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Micro bluetooth speaker idea (tiny) - Visatron BF37

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  • 3rutu5
    replied

    Originally posted by Chris Roemer View Post
    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

    Leave a comment:


  • 6thplanet
    replied
    That Bose mini has about 1" drivers and two oval passives in it

    Leave a comment:


  • tomzarbo
    replied
    They are tiny. They look to have a decent little bit of surround for some excursion. It makes most tweeters look like giants. You could really make something tiny with those.

    Keep us posted, this looks fun.
    TomZ

    Leave a comment:


  • 3rutu5
    replied
    Wow, I don't know what I was expecting, but let's just say I was taken back at how small these drivers are...I thought the ND65 was a small driver but these take the cake lol. Had to take a pic next to the Nd64 and TEBM65 for scale.

    They are light and my hole can be drilled with a 35mm forsner bit I have. Just waiting on the piece of rubber to come on the boat from china.
    Attached Files

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  • 3rutu5
    replied
    Originally posted by tomzarbo View Post

    Yup. Without the magic that the DSP supplies, it would sound like it looks... tiny.
    Plus that one has enough battery inside for 7 or 8 hours of music at a decent volume, kind of amazing.

    As far as the construction materials; it sounds like you've got a solution that will work. I have parts to make something similar but a bit larger. I plan on using 1/8" HDF as it is fairly rigid for it's size. Two layers glued up makes a nice rigid panel assuming it's fairly small. Add a slight curve to it and it really becomes rigid.

    What amp are you thinking about for this?

    TomZ
    Hmmm didn't think of using thinner and bending/layering into place.....so many options.

    I came across this site and have been a bit intimidated by these circuits and the Linkwitz transforms

    https://electro-dan.co.uk/electronics/bassboost.aspx

    Leave a comment:


  • 3rutu5
    replied
    The amp could be the issue, when I got the Bluetooth boards I also picked up a 5 pack of pam8403 5v chips and a 12v Pam8610...let's just say this will be a very cheap electrical build....if the 2*15w board doesn't blow the drivers and if it sounds bad, I'll probably get a 2x3w sure board.

    I was also thinking a 1s bms/charger and incorporating a 5v to 12v boost chip. All uncharted territory for me.

    If all fails back to the DA DTA_2 Board haha

    Leave a comment:


  • tomzarbo
    replied
    Originally posted by Dukk View Post
    Mimicking the form factor is not so hard. Trying to mimic the amount of DSP that Bose has going on in that thing is the real challenge. I like the current products coming to market but have yet to find a DIY piece that comes remotely close to what these OEMs have going on.

    Good luck - have fun.

    Yup. Without the magic that the DSP supplies, it would sound like it looks... tiny.
    Plus that one has enough battery inside for 7 or 8 hours of music at a decent volume, kind of amazing.

    As far as the construction materials; it sounds like you've got a solution that will work. I have parts to make something similar but a bit larger. I plan on using 1/8" HDF as it is fairly rigid for it's size. Two layers glued up makes a nice rigid panel assuming it's fairly small. Add a slight curve to it and it really becomes rigid.

    What amp are you thinking about for this?

    TomZ

    Leave a comment:


  • Dukk
    replied
    Mimicking the form factor is not so hard. Trying to mimic the amount of DSP that Bose has going on in that thing is the real challenge. I like the current products coming to market but have yet to find a DIY piece that comes remotely close to what these OEMs have going on.

    Good luck - have fun.

    Leave a comment:


  • 3rutu5
    replied
    Thats the one Tom, my folks and my sister both have one and i just show them i can do something better well i want to anyway, gives me a sense of acheivement when people say dont do it haha.

    I had a go carving out the inside of some timber the other day, i think i could refine it, but also found 8mm timber, so will be going that as it is the thinnest pine i could find. Im trying to steer clear of ply as the premium stuff i bought last time was too thinly layered and sanding took too much off. ive even contimplated bending the thinner timber to get a similar profile to the bose.

    It is going to be small and fiddly i would assume

    Leave a comment:


  • tomzarbo
    replied
    This one.

    Click image for larger version

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    Leave a comment:


  • tomzarbo
    replied
    I like where you are going with this. A friend had one of those tiny Bose bluetooth radios, the one that's like 5 or 6 in wide. Given it's size, the sound was incredible. I think that's what you're going for here?

    I've wanted to do something similar just to see how small you can go while keeping some semblance of bass. You know by now from your experience just how hard it is to squeeze all the stuff in there.

    I'll be watching... do it!

    TomZ

    PS the ND65 passive radiator is on sale for 5 dollars ea if you want to experiment.

    Leave a comment:


  • 3rutu5
    replied
    Originally posted by Chris Roemer View Post
    There ARE parms on Visaton's site...
    ( and graphs, too )

    - and if you're driving 2 diff drivers w/2 diff signals (stereo) then the int. volumes need to be separate to function as designed.
    I'm not sure if one would notice the difference between stereo or mono in something this size? Either way it's been great counsel in the past so I'll widen the box slightly to compensate for the split chambers.

    Only downside is for all to be tested you really need to airtight the box right? Which I thought would mean almost finishing the unit? I really don't know how these rubber things will go, but YouTube seems to have success at 300mm filming away so what could go wrong I know sarcasm doesn't really translate though typed text but it was intended. Let's just say the shipping cost more than the unit and shipping was almost free

    Leave a comment:


  • 3rutu5
    replied
    Option 2 was sort of thinking of the BOOMINATOR from the diyaudio site, but instead of ports and large drivers, it would be drivers the size of tweeters and cheapo passive radiators....well I'll call them membranes as they are only a bit of rubber

    Leave a comment:


  • Chris Roemer
    replied
    There ARE parms on Visaton's site...
    ( and graphs, too )

    - and if you're driving 2 diff drivers w/2 diff signals (stereo) then the int. volumes need to be separate to function as designed.

    Leave a comment:


  • Serpentus
    replied
    Pros of more drivers are more max output, even if sensitivity doesn't rise, and more power handling. Cons are size, cost and possibly interference in dispersion causing worse imaging.

    Leave a comment:

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