This system was started off cobbling together assorted spare parts that were in the garage gathering dust, to create a small battery powered (and partially solar) system that can fit in the boot of the car and be moved on a small trolley. But of course then I added some extra bits as well to get it how I liked it, so it’s not really assembled from “junk” any more, but it is all inexpensive low power use.
The components are:
Subwoofer:
Pioneer TS-W254C car subwoofer. 500Wmax/250W nominal. 10″ driver 4 ohm. This is in an MDF box, the pioneer was added later and doesn’t match the enclosure. I have discarded the busted plate amp and made 2 small bass reflex ports from PVC tubing which has given it a bit more bass.
Satelites:
Pioneer 6×9 “4 way” car speakers Pioneer TS-A6980S purchased second hand from ebay, mounted in some 6×9 speaker boxes, also purchased from ebay. These have OK response above 200hz, but quite terrible bass. But that’s ok combined with the subwoofer. The speaker boxes sit on some $4.50 plastic stools that make quite fine speaker stands.
The “official” specs are:
- 1-1/2″ PET silver film cone tweeter
- 3/4″ PET silver film dome supertweeter
- 2-5/8″ PPC balanced dome midrange
- Aramid fiber reinforced IMPP woofer with durable rubber surround
- frequency response 25-30,000 Hz
- recommended power range 2-80 watts RMS
- peak power handling 350 watts
- sensitivity 93 dB
Above: Smoothed graph taken indoors approx 1.5M from one of the satellites, one satellite + subwoofer only. This is with sub polarity reversed (there is a bit of a dip otherwise) and the sub cutoff control on the amp at max. The 60hz bump is a room effect I’m fairly sure, so without needing too much tuning these drivers and the amplifier match fairly well.
Amplifier:
Class D TDA-3116 2.1 amp “100W” sub channel and 50W per side stereo. Fairly crude control of the bass cutoff freqency, but it turns out it works quite well with the drivers I have (see the above graph)
Power supply:
Ebay 12VDC 120W “laptop” power converter – this can run from 240VAC mains or 12VDC – using this to feed the TPA3116 amp 24VDC which gives it the best output. As I’m using 2 x 12VDC 7AH batteries I could also rig these in series to get 24VDC, but right now I’m using the voltager converter and can use 1 more 12VDC batteries.
Solar:
very simple. entry level 5W solar cell with a very basic charger on it. At medium volumes the system uses about 10-15W or more so this just helps stretch out the battery life on a sunny day, and is used to charge the batteries when the system isn’t in use.
Mixer:
iRig mix USB powered mini mixer.. despite the “i” branding there is nothing particularly apple specific, its just a minimal, but adequate DJ mixer that can be powered from a 5V USB power supply. The 120W power adapter also has a USB power out that can power this, but I also have a small USB power pack phone charger that can charge this as well.
I originally had a small DIY mixer made from a CMOY heapdphone amp kit but the lack of EQ and cue function annoying.
Audio source:
Mainly a Samsung android tablet running the quite excellent Mixvibes Cross DJ app, also CD walkmans or whatever else is about.