DIY Tinfoil Ribbon Speaker


18,241

216

60

Introduction: DIY Tinfoil Ribbon Speaker

Just another tinkerer

Hello everyone,

In this Instructable I'd like to share with you how to make a simple ribbon speaker with tinfoil as the ribbon diaphragm.

I started this project to see if a ribbon driver design like this could be a viable candidate for some ribbon headphones that i'm planning on building.

They can also be used for a high frequency driver instead of a regular tweeter.

The results that I received greatly exceeded my expectations.

Join me on my journey of creating these...


What is a ribbon speaker?


"These speakers are based on the same principle as cone speakers, i.e. the interaction of the magnetic field of a magnet with that of a wire through which the signal coming from the amp passes. However, the wire is not coiled around a cylinder extending from the diaphragm. The diaphragm itself is the signal conductor, taking the form of a rectangle held by two of its sides. The electronic circuit is drawn on top, trying to spread it as evenly as possible so that the magnetic force is uniform. The fact that the voice coil and the diaphragm are combined in a single piece makes the moving section lighter, thus avoiding, at least in theory, the displacement of the diaphragm. The conductor is spread across the entire surface, exercising a more homogeneous motive power than a voice coil which has to drive a cone at one end." - audiofanzine.com

Step 1: What You'll Need:

To replicate this Instructable you will need the following:

- Access to a 3D printer.

- ~5m 3D printing filament.

- A piece of new lightduty tinfoil that does not have a lot of creases.

- 6X 10mmx3mm round neodymium magnets ( This can be other shapes and sizes but the printed holder will need to be altered )

- 6mm Copper foil tape with adhesive.

- 2 part CA glue or 2 part epoxy.

- A wide gear with quite aggressive teeth .( 3D printable file available )

- Some speaker wire.

- Soldering iron.

- Solder.

- A very sharp hobby knive.

- Foam art sheet or soft rubber sheet

- Some Blu Tack.*

- To drive the speaker you'll need a suitable transformer or a series resistor, I used a 5ohm 40W resistor in testing (links to come)

Step 2: 3D Printing:

First we will need to get the main body of the speaker printed.

I designed it using Fusion 360, it can be easily modified to either use different magnets or change the dimensions of the speaker.

Moving forward for using these as headphone drivers I will alter the design to fit lower profile bar magnets so that I can reduce the overall thickness and i'd duplicate and merge the design so that there are two speakers next to each other.

I also made a quick horn/wave guide to see if it would have a major impact on the volume, but for the intended use I decided to ditch it.

Everything was printed in ABS filament to avoid any deformation from the soldering heat. But PLA and PETG filament would also work.

Printed at 0.28 layer height with a .6mm nozzle.

Step 3: Assembling the Magnets:

Now that we've printed the main body we can start assembling the magnets.

Orientation of the magnets inside the body is very important, if one of the magnets is not facing the correct way it will cause major issues with the sound.

To start I stacked all the magnets on top of each other so that I know they are all facing the right way,

Then you want to take a marker and mark the top of each magnet making sure not to flip them over as you go.

Next I place the printed part on it's side on a metal table, this will keep the magnets in place while gluing, now add a drop of glue in each of the indents on the one side of the body and slip a magnet into each indent, the mark you made on the magnets should be facing upwards.

Now if you are using 2 part CA glue you can give it a spray of activator, now you can flip it over and glue in the magnets on the other side. This time the mark on the magnets need to face downwards.

With all the magnets in their places I took a spare magnet and just double checked that all the magnets are facing the right direction, then I just added a layer of glue over all of the magnets to make sure they don't come loose as it would destroy the diaphragm if it did.

Step 4: Assembling the Electrical Connection:

I did a lot of thinking of how I would make an electrical connection between the foil and the speaker wire.

Using copper tape seemed to be the easiest way, it's flat so the very fragile tinfoil lays against it without distorting, already has an adhesive backing which made installation a breeze and because it is copper it's an excellent conductor and easy to solder to.

All I had to do was cut off a strip of about 5cm and wrap it around each side of the main body as shown in the picture.

