Portable Speaker, need guidance on design

Hi everyone, I'm looking to begin my first build and I would like some input from those more knowledgeable than I.

I have a pretty good idea of what I want to end up with and have the skills to make it happen, but I need some guidance to help flesh out the details and make it really shine. I'll lay out the goal and constraints below in hopes of some feedback on what to focus on in further topic researching. I know these may seem kind of all over the place, but I can make more pointed requests if necessary.

Main goal: Portable wireless speaker.
- a while back I found the Thodio speaker and fell in love with its design, but knew I could make my own for wayyyy less and also cater it to my own needs. Plus, 75% of the fun is in making the damn thing!

The main use of this speaker will be in a small room, or outdoors. I want to be able to use it in the garage, hanging at the lake, or in my room at home.


Questions I need help with:

- mainly will stream from a cellphone. Is it easily feasible to create a wifi network to stream to the box? Im imagining AirPlay, but only for the speaker and not a home network. If so, are there any benefits to this over a simple bluetooth board other than a No loss codec? If it ends up using more battery to do wifi, I'll stick to bluetooth.
- how can I best achieve a low end without sacrificing battery life? Long excursion driver or a design specific enclosure? Passive radiator? Transmission line?
-is there a general consensus on NiMh vs Li-ion batteries?
- which woofer load would be better for efficient use in a portable setup? I think I read that 8ohm is better than 4ohm in terms of energy efficiency.
- which kind of amp board should I look at for efficiency? By that I mean do I need to look for T path, class d, class AB, etc. Or do I need to get a specific one like LM3886?
- since the 2 woofers won't be able to be separated, should I worry about stereo? Anything wrong with using one mono amp? (Or even 2 mono amps in stereo I guess)
-
Note: woofer type will come later I believe, once some of the questions get fleshed out more.

Here are some pics that come to mind:

Original inspiration:
a1e16a7e5ee839df94e5fc5822ce7eac.jpg


T line box
8d30b1f5ec11902f0b279edc0884af28.jpg
7e9004117dd8bb0686b2c27c0c1356fd.jpg


General idea in mind
774317f594abc1a6301e6553b9a6ef61.jpg



What I'm looking for is some guidance on where to focus my efforts. For example, I want to know which type of enclosure will work best so I can study up on them and design one that best fits my end goal.

Thanks in advance for any help you can give!

Sent from my SAMSUNG-SM-N910A using Tapatalk
 
- since the 2 woofers won't be able to be separated, should I worry about stereo? Anything wrong with using one mono amp? (Or even 2 mono amps in stereo I guess)

Well, the thing becomes philosophical at this stage: I'd say ethical! Or maybe creationist/evolutionistic; since we have two ears positioned the way they are and most if not all the sound/music media is encoded with two channels ...:rolleyes:

Well, I agree that since the two speakers are very near each one, the distinction becomes rather ininfluent 'cos they mix themselves. In this case you oughta look at some boomboxes or mini stereos where the speakers are angled or there is some sort of effect speaker(s) to give the surround sound effect. Think of the Bose 901 !

For my personal needs, though I haven't built it, I'd say that 3 W provided by TEA 2025 ( BTL mode) with 9-12 V supply and a 4-6-8 Ω speaker ( see the relations between Vs, THD and load in the datasheet ) would suffice. Three cubes, the central one being the battery and amplifier location. And, oh yes, the BT module !:)
 
... angled or there is some sort of effect speaker(s) to give the surround sound effect. Think of the Bose 901 !

now THAT's an interesting idea! Maybe I'll just angle two of the 3 cubes.


For my personal needs, though I haven't built it, I'd say that 3 W provided by TEA 2025 ( BTL mode) with 9-12 V supply and a 4-6-8 Ω speaker ( see the relations between Vs, THD and load in the datasheet ) would suffice. Three cubes, the central one being the battery and amplifier location. And, oh yes, the BT module !:)

Only 3W? I know low power always deceives me, but I was thinking at least 10W per channel. Does 10 require too much juice on a battery operation?