Taking a Crack at a Tiny Bluetooth Speaker

[tomzarbo]

Ever since I heard my friends tiny Bose Soundlink Mini thingy, I've been intrigued by it's relatively full-range sound compared to it's tiny size.
I know, it's Bose and expensive, but in my mind at least, it sounded pretty good within limits, and was tiny enough to be kind of amazing (again, to me anyway)

I also realized that duplicating it wasn't realistic given the parts that were readily available back then (this was 4-5 years ago if I recall)

I've been looking at 3rutu5's project here: http://techtalk.parts-express.com/fo...-visatron-bf37
and another here:
http://techtalk.parts-express.com/fo...ith-bf37-issue

...and he's inspired me a bit to try and go smaller.
I've done a few projects with the Dayton ND65 and they perform well, but even they are too big for something like the size I'm thinking of.

I'm going to use this amp from PE, and three RCR123A batteries to power it with. Should be very compact and I can position the batteries anywhere I want to. Plus they're just tiny!

I'm planning on using the Dayton DMA 45-4 1 1/2" full range driver, along with possibly a matching PR or the Dayton ND65 PR... still not sure.



I didn't find any RCR123A battery holders, just the CR123A ones, which a just a bit snug for these batteries. So, I cut the holder in half and will use strategic placement to keep the battery in place. This will have a hinged or removable bottom to be able to remove the batteries to put them in a charger. I have a few different chargers for this size, as well as the more common 18650 Lithium batteries frequently used in flashlights, (my other hobby) so charging them up this way will be easy, and make putting this thing together a lot easier.

You can see from the pic below that one of the batteries came with the nub off-center, so it has to be rotated just so to fit snugly in the holder. The amp powers on with only two of them... about 8 volts or so when fully charged, so I plan on having at least 4-5 hours of play time before I need to recharge them; maybe a bit more.



This is kind of in the final-planning -- almost ready to start cutting wood stage, and as with everything in my life right now, it will likely proceed slowly, but it's good clean fun for not a lot of $$$, and it should be 'relatively' easy to assemble. The amp unit is all-in-one for the most part.

I like the look of the Bose unit, so I think I'll probably just try to emulate that shape-wise for the most part unless I get some specific inspiration otherwise.

More to come...

TomZ

[djg]

Retro?

https://duckduckgo.com/?q=vintage+am+radios&t=ffab&atb=v187-1&iar=images&iax=images&ia=images

[tomzarbo]

LOTS of good ideas there.
I may go semi-simple on this first one and 'tweak' number two.

But man, they really made some cool looking stuff back then.
I'm probably going to be retrofitting my friend's Vintage stereo console from the 60's with modern components. That thing still works, and boy, is it beautiful!

TomZ

[Psycoacoustics]

LOTS of good ideas there.
I may go semi-simple on this first one and 'tweak' number two.

But man, they really made some cool looking stuff back then.
I'm probably going to be retrofitting my friend's Vintage stereo console from the 60's with modern components. That thing still works, and boy, is it beautiful!

TomZ

if it still works,,, don’t retrofit it,,, REBUILD it! New caps, new resistors, maybe new tubes...

You seem to like to solder.

Have Fun! Mark

[3rutu5]

Awesome Tom, I'm interested in seeing how those speakers go in this build I finally pulled out my one from the garage yesterday and trialled the tinysine BT amp...I'll update my threads

[Wolf]

Funny you posted that you're doing one, as I started the build of mine today. I'm using a cheap 5" x 12" CD crate from either Wally-World or Joann's as the basis for the construction.
3" poly-fiber Dayton PC83-4 coupled to 3" ND90 PR, and a DSN25F-4 to round out the top end. Full encasement grill, so you won't see the W/T anyway.
I internally skinned the crate with 1/4" ply, and glued to pieces of 1/4" ply for the baffle to be 1/2". 1/4" ply bracing. I managed to use all scrap pieces to do it.

PRs are in the ends internally mounted, and the t are in the upper front corners with the midbasses close at the lower front. Amp is the KAB230, mounted inside on the top. I have some cheap tent-sale xovers I intend to use, and I'll model those up to see here in a bit.

Just thought I'd share too!

I'll start a thread later,
Wolf

[3rutu5]

Funny you posted that you're doing one, as I started the build of mine today. I'm using a cheap 5" x 12" CD crate from either Wally-World or Joann's as the basis for the construction.
3" poly-fiber Dayton PC83-4 coupled to 3" ND90 PR, and a DSN25F-4 to round out the top end. Full encasement grill, so you won't see the W/T anyway.
I internally skinned the crate with 1/4" ply, and glued to pieces of 1/4" ply for the baffle to be 1/2". 1/4" ply bracing. I managed to use all scrap pieces to do it.

PRs are in the ends internally mounted, and the t are in the upper front corners with the midbasses close at the lower front. Amp is the KAB230, mounted inside on the top. I have some cheap tent-sale xovers I intend to use, and I'll model those up to see here in a bit.