Easy as that!

Step 5: Making the Tinfoil Ribbon Diaphragm:

Start by placing your piece of tinfoil on a flat cutting surface, then using a new sharp hobby knife cut off a strip that is just narrower than the centre slot of the main body ( 13-14mm wide ) and about 10cm long.

I suggest cutting a few as forming the ribbon may take a few tries .

Next I went through my box of salvaged gears to find one that is wider than the strip of foil and has an aggressive tooth profile that would create a nice deep crease in the tinfoil.

EDIT: Included a 3D printable gear to use


Now lay a strip of tinfoil on your foam/rubber sheet and start rolling the gear from one side with enough pressure to create a deep crease being careful not to tear through the foil. Uneven pressure on the gear tends to make the foil strip curve to the side, It took me 3 tries until I got a good even strip.

Step 6: Assembling the Tinfoil Diaphragm:

Now that you have a formed tinfoil ribbon we can attach it to the main body.

I had to do this step twice as the first time I just attached it directly to the main body, this caused a distortion at higher volume as the ribbon started to vibrate against the hard plastic.

To stop this from happening I smeared a tiny amount of Blu Tack against the corner where the ribbon meets the main body, this instantly solved the problem and tightened up the sound.

Cut the ribbon you made to ~65-70mm (If you did not change the dimensions of the main body)

To attach the ribbon to the main body I added a small square of the copper tape to each end of the ribbon, then stick the ribbon in the centre of the main body as pictured.

You want to add slight tension to the ribbon but not so much as to unfold the creases that you made.

Luckily the ribbon is never completely attached to the main body ( it's only held on by the copper tape on the ends ) so it is easily replaceable if it is damaged.

If you have a multimeter it would be a good idea just to make sure you have an electrical connection between the ribbon and the copper tape on the main body.

Step 7: Soldering:

The only thing left to do is solder on the speaker wires!

Because we are soldering on plastic I let the soldering iron heat up completely, added a good amount of flux to the copper tape and then quickly put a blob of solder on each side of the body where your wires will attach.

Wait for the for the places to cool down and then tin your speaker wires and quickly solder them to the main body.

..............Now the time has come

Step 8: Enjoy!

Now you can sit back and enjoy your creation...

Because ribbon speakers have very low impedance you will need either an impedance matching transformer or a suitable resistor in series to connect it to your amplifier.

Unfortunately I'm still waiting on a transformer to arrive so I had to use a resistor, using a resistor has a large negative effect on the output of your speaker so I would highly recommend getting a suitable transformer when making these.

The sound really surprised me, I knew they were going to sound clear and open but I did not expect the amount of bass I got too. They are really nice full sounding drivers and I think will make excellent headphone drivers!

The YouTube video is a sound clip of the speaker playing, they do sound a LOT better in person as it is really difficult to record low volume audio on just a phone mic.

I hope you guys enjoyed this Instructable and share your creations with me.


Happy making!

Tinfoil Speed Challenge

Grand Prize in the
Tinfoil Speed Challenge

1 Person Made This Project!

Recommendations

  • Pi Day Speed Challenge

    Pi Day Speed Challenge
  • Trash to Treasure Contest

    Trash to Treasure Contest
  • Sculpt & Carve Challenge

    Sculpt & Carve Challenge

60 Comments

0
Milan123456
Milan123456

Question 4 days ago

Could you send me how far the 2 lines of magnets are from eachother?

0
JGJMatt
JGJMatt

Answer 2 days ago

They are 15mm apart.

0
sky_jim
sky_jim

15 days ago on Step 8

Great Instructable. Well written and executed. I am not an audiophile, and haven't seen the word "drivers" used as it is here. I think of drivers as being something that powers something else. A driver might for example be a preamp stage. Here it seems like you are calling the audio transducers, drivers. Doesn't matter, it is a great project.

1
BradenE1
BradenE1

Reply 2 days ago

"Driver" is a common term used for a loudspeaker transducer in the world of loudspeaker design. Rolls off the tongue a little easier.

