Micro bluetooth speaker idea (tiny) - Visatron BF37

[6thplanet]

That Bose mini has about 1" drivers and two oval passives in it

[3rutu5]

posted by Chris Roemer View Post
I'm using Qes 0.86, Qms 5.11 (Qts 0.736), Vas 0.002cf, Fs 155

I get YOUR curve in 0.009cf (around 18 cu.in.) tuned to 90 (Fb - actually).
That's a 20mm port around 440mm ! long. But EYE'm only using a 1/2 port (say, 13mm), which shortens it to 7" (near 175mm).

I'm SHOOTing for a higher tune in MY 0.014cf box (Fb = 106) to use it as BSC (about +5dBSC) w/a 1/2"id x 3" long port tube (cute).
I don't judge the diff. between 100Hz and 80 (your box) to be significant - but YMMV..

I might end up doing two different builds as I do have two pairs of these things. Might be cool to try the above with the small port and one with the passives

[3rutu5]

That Bose mini has about 1" drivers and two oval passives in it

Yeah I know, I was using 2 ovals as well but only because I wanted to be that rule of thumb of 2* the SD etc. looking by eye I should be 2-3 times that each driver.

My issue will be trying to test the weights in the back whilst not finishing it off totally and maintaining a good seal

[6thplanet]

I measured them, they are 1.5". Couldn't find the tuning frequency.

[3rutu5]

I measured them, they are 1.5". Couldn't find the tuning frequency.

Should still be interesting, would be cool to crack open one of them one day to see what they do differently, but only if it is broken and almost free lol

[3rutu5]

On its way.......I found 8mm wood which was the thinnest pine I could source. Why pine? I can sand the crap out of it without sanding through layers and it is cheap/readily available.

I dislike working at this size, the slightest movement in a drill or cut and you really notice the imperfections. That and trying to cut a stupid oval, that really is my nemesis....let's say after that I started looking at cheap 3d printers

i would recommend a drill press, I was silly enough to use a forsner bit and a homemade template/router for the oval, can't help but thinks there wouldn't have been tear outs or bit sliding with a press

This thing is as per image at the start, being 200x65x81 (external dim)

[3rutu5]

Also experimenting with a different finish,to wrap it in this antiskid surface.....

Many moons ago I bought a OnePlus one which had a sandstone like back, which felt cool. This feels more like a heavy duty skateboard deck and has too much glittery sparkle, not sure how I feel about it to be honest, probably a failed venture. Put it on a piece of scrap I didn't use and dodged in the overlap with a felt pen

[6thplanet]

That's looking fantastic! Very similar to the Bose unit.
Lucky for me I work at Bose, the inside is one common chamber. They stuff the audio/DSP board, the battery charger board and the battery in there. I did some playing and figured out the tuning is around 70hz and high passed at prolly 50, with little to nothing happening around 45hz.

[tomzarbo]

Agreed, it's looking pretty cool. When you get it finished up, you're going to have to take it someplace where they have the Soundlink radio and take some pics side-by-side for comparison!
This is the one realm that I thought we'd (us DIY'ers) never be able to compete in, maybe you'll prove me wrong!

TomZ

[3rutu5]

Next family gathering there will be a sound off haha...my folks and sister both have the mini's....maybe it should be a random test where nobody know me, so if it doesn't work as intended I can run and leave everyone scratching their heads with confusion.. just kidding

I just purchased a 3d printer so might look at printing a faceplate cutting template for a router. In anticipation of it coming this week I started downloading various packages to see how my AutoCAD skills translate and I must say I don't understand so far, been using ACAD professionally for 21 years and you would think I could pick up fusion 360, but nope, like a trainee all over again lol. I was thinking of using Chris Roemer suggestion of larger box and port and 3d printing it as I have another pair, but going to see what magic I can do in CAD.

[jdhill]

That's an impressive tiny case, very nice work. I've built a few mini BT speakers for people using this BT amp -- I can't link the picture but search for DW-CT14 and a bunch of results come up. I've always had success with it. I've paired it with an 18650 battery and a small charge controller/boost board... but my latest venture is to simply power it with 4 AA batteries when it's not plugged into a 5V wall wart. It's a good way to keep the internal circuitry as small and as simple as possible. The only drawback is that you're only pushing about 3W.

BTW -- where did you find the oval passive radiator?

[3rutu5]

Cool, I was thinking (and still may change my mind) of using a BT amp chip which had APT-X and a customisable module as you can edit the EQ settings on some. I know there is a tinysine range and some Chinese ones.

This guy did it on this build and sells kits, I just felt like doing my own thing....plus I wanted to push the limits of my knowledge which didn't take long in the realms of loudspeakers lol

https://youtu.be/LGlBBSFsC_Y

As for the PR's I sourced them at a place online which has good in the title. Still haven't got them yet, could be a little off still, probably quarentined at a port somewhere coming from China.

would like some advice on using cheap PR's in relation to weights considering.it is just a bit of rubber. I've been asking various YouTubers questions relating to "how does it sound a few meters away" and "what would you do differently of any" and most have replied not much except add weights to the PR's. There is another YouTube dude Erik did it who made a BT unit similar to my last boombox but added rectangular passives and that was a similar response. Check it out if you like experimenting with woodworking.....yes I know people's stance on YouTube but great for inspiration

[3rutu5]

Don't know if you guys watch Hexibass on YouTube, but latest video is a very small t line using a 1.5" tectonic tebm driver, I think the concept is pretty cool

https://youtu.be/lU4_E83RwUw

[3rutu5]

Some presents arrived on the slow boat.....this build will test my patience I'm sure of it.

[Jake]

Don't know if you guys watch Hexibass on YouTube, but latest video is a very small t line using a 1.5" tectonic tebm driver, I think the concept is pretty cool

https://youtu.be/lU4_E83RwUw

Saw that last night, made me take a look at those drivers.

[Jake]

I'm not a fan of those pam8610 boards, I find them to be bright once settled, and noise floor isn't the best. I prefer the pam8403 for low wattage projects for a more balanced sound. Jmo