Atlantic Technology T70.1PBM Care and Feeding of Your Subwoofer, Phase Invert Control

Model T70.1 PBM

Higher crossover frequencies pass more bass but can sound boomy and may be more easily localized to the subwoofer. Higher crossover frequencies may be suitable, however, when using very small satellites that have no real low frequency performance. Settings lower than 90Hz should be employed if you are using full range speakers that have extended bass response. This way, the subwoofer will only reproduce the very lowest bass frequencies that are in the range where the large main speakers begin to roll off. It’s generally undesirable to have the main speakers and the subwoofer overlap too much. Larger speakers generally require a lower crossover frequency, smaller speakers generally a higher crossover frequency. Consult the manufacturer’s specified low frequency response for your main speakers to determine the appropriate setting on the subwoofer. In the end, however, a little time spent experimenting will generally result in dramatically better bass response.

The Phase Invert Control

A subwoofer operating out of phase with the rest of the system won’t provide optimum low frequency performance. Also, the correct subwoofer phase can enhance room acoustics. Since there is some variation in the industry regarding phase, and no standards have been established, a switch that will reverse the phase of the subwoofer is provided on the amplifier panel. Listen to a monaural musical source with strong bass content. (For example, you can use the mono switch on an FM tuner or preamp, or use a Y-connector on the outputs of one of your source components to get a mono signal.) Have someone experiment with the position of the phase switch to get the most extended bass while you’re sitting in the prime listening position. It should be obvious which is the correct setting. In particular, there will be a smoother more integrated transition between the satellites and the subwoofer when they are properly phased.

A Word About Bass, Center Channel Modes, and System Set Up

Many Dolby Pro Logic surround processors and surround receivers feature a “Wide” and “Normal” mode for the center channel speaker. Atlantic Technology recommends that the center channel be operated in the Normal mode when using a powered subwoofer. The center channel speaker will sound more dynamic and the intelligibility of the system will generally be improved when in the Normal mode.

With discrete digital “5.1” channel systems (Dolby Digital AC-3, etc.) many controllers provide a Bass Management option, which lets you set the front and rear speakers in a limited bandwidth (Small) or full range (Large) mode. All Atlantic Technology speakers are designed to be used in the Small setting with such a controller. However, when using high level connections, the Large setting should be used.

Care and Feeding of Your Subwoofer

The T70.1 PBM is constructed from 3/4" Medium Density Fiberboard. MDF is a non-resonant material ideal for speaker system enclosures. The outside of the woofer is layered with a high quality Black Ash finished vinyl laminate. To clean the cabinet you may use a soft cloth either dry or slightly dampened with clean water. Be careful not to wet the cabinet or allow any water to enter the cabinet seams.

Avoid placing your speakers in direct sunlight or near a heat source that may, over time, damage the finish.

Important: Save Your Boxes! If you can do so, save the carton, packing pieces and plastic bags that came with your subwoofer. They will be useful in case you move or have to ship your subwoofer for any reason. In any case, save all packing materials until you are certain that the system has suffered no damage in shipment. If you find such damage, either visible or internal, contact your dealer immediately for the proper return procedure.

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