Duncan A E C Kullanıcı El Kitabı - Sayfa 4

Amplifikatör Duncan A E C için çevrimiçi göz atın veya pdf Kullanıcı El Kitabı indirin. Duncan A E C 7 sayfaları. Acoustic environment control preamplifier

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Notch Filter - The notch filter is very useful in combating regenerative feedback (see

section on feedback). It reduces the signal at a particular frequency where the feedback

is occurring (such as your acoustic guitar's sound board resonant frequency). The notch

filter has two controls: notch DEPTH and FREQUENCY. The notch frequency control

varies the notch from 70Hz to 340Hz . The depth knob controls how deep the notch is,

up to -25 dB!. Turning the knob clockwise deepens the notch. You should use the depth

control to notch out "just enough" of the feedback frequency to stop the feedback, while

preserving the natural timbre and characteristics of the acoustic guitar. Although most

acoustic preamplifiers and amplifiers do not offer it, the depth control is essential in

maintaining a transparent, flat response.

Bass and Treble - These are a shelving type controls with ±10 dB and ±7 dB of

adjustment, respectively. The 12 o'clock position on the pots is "flat" The sound of brittle

piezo-ceramic pickups can be improved by boosting the bass and treble and turning

down the volume slightly. This has the effect of "cutting" the midrange, which helps

some piezo pickups sound more natural. As room acoustics change from gig to gig,

these controls can be used to get a good sound regardless of quirks in the room.

Volume - This potentiometer is the overall output control for the entire preamplifier. It

adjusts the level of the two 1/4" output jacks. The level of the XLR balanced output is

determined by which input jack is being used.

Phase Reverse Switch - This switch reverses the phase of the amplified guitar signal

coming out of the preamp, and thus the speaker, relative to the guitar. This can be an

extremely helpful one-shot cure for feedback. Keep in mind that the air-cavity resonance

feedback depends on the distance and direction of the guitar in reference to the

amplifier. For example, if the air-cavity resonance is IOOHz, there will be a

feedback-canceling "node" every 11.2 feet. Halfway between those nodes are the

feedback nodes, where it'll be the worst. Flipping the phase switch changes the

feedback nodes into feedback-canceling nodes and vice versa. Direction of the acoustic

guitar in relation to the speaker will also affect air-cavity resonance feedback, so the best

way to keep this kind of feedback under control is to stay in relatively the same area and

facing the same direction.