[Tofty]

Repairs and Modifications

Hi all,

I've recently picked up the hobby of repairing headphones, bought in job lots or as spares/repairs.
For many of them the repairs have been quite straight-forward, but when it comes to physical damage; it's rarely a simple fix.
Using a 3D Printer however can really help solve many of these mechanical issues that might otherwise condemn a set of headphones to the bin (or ebay for hopefully a bargain price).

The printer I've been using was ~£300 new and has a 300 x 300 x 400mm print volume, which is larger than is usually required. The filament is 1.75mm PLA, extruded in 0.3mm layers, so nothing special in terms of detail resolution but not too painful on print times.

Roccat Khan
The headband for this headset snapped, so I replaced it with a Logitech G Pro headband, printing four adapter pins to make up the difference between the earcup and headband fork sizes.

Logitech G332
On this headset the swivel retaining tabs had broken, so I found a model online for the replacement part. Unfortunately it wasn't quite right, as it was for a similar, but slightly different model. However with some adjustment using a craft knife it was made to fit. I suppose I could have modified the original model to better suit this headset, but since this fix works it wasn't worth spending any more time on what is a fairly budget headset.

Sony MDR-1R
These headphones had one of the ear pads missing, which normally wouldn't be an issue, as cheap replacement ear pads can be found on ebay for almost all popular headphones, including for the MDR-1A/1R. However these particular models use a proprietary plastic ring to clip the pads onto the frames, which was of course also missing and this part cannot be purchased anywhere that I looked. Fortunately I had one of these rings to reference, so after a couple of attempts I was able to print a pair of working replacements.

The original ring is at the top of the picture, with a printed replacement mounted in a new pad on the right. The headphone cups have four clips which slot into the holes in the pad's corners, while the plastic ring itself has two clips on each side. The clip positions are subtly keyed for left and right, so getting these right was a bit of a challenge.

Roland RH-5
One of the forks had snapped at the fork to headband swivel, so I printed a pair of replacements.

One of the advantages of 3D printing is you can make shapes that injection moulding can't, so here the crossover cable can be better retained within fully enclosed tunnels in the fork, rather than the open channels of the original forks.

Google GID5B
This is a bit of an odd one; a pair of noise cancelling bluetooth headphones, manufactured specifically for Google, to supply internally to it's employees. I received them with rotten ear pads and a cracking headband, but otherwise working correctly.

The printed headband still needs some work as its clamping force a little weak, so I'll try a 2.5mm wall thickness, instead of the current 2mm. Also it doesn't pull the bottom of the ear pads in enough, so I'll have to tweak the overall shape somewhat as well.

Razer Kraken X USB
I have a few of these and they all seem to suffer from a broken headband or adjuster arm. For those with broken headbands I modeled up a printable replacement headband. It's non-adjusting, so has to be made specifically for the head size of a specific user, but I feel this is the best option due to how fragile the adjuster arms seem to be at any amount of extension.

The screws are UNC 6-32. I find that this thread is course enough to work well in this kind of printed plastic, so long as the holes are drilled and tapped. They will of course strip if over torqued, but they are much better than an M3, while not being that much bigger (3.6mm vs 3mm diameter) and in my opinion a whole lot better than self tapping screws, as they have a bad habit of splitting the layers apart in printed plastics.

Logitech G35
This one is more of a complete rebuild and a bit of a labour of love, since this was my first proper gaming headset, bought more than a decade ago. After a few years the fork to headband swivels broke on both sides, so with no other recourse I removed the headband entirely and wore the cups under a beanie hat.
The headset's microphone got in the way and the buttons on the side of one of the cups kept getting pressed and pausing/skipping any music being played, so they all had to go. After a while the crossover cable, which was just hanging loose started to fail, so I replaced it with some armoured 2 core, which stood up quite well.
I put up with this arrangement for far too long before eventually moving on and putting them away in a box of junk.

With my recent interest in headphone repair; it would be a shame not to attempt to bring these long neglected workhorses back to life. The headband is from a set of Numskull NS05s, a model with inherent cable issues, making them not worth repairing, but still a source of 50mm drivers, big round ear pads and the aforementioned headband.
The ear cups were covered in that horrible rubberised coating that had gone sticky and needed scouring off.
The nearly three metre USB cable had been run over by my office chair one too many times and had started to fray and kink, while the USB connector had been ripped from the computer at harsh angles to a point where it was deformed, but amazingly still worked. It needed replacing in any case, hence the nice new red cable. Splicing the headphone end of the cable with the short wires coming out of the tiny internal connector (picoblade?) wasn't much fun, but I didn't have crimps for it and definitely didn't have the expensive crimping tool needed either, but it works and ended up quite neat.

