Hey guys, so this is a new revised guide on selecting parts to use in building portable bluetooth speakers! In this guide I won't be focusing on one specific build, but listing, explaining and showing you different parts, their functions, which ones to buy, where to buy them, and my personal opinion/review of them. I would like to make this Instructable a fun and interactive place for us all to share our experiences with certain parts, or ask questions etc. So if you would like to have an input, comment below, and we can all help each other out in creating the ultimate bluetooth speakers! I will also constantly add and edit this Instructable to add in all your personal findings! :)
(Picture above: One of my more recent speaker builds)
Step 1: Where to Buy:
Sourcing and buying parts can sometimes be a little difficult, so here are the online shops that I buy from:
Aliexpress: Aliexpress is excellent. Most of the items I buy online come from here. The buyer protection is very good (much better than eBay from my experiences), items are generally cheaper, and they have a huge variety of stuff. Sellers seem to provide (valid) tracking numbers more often than on eBay. One thing to remember is that its all coming from the same place, whether you're using eBay or Aliexpress (unless in the unlikely event that you buy electronics from a seller on eBay outside of China). Aliexpress is great because it's much more structured than eBay (from my experiences). http://www.aliexpress.com/
eBay: I use eBay quite a bit too. I find that items are generally around 5-10% more expensive on eBay, and the user interface is a little bit more difficult to get around. I would still recommend using eBay to compare prices of items just in case. The folks at eBay customer service are also extremely helpful and polite, they're really lovely to deal with :) My online shop where I sell passive radiators and speakers is also on eBay.
Hobbyking: I've only used Hobbyking once, but I thought I ought to put it on the list. Hobbyking are very cheap, and have warehouses across the globe which means that shipping is quite fast. Although they don't focus on speaker parts, they have some great deals on miscellaneous essentials for speaker building.
Step 2: Parts Needed for Portable Speakers:
The essential parts that portable speakers need are:
- A Power Source
- An AmplifierSpeaker
- An Input
Portable speakers also need several other things:
- Buttons and Switches/controls
- An Input for the power (charging jack)
- An Enclosure
- A Port/Passive Radiators
Step 3: Choosing a Power Source:
In order for your portable speaker to be truly portable, you're going to need it to be battery powered. This section covers everything power source related. There seems to be a lot of confusion regarding this, so I thought I would try and answer this. If any of it is still unclear just let me know :)
When it comes to batteries, Lithium Ion/Lipo batteries are best, as they provide a lot of power in a small form factor. Single cell lithium ion batteries have a voltage of around 3.6v/3.7v, and generally reach 4.2v when fully charged. When used properly they're safe and easily rechargeable.
There are two shapes of lithium ion batteries that I commonly use in portable speakers; 18650 batteries and phone batteries.
18650 batteries can be pretty diverse considering that they're commonly used in many different applications. 18650 batteries measure 18mm x 65mm, and are great for portable speakers. My favourite 18650 batteries are these 'genuine' Panasonic batteries. Whether they're actually genuine or not, they have an incredible battery life, and are quite cheap. Postage has been very fast every time I've bought them. http://www.aliexpress.com/item/4pcs-lot-New-Origin...
One downside is that if you're building a very compact speaker, 18650 batteries may be too big. This is where phone batteries come in handy.
The main benefit to phone batteries is that they come in all shapes and sizes, which makes them ideal for compact portable speakers. They can be sourced for free as well, just pull them out of your old phone! Make sure to test them first to make sure they have a long battery life before they need recharging.
Increasing the Voltage:
Sometimes you may need to increase the voltage for more powerful amplifiers. Generally if you're going for an amplifier that puts out more than 6w, you're going to need to increase the voltage. There are two ways of doing this: You can either:
- Add another battery in series
- Step up the voltage using a converter
Adding extra batteries/cells:
This is the ideal way of doing it. Adding an extra battery in series doubles the voltage. You may even need to add 3 or 4 cells depending on the voltage you're after. Make sure your cells don't have protection circuits on them! Remove all protection circuits. You will need 1 large one for the whole battery, not for each cell. Phone batteries have protection circuits built into them, so you will need to remove them if you plan on setting up batteries in series. ASCAS has a great tutorial on it over here: https://www.instructables.com/id/Make-A-Cheap-Lithi...
