from the RME) for a sample rate to use (set in the RME's settings - see below). If you’re recording up to 48KHz, you do not need to play with the Ferrofishes' SMUX settings (for which see p9 of the Ferrofish Pulse 16MX manual).
To use fiber optic cables to connect a Ferrofish to an RME MADIface USB interface, your Ferrofish must each come with an SFP module. See:
https://www.ferrofish.com/?s=sfp
Ferrofish Pulse MXs come with these modules already inserted.
A word about BNC: it’s not mentioned in the Ferrofish manual that the Ferrofish’s BNC ‘in’ and ‘out’ sockets are for wordclock only, and will not work to daisy-chain more than one unit for digital audio transfer. For that, you have to buy an additional device to connect to the BNC terminals on each Ferrofish.
It’s worth checking that both your Ferrofishes have the same firmware version and that this firmware is up to date. You can see which firmware version your Ferrofish has, by going to the first menu page, left-hand screen (that says 'PULSE 16' in big blue and white letters), bottom left. At the time of writing, the latest firmware version was 5.04.
Download the latest drivers (with instructions on how to install them) from:
https://www.ferrofish.com/downloads-2
Now to the RME MADIface USB: this will have three connectors attached: a USB connection to your Mac (or PC), and the in and out fiber optic cables to the 2nd and first Ferrofish in your chain, respectively.
Strangely, both of RME’s drivers need to be installed and opened simultaneously on your Mac for the RME to communicate with the Ferrofishes. These drivers are apps called ‘Fireface USB Settings’ and ‘Totalmix’ available from rme-audio's website
If you use an RME regularly on your computer, you might want to set these apps as 'login items', so that they open automatically each time you switch your computer on.
The settings of the RME are controlled from the Fireface USB settings app. (see above). How these are set is critical. If one setting is wrong, communication can be lost. It’s not always obvious which setting to use. I am grateful to Leon at Ferrofish in Germany for his tips on setting these correctly. Here is how my window is set up on Mac; set thus, this works with two, daisy-chained Ferrofishes. As you will have set the RME as master clock source, the sample rate that the Ferrofishes use will be determined by the sample rate setting in the Clock Mode section (see attached image).
One last thing: on their main ‘ANALOG INPUT | ANALOG OUTPUT’ page, the Ferrofishes show a row of icons at the bottom on the right. The left-most of these looks something like this: [color="#5AC10E"][o][o][/color]. If your Ferrofishes are correctly slaved to your RME, then this icon should (i) glow [color="#5AC10E"]green[/color] on each Ferrofish and (ii) show a flashing black and white square-wave icon blinking on the top of the green icon.
Good luck in setting up your devices. If you get stuck, I have found the Ferrofish company in Germany to be very helpful. See ferrofish dot com
