10" high excursion subwoofer and 250 Watt dedicated amplifier designed for single subwoofer applications in small listening rooms and subwoofer arrays in larger listening rooms.

The chicken, the egg, and the chicken coupe all arrived at once.

The vast majority of subwoofers available today were designed using existing drivers and plate amplifiers, hence the designers were unable to take a system-oriented approach to engineering the product.

The North Creek approach is to define the optimum parameters first, then design the system to meet those parameters.

The North Creek Poseidon subwoofer was conceived of as a system. The driver, the amplifier and the cabinet were optimized together to fulfill our design goals, providing the cleanest, tightest, most articulate deep bass we have heard. We feel the North Creek Poseidon to be the ultimate statement in small subwoofers for today's most demanding applications.

For a subwoofer to perform optimally in both two channel and home theater applications, it must:

1) Be capable of considerable output down to 25Hz

2) Reproduce high SPL at very low frequencies without overloading

3) Not self-destruct under subsonic overload

4) Cleanly reproduce mid-bass up to its high end cut off frequency

5) Third order roll off at the top end to mate cleanly with the main speakers

Both the front-firing and down-firing version of the Poseidon share the same driver, the Peerlexx XLS-10, a design with enormous strength for a very low Qts, a self-cooling voice and extremely high excursion capability. The combination of the and our acoustic suspension cabinet yield a Qtc of about 0.30 in the neighborhood of 30 Hz. The central benefit of acoustic suspension loading is that it provides the lowest distortion at high excursion, hence the cleanest deep bass, while limiting driver excursion below resonance. In this application, the driver/cabinet combination is 10dB down at system resonance, and the low Qtc means cone motion is optimally damped.

Matching this driver/cabinet combination is our 250 Watt dedicated amplifier, which combines 6.5dB of bass boost at 25 Hz and a third order subsonic roll off. The product of the amplifier and driver/cabinet transfer functions yield a system exhibiting frequency response that has a very gentle 2dB frequency contour from 75 Hz to 25Hz, a -3dB point of 25Hz, and a fifth order roll off below 20 Hz. The possibility of overexcursion is eliminated by the amplifier high pass roll off, and the woofer motor is capable of thermal dissipation up to the amplifier's power limit.

The high frequency low-pass section of the amplifier is also third order, switch selectable at fixed frequencies (55, 80, 100, 140 Hz, bypass). Switch selectable is superior to "infinitely variable" low-pass crossover frequencies because it allows the left channel to be precisely matched to the right channel, and incorporates much better sounding discrete components. Likewise, the third order slope is a good match to acoustic suspension satellites and a perfect match to aperiodic and first order high-passed satellites.

All told, the North Creek Poseidon subwoofer system provides exceptionally dynamic, clean deep bass, a tight mid-bass, and rolls out quickly to allow the satellites to perform at their best. The system design approach has yielded a subwoofer that surpasses all of our design goals while eliminating the shortcomings of subwoofers designed using existing drivers and amplifiers.

The Poseidon kit includes the Peerless XLS-10" driver, dedicated amplifier, cabinet stuffing, NCMS soft glue, Big Toe spikes, and all required mounting hardware. Everything except the wood.

Poseidon Woofer Theile-Small parameters:

Fs = 18.9 Hz ± 1.5 Hz

Qts = 0.17

Qes = 0.18

Qms = 2.63

Vas = 3.17 cubic feet (89.73 liters)

Sensitivity = 88.4db (2.83V, 1 meter)

H = 33mm (voice coil height)

G = 8mm (gap height)

Xmax = 25mm p-p

Acoustic Suspension, Vab = 1.5 cubic ft., Qtc = 0.30, fc = 33 Hz.
This alignment is optimal for most plate amplifiers that offer 6dB of bass boost below 30 Hz in smaller rooms where extreme volume levels are not required. Vented box alignments are not suggested for the downfiring version of this woofer as no overexcursion precautions are taken - the cone travel is linear all the way to the back plate.