Just thought I'd share too!

I'll start a thread later,
Wolf

Cool wolf, that KAB board is a good one, I got one a year ago and been happy with it. I think the ultra compact units are a bit of fun, albeit frustrating to assemble for big fellas with massive hands, look forward to seeing yours as well

[tomzarbo]

if it still works,,, don’t retrofit it,,, REBUILD it! New caps, new resistors, maybe new tubes...

You seem to like to solder.

Have Fun! Mark

Just heard back from him, he doesn't want to spend any serious dough on it since he will need to replace his A/V receiver soon. I'll probably give cleaning the contacts and pots a try and see if that cleans up the scratchiness enough to sell as a working unit.

Awesome Tom, I'm interested in seeing how those speakers go in this build I finally pulled out my one from the garage yesterday and trialled the tinysine BT amp...I'll update my threads

Good! I'll check it out.

Funny you posted that you're doing one, as I started the build of mine today. I'm using a cheap 5" x 12" CD crate from either Wally-World or Joann's as the basis for the construction.
3" poly-fiber Dayton PC83-4 coupled to 3" ND90 PR, and a DSN25F-4 to round out the top end. Full encasement grill, so you won't see the W/T anyway.
I internally skinned the crate with 1/4" ply, and glued to pieces of 1/4" ply for the baffle to be 1/2". 1/4" ply bracing. I managed to use all scrap pieces to do it.

PRs are in the ends internally mounted, and the t are in the upper front corners with the midbasses close at the lower front. Amp is the KAB230, mounted inside on the top. I have some cheap tent-sale xovers I intend to use, and I'll model those up to see here in a bit.

Just thought I'd share too!

I'll start a thread later,
Wolf

Sounds like a good plan. I've imagined those PC speakers should be pretty good at sounding "un-bad" if you know what I mean considering the cone material being a poly type.
I got a pair of those when they first came out, but haven't gotten to messing with it yet. Maybe this will be another one of your designs that I build... how many would that be? Five I think! I have drivers and Xover parts for another set of RubyK's which will hopefully end up becoming a white painted table radio using one of the car radio head units that I'm trying to mod. I think that will have a cool look with the white drivers... no grills for that one.

Having the PR's on opposing ends is a great idea to reduce possible cabinet movement. My little Bantam's still move around a bit even with softer rubber feet on them. Looking forward to seeing it come together.

What do you guys plan on using your radio for? I'm thinking this will probably be used outside on the deck watching deer and turkey fertilize my lawn, or even washing the car, stuff like that. I have a RadioShack transistor radio that I use for when I'm doing hard/dirty work outside because it plays forever on a set of batteries, and take a beating well. It's just hard to deal with FM radio at this point, so many commercials... but it is nice to have noise going on to distract me from the pain of digging holes for a plant, or putting in hardscaping, stuff like that.

On the same topic sort of... I've started constructing a "Test Box" of sorts to listen to various small drivers in sealed, PR, and vented combinations before I build the actual cabinet.

It's roughly 9.5" wide by 3.25" high (enough area to mount three 2.5" driver frames [1 driver, 2 passive radiators] side by side) and will have a sealed movable piston on the back that will slide in and out to give me various cabinet volumes. It will have a locking arm on the top to keep the piston stationary and a sliding scale that will indicate the cubic volume in liters. The baffle will spring clamp on and will use 4x10" 1/4" thick MDF blanks that will be cut for speaker openings. I will also make a few blocks to put inside of known volumes to reduce the interior volume a bit more if needed for very small drivers like the 1.5" Visaton or Dayton drivers.

My reason for doing this is really probably because of my ignorance in determining frequency response.

I can model smaller woofers like the ND65, 90, etc.... those sizes and pretty much know what the low end will sound like from the frequency response projections in WinISD because they reach low enough to produce genuine 60-70 Hz bass -- and I know what that does, and should sound like...

But for the smaller drivers whose low-end response is a bit higher, like these tiny drivers whose low end may barely breach the 100 Hz region, I don't know what to expect from those. Plus, it would be cool to be able to change a cabinet volume in 5 seconds and hear the changes, or change the weight on a PR in 30 seconds to see the change.

I've wanted to do this for awhile, but hearing the two tiny 1.5" Visaton BF 37 and Dayton DMA45 drivers back-to-back, and hearing how much 'fuller' the Dayton sounds made up my mind. I need to hear these smaller drivers before committing to building a fancy cabinet for them.

Anyway, I'll start a thread on that as well once I get farther along with it, but I thought I'd mention it since I will be using that before committing to a fancy-schmancy cabinet for this project. I have some really cool veneer sheets (like 8x10 or so) that I've had for awhile just for something small like this and I plan on going for a really glossy, high-end finish for this, even though its just a little radio.

Blabberfingers once again!

