Look here

I wrote a blog article about 1st time setup and routing in german and english: https://www.tonstudio-forum.de/blog/ind … rnal-equi/

RME tutorial videos: https://www.tonstudio-forum.de/blog/ind … al-Videos/

Before we talk about routing you should see an input signal under Hardware Inputs.

What connector do you use as LINE INs ?
According to the Handbook the 2 XLR Inputs are for Mics and useable as LINE IN.

So you need from your synthesizer 2 TS -> XLR cables

Synthy OUT L ---->  TS-XLR cable ----> BBF XLR Analog 1 IN
Synthy OUT R ---->  TS-XLR cable ----> BBF XLR Analog 2 IN

What cable / ports do you have in use ? Please detail your setup.

You should also check chapter 9.6 of the Handbook.
AN 1/2 Stereo
48V to be deactivated
Inst to be deactivated
Adjust gain

Routing:

TM FX: ensure to be in submix mode

1. Main Out
Assign Main Out to > AN 1/2
Click to channel Main Out, you see now the submix for main out
Raise the fader of Hardware Input AN1/2 (Synthie)

2. Phones
Assign Phones -> (you need to look which output channels are for phones)
Click to channel "Phones", you see now the submix for main out
Raise the fader of Hardware Input AN1/2 (Synthie)

> Phone means Monitors?
Monitors are monitors, phones are phones, what a surprise

> but here's another challenge,the sound from synth is very quite
You are sure that you turned the output volume of the synth fully on ? Check !
Up to what input level you get an input ? -xx dB ..

You are aware of
- that in TotalMix behind the tool symbol there are more knobs for i.e. input gain and input sensitivity ?
- that you need to raise the input fader of AN1/2 to ~0dB for the Monitor and Phones Mix separately
I explained to you already that you need to be in Submix Mode and then click to the HW Output
(either Main Monitor or Phones) to make the submix for this Monitor ?

Ok nice. Read the TM primer which I wrote and watch the RME TM FX tutorials.
Its worth it to become more familiar with TM FX.

Via ADAT, the BBF has 1 ADAT port IN and 1 OUT.

Of course, industry will be thankful

Maybe you should start describing your setup and the gap/limitation that you have
1. what inputs and outputs are you using already from the BBF with which device
2. what analog or digital ports are missing for what devices
3. what is your budget, shall a new device be required

I personally would go then for UC or better UCX, optionally in combination with ARC USB.
Or you need to expand via ADAT. But then you have 2 devices. Could be smarter to have only one.

Because then all your inputs and outputs have the same RME quality.
This could be cheaper to achieve in only one device.

Otherwise you would have mix RME and non-RME equipment and this could be a quality degradation
if you add cheaper equipment via ADAT. I.e. worse SNR, bad potis, etc.
With UC and UCX you can i.e. digitally store the settings for all channels that you require in snapshots / workspaces,
so that everything is ready to use for you, which is a big timesaver and adds much comfort into your workflow.
ARC USB can be bought in a 2nd step, which is also very comfortably to work with.

To get an overview about RME interfaces you can have also a look into my blog article here, it contains an Excel / PDF file comparing all interfaces: https://www.tonstudio-forum.de/index.ph … 017-12-pdf There you can see the exact differencies between UC and UCX.

Available only in german: https://www.tonstudio-forum.de/blog/ind … B-MADIfac/

You're welcome.