Seismix 3 Mk8

Krix Seismix 3 Mk8 Active Subwoofer

Powerful 11-Inch Active Subwoofer for Home Theatre & Hi-Fi

The Krix Seismix 3 Mk8 is a high-performance active subwoofer designed to deliver deep, controlled and room-filling bass for home theatre, music and premium entertainment systems.

Featuring a 275 mm (11-inch) long-throw woofer and a high-efficiency 350-watt RMS amplifier, the Seismix 3 Mk8 combines substantial low-frequency output with the precision required for both cinematic soundtracks and music.

With an in-room frequency response extending down to 22 Hz and maximum output of 122 dB SPL, it delivers the scale and authority required for dedicated media rooms while remaining versatile enough for larger living spaces.

Highlights & Benefits

• 275 mm (11-inch) woofer — delivers deep, powerful low-frequency performance.

• 350 W RMS amplifier — provides strong, controlled power for music and movies.

• 700 W maximum instantaneous power — additional headroom for demanding bass transients.

• 22 Hz–200 Hz in-room response — reaches deep into the low-frequency range.

• 122 dB maximum SPL — substantial output for larger rooms and serious home cinema systems.

• Bass-reflex enclosure — front-vented design supports powerful low-frequency extension.

• Doped paper cone — engineered for controlled and responsive bass reproduction.

• 50 mm voice coil — wound on a high-powered Kapton former.

• Variable phase adjustment — continuously adjustable from 0° to 180°.

• Adjustable low-pass filter — variable from 50 Hz to 200 Hz or completely bypassable.

• Stereo RCA input — straightforward integration with AV receivers and stereo systems.

• Wireless receiver support — compatible with an optional wireless audio receiver.

• USB-C power output — provides 5 V / 1 A for an optional wireless receiver.

• Automatic signal sensing — automatically enters standby after 15 minutes without a signal.

• Australian made — engineered and manufactured by Krix in Australia.

Powerful 11-Inch Long-Throw Woofer

At the heart of the Seismix 3 Mk8 is a nominal 275 mm (11-inch) doped paper cone driver engineered for high-output low-frequency reproduction.

The driver incorporates a 50 mm (2-inch) voice coil wound on a high-powered Kapton former, along with a vented magnet assembly.

This long-throw design enables the Seismix 3 Mk8 to move substantial amounts of air while maintaining the control required for accurate bass reproduction.

350-Watt RMS Amplification

The Seismix 3 Mk8 is driven by a high-efficiency amplifier delivering 350 watts RMS, with 700 watts maximum instantaneous power available for demanding transient peaks.

This combination gives the subwoofer the headroom required for explosive movie effects while maintaining definition and control during music playback.

Deep Bass Down to 22 Hz

With an in-room frequency response of 22 Hz–200 Hz, the Krix Seismix 3 Mk8 reaches deep into the low-frequency spectrum.

For home cinema, this means greater impact from explosions, effects and soundtrack bass. For music, it adds weight and extension to bass instruments, drums and low-frequency ambience without overwhelming the rest of the system.

122 dB Maximum Output

The Seismix 3 Mk8 is capable of reaching 122 dB maximum SPL in-room, providing considerably greater output capability than smaller compact subwoofers.

This makes it particularly well suited to:

• Dedicated home theatres

• Larger living rooms

• Media rooms

• High-performance stereo systems

• Gaming and entertainment systems

Its combination of deep extension and high output allows it to deliver both physical impact and controlled low-frequency reproduction.

Front-Vented Bass-Reflex Enclosure

The Seismix 3 Mk8 uses a front-vented bass-reflex enclosure.

The front-firing vent helps extend low-frequency output while providing practical placement flexibility within a room.

This design makes the Seismix 3 Mk8 suitable for installations where rear-port clearance may be limited, while still providing substantial bass output.

Adjustable Phase Control

A continuously variable 0°–180° phase control allows the subwoofer's acoustic output to be better aligned with the main speakers.

Correct phase adjustment can improve the transition between the subwoofer and speakers, helping create smoother, more cohesive bass throughout the listening area.

Adjustable 50 Hz–200 Hz Low-Pass Filter

The integrated low-pass filter is continuously adjustable from 50 Hz to 200 Hz.

It can also be bypassed when bass management and crossover settings are controlled by an AV receiver, processor or another external component.

This flexibility makes the Seismix 3 Mk8 equally suitable for home cinema and stereo Hi-Fi systems.

Automatic Signal-Sensing Power

The Seismix 3 Mk8 incorporates signal-sensing automatic power control for convenient everyday use.

When an incoming signal is detected, the subwoofer activates automatically. If no input signal is detected for approximately 15 minutes, it switches to standby.

Optional Wireless Connectivity

Alongside its stereo line-level RCA connection, the Seismix 3 Mk8 supports an optional wireless audio receiver.

A dedicated USB-C 5 V / 1 A output can provide power for the optional receiver, allowing greater installation flexibility where running a long RCA cable is difficult or undesirable.

Premium Finish Options

The Krix Seismix 3 Mk8 is available in a selection of finishes designed to complement both contemporary and traditional entertainment spaces.

Available finishes include:

• Black Woodgrain

• Blackwood

• Atlantic Jarrah

• Walnut

Australian Designed & Manufactured

The Krix Seismix 3 Mk8 is engineered and manufactured in Australia.

Krix has been producing loudspeakers in Australia since 1974, with the Seismix range bringing the company's loudspeaker and cinema expertise into dedicated active subwoofers for home entertainment systems.

Why Choose the Krix Seismix 3 Mk8?

The Krix Seismix 3 Mk8 Active Subwoofer is an excellent choice for listeners wanting greater bass extension and output than a compact subwoofer can provide without moving to a much larger dedicated cinema model.

Its combination of an 11-inch long-throw woofer, 350 W RMS amplification, 22 Hz extension, 122 dB maximum output and flexible crossover and phase controls makes it suitable for both serious home theatre and high-performance music systems.