ADAM A7 nearfield monitor

The A7 is a two-way ported active system that uses a single ART tweeter, ensuring full compatibility with the latest expanded high frequency resolution media formats, and a conventional bass/midrange driver below the crossover frequency of 2.2 kHz. Each section uses an individual amp with continuous output of up to 50 Watts (RMS).

Electronics

The A7 electronics include almost everything needed to build an MFB enclosure, the amps, crossover, powersupply etc are all there and all that's left to do is add some MFB correction logic..

Low note driver

Being designed to work in a bass reflex setup the A7 woofer has the correct efficiency bandwith product to be used in a MFB setup. All it needs is an accelerometer to take control of it's cone movements.

Accelerometer

The second version of the StarBass prototype is geared towards use with larger drivers and voicecoils, among its design parameters are low weight, high G capability, prevention of non-axial pickup and optimal aerodynamics.

ADAM/mfb

After removal of the dustcap the StarBass accelerometer was glued on top of the voicecoil.

Accelerometer kit

Like the Little/One accelerometer kit the Starbass kit also includes a nifty connection board to hookup the Starbass to the outside world.

MFB injection

After receiving the A7 schematic diagram from ADAM Audio Support a suitable insertionpoint for the MFB logic was located.

From reflex to closed

In order to work properly MFB requires the enclosure to be closed. The bass reflex opening is used to bring the neccesary connections outside the cabinet to allow easy tuning of the MFB logic.

Preliminary measurements

Shown are the initial measurements without having done any tuning to the MFB correction and with the ADAM bassreflex XO corrections still intact so there is still some work to do but the effect of the feedback loop on the overall frequency response is already clearly visisble.