Installing the sound system

Mike

December 21, 2013

Converting my van

Wherever I live I need to be able to reproduce sound to an OK standard. For the last 8 years I’ve used my Alesis speakers. I’ve discovered and shared nearly all of my mammoth music collection on these speakers. All those last minute bedroom parties that would never have happened without these speakers. All that fun we had making weird music in my pit of a bedroom on hot summer days. These speakers provided the sound track to my university life, blasting Sonic Youth and The Smiths down the corridors of my first year accommodation at whatever hour. Another year goes by and I’d be pushing my possessions up the Sheffield hills in a Tesco trolley to move to my next house, and these are the only items that deserved the luxury of extra cardboard.

OK enough reminiscing but what I’m saying is that I really love my Alesis monitors and if I am away for a while, being able to come back and plug my computer into these speakers is a real treat–more than having a hot shower.

The problem is, I have to find some smaller speakers to put in the van! Apart from not sounding very good in such a small space, the Alesis monitors are just too large and heavy to mount on the walls of the van.

A pair of speakers to suit my new home

Its time to do some research. Here is what I think I need:

a nearfield (short throw) speaker designed for a small space
light enough to be wall mounted
not too decent for people to bother breaking windows to get to
doesn’t need too big of an amplifier–I’m only running a 12V system
passive. I shall provide my own 12V amp

I think I may have found the perfect speaker for this: Berhinger 1C passive monitors – Speakers for a van!

Each speaker is 225 x 150 x 142mm and weigh in at a measly 1.8kg - great for wall mounting i guess but i probably cannot expect anything like the punchy (and rather weighty) low end response of my Alesis monitors — Each speaker is 225 x 150 x 142mm and weigh in at a measly 1.8kg – great for wall mounting I guess but I probably cannot expect anything like the punchy (and rather weighty) low end response of my Alesis monitors

speaker-bracket — I like that they come with a mounting bracket although they do have a tendency to flop around quite a bit since the bracket is made of a thin springy steel construction so I set the fixing hole a little further back for a more rigid and imo neater mounting.

fixing-speakers-to-wall — The last thing I want to do is rip this cladding off. I fixed a strengthening piece of leftover 22x47mm pine to distribute the weight and give more depth for the bracket screw to get in to.

berhinger-1c-wall-bracket — Not the prettiest solution but its surprising how strong 8mm cladding is when the weight is spread out.

mounted-to-wall-of-van — All good up to now although I am yet to hear them

100w-monitors — Quite a wide stereo image but it’ll do

The amplifier

alpine-vpower-amp — I went with an Alpine V-power car/marine amplifier. In terms of 12V amplifiers, it seemed decent and a fair price at £30 second hand. It does 50W per channel at 4 ohm with a THD of 0.08%. This will do just fine!

amplifier-wiring — I used 2.5mm2 for the power. I ended up wiring the remote on/off terminal to a big switch

speaker-wires — My favourite thing to do: finding places for wires to hide.

fitted-12v-car-amp — Screwed onto the inside of the bed. I didn’t use the filtering since my speakers are full range. I did turn up the bass by a few dB though and left the gain in the middle.

Testing and eliminating noise

The speakers sound great but there was a problem with noise! Most of the time I’d be playing music from my computer straight into the amp. The noise problem was when the computer plugged into the mains power supply via the on-board inverter (seen on the 12V electrics wiring page). I think the problem was due to a combination of a poor quality (quasi-sine inverter) and a bad ground due to being in a vehicle.

I really cannot live with hums and buzzes through my speakers so I decided to buy a pure sine inverter and this amazing device; a ground loop isolator