Ever wished you had a device that would allow you to load your system however you wish regardless of coil configuration? That’s what the Veritas Accumatch does. They are an "impedance driver" that can divide impedance by 1/2, 1/4 or 1/8, or multiple impedance by 2, 4 or 8. Sounds ideal for those stuck with high impedance subs and amps that make big power at low impedances.
But how do they perform? The following are test results I conducted using the Accumatch AM-500, a JBL BPX2200.1 amplifier & JBL's W15GTi subwoofer with duel 6ohm coils. The BPX2200 features two modes of operation. High voltage (bridged) for 2ohm & higher impedances, and high current (parallel) for 2ohm or lower impedance work. This allows it to deliver full power into any load between 4-1ohm. Ever wondered what makes JBL Crown amps special? Now you know.
Tests conduct without clipping and 5 minutes charge time between tests, at about 1/3rd full volume. Tested with Accumatch first, then without.
With Accumatch, 1/2 divisor (1.5ohm load):
Bridge = Protection
Parallel = 140.5dB
Without Accumatch (3ohm load):
Bridge = 144.5dB
Parallel = 142.5dB
So a solution to a problem, but not an ideal one. The power losses counter-act the benefits enough that it warrants buying new subs with the correct coils.
Note: The Accumatch was also marketed as the Stinger Accumatch by Veritas. But I don’t believe they still market the device.