[Harp-L] Re: Kinder AFB+ and Volume Control

<<But I don't think that's the case. I think the mic's output is being
measured. And anytime you reduce that, the box is now seeing something
different. >>

Ray, you calibrate the AFB+ with the mic volume set at max because
calibration does two things--it reduces the chance of the SS input
distortion that's possible with any SS device when too big a signal
comes in, and it keeps the AFB+ from "overprocessing" your signal
beyond what your actual feedback reduction needs are--part of what
creates the notorious "AFB+ doesn't sound natural" tonal signature is
somebody having the Calibration knob turned up too far--it's not just
the AFB knob that can create that overprocessed sound, in fact the
Calibration knob probably contributes more.  Turning the Calibration
knob up too far makes the unit assume a bigger max mic signal will
come in than you actually ever send it, and it overreacts to the
possibility of feedback by doing more than you actually need.  To
prevent feedback, it has to actually predict the feedback loop, and
your mic volume knob @ max is the worst-case scenario, so it stays
ready for that via the Calibration knob.

With your mic knob at any setting, your signal may be overprocessed if
you've overdone the Calibration, the same as it would be overprocessed
@ any playing attack with a non-VC mic.   Index the Calibration
properly, and you'll be fine at any mic knob setting--at least, as
good as the playing context allows the AFB+ to sound.  Smaller mic
knob settings send the AFB+ a less-than-worst-case feedback situation
due to the smaller size of the incoming signal, and the unit reacts
accordingly *if* you have calibrated it well.

And although one does lose harmonic content (frequencies) when turning
down any volume control (mic or amp), the AFB+ *minimizes* the impact
of turning down the mic volume control because the AFB+ buffers the
mic signal--you don't get additional signal loss due to parallel input
impedances down the line (other pedals, amp input) because the AFB+
does Jayphat-style isolation of the mic.  So your VC mic sounds better
thru the AFB+ in that respect than it would *going straight into the
amp*--if you have calibrated well.

In other words, don't worry, be happy.  Calibrate with mic @ max +
your playing attack @ max.  If you want a reason not to use a mic
volume control, sorry, the AFB+ ain't it :)

If you research the subject, however, you will find archived
discussions where users say they get their most natural tone with the
Calibration light doing something other than what the instruction
manual says.  IIRC, some people say they can get the light to come on
too much with a given mic even with the Calibration knob maxed out, so
they have to back the Calibration knob off to the lowest setting they
can use in that situation--doing it by ear rather than by eye, in
other words.  A mic volume knob doesn't change that.  Like Mike says,
always calibrate, if the Calibrate light is usable with that mic, or
by ear if not, and calibrate with mic + player @ max.

Stephen Schneider

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