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

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

*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)

Picture of 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)

Picture of 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)

Picture of 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)

Picture of 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:

Picture of 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

Picture of (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 :)


Msgravel (author)2016-12-05

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.

FokkoP (author)2015-06-25

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?

M L G (author)FokkoP2016-12-01

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

FokkoP (author)M L G2016-12-05

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

Barry_L (author)FokkoP2015-06-27

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 :)

FokkoP (author)Barry_L2015-06-28

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).

Barry_L (author)FokkoP2015-06-29

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.

FokkoP (author)Barry_L2015-06-29

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 (author)2016-12-01

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.

TanguyC1 (author)2016-11-09

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


valdemirs (author)2016-01-01


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 ?

GeronP (author)2015-10-23

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

mplatteeuw (author)2015-04-15

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 :)!

Barry_L (author)mplatteeuw2015-06-27

Hi man, any progress on the build? :)

mplatteeuw (author)Barry_L2015-06-28

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.

vinz3nt (author)mplatteeuw2015-10-03

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.

mplatteeuw (author)vinz3nt2015-10-08

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 :)

Barry_L (author)mplatteeuw2015-06-29

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?

mplatteeuw (author)Barry_L2015-06-29

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 :) !

Barry_L (author)mplatteeuw2015-07-07

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..

mplatteeuw (author)Barry_L2015-07-11

Hey Barry,
let me know if the cells are the real deal ;) !
I had to quit the entire project because the main module has failed.
apparently when it reads the sd card wrong, the entire module breaks.
The seller and maker didn't know about this problem. The buttons on the board don't work, nor can you turn it off... function switch neither works anymore.
It seems to have been a waste of my time and money. + Bluetooth has strong interference with 2,5GHz WiFi (same frequency)
will be using seperate modules next time: seperate amplifier and usb/sd card reader ;) !
I will be figuring out an other way towards my project. But for now it came to a abrupt stop :/

Barry_L (author)mplatteeuw2015-07-14

I'm not too sure how to test if the batteries are genuine or not, but people reviewing them from the seller are saying that they're genuine. I just fitted some of them into my latest speaker. The speaker puts out 30W RMS and I've been using it at max volume almost all the time, and it's still going strong after 12 hours without a charge. These batteries certainly have some serious capacity, genuine or not! I just got another 12 of them in the mail xD Would definitely recommend

lumpylouis (author)Barry_L2015-07-14

If that one is too big, here is another one I was looking at:

It requires a little more DIY and I have no idea if any of its claims are real since I dont own one, but it looks legit and has APT-X support. I have had several of the TA-2024 based amps that the Sure is built off of but I have only ever owned a sure BT receiver and didnt like it. The Yamaha Class D amps are smaller, get louder and run more efficiently in my experience so I dont think Ill get a TA-2024 again.

mplatteeuw I haven't had any issues with WIFI interfering with my BT receivers before. My router is in the next room. You may be having an issue with you unit and/or your power source. If you are powering you amp and BT receiver with the same source you may need a ground loop isolator or to wrap your positive line around a ferrite core to reduce interference.

lumpylouis (author)mplatteeuw2015-07-13

I received and tested my LN-BT02 from Banggood last week and it is actually really good. The Bluetooth range is better than anything I have ever had and it runs off anything from 3v - 30v. The buttons work and everything is modular too. Really happy with this thing. The YDA-138 amp works well too but I found that my TA-2020 powered these little Bose knockoffs much louder with no distortion until full gain. I think I will opt for the Y-148 from DX because it puts out 15W per channel max. This thing is going to bang!

Barry_L (author)lumpylouis2015-07-14

That module looks great!! I need to get one. Its too big for most of my builds but for my more roomy builds it'd be great. I love that it has mic support. Also if you're looking at such large amps for 15w of power, would you not consider the sure-hifi amps? I picked up a few last week, they're excellent and only cost a few more dollars than the amps above^

mplatteeuw (author)lumpylouis2015-07-13

hey louis,
how wel does the module handle interference? Interference with 2.4 GHz wifi network present?
Does it make a crack sound?

Barry_L (author)mplatteeuw2015-04-22

Sorry for the slow response. Your project is looking very good already! 4 6000mAh batteries is insane! You'll pretty much never need to charge it! Perhaps you have a use for that much battery capacity, but if it was me I would only use 1 2000mAh battery and it'd be plenty for my use and most people's too. Any reason for such a huge capacity? I'm sure it'd be pretty expensive to get 4 decent 6Ah batteries. I have yet to find a reliable way of sourcing good quality batteries. Any body else out there find somewhere safe to get them from as well as relatively cheap? Keep me updated on the project man, I'd love to see how it turns out :)

mplatteeuw (author)Barry_L2015-04-22

hello :) !
I may be fooled by the large capacety of ultrafire batterys, so I don't think I will be using them. Many people bought them, and noticed that they are 2000mAh instead of 6000mAh.
I will be buying quality batterys of panasonic. they cost more, but will be better :D

+ I am thinking of using a capacety checker, to see the battery level :)

I will keep you updated!
kind regards,
Michiel P.

lumpylouis (author)mplatteeuw2015-04-22

Why not get 4 of the same battery for another $3? Sold directly by Panasonic.

mplatteeuw (author)lumpylouis2015-04-22

The amazon in America is way more cheap then the German one. Unfortunately I am from Belgium, so I cant buy electronics on the American Amazon :/ .