0
JGJMatt
JGJMatt

Reply 9 days ago

Thank you!

0
Argyle Newsy
Argyle Newsy

Reply 11 days ago

Yeah i click and it says video unavailable, just watch it on YT

0
madaeon
madaeon

12 days ago

Very cool! I love this project!
I made one. With creases, or without, sound was almost the same. I put a resistor i had already, 5ohm, 20w. Sound quality seems very good! But sound volume is very low (if connected directly to an headphone jack), and if connected to some small 1W Usb amplifier, there is distortion and sound quality is not very high. Any suggestion to improve it? Thanks!

IMG20210223114219.jpg
0
JGJMatt
JGJMatt

Reply 12 days ago

Hi, did you design your own main body?
The first thing I would do is to make the foil ribbon a little narrower and to put the magnets on the inside so that they are closer to each other and the foil. All of the distortion I had came from the foil ribbon not being tensioned correctly, I would reccomend you pull the foil a little tighter and see if it improves or gets worse.

0
ShannonW49
ShannonW49

13 days ago

Very nicely done. I am sooooo gonna have to make this. At least twice.

I have long bar magnets, and my printer is down (going to carve some wood), so they are going to look a bit different...

Any ideas on how the width of the folds (size of gear used for imprint) would affect things like power, response, etc? Or depth of folds? Or non-equal folds? Or embossing patterns instead of folding? Some ideas for experimentation maybe. Any electromechanical/acoustic engineers out there? :)

0
JGJMatt
JGJMatt

Reply 13 days ago

Thank you!... Personally I think the wood would look very good and might even change the sound slightly.
As for the embossing of the foil, it's definitely going to need a lot of experimenting. I think making the folds too deep might make the ribbon "sloppy"? Whereas a fold along the length of the ribbon might tighten up the upper frequencies, sacrificing some bass.
Luckily it is easy to swap out the foil for a different design.

0
djwhouse
djwhouse

16 days ago

Nicely detailed! I'm unclear on just what is 'blue tack'. Also, does the adhesive side of the copper tape also conduct? (is the adhesive conductive) and that is why it connects to the foil?

1
ShannonW49
ShannonW49

Reply 13 days ago

There is copper tape that has conductive adhesive. It is often sold for guitar EMI shielding, I have a few rolls of differing sizes (very thin to quite wide). I can stack layers and have good connectivity from top to bottom. -- (very good for many uses)


Yeah - Blu Tack = sticky putty (pressure sensitive adhesive, like Playdoh mixed with Elmers glue). Blu Tack is the brand name, similar items may go by other names (I don't find Blu Tack at box stores in my area of Texas). Could probably use a drop of wood/white glue on the corners, spread around with a toothpick, before taping down to achieve the same result. You just need something to keep the edges of the foil from rattling, something tying the corners down to keep the edge under a little bit of tension.

0
JGJMatt
JGJMatt

Reply 16 days ago

Hi,
The adhesive side of the copper tape is not conductive that's why I first wrapped the piece of copper tape around the main body so that the conductive copper side makes contact to the underside of the foil ribbon.
As for the blu tack: https://en.wikipedia.org/wiki/Blu_Tack hope that helps.

0
JGJMatt
JGJMatt

Reply 13 days ago

Thank you!

0
ramimoca
ramimoca

15 days ago

Very cool project, i like it. About transformer I think it would be possible to use a low impedance transformer imput 4 ohms, ouput 0.5 ohms. I know it is no standar, but if you rebound an old one you will get it. As i wont to make it, I shall share how did it.

1
jabutleratmacdotcom
jabutleratmacdotcom

19 days ago

Your Plywood DMLs have become my daily drivers. I'm lovin' the high end audio! So, thank you VERY much. I expect this project to take me to new heights, but tell us more about "impedance matching transformers," please.

0
JGJMatt
JGJMatt

Reply 19 days ago

I'm very glad to hear that and I'd love to see some pictures of your build! As for the transformer I'm still looking for a link to a suitable transformer but I'll let you know as soon as I find something.