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

[David Brown <nonidesign@xxxxxxxxx>]

Man, do I love Harp-L when I read posts like this one. Imagine trying to
find info like this before the age of internet and Harp-L.
BIG thanks Stephen!

On Wed, Jan 5, 2011 at 5:49 PM, HTownFess <Spschndr@xxxxxxx> wrote:

> <<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
>