TomZ

[Chris Roemer]

Tom, could you expound on your BF/DMA comparison?
Looking at both (DMA45-8 vers.) in 0.01cf (about a 2.5" cube - internal) tuned to 90 LOOKs like it'd be a toss-up, and while the DMA CAN take more power higher up, @ 80Hz it looks like the BF can take a tad more. What did you hear?

[Jake]

Hey Tom, I'm interested in your thoughts on those Dma speakers. Reviews seem to be all over the place on that line.

[tomzarbo]

My exposure to the Visaton BF37 and Dayton DMA45-4 drivers were not very scientific... I Xacto'd a hole in a cardboard box and placed each speaker in it and played some music through each of them. It wasn't sealed well as you can imagine...but... the Dayton had a much 'fuller' sound to my ears. The BF37 has about 27 mm of cone width to the Dayton's 32mm, so the Dayton is a larger driver as well. No numbers, but the BF37 sounded a bit lifeless in comparison. I noticed the difference with the drivers playing in free air as well, which I did first to make sure there were no issues with them.
Also, the DMA45 had a fair amount more to give before it gave out; again, to my ears.

I don't want to sound like I'm poo-poo'ing the BF37, it is a bit smaller than the Dayton and it didn't sound 'bad' at all, just 'thin' in comparison. I'm just callin' it like I hears it.

Some comparison photos:



I'll know more about the DMA45 in a few days, once I get my test box up and running.

TomZ

[Jake]

Thanks for the impressions Tom. Those Dma's look fairly nice from your pic. I might jump on the 2" 😉

[3rutu5]

Wow they look massive against the BF's. Honestly if I could get my hands on those DMA"s I would have, but when I have to spend more on shipping than the product i just.cant justify it.

Quite excited to see how yours go

[Mike E]

they are on sale, how much is the shipping?

[Mike E]

Ever since I heard my friends tiny Bose Soundlink Mini thingy, I've been intrigued by it's relatively full-range sound compared to it's tiny size.
I know, it's Bose and expensive, but in my mind at least, it sounded pretty good within limits, and was tiny enough to be kind of amazing (again, to me anyway)

I also realized that duplicating it wasn't realistic given the parts that were readily available back then (this was 4-5 years ago if I recall)

I've been looking at 3rutu5's project here: http://techtalk.parts-express.com/fo...-visatron-bf37
and another here:
http://techtalk.parts-express.com/fo...ith-bf37-issue

...and he's inspired me a bit to try and go smaller.
I've done a few projects with the Dayton ND65 and they perform well, but even they are too big for something like the size I'm thinking of.

I'm going to use this amp from PE, and three RCR123A batteries to power it with. Should be very compact and I can position the batteries anywhere I want to. Plus they're just tiny!

I'm planning on using the Dayton DMA 45-4 1 1/2" full range driver, along with possibly a matching PR or the Dayton ND65 PR... still not sure.



I didn't find any RCR123A battery holders, just the CR123A ones, which a just a bit snug for these batteries. So, I cut the holder in half and will use strategic placement to keep the battery in place. This will have a hinged or removable bottom to be able to remove the batteries to put them in a charger. I have a few different chargers for this size, as well as the more common 18650 Lithium batteries frequently used in flashlights, (my other hobby) so charging them up this way will be easy, and make putting this thing together a lot easier.

You can see from the pic below that one of the batteries came with the nub off-center, so it has to be rotated just so to fit snugly in the holder. The amp powers on with only two of them... about 8 volts or so when fully charged, so I plan on having at least 4-5 hours of play time before I need to recharge them; maybe a bit more.



This is kind of in the final-planning -- almost ready to start cutting wood stage, and as with everything in my life right now, it will likely proceed slowly, but it's good clean fun for not a lot of $$$, and it should be 'relatively' easy to assemble. The amp unit is all-in-one for the most part.

I like the look of the Bose unit, so I think I'll probably just try to emulate that shape-wise for the most part unless I get some specific inspiration otherwise.

More to come...

TomZ

did you get those cheap? the mah rating looks a bit low to me for what looks to be a large lipo cell. if you looked at these by any chance? you would have been able to use a AA holder.

https://www.18650batterystore.com/18650-p/lg-f1l-protected-pcb.htm

https://www.18650batterystore.com/Samsung-18650-p/samsung-35e-protected.htm

https://www.18650batterystore.com/Sanyo-18650-p/ncr18650ga-protected-pcb.htm

https://www.18650batterystore.com/Protected-p/panasonic-18650-protected.htm

[Millstonemike]

did you get those cheap? the mah rating looks a bit low to me for what looks to be a large lipo cell. if you looked at these by any chance? you would have been able to use a AA holder.

https://www.18650batterystore.com/18650-p/lg-f1l-protected-pcb.htm

https://www.18650batterystore.com/Samsung-18650-p/samsung-35e-protected.htm

https://www.18650batterystore.com/Sanyo-18650-p/ncr18650ga-protected-pcb.htm

https://www.18650batterystore.com/Pr...-protected.htm

Comparing apples and oranges. The CR123 are primary cells. The 18650 are chargeable. .