Here at ABTEC we have been known to build Subwoofer Enclosures that can be a little different to the norm. We have built SPL Enclosures capable of 155+db (With the right amp, subwoofer & environment), low tuned Ground-Pounder Enclosures, beautifully sounding Loaded Horn Enclosures and everything in between. The one type of Enclosure we had not spent much time building were Band-Pass Enclosures, the reason behind this is that the design is very crucial and so is the driver selection but after hearing some very beautiful 4th Order Band-Pass Enclosures we just had to give it ago ourselves!
I already had a Subwoofer in mind for this build however that was thrown out the window once Ashley ‘MADD BASS’ Burrell had talked to our friends at Polk, the Subwoofer of choice even had me a little surprised and to be honest at first I wasn’t sure if it was going to be up for the task. The Subwoofer chosen for the job was the Polk MM1240 DVC, this little Subwoofer almost looks like a Passive-Radiator at first glance. That is until you notice the magnet has been designed to sit flush with the bottom of the basket allowing it be installed in smaller Enclosures, this was something that was going to work to our advantage since we wanted the 4th Order Band-Pass Enclosure to be able to fit into the boots of most cars.
Choosing the material’s for this 4th Order Band-Pass build was relatively easy since we already knew it would need to be strong and look the part too! So 25mm hard-wood ply for most of the Enclosure with a 25mm Perspex removable lid so you can not only appreciate looking at the Subwoofer/Enclosure but also as an access point to install/remove the Subwoofer in those worse case scenario’s when you push things over the limit. Now we had the materials sorted it was time to get the Enclosure built!
Now that a couple weeks had past and we had finished building the Enclosure including the finishing touches like the brass rods for the voice-coil inputs, carpeting and painting the interior of the Enclosure it was now time to have a listen to it in our showroom. The amplifier we have powering it is a Orion Cobalt CO1200.1D which puts out a clean 600w RMS @ 1 Ohm, which should push the Polk MM1240 DVC quite nicely being rated at 425w RMS.
Now it was time to let the Polk MM1240 DVC run in for a good twenty hours but lets skip to my favourite part, listening to some music!
As usual when we get a new Subwoofer and/or Enclosure into our showroom I have a set playlist that I like to try out so I can get a fair comparison to the other Subwoofer Enclosures we also run in the showroom, this time I decided I’d try a couple of different songs that Ashley had been playing in the showroom before I had a listen to my playlist since he had been demoing them for a good two weeks. The first song tested was Enya – Only Time, this song surprisingly has quite low deep bass and this became even more apparent with it playing through the 4th Order Enclosure. The next song on the cards was The Eagles – Tequila Sunrise, the reason for choosing this song is that I really needed to know what it was going to sound like on older rock as a lot of Ported Bass-Reflex Enclosures struggle to play a wide range of genres but this is not the case with this 4th Order Band-Pass Enclosure.
Now I had got those songs out of the way it was time to try some bass heavy songs with various bass frequency ranges, so far I have not come across a music genre that will not play loud and clean in this Enclosure. I must also say that it is the most clean sounding Enclosure in our showroom and have had several people in the last week alone use the word “WOW” after being demo’d a song or two, because of this reaction I am going to try replicate this Enclosure but in a larger scale for two 12″ Subwoofers for my own personal car as it produces the exact sound I am looking for.
So if you have time I recommend dropping into our ABTEC Showroom in Petone with some of your own music and ask for a demo, as I can most definitely can say the Polk MM1240 DVC in our Custom 4th Order Band-Pass Enclosure Sounds Alive!
Lance ‘Captain Z’ Wilson