Stepping up the voltage:
Another way of increasing the voltage is by stepping it up using a step up converter. This method is good for stepping up the voltage by 1 or 2 volts, but shouldn't be used to step up the voltage too much, as it draws a lot of power which could easily strain the battery. Step up converters can be purchased easily and cheaply: http://www.aliexpress.com/item/Cool-XL6009-4A-DC-D...
Stepping down the voltage:
If you have several cells and want to use a bluetooth module that runs off 5v, you may need to step down the voltage: http://www.aliexpress.com/item/New-Arrival-LM2596-...
Step 4: Battery Protection and Charging
Lithium Ion batteries can be very dangerous when mistreated. Make sure you fully understand them and the consequences of misuse before you begin using them. All lithium ion batteries should have protection circuits and suitable charging circuits.
1 cell batteries are quite simple. If you're using a phone battery it will already have a protection circuit built in. If you're using an 18650, you can also get batteries with built in protection circuits.
Charging them is also quite simple, one of these charges works perfectly. http://www.aliexpress.com/item/Hot-Sale-5V-Mini-US...
2 cell & upwards:
2 cell and upwards protection may seem a little tricky at first but its really not too difficult. Here's a 2 cell one for example, but you may need a different one depending on what batteries you use. Check the specs of your batteries first. http://www.aliexpress.com/item/Li-ion-18650-7-2V-7...
Charging multiple cell batteries is really not as daunting as it seems. All you need is the correct charger. I would recommend sticking to 1 amp chargers as they charge batteries reasonably quickly but don't stress the battery. Take the amount of cells you have and multiply that by 4.2, then take that number and search for "."v lithium ion charger online. Here's a 2 cell 8.4v 1Ah charger for example http://www.aliexpress.com/wholesale?catId=0&initia... Since all the circuits are integrated into the charger, you don't need to have any charging circuits on board the speaker which saves space. Again, check your battery's specs and compare them to the chargers to make sure they're compatible.
Remember: The more cells you use, the more dangerous a short in the circuit can be.. Be cautious.
Step 5: Amplifiers:
Here's just some amplifiers that I have used and my opinions on them. I know quite a few of you have used different amplifiers, and if you have anything to say about any of them, please do so, so we can create a little database on this Instructable :)
1 cell amps:
PAM8403: This amp is great. Super compact and super powerful for its size. Its great for very small speaker builds, and is very compact. Also very cheap! You should be able to get 5w of clean power out of this amp. http://www.aliexpress.com/item/3pcs-Lot-Super-Mini...
PAM8406: This amp manages to kick even more power out of 3.7v. Its not quite as compact but very very good for small budget bluetooth speakers. You should be able to get 8w of clean power out of this amp. http://www.aliexpress.com/item/1pcs-PAM8406-Digita...
2 cell amps:
PAM8610 (blue): There are very few options when it comes to 2 cell powered amps. This is the only decent option that I can find. You will get distortion at high volumes since it can only run off a max of 8.4v, but you will get around 14w of clean sound out of this amp, which is quite impressive for 2 cell. This amp isn't the best quality, and I have had a lot of issues with them (I have gone through 6 of them already..) They're still worth trying out though. http://www.aliexpress.com/item/PAM8610-Audio-Ampli...
3 cell amps:
PAM8610 (black): This amp seems to be of better quality than the blue PAM 8610s. There super small form factor is the only reason I use them really. They're quite good, not too much distortion, and you can get about 20W of clean sound out of them. http://www.aliexpress.com/item/PAM8610-digital-pow...
4 cell amps:
MAX9736A: I love this amp. Its cheap enough, looks amazing, sounds amazing, is very reliable and is quite excellent all around. You may need to step up the voltage depending on the impedance of the speakers you're driving. http://www.ebay.com/itm/2-x-15Watt-8ohm-Class-D-Au...
