Passive Speakers, Portable Speakers and More! Guide to Buying Parts for Bluetooth Speakers




About: Hey everyone! I'm Barry, an aspiring product designer from Dublin, Ireland. I'm passionate about aesthetic, yet functional/smart design. You can take a look at my Instructables projects or other projects on ...

*UPDATE: New Updated Article is Up! *

Hey guys, so here's my first post on Instructables!

So this isn't much of a tutorial, but more of a guide to buying parts for building portable speakers. Over the past 4 months I've been putting a lot of time into research and development into making handheld portable bluetooth speakers. As a result I've acquired a good bit of knowledge on the topic. So I've made this post to basically share my ideas and knowledge and hopefully help all of you guys build yours :)

Short Bio: I'm a 16 year old aspiring industrial/automotive designer from Ireland. Electronics isn't my main field, so this has been quite an educational adventure for me.

I want to make this Instructable to be communal. If anyone has any wisdom/knowledge/interesting things to share/suggestions, share them below please! Lets all work together to get a better understanding of portable speakers :)

Step 1: Sourcing Parts (Basics)

When it comes to sourcing electronics, your only hope is buying from China. Yes, it is possible to buy elsewhere, but it costs significantly more. The most practical and safe site to use is Aliexpress. Other sites that I buy from include Ebay, DX.

Despite parts being very cheap from China, there are drawbacks/risks too. Eg. buying knock offs of original products (which isn't always a bad thing), products never arriving, products not as described, and products having little to no specifications included.

If you live in Europe and other far away lands, shipping can often take up to a month, so be sure you know what you're buying and have everything planned out beforehand.

Step 2: Some Useful Parts (Speakers)

So below I've just included some useful, very good value for money parts that I can recommend trying out:


36mm 4ohm 3W Speakers:

These are pretty great speakers. Good build quality, very good high to mid frequencies, and pretty decent low frequency range too, I can hit about 100hz before it starts to fade out (Tested in a 160mmx50mmx50mm ported enclosure with 4 speaker drivers). In terms of power they're pretty underpowered. I can only achieve clean sound up to about 2W before it starts to distort.

Overall they're the best generic '3w 4ohm 36mm' speakers I've bought, I would recommend, but they're not ideal for powerful builds.

10W 38mm 8ohm Speakers:

These are pretty excellent. They were originally used in LG TV's, so they're definitely reliable. These are really high quality speakers. Great build quality. High frequencies aren't so strong on these, but they're still pretty good. Low frequencies are alright too, but the speakers don't move under around 65hz, whereas the speakers above would move right down to 35hz. These are really excellent speakers, but I wouldn't recommend them for portable battery powered systems because they're 8 Ohms instead of 4.

Bose Soundlink Mini Speaker Driver Knockoffs:

Step 3: Some Useful Parts (Circuit Boards)


This seems like pretty much the best amplifier that runs off 5V:

Charging Circuit:

(5V 1 Amp Input, charges 1 cell li ion batteries to 4.2V)


Found these modules a couple of days ago. They have bluetooth 4.0, connectors for function keys and an LED, and its super compact at just 30x30mm. I've bought a few of them so I'll let you know how they go once I try them out :)

Step 4: Some Useful Parts (PASSIVE RADIATORS!!! :D <3)

If you're familiar at all with mini portable speaker systems, you'll know that getting passive radiators/subwoofers is pretty much impossible. After a crap tonne of looking around for nearly a year, I managed to bulk buy a load of them from manufacturers in China through an agent. I now have them for sale on my eBay store!

I have stock of every passive radiator and speaker in the image above. Simply hit me a message if you don't see the exact item you're looking for on eBay :)

** Note that I may be out of stock on the eBay listing. That's simply because I have very low monthly eBay selling limits.. If you want more stock than what's below, or if its out of stock, just drop me a message on eBay, gmail, Facebook or Instructables and you can buy them off me through PayPal :) **

Classic Flat Passive Radiators:

Soundlink Mini Design:

Passive Radiators with frame:

Bose 40mm Soundlink Mini drivers:

Bose 48mm Soundlink 3 drivers:

I also have several other variations of the classic flat passive radiators, if the ones above don't match what you're looking for, send me a message and I can show you the other passive radiators I also have in stock :)

Step 5: Bose Soundlink Mini Specs, Parts and More

So there's no doubting that the Bose Soundlink Mini has a crazy amount of bass and power for its size, and I believe that its a product that we should really look at for inspiration.

Below are some specs I found on it off a Chinese forum. I believe they are correct but there's a small chance that they're not.

