I thought I'd re-animate this project because it my promote discussion between the factions. Summer's here. It's barbecue time so I want to create a blue-tooth boom-box. It has dual power sources AC mains and a 12v rechargeable DC battery. Somebody has to carry this so I'll limit the size to 20 litres.
At this point anybody in the car stereo business need to seriously re-think their priorities. The 12v battery needs to last all day. throwing more power at a problem can never be the answer. (Within reason) the priority has to be dB per watt. Having torn down more systems than I can recall I have an inkling how the big box manufacturers have addressed this issue.
My draft design incorporates 6 drivers (2 x 3-way speakers) in a shared 20 litre box. The woofers are 6" and the single port is tuned to 90Hz. The efficiency theory starts at the signal: do not ask the amp to waste power amplifying inefficient signals. If the amp is not amplifying signals below 70Hz (12dB per octave) then it has twice as much power to power the rest.
It's just a holiday Boom-box. It doesn't have to be perfect.
At this point anybody in the car stereo business need to seriously re-think their priorities. The 12v battery needs to last all day. throwing more power at a problem can never be the answer. (Within reason) the priority has to be dB per watt. Having torn down more systems than I can recall I have an inkling how the big box manufacturers have addressed this issue.
My draft design incorporates 6 drivers (2 x 3-way speakers) in a shared 20 litre box. The woofers are 6" and the single port is tuned to 90Hz. The efficiency theory starts at the signal: do not ask the amp to waste power amplifying inefficient signals. If the amp is not amplifying signals below 70Hz (12dB per octave) then it has twice as much power to power the rest.
It's just a holiday Boom-box. It doesn't have to be perfect.
I would look towards what e.g. Soundboks is doing (and many others): https://www.soundboks.com/products/soundboks-go/
Go for 10" 4 ohm woofer (high sensivity pro driver) + horn / waveguide loaded tweeter.
Go for mono, not stereo ... you'll not be able to hear any effect with the drivers sitting as close to each other in the same box anyway.
Use a 2 way class d amp, preferably with a programmable DSP form AD like the ADAU1701, to do filtering, limiting, and bass boost and/or overtone based bass enhancement (in Sigmastudio called SuperBass .... can be found in ADI Algorithms/Dynamic Bass/Steroe/SW Slew/).
Go for 10" 4 ohm woofer (high sensivity pro driver) + horn / waveguide loaded tweeter.
Go for mono, not stereo ... you'll not be able to hear any effect with the drivers sitting as close to each other in the same box anyway.
Use a 2 way class d amp, preferably with a programmable DSP form AD like the ADAU1701, to do filtering, limiting, and bass boost and/or overtone based bass enhancement (in Sigmastudio called SuperBass .... can be found in ADI Algorithms/Dynamic Bass/Steroe/SW Slew/).