If I was to print the forks again I'd bring them in closer to the head, so the headband wasn't quite so expanded and therefore clamped a little less firmly. I had to guess at the final positioning and it looks like I was a bit off from where it should have been. Still an overall success as these headphones are back to being usable again.
The only other thing I'd potentially like to do is add the mic and missing buttons back in, but that relies on finding a donor headset, so I'm not holding my breath.

So that's almost all the things I've done so far that involve combining headphones and 3D Printers. The only other thing I've done will be shown in the DIY forum soon and it's possibly even more ridiculous than the G35 build above.

Thanks for reading.

 

[gimmeheadroom]

Great job! I wish I had a clue with 3d printing.

 

[Tofty]

Thanks gimmeheadroom,

My intentions with this thread was to demonstrate that current 3D Printing options are not all that expensive and can give functional, if not visually appealing results.
It should be noted however that actually creating the 3D files and making them suitable for printing can be quite a learning curve.

 

[Tofty]

After having used a fair number of different over-ear headphones and headsets, as well as trying to repair many of them; some features became clear as to what I do and don’t like for comfort and practicality.
I thought that as I have a pile of available donor parts from otherwise terminal headphones; I’d try to design and build my own headphones, incorporating my preferences.
This is not (at least not yet) a journey into audiophile listening perfection, rather a mechanical engineer’s design exercise, so please bare that in mind.
It's also very much just a version one prototype. Lessons learned here will inform version two, which will likely look completely different.

I started with the features I disliked:
- Small ear pads,
- Pads thin enough to let my ears touch the speaker grills,
- Cables that don't detach,
- Ear cups with a lack of up/down rotation,
- Headbands with loose adjustment (I'd personally prefer a fully locking adjustable headband),
- Cable connections only on the left side of the headphones (right side connections would suit my setup better),
- Headbands that rest on the very top of the head and that don't spread the headphone's weight better,
- Short internal driver wires that require desoldering before allowing proper internal access,
- Overly convoluted routing of the bridging cable, using thin sleeving that wear and get pinched too easily.

By trying to avoid all these above mentioned features, the basic design started to take shape.

I bought the largest ear pads I could find: 120mm diameter with ~30-40mm depth, and designed the headphones around them.
A removable microphone was added because why not. It's designed to take any straight mic with a 3.5mm jack connection, with the one shown in the renders being from the Logitech G Pro. However because these mics are uni-directional, they have a keyed shape at the jack connector to prevent them from rotating. I therefore made screw-in plates that could have the correct keying for various different mics.
I went for a suspended strap for cushioning below the headband itself, so there are no potentially fragile length adjusters in the band itself.

All external connectors except for the mic use the Mini XLR type, including the bridging cable, allowing it to be completely swapped out or removed altogether, without disturbing the ear cups.

The wiring layout is modular with all the wires running to both ear cups.
This allows the headphones to be used in a number of different arrangements:
Left mounted input cable, with bridge cable,
Right mounted input cable, with bridge cable,
Split left and right input cable, with bridge cable removed.
Microphones can be used in either the left or right side (or both together) for any of these arrangements.

The general layout of the driver mounts and grill were heavily inspired by forum member Kakaworu's :
printed Koss KSC75 Mod

I wanted to have a removable back to the ear cups; allowing the drivers and other connections to be tested in situ, but this wasn’t achievable, so I decided to have internal connectors, so in theory all the external connectors and drivers could be removed from the ear cup without desoldering anything.

So, how did it all turn out?

 

[Tofty]

It turned out like this:

Here is a size comparison with a large-ish set of headphones many will be familiar with: The Beyerdynamics DT 770 Pro.

As you can see this was all a "HUGE" mistake. They work, but they're so big that parts can be seen in my peripheral vision.
definitely back to the drawing board to shrink as much down as possible.

The "Fibonacci" driver grills didn't come out too well, due to the orientation they were printed in. I should have made them as a separate part from the ear pad mount.

The drivers are clamped in place and the wiring is detachable from the ear cup, so different drivers can be easily swapped in and out.
These drivers are 50mm in diameter.

The ear cups have a cable loom; connecting the input connector, bridge connector, mic connector and driver together

All the internal connectors are JST SMs

With all this done I'm left with some questions.