1. MCU: Motorola 16F723A

2. Bluetooth module : CSR 57H687CG

3. AD: AKM 5381ET

4. DA: Cirrus Logic CS4350-DZZ

5. Power Management Chip : TPS62111 Ti

6. Amplifier : TPA3118 2 * 10W with 12V

7. PSU: 12V 0.833A

8. Battery : 7.4V-2.23A / 17Wh

Notice how the Amp runs off 12V but the battery is 7.4. Im guessing this was achieved with a step up converter. But from what I know they're not very efficient.. Does anybody have an explanation for why Bose chose to step up the voltage? If so explain in the comments :)

(Active Speaker and Passive Speaker knock-offs available to buy at the links on the previous steps)

Also here's a cool video of the Soundlink Mini without its front panels

Step 6: What's Coming Next:

So far I've built 6 prototype speakers, no.7 on the way! Does anyone want tutorials for anything else? If so comment below!

I want to make this Instructable to be communal. If anyone has any wisdom/knowledge/interesting things to share/suggestions, share them below please! Lets all work together to get a better understanding of portable speakers :)

If you want to be kept up to date on my speaker projects and more, you can follow me over here:

Step 7: My Latest Prototype

So I'll probably update this step with every new prototype I build. I initially built this one to enter into the Audio competition by radioshack, but I missed the deadline by 12 hours, so I decided not to bother uploading it. I'll upload a more refined instructable in a few days hopefully.


2x10W speakers 2 passive subwoofers


Bluetooth 4.0

Aux in

Function Keys

See my design page for more info, pictures and updates:

Like my Facebook page for all the latest updates/prototypes ;)

Step 8: (real) 30W RMS BT Speaker

Just finished building this bad boy. Runs off 4 18650 Panasonic batteries stepped up to 18v. Powered by a sure-hifi 15wx2 amp. Uses 4 Soundlink 3 drivers and a large square passive radiator (speakers & pr available on my ebay). I documented the whole process, so I just need to put together the Instructable while I'm holiday. It goes up when I'm back on the 14th of August. More photos available on my Facebook page :)



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    143 Discussions


    2 years ago

    Hi Barry.
    Congrats for the poste. It's very usefull.

    I'll like to know what size/type of passive and amolifier should I use with a 2x 40w 5"1/4 speakers.


    3 years ago on Introduction

    Hey Barry,

    I was wondering how you've got the 4 drivers running, with regard to phase. Do you have the ones in the back in antiphase with the ones in the front or in phase?

    6 replies
    M L GFokkoP

    Reply 2 years ago

    got to be a saffer with that username?! lol!

    FokkoPM L G

    Reply 2 years ago

    Funny thing is, that's actually my first name and the first letter of my surname. Not everything is vulgar ;)


    Reply 3 years ago on Introduction

    Hi, which speaker is this relating to? I'm guessing the transparent enclosure one? If so, I actually used 2 amplifiers chips (PAM 8403), so I had 2 right outputs and 2 left outputs. Its an interesting idea but not very effective since a single 3.7v battery isn't enough to properly power both amps. Instead I would recommend sticking to 2 more powerful drivers hooked up to 1 more powerful amp :)


    Reply 3 years ago on Introduction

    I know that you´re using 2 amps. What I mean is. You got the speakers at the front and those at the back. Are the ones in the front connected differently to the ones on the back or not. This is kindof hard to explain if you do not know what phase is, ;p. Basically, do the speakers on the front and on the back move in the same direction (outwards or inwards) or in oposite (front forwards back backwards, or front backwards and back forwards).


    Reply 3 years ago on Introduction

    Ah yes I misread the question sorry. The speakers are in phase. I was curious to see how they would react if they were antiphase but I never got around to it. I've since moved on from that design though so I most likely won't be trying it out.


    Reply 3 years ago on Introduction

    Ah thanks a bunch, if I think about it antiphase would also probably cause acoustic shorting, so it makes sense. Once again thanks so much.

    M L G

    2 years ago

    pretty amazing idea! I love the fact that you had added a stereo output to increase the actual volume by being able to add some more speakers if you ever felt the need, I hope you have managed to work on this again, sorry it failed. I have the amp shown in the uploaded photo, what are the chances of using this in a portable speaker and how much power would I need to power it and what size and Watts and ohms speakers woudl I be able to run off it, look at the speakers I had in mind, would this take a small 6v battery. I dont mind if its reasonably heavy as it will just be something that clunks around with me at work, obviously I want volume as on site it can be potentially nosiy (machinery) so I want to make a Site Radio but not in the strict sense of the word, more of a site mp3 player but one with the capacity to be charged by solar power when sun is shining? is it very likely or am I pipe dreaming? the speakers are a pair of JBL studio speakers, you know the kind that usually get hooked on to rigging on a small stage, I think they are 20W havent actually opened them up yet to check.


