Wisdom Audio DCAB-1 - Manual (Page 29)

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into the DCAB-1. You can do most of the work on your own RTA, fairly quickly
(since you don’t have to wait for screen redraws), and then do the final dialing
in of the system using the DCAB-1. (The main advantage to doing so is that the
DCAB-1 comes with a precisely calibrated microphone of known quality.)
response The response time parameter determines the degree of averaging used with the
pink noise. Slower response is generally more accurate, but of course it takes
longer for the response to settle after a change.
The Medium setting is appropriate for most of what you will be doing, espe-
cially since the pink noise generator in the DCAB-1 is of unusually high quality.
(“High quality noise” refers to the spectral content and uniformity of the signal
as well as its freedom from unusual spikes.)
step The RTA Display section of the terminal window can be set up with a vertical
scale of 2 or 3 dB per division. Each time you increment or decrement the step
value, the DCAB-1 redraws the RTA Display section of the terminal window to
reflect the change.
You should start with a 3 dB per division scale, at least until you have gotten
the system significantly “dialed in” and smooth in your room. This gives you
the most useful perspective on the often large swings in response introduced
by most rooms. Once you have the system closer to the target curve, you can
expand the scale to fine-tune your filter settings a bit.
offset The offset simply moves the response curve up or down in the RTA Display in 1
dB increments. This can be useful when looking more closely at the behavior of
the system at or near a display threshold (e.g., 3 dB per division).
Of course, you can also change the step (vertical scale) to examine such transi-
tions more closely, but many people find that constantly changing the vertical
scale (step) is a bit disorienting. Try it both ways and decide for yourself.
RTA Display The RTA display in the lower left area of the terminal window shows a frequen-
cy response curve, based on input from the microphone.
Note that the screenshot above is an approximation of what you are striving to
achieve. Few rooms are good enough to allow this degree of precision; but you
will get a lot closer with your Wisdom Audio system and a DCAB-1 than with
any alternatives.
Because RS232 is relatively slow, the display on your computer takes several
seconds to redraw. But thanks to the calibrated microphone included with the
DCAB-1, this RTA Display is extremely accurate.