Mach 5 Audio IXL 18" subwoofer.
[IXL-18.2.2]

Several months ago I embarked on a quest to find a DIY subwoofer project to replace my 12 year old Electronics Australia designed dual bandpass box, powered by a 12" Response driver. I had destroyed a couple of drivers in that box during extreme listening sessions and discovered that the importers, Jaycar, were no longer stocking them.

I searched the internet for DIY audio sites and came across this thing called Infinite Baffle (IB). I was very curious about this subwoofer configuration that promised large output down to very low frequencies and with very low distortion. After some more searching I found a site called The Cult of the Infinitely Baffled. It sounded a bit weird, but I registered so I could have a look around. Wow!, was it an eye opener. There is a wealth of information freely available, as well as a forum to discuss IB's and other audio topics. I won't go into much detail on the technical or constructional aspects of IB because it is all explained in the FAQ. In a nutshell an IB is a subwoofer in which the output from the front of the driver is kept totally separated from that coming from the rear. There are no ports and no air cushion from a box.

Whilst in the early stages of my research, I saw a notice in the Vendor's section from Sam Bailey, the owner of Affordable Drivers, that the Canadian Mach 5 Audio drivers were now available in Australia, at very reasonable prices. These drivers are a popular choice for the largely US based builders of IB's. The goal with an IB is to have large displacement with minimal cone movement, thus minimising distortion. They also meet all the other criteria, with regards to their specifications and build quality.

After a bit more homework, I decided to build a 4 driver array, utilising the IXL 18's. I could also have gone with the MJ 18's (as others have done), but felt that amongst other things, the extra power handling was worth paying a bit more for. Drivers in an IB have no protection from a box or air cushion, they are essentially in free air and need adequate power handling capabilities to avoid any possibility of over excursion of the cone.

The IXL 18's were duly ordered, and arrived in three working days, in perfect condition. They are very solidly constructed, with massive magnets and good quality binding posts. Mine are the dual 2 ohm voice coil configuration, which provides a variety of wiring options.

I then built my array, which is horizontal and bolted to the concrete floor of my listening room. There are many ways that an IB can built, and many locations where they can be placed. Pictures of different builds can be viewed on the Cult Website. I too have a build thread there for anyone interested.

I am currently driving my IB with a Playmaster (Electronics Australia kit) 300W subwoofer amp, which does a pretty good job. The usual recommendation is something like a Behringer pro sound power amp, which I now have but have not connected yet. This amp is capable of 1200W per channel X 2. Plenty of headroom there!

The listening experience is something else. The response is crystal clear and clean. No muddiness or peaks at certain frequencies. These IXL's dig right down into subsonic territory, whilst barely moving. If you want to hear every note on the bass guitar or pipe organ, as it was meant to sound, this is the way to do it. Movie sound tracks and LFE are where these drivers show their other side. This sort of sound reproduction can be very harsh on a sub driver, but these IXL's handle it with ease.

All in all, the Mach 5 Audio IXL 18's offer very good "bang for the bucks", and Affordable Drivers has been an excellent company to deal with. Sam Bailey is also a member of the "Cult", so he is quite familiar with the concept of IB's, as well as many other areas of audio no doubt.


Cheers,
Jim.