HollowPoints install on Nautique 210

'09 Nautique 210

Click on any of the pictures below to see a larger version.

Four Bullet HollowPoint 770 HLCDs in black including powdercoated aluminum pods and collars, plus black grills.

For weight distribution and strength, considering the extra mass of HLCD drivers, four double-sided collars are used in a configuration so that each pod is mounted to the same side of two collars and each collar supports two pods from opposite sides.

Initially we were aiming for an over-under arrangement for better off-axis and horizontal phase characteristics, which also results in a slight but audible increase in output. We decided to rotate the over to the interior and rotate the under to the exterior. This better flows with the shape of the tower. The rotation also serves to compress the collective height of the over-under pods and reduces the hang height.

This positioning looks more streamlined than factory, even with larger pods, and keeps all four drivers high. The lower factory locations half way up the vertical tower rails tend to drill the passengers sitting in the rear of the boat.

We powered the four HollowPoint 770s with a Boston Acoustics GT-28, which delivers over 200 watts per speaker. Getting seriously loud with great articulation at 80 feet is a stroll in the park.

Even with the four HollowPoints, lowering and raising the tower can be done by one person.

The factory Polk Audio MM series 10-inch sub is a good one but its definitely not suited for infinite baffle usage and is rendered ineffective.

Since the 210 really doesn't give you an option under the driver's helm, the only alternate location is in the port side storage locker behind the observer's seat. This would normally mean that a 10-inch bass reflex enclosure would replace the cooler. But the boat owner did not want to give up the cooler or the access via the pass-through area hatch.

Normally we would avoid a combination mixing a downfiring subwoofer that was contained inside a storage locker or console. This tends to choke the output and loses much of the midbass transients and tonal construction. You may get alot of bass rumble and boat shaking but its hard to get quality musical bass.

There is a perfect physical location for an enclosed sub directly under the observer's seat that consumes very little storage area. If we were pleased with the results we would see it through. If not, we had the go ahead to replace the cooler. So we did a trial box before committing.

We used a JL Audio TW5 13-inch slim line subwoofer downfiring in a .8 cu. ft. internal net displacement. We did a few things to give us the best chance for really good bass performance.

The box was absolutely airtight under the greatest degree of internal pressure.

We even fully encased the terminal cup for a dual seal.

We elevated the woofer off the sole as much as possible and this required different heights of mounting pads to compensate for the uneven sole.

We used a JL Audio XD 600 watt Class D monoblock amplifier so we had plenty of power available.

As it turned out the TW5 had all the authority that you would expect from a JL Audio 13-inch subwoofer. However, we did lose alot of output when the observer seat was closed. We expected this. Next, we had to vent to the locker with as much surface area as possible to allow the bass radiation to freely flow out of the locker.

We vented the existing hatch, added two vents to the base of the seat console and added a forth vent hidden under the observer's seat. The venting made a substantial difference in a.) the output and particularly in the bass attack, b.) the quality of bass, and c.) limiting how hard the subwoofer and amplifier would have to be taxed to overcome the locker.

The enclosure still allowed the cooler to be removed and reinserted through the observer seat opening.

By hammering out every detail and paying alot of attention to the tuning this subwoofer definitely rocked. I would highly recommend it.

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