MJ Acoustics Seismic Subwoofer

MJ Acoustics Seismic subwoofer lives up to its name by delivering seismic bass performance to improve your multi-channel viewing experience. The Seismic is good for medium to large rooms and is small enough to have two on either side of a large screen.

This subwoofer features a 12 “ long throw woofer that can produce a high sound pressure level and can also reproduce LFE signals. The amplifier is a Class D unit with Mosfet output and 200 Watts output. There is also a unique app available that allows you to control the subwoofer from the listening position.

Long throw bass driver

The Seismic subwoofer features a 305mm (12”) long throw sub bass driver that sits in a sleek cabinet. It can output a high sound pressure level for floor shaking bass. A digital display shows the power output.

There is also tuned port that fires downwards towards the floor. Bass ports are usually used to increase ultra-low-end performance. They can be placed to the rear or front of the cabinet. However, with subwoofers, they are usually on the bottom.

Remote control and smart remote

The Seismic comes with a remote control that has a remote eye receiver. This makes it easy to select one of the four user pre-sets. Seismic comes with an iOS or Android app that will let you select different settings for different sources such as music or movies. This can be used from the listening position and is unusual for a subwoofer. It can also be used without a network connection.

200 Watt Class D amplifier

Class D amplifiers are almost 90% efficient. They also generate less heat and use less power than linear amplifiers. As a result, they are often used for active speakers and subwoofers. Class D amplifiers' output signal is a series of pulses. This is known as pulse code modulation. The closer the pulses are together the higher the output signal. The output transistors are either fully on or fully off which makes the system so efficient. Mosfets are often used as they can switch at high frequencies.

What is LFE?

Most smaller speakers cannot reproduce ultra low frequencies. These are mostly found on movie soundtracks. However certain instruments also have low frequency components, such as pipe organs. Therefore, without a subwoofer, most of this information is lost. Additionally, movies are encoded with LFE information. LFE stands for low frequency effects and is different from the normal bass sound. The Seismic subwoofer is designed to recreate these ultra low frequencies.

Connecting a subwoofer

A subwoofer can be connected to an amplifier that does not have a subwoofer output by using the Neutrik Speakon connector. This will take both speaker level outputs and feed them to the Seismic. The best way to do this is via the second speaker set, output, if your amplifier has one. However the Seismic also has RCA inputs for both the standard subwoofer output as well as the LFE output. Most high end preamps and receivers with have a subwoofer output. While AV receivers often have an additional LFE output.

Who are MJ Acoustics?

MJ Acoustics specialise in sub-bass systems, from entry level to no compromise models. Notably, MJ subwoofers are hand built entirely in the UK. The company was founded By John Jefferis, who has a background in acoustic sound engineering, electronics and computing. He also has experience with cabinet making. This combination of skills has made MJ one of the leading subwoofer manufactures. The company ethos is reliability and the subwoofers are all made with this in mind.