Hi all, just wanted to share a recent build with you all...
Here are the specs:
- Dayton Audio PS220-8 Full Range Drivers
- 15w x 2 T-Amp
- Plywood sandwiched together and glued
- 12 volt rechargable battery
- BT-1A Bluetooth module + ground loop isolator
The sonic results:
Pretty amazing how far 15 watts can go with super efficient speakers. This thing gets loud! Of course given the size limitations and nature of these drivers, the low end is not all that deep (rolling off at around ~70hz) but it's suitable for my listening taste. The mids and highs are sweet as nectar and yet some may even say too sweet, as these drivers are somewhat known to waver in the higher frequencies. Nonetheless, I like appreciate the detailed soundstage especially in open environments like parks and beaches where I imagine I'll be using this thing.
Portability
I'm most excited about being able to take high quality audio on the go. My tiny store-bought Bluetooth speaker is super convenient but let's be honest, no 1-inch driver is going to produce adequate sound, it's apples and oranges. Weighing in at a whopping 24lbs, this boombox is not super convenient to tote around. I underestimated the weight of the materials, especially the plywood layers. Still, this box is a beast...even at max volume the thing barely shakes, it's solid. My 12 volt battery pack is nice too because it will run for about 10hrs, charge my iphone via it's own dedicated USB port, and also power the bluetooth module.
Conclusion
So all in all, I believe the project was a success. I had these drivers laying around from an open baffle project and the t-amp was just collecting dust so I figured, why not make use out of these well paired components. In the end, I discovered that this was a very fun project to do with my son and also learn a thing or two about product design. Speaking of which, I'm already planning a second build that I plan on launching on Kickstarter to see if there's any interest in selling to the public. This next version will use a 2.1 amp, 4 inch full ranges and a 10" low profile sub. I'll post pics when I start the build! Until then, Cheers!!!
Photos
You can check out some pics of the build here:
CLICK CHERE TO VIEW PICS OF THE BUILD
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I used some of that Quiet Kote rubberized spray to (1) create a seal for the drivers and the back side of the box when I screwed it in (2) dampen sound internally (3) to make sure the plywood wouldn't leak (i used a medium grade russian birch ply that wasn't super solid). It may have been overkill, what do you guys think?
Great looking build! Glad to see you find a use for the PS220-8 in a portable application. That driver is under utilized around here. Is this sealed or bass reflex? Are the chambers shared? Which isolator did you use for the BT? Note that cheap class D TPA3116 amps are now available with built in BT for $20.
That's really cool, and I agree, it looks great. 
I wouldn't worry about the comb filtering. Boomboxes are for fun and outdoor picnics, etc. One suggestion I would have would be to sneak an EQ or passive LCR filter in there. The PS220 is going to have a bright climbing response if direct wired. Then again, since it's blue toothed, you could do it at the source on your iPhone or whatever you're using.
I wouldn't worry about the comb filtering. Boomboxes are for fun and outdoor picnics, etc. One suggestion I would have would be to sneak an EQ or passive LCR filter in there. The PS220 is going to have a bright climbing response if direct wired. Then again, since it's blue toothed, you could do it at the source on your iPhone or whatever you're using.
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@xrk971 It's sealed... the chambers are separated by a chamber that houses the battery and the amp. I used some cheap isolator off of Amazon but frankly, the BT-1A module has poor sound quality so I just plug in direct. I think bluetooth 4.0 has way better audio than this module. I'll check out that other t-amp too, thanks!
Totally, I actually already tried a source EQ and it sounded awesome with a quick Bass Boost curve. I'm usually anti-eq but in the scenario, it fits the bill.
Hmmm... I was in another thread ( so...stay there !! ) thinking about something
http://www.diyaudio.com/forums/multi-way/279758-effective-internal-cabinet-vibration-control.html#post4450493
when I saw the tiny shell containing the electronics and I say :
Why do you want to keep it there ?
Oh, it shall be one-unit, easy transportable...I see
BTW the sub section is already filtered, so the passive crossover might be redundant
http://www.diyaudio.com/forums/multi-way/279758-effective-internal-cabinet-vibration-control.html#post4450493
when I saw the tiny shell containing the electronics and I say :
Why do you want to keep it there ?
Oh, it shall be one-unit, easy transportable...I see
BTW the sub section is already filtered, so the passive crossover might be redundant
IS it? I couldn't find any documentation on the amp. I was wondering the same thing and asked a question on Amazon but haven't heard back from Nobsound. I guess I could use my plain ole' ears in an A/B test but haven't tried yet. This would be great because that low-pass filter is pretty bulky.
Yeah a couple thoughts on that...
- I want this thing to be shallow so you can carry it over your shoulder like a briefcase.
- I actually like showing off this cool subwoofer. It's really beautiful and flat in person. Somewhat of a showcase piece IMO.
- Also, firing it down may encourage someone to place it on an uneven surface which would puncture the woofer unintentionally.
It could be useful...The more the merrier : the actual Fc point might be too high;
you can play a little with driver's efficiency and you can start using the coil only and after also the capacitor
OR
just direct drive from amp's output, which brings no losses.
you can play a little with driver's efficiency and you can start using the coil only and after also the capacitor
OR
just direct drive from amp's output, which brings no losses.
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