    2 years ago

    Bonjours tous les lien vers les radiateurs passifs sont mort et je cherche à savoir où en acheter de bon car ils sont introuvable et aucune caractéristique n'est donné



    3 years ago


    I'm using this speaker in the IhomeIHM63 Rechargeable mini speaker.

    The speaker sound is good, but low frequencies are arrested inside the Ihome

    speaker. Is there any way to fix this issue ?


    3 years ago

    With regard to Bose using a lower voltage battery, is it possible that they are just not running the amp at full power? My portable speaker, a bookshelf speaker connected to a 12v amplifier board, works quite adequately at 5v 1A. I think that as long as the quoted voltage is not exceeded, there is little that can go wrong


    3 years ago on Introduction

    Wow, that look just aweasome :) !

    I am planning to build a bluetooth speaker myself, with 2 x 3W rms and 1 passive radiator. Still working on how much batterys I will be using. As capacity rises, it wil be harder to charge it, charge time increases.

    I am looking for some high capacity battery, to buy online (lets say ebay or something). With all those fake batterys on the market (ultrafire).

    Currently, my assembly in Solid Edge has 4x 6000mAh batterys. I am planning to perhaps use 2 instead. Otherwise charge time will be 12h at least. (with 2 lithium chargers)

    has anyone experience with good batterys from online sources?

    Thank you for your time :)!

    samenstelling 2.bmpsamenstelling 3.bmp
    7 replies

    Reply 3 years ago on Introduction

    Hello man :)
    Well, I am working on the project right now actualy.
    Had a hicup with finding 18650 cells in Belgium, Amazon germany was charging an extra cost of €15 (cells cost 7.5€ / piece 3400mAh) :/.
    I went to a local specialist of batterys, and they sell them @ €13 (2600mAh).
    That's a bit more expencive than expected, Will be investing in a powerbank instead.
    The speaker itself will be powered with that one cell of 2600mAh, and also a backup cell, in case the main cell is dead (1 x samsung li-ion 1000mAh)
    The speaker is running on a bluetooth board, featuring a Aux, Sd-card and bluetooth connectivity. Also has an amp of 3W, aux output and on-board buttons
    (will be extended to outside). The board comes from ebay @€12.
    Other features of the speaker:
    1) can be powered with 5V 1A or higher (standard android charger or powerbank!)
    With switch, you can choose the power source.
    - DC will power the speaker only, without charging the cells
    - Battery will run it on the internal cell (and backup), when connencted to charger, also charges the cells.
    + fast charge the 18650 with a charger pcb (with mini usb socket)

    2) A led pcb will indicate the battery level with 4 blue leds
    3) a usb port will allow you to charge your phone in case of emergancy
    ( is not realy usefull, since the capacety is a bit low :/ )

    4) a sterio socket to bring the amplifier output to the body of the board.
    This allows me to connect 2 speakers of 15W. (they go realy loud when used with bluetooth or SD-card function)
    + can turn off the internal speakers, to create a more sterio efect.
    You can connect almost any speaker to it, as long it satisfies the loudness.

    Will be placing it on this site, when I have more time to write it down.
    (this mesage is long :p)
    kind regards,
    Michiel P.

    s-l500 (1).jpgpercentage meter.JPGPHOTO_20150621_141529.jpgPHOTO_20150621_180944.jpgmain assembly 5.jpgPHOTO_20150626_214038.jpg

    Reply 3 years ago

    Very nice design but keep in mind that the diameter of a passive radiator should be at least 1.5 to 2 times bigger than the used active driver, or in your case the combined diameter of 2 drivers.

    It's also possible to use 2 radiators but the combined diameter should also be 1.5 to 2 times.


    Reply 3 years ago

    Hello vinz3nt,

    Hmmm, you are right, I had found the radiator in a broken speaker.

    The passive radiator is definitely not big enough.

    My project is almost finished, then I will know if the radiator actually is usefull, despite its small size. Thanks for the tip :)


    Reply 3 years ago on Introduction

    Ooohh, very cool build. Interesting set of features in the system. Pretty unique. I'm looking forward to the Instructable. Keep me posted! :) Also where did you get your passive radiator from?


    Reply 3 years ago

    I was going to use cheap a speaker from the shop, break it down, and use the components.
    The amp turned out to be much lighter than expected. (bought my speaker drivers before the cheap speaker). The high impedance was verry bad for overall loudness :/
    The only thing I could salvage was a passive radiator. Bit a shame that I destroyed a 20€ speaker just for research.
    I will keep you updated.
    It schould be finished very soon :) !


    Reply 3 years ago on Introduction

    That's a pity.. Its looking good! I managed to find some panasonic batteries that claim to be genuine. Haven't tested them yet but they seem to be quite legitimate..