Thanks guys. The search for the ultimate sounding portable boomer is never ending!! I've learned a lot building the past 4 boxes. Some things worked, others didn't. It's all trial and error but I think I've finally nailed the basics of a great sounding combo. For anyone else contemplating such a build, here are the bits you need to make a guaranteed screamer:
1. D class amp with tone controls - (being able to shape the sound is still important with a modern setup - for some reason, most D class amps don't offer this control). I recommend the Lepai LP-2020 amp. I can promise you 20 watts RMS per channel is plenty!
2. Big DC power supply - battery power is best for a 'clean' power supply. A 7.2aH SLA battery will give you days and days of cranking time - much better than commercially sold Bluetooth speakers that only offer you 'hours' of runtime.
3. Efficient speakers - this is very important (90dB and up is best). For maximum loudness, 4 ohm speakers work best with the Lepai amp. Each 3dB increase is a doubling of loudness. My Pioneer drivers have a sensitivity of 90dB.
4. Solid cabinet - thick plywood works well - the last thing you want is a 'sing a long' cabinet polluting your sweet tunes with a horrible drone or vibrations.
5. Separated L & R cabinets of a sufficient size to allow the drivers to grind out big bass. My Pioneer drivers didn't sound anywhere near as strong when they were housed in the much smaller V1.0 cabinet.
6. A well matched tweeter to balance the big bass. Again, a sensitive tweeter that can keep up is the key ingredient. Big bass with flat highs sucks!!
7. Although it's tempting to go with a bigger 24-48volt amp, resist, resist, resist!! 12 volts is a much more convenient system as almost every accessory (Bluetooth, VU meters etc) needs 12 volts. You can always use step down converters but these devices often generate 'noise' which results in ugly hums and buzzes that destroy the SQ.
And yes, VU meters are planned for this box!
Thanks again for the feedback guys.
James....
