Interface question: Inputs

R

rose62

New member
The answer to this question is probably painfully obvious, but I don't know it. How are inputs in interface devices counted? I see units described as having, for example, 18 inputs. How do they arrive at this number?
 
Depends on the interface. With 18 as an example, this means there are 18 total input channels available for use on that interface. Those channels could be all the same type of input, or a mix of different types. So for an imaginary interface, let's say it has 18 input channels with 6 analog inputs built into the interface. That means as a standalone unit for recording analog stuff, you only have 6 input channels but there might also be an additional 12 digital inputs via ADAT or some other digital protocol. (there are several) In order to use all the channels in that case, you'd need additional hardware to expand the available analog inputs, or you'd be connecting a device that has audio that's already in the digital domain. On other interfaces those 18 channels might all be analog inputs. There are different types. Mic inputs would have a mic preamp built in. Dedicated Line inputs typically would have no mic preamp, so you'd need to use an external preamp if you wanted to connect a microphone. Instrument inputs are similar to mic inputs but have a different impedance value, and would typically be found on a channel that has a mic preamp and both 1/4 inch phone jack input connectors as well as XLR. These are all pro level inputs that would be operating at the +4 dBu line level standard. If you wanted to connect comsumer stuff like home stereo equipment, there is a consumer line level which runs at -10 dBV. Typically RCA connectors, but could also be 1/4 inch or 3.5mm.

The user manual for specific hardware should cover all of this.
 
So, MIDI, RCA, mic and instrument inputs are all counted? Where can I read about ADAT? Not familiar with that term. BTW, I have a Focusrite 2i4.
 
I don't think MIDI should be counted. MIDI signals don't have any audio information, just control signals.
 
snow lizard said:
I don't think MIDI should be counted. MIDI signals don't have any audio information, just control signals.
Click to expand...

No but "they" often do! Well, used to, the situation has improved in the ten years or so I have been infesting audio forums. The provision of ADAT stands watching too. Not only is the fact that an external box is needed not often made clear but quite a few interfaces have just an ADAT INput.
Useful I agree but to the casual looker possibly confusing.

So, Caveat bloody Emptor! If a bit noob but in the market for an AI, study specifications closely. Download user manuals* and look for hookup diagrams that show how many ACTUAL ins and outs you might get. I cannot see that more than 4 outputs would be useful to the solo home recordists but think "future proofing"..You MIGHT want to get into 4k 7.1 video!!

*And, IMHO, if the company want you to register, ask for personal details and have you prove you are not a 'bot? Blow them out!

Dave.
 
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