Hot on the heels of the Earthquake "Quake"
shaker and XJ-600R power amplifier that
we reviewed, Earthquake Sound is getting ready to release the XJ-300
The XJ-300 has a 225 watt output, and does not
have Room Correction, a remote control, XLR input, or some of the other
features that the XJ-600R has. It is also much less expensive ($299 compared
The XJ series are Class J, which is a
quasi-linear design, with some AB bias, but also some switching
characteristics. It is a new type of amplifier design said to be extremely
(99%) efficient. This means that a lot of power can be packaged into a small
chassis, and that is important for a shaker amplifier that might end up
under the couch, as it has in my situation, where space and heat dissipation
are at a premium.
The photo below shows the XJ-300 sitting on
top of the XJ-600R. The XJ-300 is about half the size of the XJ-600R. It's
very light in weight, and comes with either a standard rack mount sized
front plate, or a narrower plate that is the width of the amplifier itself.
Unlike the XJ-600R which has controls that
make it suitable for driving a subwoofer, the XJ-300 is minimalistic. There
is just an On/Off toggle (it is also Auto/On), Volume, Crossover Frequency,
and Phase. To me, the XJ-300 is the best choice for use with the shaker,
because it is simple, and I don't think the advanced features of the XJ-600
are necessary with this device.
Shakers are low impedance and usually require
high power if the shaker mechanism has a lot of mass. So, I was a bit
worried that 225 watts might not be enough to give me the tactile sensations
I want when I watch such movies as Battle of the Bulge, which just
came in for review in Blu-ray High Definition.
Below is a photo showing how one of the Quake
shakers is mounted on my reclining chair. You can see two aluminum arms that
are bolted to the side baseboards on the chair, and the other ends of the
arms are bolted to the Quake. So, when the shaker vibrates up and down, this
transfers energy to the chair by means of a lever.
I cranked this baby up with a bunch of movies,
with the latest one being the Battle of the Bulge film I mentioned
This particular movie was made a long time
ago, way back in the 1960's, but it had a powerful multi-channel sound track
because it was produced for Cinerama by Warner Brothers. However, even
though it was a big budget film, the sound shows its age, but the picture -
having been shot in UltraPanavision (70mm) - is spectacular.
The Quake and the XJ-300 were more than
adequate to practically raise my chair off the floor when the Tiger tanks
stormed across the Ardennes forest of Belgium in December of 1944. This made a huge difference
in the experience of the story because when I was seeing a 57 ton tank on my
6 foot screen, my chair should darn well shake.
Of course, more modern films have deep sound
effects all over the place, and in fact, I had to turn the XJ-300 volume
down a bit just so my eyeballs would stop rattling in their sockets.
Regardless of the volume, the XJ-300 barely got warm.
The XJ-300 will be offered with the Quake in a
package deal, competitive with other shakers out there.
The bottom line on the XJ-300 is that it has
all the power you will need to drive a Quake chair shaker. It is very
affordable, about as easy to use as any amplifier I have ever tested, and
stays cool enough to keep under the couch with Auto/On engaged. I now use
one amplifier to drive a shaker on the couch where my wife sits, at a more
respectable volume setting, and one amplifier to drive a second shaker on my
chair, set to a much more disrespectable volume level that borders on the
- John E. Johnson, Jr. -