Kenwood XR-S17P Amps at Work, Dual SigmaΣ Drive, Dial in the Decibels, Stay in Phase, OhmStable

(1200 Watts max power) is well suited for any number of system ap- plications because all functions are performed in the digital domain. Its on-board DSP includes features like time alignment, parametric EQ, and audio feedback circuitry for clean, precise power.

Amps at Work

A very cool feature of both of our Reference Series amps is the 14-seg- ment, five-digit blue fluorescent display that shows voltage, current, tem- perature, and setup menu. Here’s a plus for installers: the eXcelon Digital Reference line retains installer memory so you can

lock in those settings. The amp information dis- play also includes an over/under input setup. This feature helps precisely match the input sensitivity to the headunit for best sound quality and volume. (The KAC-X4R full digi- tal amplifier comes with a setup disk to adjust input sensitivity.)

Dual Sigma(Σ) Drive

eXcelon Class D mono amplifiers (KAC-X1R & KAC-X10D) use Dual Sigma Drive, which is an advanced negative feed back circuit. When a signal is passed to a subwoofer, say a 50Hz note, the speaker will move and create the note. However, because the speaker has mass and a sus- pension, it won’t stop moving once it’s in motion. This extra movement (sound) creates a type of distortion because it is not part of the original signal. The negative feedback circuit senses this unwanted movement as back EMF (electro motive force), which are voltage pulses sent back to the amplifier caused by the speaker movement. The negative feed- back loop senses these pulses and sends out an opposite pulse to stop the speaker. Think of it as an electronic brake for your subwoofers.

Kenwood’s Dual Sigma Drive extends the negative feedback loop out to the speaker output terminals. This makes the feedback loop more accu- rate because it considers all of the impedance-changing devices that are after the output transistor (like crossovers, etc.).

eXcelon Digital Reference amps are de- signed to provide more contact with less resistance for maximum performance, and you don’t need external connectors!

Dial in the Decibels

The KCA-WR10 optional remote controller is designed for the KAC- X1R, KAC-X10D, and the KAC-X20.

This little knob allows bass boost frequency adjustments and level adjustments for bass. Say

you want to add 8 dB worth of boost at 43 Hz. With the KCA- WR10, it’s just a matter of turning the knobs. And if you are using two amps, you can use a phone cord splitter so one bass boost controller operates both amps.

Stay in Phase

Phase inverter for subwoofer applications is a key feature on all eXce- lon amps (and the Kenwood KAC-9104D). A phase inverter switches the output of the amp 180 degrees out of phase. Why would you want to do that? Because it can help when the installation results in a subwoofer being out of phase in the listening position. Flipping the phase inverter switch can increase volume by putting the system back in phase.

Dual Sigma Drive circuitry ensures a precise reproduction of music by con- trolling unwanted speaker movement.

The KAC-X10D Class D mono power amp pumps out more power than Class A/B amps of the same size and will give your customers stronger, louder, more chest-thumping bass.

1-Ohm Stable

The eXcelon KAC-X1R, KAC-X10D and Kenwood KAC-9104D are 1-Ohm load capable. There is little benefit to running a Ken- wood amplifier at 1-Ohm, because in most cases they produce the same power at 2-Ohms. There is also a down side to running an amp at 1-Ohm. The amp will run hotter, which can affect longevity and put large demands on the car’s electrical system. So why bother with 1-Ohm? There are cases where the number/imped- ance of speakers you’re connecting will create a 1-Ohm load. If you do run an amp at 1-Ohm, it will draw more current and should be addressed by running heavier gauge power and ground wire to the amp from the power source. Note: Always match up your speakers properly to the specification of the amplifier.

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