The next step on my audio analyzer verification checklist
is setting my audio interface microphone preamps and I basically just have two
things that I'm concerned about. Number one, making sure that the signal level is
healthy but safe and also matching inputs. So let's go through that quickly.
When we're looking at Smaart here, and we can do this in any audio analyzer,
when we're looking at Smaart though, we've got these measurements over here on the
right and what I want to do is I'm going to start the signal generator and I'm
going to bring up my preamps until I'm just about to turn into the yellow color
here which is where my mouse is right now I don't let my speaker on yet but I
can go ahead and turn on the signal generator so we can just start here
without any noise and let me turn over here so you can see these preamp
settings
all right so here's my measurement microphone input and here's my reference
input and what I'm gonna do is I'm gonna start turning up my reference input
until I see that input going up over there okay great that's working so I'm
gonna adjust it until it's just about to turn into the yellow okay so there see
how it's hitting yellow so why do I care about hitting yellow I wanted to hit
yellow when it's at minus twelve on the signal generator because then I know
that if I turn this up to zero it should be either right at clipping or just
under clipping and so you can see it's red on the signal here but if you look
on my audio interface here I am not hitting the clipping LED oh just a tiny
bit there so I might want to back it down just a tiny bit but anyway this is
the best way to get a really healthy signal but it's still safe okay so then
I can back this back down to twelve
okay so I've set the reference input now let's turn on the speaker and I'll set
the microphone input alright so same thing here right I want to bring up my
microphone preamp until it's hitting the same level there -12 so here's my
microphone preamp i'm going to start turning it up and i'm going to be
watching those meters
they're just turns to yellow and I can also see that they're matching here so I
can turn it down a little bit okay why do I care about them matching and being
at the same level well when I switch back to my transfer function the
important thing for me is just that I get a measurement kind of centered
around the zero DB line here I don't want it to be way too high or way too
low so let me give you an example I'll turn back on the signal generator and
then I'll show you what it looks like if it's too far off so turn on the signal
generator we're looking at a measurement here now if our reference signal is too
low then the measurement is gonna go higher now if I reference signals too
high the measurement signal is gonna go too low okay so turn the measurement the
reference signal back about to where it was and the same thing with the
measurement microphone if I turn the preamp down it's way too low I can't see
it if I turn it way too high then we're not centered around the zero line
anymore so this can be just another way to fine tune it so I might go here in
spectrum view and I can see okay they match or you know maybe that's too hard
to see look at it with the banding on okay look this they match they're
hitting about where I want them to switch over to the transfer function
take a look at the amplitude trace here and then I might fine-tune these a
little bit so I can get a trace centered around C or zero dB
all right and that is how you set the microphone preamps on your audio
interface as you're going through your verification checklist again if you want
to get this checklist that I'm using there's a link below this video and you
can download your own and use it in the field or to practice at home
sound design