JP Bluetooth Speaker Build

[Altoid]

Well it's that time again. I have decided that I will do another video series on how to build a bluetooth speaker build. I actually used Sprite Build by Paul Carmody as my major influence. So I am using the same drivers and even BSC (at least to begin with), but I am making it a smaller box with a passive radiator. The plan is for it to be 13" wide, 8 inches tall by 5.5" deep, using all 1/2" material. The box will be out of MDF and the front and rear baffle will be made out of oak. Here is the Parts list as well as the first video int he series. I will update it soon.

Update: I decided to use a 16 ohm resistor, which hs been changed in the parts list.

1. 2x2 Sheet of 1/2" MDF
2. 1/2" oak board that is 7 inches tall (or glue 2 3.5" boards together like me)
3. 2x Dayton 3/12" full range speakers ND90-8 - part number 290-210
4. Dayton 6 1/2 PAssive Radiator SD175-PR - part number 295-498
5. 2x Dayton Audio 16 ohm resistor DNR-16 part number 004-16
6. <s>{2x Jantzen 1526 .90mH 20 awg Inuductor part number 255-046}</s>
7. Sure 2x50w Amp AA-AB32178, part number 320-3342
8. 2.1 x 5.5 power jack. part number 090-5012
9. 3.5mm stereo panel jack part number 090-317
10. Bluetooth Decoding Board with AM/FM tuner from China model number: APE04
11. A 12volt Power Supply. I am using a 12v 6a


You do not have to use this amp. If you want this to be portable, I would probably encourage getting the sure wondom boards with the battery pack. I considered this, but the battery packs were sold out. Also I am not using anything near the max power or this board. So you could go less.

Here's the first video in the series.

[Altoid]

Here are the finished Pictures as well as the measurements. I get usable bass down to 50hz, which is better than I expected. The sound is very nice and clear. I really enjoy the sound. I should note that every speaker I tested had a major suck out at 115hz, so I am chalking that up to the rooms acoustics.

I'll post some more videos and pictures as I get to them. I hope you enjoy! This is an easy build and I love the results!

[Altoid]

Here are a few pictures throughout the build. I do plan to lower the resistor value as I believe the highs are attenuated a little too high right now. Once I get it, where I really like it, I'll put up a video on what it sounds like.

The plan was to use MDF on for the main body of the speaker, but to use Oak for the baffles. Unfortunately, I needed the Oak to be 7 inches wide, but only wanted 1/2" stock. Seeing as, I did not want to spend a ton, I bought these 1/2" x 3.5" Oak Hobby boards. They were super inexpensive (compared to by a 1/2 x 7 oak board). I just used wood glue and clamped them together.




Although, you can see the seam here, you can't once it is stained. It really did turn out nice.



On the front baffle I cut out holes for the speakers and used a jig say to cut out for the radio module.



Here's the radio module I plan to use.

[Altoid]

Now that the baffles are done, it is time to work on the box. The box, I cut at 45 degree angles and glued it together. It was help by tape. I must say this is a great way to save money if you are on a budget and or do not have clamps. I personally, thought it might be easier to get perfect 90 degree angles, since the baffle were going to be inlaid.

Here's the box glued together. On the front, inside of the box, I added 1/2 x 1/2 MDF. This is 1/2 inches deep in the box. This will allow the front baffle to sit flush with the front of the box. It also allows the front baffle to be glued to it, so there won't be any leaks.



This is the frame, I made for the back. It is wrapped with speaker gasket to prevent leaks. I also routed out where the passive radiator will sit. This will help ensure the back will sit flush and seal tight.




Finally, I wanted to make sure there were no air leaks from the front USB and SD card readers. SO I built this box which hides the unit inside of it. I just used some leftover MDF.



Lastly, I test wired it. I know, it looks scary! But do not worry, I plan to clean it up. This was just to make sure everything was working. I did drill holes in the back of the box, that houses the radio for the wires to come up. These will be gorilla glued to prevent any air leaks.

[Millstonemike]

Very nice.

What, no handle?

[Altoid]

You got me. I actually have a handle for it too. But i think this is going to go in my office, so it won't move. Although, I've considered building another one for my friend using a handle, the sure wondom board with the battery pack, so it could be portable. I did change the resistor. The results were much better. Here it is with a 16 ohm resistor instead of the 20 ohm.