Should I run a dedicated ground wire for both the left & right channels and mic?
Currently I only have four separate wires: Left, Right, Ground & Mic, but I've noticed that some cables have an extra wire for the Mic -, separate from GND, while some also split Grounds for each audio channel.
Is this something I should consider doing?

Is the number of connections (potentially 8 from amp to driver) too many?
I've measured the resistance from the end of the 3m input cable to the furthest connector away from it and I got 0.5 Ohms from all 4 wires. Just the cable itself measured 0.4 Ohms, while from one ear cup to the other (at the connectors on the bottom of the ear cups, via the bridge cable) I measured 0.2 Ohms.
Is this level of resistance acceptable or should I look at simplifying the wiring setup?
Are there any other internal connectors that are smaller and/or are likely to make better electrical contacts?

Is there anything else I've neglected that I should be made aware of?


Future changes/improvements:
Make the headphones much smaller overall (obviously). I think I'll start by using 110x90 ear pads instead.
Move the bandband up more, so the ear cups can protrude out below it, rather than be constrained with the headband ending around the ear cups. This will also reduce the clamping force slightly, which is on the high side for me.
Make a proper head strap cradle thing, rather than using double sided velcro.
Make a provision for the connection and mounting of a Bluetooth amp, like the Fiio BTR series. I really like the concept of the Fiio BTA10, which makes the Audio Technica ATH-M50x headphones wireless, with no cables.

I'm a little way into designing version two, but there's still a long way to go yet.

Edit:
I've redesigned the headpad/headstrap using TPU rubberised filament and added some filter paper to the vents around the driver.
All files for this design can be found here: https://www.thingiverse.com/thing:5100797

 

[Tofty]

Grado SR80e
Despite rather liking them, I feel that Grados have a significant design flaw as there is nothing to prevent the ear cups from fully-rotating in one direction over and over again, twisting the non-detachable cables and causing them to eventually fail. I’ve seen this happen a few times, including to the pair I found.
This issue could be mitigated by periodically removing the ear cups from the head band and letting them un-twist themselves, except that the black caps on the ends of the adjustment rods prevent the ear cups removal.

Detachable cables help solve this problem, so since my cable was faulty and Grado don’t sell replacements, this felt like it was worth doing.

I generally don’t like modify things in a way that prevents them being returned to their original spec, so I wanted a smaller connector than a 3.5mm jack, which would require the original opening to be enlarged.
I settled on the MMCX connector, which has a tiny M3 mounting thread.

This printed part gets sandwiched between the two ear cup halves, with the MMCX connector threaded into it

The way the two ear cup halves were glued together, which prevents convenient servicing, is something I also wasn't a fan of, so I looked at a way to change this:

This breaks my previously mentioned preference for avoiding irreversible modification, but sometimes it's unavoidable.
I printed a plastic ring jig, which sat in the channel the ear pads hook into. This helped to get the spacing between the two halves consistent all the way around. It took a few tries to get the ring's height perfect; to ensure the MMCX holder was being tightly retained. Holes were drilled through both halves in four positions. Then the inner holes were tapped, while the outer holes were drilled out and countersunk.

The cable is a cheap replacement for the Audio-Technica ATH-ES9, which uses their A2DC connectors. These had to be cut them off and re-terminated. I struggled to find an MMCX cable with a thicker cable diameter than the ones sold for in-ear use. I’m sure they’re out there somewhere, I just couldn't find one.

 

[Tofty]

So...I finally finished my second attempt at making some DIY printed headphones.
Are they any good? No, obviously, but some aspects of them worked well enough to show promise.

Persevering with the same headband I used on my first headphone attempt turned out to be a big mistake.
I initially designed the band to sit higher relative to the ear cups, but this left such a big gap between the top of the head and the band that it looked ridiculous (more ridiculous than they currently look) and didn't have quite enough clamping force.
I therefore remade the printed forks to bring the headband down, but this forced it to be much wider and it now clamps too tightly. I should have looked at a different headband solution much sooner. It's a shame that I had to change the forks as the originals were a lot less clumsy looking than these replacements.

With thinner pads; the lack of swivelling ear cups has become more of an apparent issue, with pressure points becoming over time

The rectangular rings that hold the head pad in place (same pad as used on a pair of Steelseries Arctis 3 or 5 gaming headsets) were made rigid, whereas on my previous pair they flopped around and were a pain.
I don't like how narrow the headpad feels, so I need to look at other options.

The many internal connectors used on my previous design have been paired down to just one for the two driver wires, this allows easier swapping of the driver, if it ever become necessary.