Note that on the PAM8610 boards, you will need 25v 2200uF capacitors.
Step 6: Input (Bluetooth)
You will need some sort of an input so you can listen to your music on your speaker. These days bluetooth is becoming quite standard. I would strongly recommend including a bluetooth module as it will come in useful. You can also include an axillary input too through a 3.5mm headphone jack.
I would recommend this bluetooth module: http://www.aliexpress.com/item/Bluetooth-Stereo-Au...
It has function keys, bluetooth 4.0, its super compact, and has an LED (included).
I have 10 of these and they've never caused any problems.
If you're buying passive radiators or speakers off me, if you would like I can throw you in some push buttons for free to use with the bluetooth module, just hit me a message :)
Step 7: Speaker Drivers:
Speaker drivers are one of the most important parts to get right. Without good drivers its difficult to get good sound.
40mm 3W Speakers: These are ideal for using with the PAM8403. They have decent stretch to the low end if you couple it with a 'classic' passive radiator in a sealed enclosure. There are plenty of different variations of these, but I like these ones as they have a full metal casing unlike most '3w 40mm' drivers: http://www.aliexpress.com/item/10pcs-3W-4-Ohm-40mm...
*40mm 10W Bose SL Mini Design: These speakers are absolutely incredible. They can handle an insane amount of power, and produce very deep bass. The only drawbacks about these speakers are that: The magnets on the back aren't well insulated so they're quite magnetic, keep metal away from them to eliminate the annoyance of things sticking to them. The treble isn't as crisp as it could be, but its still definitely enough to be classified as a full range speaker. The treble begins to fade off after 10 kHz. In the right enclosure, you can get good bass down to 45 Hz. https://www.etsy.com/listing/244040912/40mm-10w-4-...
*45mm 10W Bose SL3 Design: These speaker perform very similarly to the SL Mini speakers above, but are slightly larger. The magnetism problem also isn't present with these speakers (which means that you could fit a passive radiator very near them). The slightly larger size means that they can move more air to drive the passive radiators. https://www.etsy.com/listing/244039846/48mm-bose-s...
Note that the 2 Bose links above (with the *) are sold by me. I'm based in Europe, so you will receive your items within a few days of purchase rather than the 2 weeks+ that you would expect when buying from China. I test all the items too, so you won't receive a faulty one or one that's not up to standard. If you would like to help me create more builds and instructables like these, I would appreciate if you could buy your parts from my store, all proceeds go to partially covering the cost of all my creations :)
Step 8: Passive Radiators (For SL Mini Speakers)
Passive radiators are an excellent way of getting deep bass out of your portable speaker. Its almost impossible to source small enough passive radiators for portable speakers. It has taken me over half a year but I've managed to bulk buy various types from manufacturers in China through an agent.
Passive Radiators for 10W 40MM SL Mini speakers:
These passive radiators have been designed to work with Bose Soundlink Mini speaker drivers. There are two variations for sale online at the moment, the older generation and the newer generation. The older generation work fine at low volumes but when you turn up the volume the passive radiators begin to create vibration noises. This is due to the rubber being inadequately glued to the metal frame. If you're interested, here's a link. They're quite good at for using with 5-6w speakers. http://www.ebay.ie/itm/Passive-Radiator-Bose-Sound...
The newer generation are definitely better build quality, but are a little bit stiffer than the older generation, which means that they don't work too well at low volumes but work great at higher volumes. They also need a few extra mm of depth since the middle moving plate is a little bit bigger. Although they're not perfect, they do work very well with the SL Mini drivers. https://www.etsy.com/listing/243936357/passive-rad...
Step 9: Passive Radiators (Other Models)
Apart from the specially designed SL Mini passive radiators, there are also many others, which fall into several categories.
Passive radiators w/ Frame: These passive radiators have a metal frame, and are similar to the front section of a normal speaker driver. These passive radiators all have spiders, which means that they're more responsive than normal passive radiators.
50mm Altec Lansing PR: This passive radiator comes from Altec Lansing speakers. Its great. Probably the best passive radiator I've tried. https://www.etsy.com/listing/244040376/passive-rad...
