MartinLogan 210, 212 user manual PBK Room Correction, Multi Out-Daisy Chaining Multiple Subwoofers

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PBK Room Correction

On the rear panel of your subwoofer is a mini-USB input labeled "PBK Input” which allows for connection of MartinLogan's Perfect Bass Kit (PBK™). The procedure for running PBK room correction is outlined in the PBK manual. PBK is sold separately.

The PBK system employs your computer*, connected via USB to a microphone and your MartinLogan subwoofer, to identify problem areas in your listening environment. The PBK processes information from multiple data points and configures the optimal solution, achieving pinpoint-accurate room response.

Like the best room measurement systems available today, PBK utilizes multiple measurement points, at least five—but up to ten—individual data positions, allowing PBK to learn the indi- vidual characteristics of your room.

The PBK employs your computer’s processor to calculate correc- tion curves for each measurement point, substantially minimizing the rounding errors of less sophisticated "calculators", like those used in standard room equalization systems. Additionally, PBK’s software is capable of calibrating itself to the individual micro- phone included in the kit, eliminating interference that would otherwise skew the data.

MartinLogan’s PBK™ (Perfect Bass Kit) is designed to adjust per- formance of specific MartinLogan subwoofers to reduce room induced bass anomalies. PBK is not a replacement for other room correction systems designed to optimize multi-channel audio systems.

When beginning the task of optimizing an audio system’s perfor- mance, the first step should always be proper setup of the front, center, and surround speakers. Proper setup of these speakers requires proper positioning, toe in, and (if available) adjusting a speaker’s built-in bass level controls. The next step should be run- ning PBK to adjust the subwoofer’s output to account for room interactions. After running PBK, the subwoofer’s performance and integration with the main speakers should be optimized by adjusting the subwoofer’s level, phase, low-pass filters, and other controls.

Only after proper setup of speakers and subwoofer(s), including running PBK on the subwoofer(s), is it time to run your processor’s full-range room correction system to help balance overall system performance within the room.

Although PBK is designed to adjust the subwoofer’s output to mini- mize sonic anomalies caused by room interactions, it is always recommended to use traditional methods to achieve a flat response

before implementing digitally based room correction. Remember, subwoofer placement is one of the most influential parameters when dealing with anomalous low-frequency room interactions—listening position is equally important to bass response but is often dictated by other factors that are more difficult to change. Some users will find that running PBK and examining the resulting graphs may help optimize the subwoofer’s placement. To do this, connect PBK and use the system to take measurements. The resulting graph displayed on the computer* will likely show peaks and valleys in the mea- sured room response. Instead of loading the PBK settings to your subwoofer, move the subwoofer and take the measurements again. Continue moving and measuring until you achieve a frequency response without any wide bandwidth response dips. The PBK will correct the peaks. After you’ve determined an ideal subwoofer placement, fine tune the subwoofer’s performance by running PBK one last time and uploading the PBK settings to your subwoofer.

When a computer is connecting via a mini-USB to the PBK Input, the light indicates the following statuses:

No color: Idle (no USB device currently connected).

Solid Green: PBK connection okay.

Solid Red: PBK connection problem.

*NOTE: Please refer to PBK manual and related instructions for computer compatibility information when running PBK.

Multi Out—Daisy Chaining Multiple Subwoofers

If you are daisy chaining multiple identical subwoofers, con- nectMulti Out from the controlling subwoofer to the LFE In / Multi In on the next subwoofer. Additional subwoofers may be connected using this same pattern. The first subwoofer in the chain will control all other subwoofers down stream (except for the light brightness setting of individual subwoofers). We recommend connecting no more than four subwoofers in a daisy- chain—more may be acceptable, depending on your specific installation. Experiment and listen for what sounds best to you.

Signal Connection:

1Connect the first subwoofer to your system using one of the connection methods previously described in this manual (e.g. 2-Channel Mode, Multi-Channel Mode, or Simultaneous 2-Channel/Mulit-Channel Mode).

30 Advanced Setup