[Millstonemike]

Hey, your design is being suggested to another DIY'er. I didn't think to ask this before ... have you noticed any issues with the L-R drivers sharing the same enclosure space?

[Danger dad]

How does this sound compared to the ported enclosure?

[Altoid]

I love passive radiator systems. You will never here me say otherwise. So I love it. Of course if a ported enclosure is properly built, you probably won't hear a difference. But a lot of store bought speakers have too small of ports which causes port noise. They end up sounding terrible. There are 2 reasons most use a passive radiator. The first, being you can usually use a much smaller enclosure than you would with a port. The second is the port needed to not have port noise would either be too long or too big. This is where a passive radiator comes in. So if you want a smaller speaker without a concern for port noise, do a passive radiator.

[bsl100]

Hi... Have built a sprite last year without a divider. I found the highs were a little brittle and they were a bit hot in the mid range in spite of the filter. Bass was great though. This time I'm planning an AMT-8 tweeter with a 1st order Solen Split crossover around 6200Hz for both the ND9-8 and the tweeter. Will also be using the Sprite filter with a 16 ohm resistor (I had used the same resistor value last year). The enclosure will be around 8.5 L without a divider using one Jantzen Audio 50mm x 185mm port. The overall port length without the flare will be 175mm.

[Altoid]

Hi... Have built a sprite last year without a divider. I found the highs were a little brittle and they were a bit hot in the mid range in spite of the filter. Bass was great though. This time I'm planning an AMT-8 tweeter with a 1st order Solen Split crossover around 6200Hz for both the ND9-8 and the tweeter. Will also be using the Sprite filter with a 16 ohm resistor (I had used the same resistor value last year). The enclosure will be around 8.5 L without a divider using one Jantzen Audio 50mm x 185mm port. The overall port length without the flare will be 175mm.

Nice! you'll have to let me know how it turns out. I have been panning to doing a build with these by adding a tweeter, I just have a few more builds to go first. I am just finishing up a custom, self powered Voxel Build. Then I have a few more custom builds to go.

[bsl100]

Will do... Also, I was looking up a write up on the Minions III and the Voxel sub. It would make a good 2.1 boombpx in about the size of a Sprite enclosure.

BTW.... I am a subscriber of your Youtube channel. Great stuff for newbies like me.&#194;&#160;

[Chris Roemer]

If you built a sub using a pair of woofers and a single vent, the only way you could end up w/it tuned "properly" would be if both drivers were driven w/the same signal (or if they each had their own port). When you've got L & R (stereo) signals, anytime you've got only one side "driven", the box volume won't be what you targeted (it will twice as big), and it's not impossible for the active driver to modulate the driver that's NOT being driven (at THAT freq. - LIKE a PR) as well as trying to move the air in the box and the slug of air in the port (or, the PR in your case). Seems like one giant tuning mess, to me.

Not saying that the little boom box can't sound pretty good (esp. compared to commercial stuff), but it's definitely not tuned properly, and could sound better if each driver had its own port or PR. If the bass does sound pretty strong, it's probably extra "distortion". There's no way to tune it (accurately) like that (unless your signal was combined in the band the PR is generating output in).

[bsl100]

Chris.... The Sprite that I built last year had two ports but without a divider. This time I was planning a single port as it was modelling quite well in WinISD. Didn't know about the L-R signals screwing up with the sound and more importantly its action on the drivers. Wish I had got this info earlier before ordering the parts. Looks like the port size and numbers will need to be reordered.

[bsl100]

Based on your inputs, I was considering these 2 ports (link below). They are tapered ports with 26.33 mm dia inside the enclosure and a flared 35 mm dia outside. The length is 165 mm (usable 155 mm because of the flare).
Do you have any inputs as to how to how the calculations are done for the dia. Do we consider the opening to the outside 35 mm or the one the one facing the back of the drivers inside 26.33 mm. Do we take an average of the two diameters.The total volume of air will obviously be slightly lower in the tapered port because of conical shape compared to a regular 35 mm dia port..
I did read up somewhere that a tapered port with a wider opening towards the outside slows the airflow and reduces turbulence / port noise at the cost of efficiency.

http://www.jantzen-audio.com/wp-cont...Tubes-2017.pdf
Part #051-0008