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Portable Bluetooth Speakers

B&WTube

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Feb 17, 2020
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I am wanting to build 2 versions of a 2.1 Bluetooth speaker, and would greatly appreciate guidance in the digital world. The goal is for both to be best anyone has heard (luckily, few are as silly as me, so there is not a lot of competition in the high end on these).

BT Speaker 1- Passive X-over, Batteries, and $300-$500 budget (not including box materials)
Upgraded version of Paul Carmody's Isetta, Li-Ion batteries, passive crossovers and these:
Sub 5 1/4" Tang Band Neo Sub (hoping 37hz -3db)
L&R 3" MarkAudio Full Range
Portable BT Small.png
Target weight 20lbs. 16"x8"x7"

BT Speaker 2- Clean Sheet Design, Active crossover/DSP, $1,000 Total Budget (including box materials).
via with Avantree Bluetooth. The XKR guy says be can easily convert his model 3255 amp to 2.1. This one may or may not be battery powered as well as wall powered.
Sub Epique 7" Neo Subwoofer (hoping 32 hz)
L&R (Option 1) 3" Tang Band Full Range + Dayton 1/2" Tweeter
Portable BT Tweet.png
L&R (Option 2) Seas Coaxial 5"
Portable BT Coax.png
Target weight 30lbs. 21"x9"x9.5"
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HERE is where I need the most help. Of course it doesn't matter how good the drivers, xover, and box are- if you feed them with garbage. I have build several kit amps, and done some minor modding but I have a fraction of the expertise that most of the folks on here have. Here is what I am thinking, but please tell me where I am wrong or could do better:

Speaker 1
Doesn't need much power for the L&R or the sub (Drivers max is 30wpc + 80 for sub). I was thinking the best solution would be something from Aliexpress with 5.0 BT, a decent DAC, tone controls like this AliExpress 3251 or AliExpress 3255 Not sure if these are worth buying, or moddable. For learning/experience sake- I would love to piece together the amp modules (like this 3eAudio), DAC/BT, tone controls, but I don't want to spend more time and money and end up with something worse. Based on what I have recently read, it sounds like I might prefer the sound of a MA12070 amp, but there are not a lot of options for this, yet.

Speaker 2
On the bigger guy I need a bit more power (Drivers mas is 220 WPC + 400 for sub). Of course 3255's will be plenty. I was considering the XRK amp module (owner is nice and told me how to set it up for 2.1). For DSP, I am looking at either MiniDSP 2x4HD Board OR EVAL-ADAU1452REVBZ9 . I know the DAC is the Minidsp is lacking, but I don't really know how to do the GUI to get the 1452 board going. Any help here would be great.

Here are some of my current questions:

-Big one- where have I gone wrong/what should I rethink? What am I missing?
-Implementation of the chips aside- Would you say the MA12070 a more ‘musical’ than the TPA32xx?
-SMPS or LLC Converter?
-For these chips- which SMPS/LLC is the best, O? Also, which is best value?
-Best favorite OpAmp for both chips?
-Input buffer suggestion, OR do you just use the Opamp as a buffer?
-Is the XRK amp the best module, or is it overrated?
-Is there a preferred simple BMS System for the Li-ion battery back speaker 1, for handling charging and keeping batteries on even charge?

Thanks in advance!
 
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