This is the cheapist I can get ;) !

vinz3nt (author)2015-10-03

Hi, really nice intstructable!!!

I've been searching these passive radiators for months now!
unfortunately I can't use any of the ebay items as they are expired. Are you sold out? Will you be offering more soon?
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

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

Barry_L (author)vinz3nt2015-10-04

Hi man, I have new passive radiators in stock, but I'm not selling them right now because the Irish postal service has just gone on strike.. I'll have them for sale though again soon when the strike is over. Keep an eye on the Facebook page for updates :)

You're only partially correct about the passive radiator sizes. It completely depends on the type of passive radiator you use. For example, I'm using 2x 2.25 inch drivers and one 3 inch passive radiator. It really depends on the type of configuration you're running.

TheChristoph99 (author)2015-10-02

do you ship worldwide? if so, i would like to buy the soundlink mini passive radiators

lumpylouis (author)2015-08-18

So whats the ETA on the guide? I have stalled with mine a little. I have switched back to the original more powerful TDA-148 but I am finding that these drivers are not terribly balanced which was what I expected/feared. They are basically little subs and I am trying to think of a way to add some crossovers and micro tweeters with this limited space.

Barry_L (author)lumpylouis2015-08-22

New Instructables is up! Sorry about the delay.. I think the highs aren't too bad when the speaker is equalised. Not ideal though.. Let me know how it goes with those micro tweeters. Sounds interesting. Any idea what ones you'll use?

hensur_ (author)2015-07-24

Hey Barry,

i ordered these speaker from ebay:

I think they are the same as the 40mm 10w Bose Knockoffs you have in your store.

Which amp did you use to drive them? I couldn't find a good Class D 10W amp.

lumpylouis (author)hensur_2015-07-27

I ordered those speaker from that seller and am using this:

I'm pretty happy with this small amp after sampling a few different ones. I can get pretty good gain and a flat response without any distortion. Barry is using a TA2024 based Sure amp but he is using it to drive 4 of the bigger SoundLink (i.e. not SL Mini) drivers. Please correct me if I'm wrong, Barry.

hensur_ (author)lumpylouis2015-07-27

Thank you!

This one looks pretty good, I'll give it a try. Which batteries do you use to power it? I have some 18650s i can run in parallel but I would need 4 of them to reach 12v.

lumpylouis (author)hensur_2015-07-27

3 18650s in parallel (3S) gets you to 12.6v (11.1 nominal). I run all my 12v class D systems on 3S. Most 12V systems will run very efficiently down to about 10.5V at which point you should be recharging anyway. Here is my basic layout in case you were interested.

Barry_L (author)lumpylouis2015-08-01

This is a cool looking speaker! Any photos of it complete? :)

lumpylouis (author)Barry_L2015-08-03

Shes not done yet but Ill be sure to share pics once I finish. Cramming the wiring, buttons, LEDs, volume knob and audio in jack is gonna be a game of Tetris.

Barry_L (author)lumpylouis2015-08-03

Definitely haha. Cramming it all in is the hardest part most of the time I find. What are the dimensions?

lumpylouis (author)Barry_L2015-08-04

The outer dimensions are 8"L x 3"D x 2.5"H. I'm working with 1/4" solid oak.The batteries are removable so I can properly balance charge them separately. Also, I have like 50 18650s from laptop pulls, so I can just run it all the way down and swap batteries. There is a trap door on the bottom with a hinge. These pics were before i put the front PR in. I'm waiting for my temporary switches and then I will start trying to fit the electronics, but I have a general idea.

Barry_L (author)lumpylouis2015-08-10

Oooh, really interesting design, I'd be interested to see how it goes :)

Barry_L (author)lumpylouis2015-08-03

Oh also lastly, check out my new Instructable, it has plenty of new information. You seem to know your amps and bluetooth modules pretty well, so if you've got any extra suggestions, be sure to comment on it so we can inform people about other alternatives :)

Barry_L (author)lumpylouis2015-08-03

Also will those strips of MDF surrounding the batteries stay there? Look a bit pointless to me, I'd say you'd be better off removing them for better acoustics, and just hot glueing the batteries in :)

Barry_L (author)lumpylouis2015-08-01

Almost right! That's for my bigger speaker. For my smaller one I'm using a black PAM8610 chip coupled with 2 18650s stepped up to 12v :)

Barry_L (author)hensur_2015-08-01

Hey Hensur, I'm using a PAM8610 (black) to power my 2 SL mini drivers. It runs off 12v, power by 2 18650 batteries boost stepped up to 12v. You could alternatively use 3 18650s, but the voltage would vary depending on the charge of the batteries.

BiggMoneyMike63 (author)2015-07-22

Do you think I could build a cheap BT speaker using 5.25" coaxials? I have 4 SSL F257s (car speakers, 2-way, 150w peak) and want to build a very bass-heavy BT speaker that can fit in a 13"x10"x3" backpack pouch, just to be an overkill build lol... I have $50 to work with (about €38.50). Any opinions?

Barry_L (author)BiggMoneyMike632015-07-24

I'm away at the moment so I can't give my input just yet, I'll reply next week :)

About This Instructable




Bio: 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 ... More »
More by Barry_L:Simple 10w Bluetooth Portable Speaker 40W Bluetooth Portable Speaker (Improved Version!)Add a Splash of Colour to your Phone!
Add instructable to: