26 Silicon chip Australia’s electronics magazine siliconchip.com.au
There’s a wide range of audio processing tasks this project can handle.
Yes, it uses DSP to provide an 8-channel parametric equaliser, so you
can adjust frequency response to exactly the way YOU want it with
really low distortion and noise. Or you can use it to “Biamplify” a pair of
speakers. Or you can simply use it to experiment with any audio signal.
And with its modular design it’s even ready for future expansion.
Design by Phil Prosser... Words by Nicholas Vinen
Is it a Digital Signal Processor?
Is it a Two-way Active Crossover?
Is it an Eight-channel Parametric Equaliser?
IT’S ALL OF THESE...
But wait: there’s MORE!!
L
et’s face it: most tone
controls don’t give you
a huge amount of con-
trol! Sure, you can boost
or cut the treble and bass
- but only centred on
particular frequencies.
Sure, you can ad-
just the level
between chan-
nels. But that’s
just about it.
Wouldn’t you like
to have TOTAL control over your sound system? You need
this active crossover/DSP/Parametric Equaliser. It simply
slots in between your sound source (no preamp required)
and your amplifier (if your amp has tone controls, simply
leave them “flat”).
We’ve published active crossovers before (the latest in
September & October 2017), and DSP-based projects before
(October 2014), but this is the first time we’ve combined
both concepts.
This is also the first time that we’re publishing a digital
signal processor that’s truly high fidelity, as it has a very
low total harmonic distortion
figure of around 0.001%.
This unit takes a stereo
audio signal and splits it
up into two separate au-
dio signals, with two
output channels con-
taining only the
high frequen-
cies and the oth-
er two, the low
frequencies. These
can then be fed to
separate stereo amplifiers, with one amplifier driving the
tweeters and the other driving the woofers. The signals
combine in the air to give an accurate reproduction of the
original audio signal.
This avoids the need for passive crossover circuitry,
which can reduce sound quality, and allows for higher
total power output, due to each amplifier only having to
handle part of the audio signal. It can be tweaked to per-
fectly suit the drivers and cabinet used, as DSP allows for
the crossover parameters to be set precisely and identically
between the left and right channels.