One of the design features I continue to see merit in is the removeable bridging cable. This setup is at least neater and less unwieldy than it's predecessor, but more work is needed. Sensible placement of the bridge cable connectors continues to be a challenge.

The Bluetooth DAC was a hard thing to fit into the design, considering it's bulky shape. Something more integrated would be much better, but sourcing the parts would be a challenge and one of the design features I'm aiming for is easy servicing and repair, so more bespoke parts should be avoided.

These originally sounded pretty rubbish before I added some filter paper to the apertures around the driver. Now they just sound mediocre.
Once I get a general design I'm happy with I need to go deep into learning about acoustic tuning.

On to versions three and four.

Edit: A few more photos added.

Files for these headphones can be found here: https://www.thingiverse.com/thing:5100835

 

[Tofty]

A while ago I saw a really nicely modded set of Philips SHP9500, with the grills replaced with glass disks. This somewhat aped the look of the much more expensive Sennheiser HD 820 and I decided that I'd like to have a go at integrating something similar for my next design.

This is what I've come up with so far:

Other inspirations include the Elega DR-631C's headband details , as well as the Kennerton range more generally.

The earpads are 105mm and the headpad is a cheap Hifiman type replacement.
External connectors are all Mini XLR, with the rear bridge cable ones being low profile right angle.
The head band will have elastic cord woven between the two halves to retain the bridge cable and to make it easy to remove and install when required.
All the metal parts will be Stainless Steel and the ear cups will be English Walnut.
Printed plastic parts will include the earpad/driver retention plate and the headpad holders.
The headband side blocks will be printed in stainless steel.

Since the clear disks may cause some unwanted reverberation, especially since padding isn't something I want in the earcup when the whole point is to show them off, the disks should easily be able to be swapped out for mesh of perforated grills, to make them open-backed.

Drivers are currently just generic 50mm dynamics. I'm yet to find a 50mm driver I really like using. The Peerless by Tymphany HPD-50N25PR00-32 driver looked promising, as it seems to have been used in a few high price models, but they appear to be completely sold out with no set date for restocking.
Alternatively the earcup cavities are large enough to allow for a number of other potential options, such as Planar Magnetics, but again finding suitable will be a challenge.

The inside of the ear cups is still to be finished and I'm not happy with the headband adjustment, as it has the same unrestricted rotation issue that I only recently complained about on the Grados.

I'll almost certainly make a printed version of this general design first and tweak things accordingly.

 

[Ferdous]

It turned out like this:

Here is a size comparison with a large-ish set of headphones many will be familiar with: The Beyerdynamics DT 770 Pro.

As you can see this was all a "HUGE" mistake. They work, but they're so big that parts can be seen in my peripheral vision.
definitely back to the drawing board to shrink as much down as possible.

The "Fibonacci" driver grills didn't come out too well, due to the orientation they were printed in. I should have made them as a separate part from the ear pad mount.

The drivers are clamped in place and the wiring is detachable from the ear cup, so different drivers can be easily swapped in and out.
These drivers are 50mm in diameter.

The ear cups have a cable loom; connecting the input connector, bridge connector, mic connector and driver together

All the internal connectors are JST SMs

With all this done I'm left with some questions.

Should I run a dedicated ground wire for both the left & right channels and mic?
Currently I only have four separate wires: Left, Right, Ground & Mic, but I've noticed that some cables have an extra wire for the Mic -, separate from GND, while some also split Grounds for each audio channel.
Is this something I should consider doing?

Is the number of connections (potentially 8 from amp to driver) too many?
I've measured the resistance from the end of the 3m input cable to the furthest connector away from it and I got 0.5 Ohms from all 4 wires. Just the cable itself measured 0.4 Ohms, while from one ear cup to the other (at the connectors on the bottom of the ear cups, via the bridge cable) I measured 0.2 Ohms.
Is this level of resistance acceptable or should I look at simplifying the wiring setup?
Are there any other internal connectors that are smaller and/or are likely to make better electrical contacts?

Is there anything else I've neglected that I should be made aware of?


Future changes/improvements:
Make the headphones much smaller overall (obviously). I think I'll start by using 110x90 ear pads instead.
Move the bandband up more, so the ear cups can protrude out below it, rather than be constrained with the headband ending around the ear cups. This will also reduce the clamping force slightly, which is on the high side for me.
Make a proper head strap cradle thing, rather than using double sided velcro.
Make a provision for the connection and mounting of a Bluetooth amp, like the Fiio BTR series. I really like the concept of the Fiio BTA10, which makes the Audio Technica ATH-M50x headphones wireless, with no cables.