48mm unbranded PR: This passive radiator isn't very good. But it is very cheap. Its a good passive radiator to be used with PAM8403 builds. There's isn't much excursion on it so you may even need 2 if you're using larger drivers. https://www.etsy.com/listing/244035662/48mm-passiv...
Large passive radiators: At the moment I only have one model, and its absolutely brilliant. It's build quality is really excellent. It's got quite a large surround which allows for plenty of excursion. I would definitely recommend this one. One thing to note is that it is quite stiff, so you will need relatively powerful drivers to get it moving (I would recommend 4x45mm Bose SL3 drivers) https://www.etsy.com/listing/243936803/85mm-x-70mm...
Classic Passive Radiators: These are the simplest, and most well known type of passive radiator. They're very compact, basic, and work like a charm. I believe I'm the only person online selling these.. I have 8 different types. There's only a few links below, but I'll have the full list (and in stock) up on the 11th of August :)
All the passive radiators for sale are sold by me, Barry. Since I'm based in Europe shipping should be much faster than from China to most of the world. Shipping in Europe generally take 2-3 days, and shipping the the US usually takes 1 and a half weeks. Buying from my shop helps me keep creating new designs and tutorials :)
Step 10: Designing an Enclosure
If you use passive radiators, and the speakers aren't very powerful, the shape and exact size on the enclosure doesn't need to be mathematically worked out, as it doesn't have a huge impact on the sound, as it does with larger, more powerful speakers. If you can work it out however, go for it! But with most passive radiators and small speakers it is impossible to get the required specifications to actually work it out.
Materials: When it comes to materials, its important to use materials that can be cut very thin, but still retain their strength. My material of choice is 3mm perspex. It doesn't flex and is very thin. Using anything any thinner than 3mm doesn't work well from my experience. It flexes too much. Wood is an even better material to use. Its natural, (can be) cheap, is easy to work with and can be finished in many different ways. You may need to use thicker wood however, as wood is generally not as strong as perspex.
CNC vs By Hand: CNCing is great. Its fast and can get panels cut absolutely perfectly every time. If you have access to CNC machines I would recommend using them. If you don't have easy access to them, that's no problem, you will survive without them :) All my speakers that I've built so far were made 100% by hand with no CNC machines. CNC is nice, but its really not essential :)
Putting together the enclosure: When it comes to putting the enclosure together, I find that using adhesives works better than screwing or nailing or friction fitting etc, unless you plan on disassembling the enclosure often. 2 piece epoxy and hot glue are my 2 essential adhesives.
Speaker Protection: When it comes to protecting speakers with a grille or cloth, you don't have to be too worried when you're making a low powered speaker. All the frequencies will easily pass through. When it comes to making a more high powered speaker however, it is important to make sure that all the sound can pass through. A fine mesh or speaker cloth works great.
Step 11: Recent Build: (real) 30W RMS Portable Speaker
Its out! Check out the tutorial over here! https://www.instructables.com/id/DIY-Bluetooth-Spea...
- 30W RMS
- 4x45mm 10W Drivers
- 5" Passive Radiator
- Bluetooth 4.0
- 20 Hour Battery Life
- 18v power supply
Step 12: Recent Build: 24W RMS 'Ice Cream Sandwich' Speaker
Tutorial coming out soon (tba)
- 24W RMS
- 12v power supply
- 14 hour battery life
- Bluetooth 4.0
- Function Keys
- Dual Speaker, Dual Passive config
Step 13: Final Thoughts
Hopefully this guide has helped you a little with building your own DIY portable speaker. Once you break it down its really not that difficult. If anybody has anything they'd like to add, or has any questions etc, please don't hesitate to write them down below and we can all work together and answer each others questions. I will keep this Instructable up to date with reader submitted content too to create a little database of portable speaker related things.
I will soon have several new, actual tutorials up on various speaker builds. If you'd like to be kept up to date, or have any questions to ask, please do so on my Facebook design page https://www.facebook.com/BL.car.design.and.renderi...
Facebook design page: https://www.facebook.com/BL.car.design.and.renderi...