Then why don't you draw up a list of devices? It's not that difficult. I'll explain the main differences between the analogue inputs and outputs here. You should be able to cope with this:
Microphone Inputs
Microphones need a balanced microphone input, unless you have a tube microphone with a preamp of its own that is connected to a balanced line input.
Instrument / Hi-Z inputs
If you want to connect guitars and basses directly to your recording interface, then you require a Hi-Z input (cable with TS plug). Or you have to bring the signals to line level via an external DI-box, which is then usually a balanced connection (cable with either TRS or XLR plug).
Analog Inputs and Outputs with line level
For instruments with analogue outputs or external effects units with analogue inputs and outputs, you must check the manual to see which connection type they support, either balanced or unbalanced.
As a side note: line levels are in the volt range and are over 1000 times higher than microphone levels, which are in the millivolt range.
If you are interested: on the Sengpiel page you get a converter and an overview about typical levels used i the studio.
Sorry, the English version of this page is not accessible anymore: http://www.sengpielaudio.com/Rechner-db-volt.htm
Analog Port – unbalanced connection
An unbalanced connection is made via a cable with 2 wires: signal carrying conductor and shield. The connectors are typically TS plugs (tip, sleeve). When recording microphone signals or using long cables, unbalanced transmission is highly susceptible to external interference. Here, only lower levels are used, consumer level = -10 dBV (which is only 0,3Veff).
Analog Port – balanced connection
In the professional environment of a recording studio or on a stage, balanced transmission is preferred because it allows interference-free transmission of the useful signals even over long distances. The plugs are XLR or TRS plugs (TRS=Tip, Ring, Sleeve). Here, higher studio levels are used.
In addition to ground and the wanted signal (A), there is another wire that also carries the wanted signal, but in inverted polarity (B). When summing the signals A+B, the polarity reversal completely cancels the useful signal, leaving the interfering signal. The interfering signal can then be removed via an electronic circuit so that only the useful signal remains. This requires appropriate electronics in the unit, which may or may not be present. You have to look in the manual of the connected unit.
The preferred connection type in the studio is definitely a balanced connection, if the connected devices support it. Cables for balanced connections are available in the following variants: XLR-XLR, XLR-TRS and TRS-TRS.
List of devices that you want to connect
All you have to do is make a list of which microphones, instruments and other devices you want to connect. This is best done in the form of an Excel list with the following columns:
— Device
— Manual URL
— Required inputs on the rec interface (1=mono, 2=stereo)
— Required outputs on the rec interface (1=mono, 2=stereo)
— Type: Mic | Instr | Line
— Mic Type: dynamic, condenser, ribbon
— Phantom power: yes/no (only for condenser microphones)
— balanced or unbalanced
— Plug type (TS, TRS, XLR)
Then add up
Total inputs: Mic, Instr, Line
Total outputs: Line
Integration of external Mixer
Your external Mixer might require more attention depending on how you want to use it.
Which is this for a mixer? Does it have digital ports or modules like ADAT or MADI to connect it digitally?
Do you want to record each of the Mixer Channels, some mixer have a CUE out port for each channel?
Or so you would like to record several submixes of the mixer or only the Stereo Sum.
Diagram for a better overview over your planned setup
Furthermore, a drawing of your intended Setup would help to give an overview, how you want the devices to be connected to each other.
General considerations
RME interfaces, usual port layout
The largest RME USB recording interfaces have a maximum of 4 microphone inputs, which can also be used as instr/line inputs. Plus 8 analogue inputs and outputs.
Upgrade port capacity with external units
If the ports on the recording interface are not sufficient, you have to upgrade as external devices, if you don't want to permanently reconnect. Usually, this type of device:
a) Mic Preamp(s) to get more Mic and Inst inputs. Often, you also get 1-2 headphone outputs, which is very practical for fellow musicians.
b) AD/DA converters to get additional analogue line inputs and outputs. If you mainly connect keyboards and synths, you might need more inputs than outputs. In that case, devices like the RME M1610-Pro are ideal because it has more inputs than outputs.
Connecting external devices
For the digital connection of external devices, there are essentially 2 possibilities (I'm excluding AVB because it requires additional network components):
a) ADAT = 8 channels at single speed (44.1/48 kHz), 4 channels at double speed (88.2/96 kHz). Often one ADAT channel can also be switched to SPDIF protocol (2 channels 44.1-192 kHz). Cable: TOSLINK, cable length according to standard up to 10 m, 15 m usually works as well.
b) MADI = 64 channels at single speed (44.1/48 kHz), 32 channels at double speed (88.2/96 kHz). Cable: multimode or single mode (laser). Cable length up to 2 km (single mode: 10 km) between each unit. Up to 8 units can be connected serially to one MADI bus. So, cable from unit to unit and back to the recording interface.
Influence of sample rate on the number of useable ADAT/MADI ports
As you can see, it also depends on the sample rate you intend to work with. The number of analogue channels directly at the recording interface always remains the same, regardless of the sample rate used. However, if you connect external preamps and AD/DA converters, the number of channels is halved for ADAT and MADI if you want to work with double or even quad speed. Basically, single speed up to 48 kHz is completely sufficient. You should only consider this beforehand.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14