I'm a little way into designing version two, but there's still a long way to go yet.

You’re just awesome. There’s literally no one pushing into these except you. At least, I couldn’t find anyone yet. You wouldn’t believe how much this thread helped me.
In my country, there is very few good headphones in the market. The better ones are gaming & rgb which sounds so....
Making a printer soon(yes I am making it. Importing isn’t an option), I ordered some drivers & 110mm ear pads to make my own. Sadly, I’m not very good at starting from scratch. I can modify a premade design with some time but that’s as far as I can do....

Though you said there is some flaw in this design I’d really like to try them out. Can you kindly share the step files for it? I look forward to modify it, mainly remove the mic & mini xlr cables ( I had bad experience with 3.5mm jack, so I’m trying to avoid any unnecessary jack).

You sire is really making the best out of this technology. Wish there Was more like you in the world. Thanks again.

 

[Tofty]

Thanks Ferdous,
I'm glad this thread has been helpful to you.
Over the weekend I'll try and gather all the model files together and make them available on Drop-box, Thingiverse or Grabcad.

What CAD software do you use? I use Solidworks, so I can share the files in the solidworks format or as a .STEP file, rather than just as .STL files.
I find modifying .STL files a real pain, so I'd like to help avoid that for others if I can.

There are quite a few others I've found using 3D printing to make custom and modified headphones.
I'll see if I can collect some of the details and post links to them, but one interesting project currently being posted about on Reddit are DIY versions of the Aurorus Borealis headphones. Several people have so far created versions, often taking and modifying the previous maker's models, resulting in an interesting evolution of the initial design. I'm currently working on my own version, which I should be finished with designing soon.

 

[Ferdous]

Thanks Ferdous,
I'm glad this thread has been helpful to you.
Over the weekend I'll try and gather all the model files together and make them available on Drop-box, Thingiverse or Grabcad.

What CAD software do you use? I use Solidworks, so I can share the files in the solidworks format or as a .STEP file, rather than just as .STL files.
I find modifying .STL files a real pain, so I'd like to help avoid that for others if I can.

There are quite a few others I've found using 3D printing to make custom and modified headphones.
I'll see if I can collect some of the details and post links to them, but one interesting project currently being posted about on Reddit are DIY versions of the Aurorus Borealis headphones. Several people have so far created versions, often taking and modifying the previous maker's models, resulting in an interesting evolution of the initial design. I'm currently working on my own version, which I should be finished with designing soon.

Thank you. I’m currently using Fusion 360. I’m looking forward to using solidworks in the coming months. As step is more widey used, it’ll also help others if you share that. And yes I just can’t modify stl. I convert it to brep then mesh & then finally to step if I ever need to work with a stl.

After sorting everything out, kindly give me your thingiverse Account link. I’ll try to closely follow that for all your awesome works. And your documentation is pretty thorough. Which makes other people understand it so easily.
I also found one of those designs. But most of those design required to have the initial product. But yours full 3D printed designs are the best. Doesn’t require anything to have to start with.
Btw, the headband isn’t 3D printed. What are you using for the headbands?

 

[Tofty]

Sorry for the delay, I got this all sorted out on Saturday night, but discovered that I had to wait 24 hours, after setting up my Thingiverse account, to post models.
Anyway here is my first headphone design as requested:
https://www.thingiverse.com/thing:5100797

I'll be posting more of my designs there soon.

I also finished my attempt at remixing the DIY Aurorus Audio Borealis: (proper post abut this to follow)

 

[Ferdous]

Well, at first I thought the first one is a solid design & it can’t probably get so much better than that. But now I’m afraid that I’ll be having bunch of 3D printed headphones in near future. Really appreciate all of this.

What are you using for the headbands now? In all of your designs, none of it use a printed one. How can we also source the headbands?

 

[IvanDrago]

Anyway here is my first headphone design as requested:
https://www.thingiverse.com/thing:5100797

Angeled drivers? How do they sound compared to a flat design?
I wanna try this for my next project. Angeled by 5-10 degrees with 5-10 offcenter in z-axes.

Here is another awesome project. Unfortunally the CAD files are no longer available.
https://www.superbestaudiofriends.o...accessible-modular-headphone-platforms.10248/

What are you using for the headbands now? In all of your designs, none of it use a printed one. How can we also source the headbands?

https://www.thingiverse.com/thing:4915305
I like this design a lot.

 

[Ferdous]

I like this design a lot.

The design is a headphone strap. I was talking about the headband. The metallic part(most of the time, bust there’s a few 3d printed designs) above.