The Wiring Book

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Active EQ Voicing

The EMG active bass and treble circuit - part of our BTC, BTS, BQC, and BQS units - is standard equipment on many of today's leading basses and one of our most popular add-ons. It's got a great feature which is often overlooked, since you'd only notice it when the control cavity is open or if you read the installation manual.

The BT circuit includes two tiny DIP switches that let you control the "knee frequency" of the treble control. By selecting different settings you can change the frequency that the treble control begins to have it's boost or cut effect which really affects the character of your tone. When you select a lower knee frequency, the control will tweak the upper mids and will let you modify the "throatiness" of your sound. At the highest frequency setting, the control will only affect the extreme high harmonics of the bass range which can be useful for tweaking the aggressiveness of your popping. These four choices combined with the powerful 12dB boost or cut of the circuit really open the door to very unique and personalized sounds.

NOTE: We recommend unplugging your guitar when changing switch settings to prevent spurious clicks or pops from damaging your amp.

The two DIP switches are in a small plastic package on the circuit's PC board. You'll need a small pointed device to slide the switches into their desired settings.

BT DIP Switch Sites

If you look closely at the DIP switch package, you'll see that the two switches are clearly marked. In addition, one position of the switch will be marked "ON" or "1". In this diagram, SW1 is on, and SW2 is off.

DIP Switch Detail

Here are the switch settings for each of the different voicings. Note that the BT (bass+treble) and BQ (bass+treble+mid) systems have slightly different frequency centers.

EMG BT Voicing Options
SW1SW2Knee Freq
onon2.1 kHz
offon3.5 kHz
onoff4.5 kHz (default)
offoff7.0 kHz

EMG BQ Voicing Options
SW1SW2Knee Freq
onon2.5 kHz
offon3.5 kHz
onoff5.0 kHz (default)
offoff8.0 kHz

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