Disassembling the Venerable Audeze LCD-4

[LuthierJeff]

Audeze's LCD-4 is a legendary headphone in my mind. It's rich, warm, and big sounding, with excellent bass and presence. I'm biased though, as it was the first flagship headphone I ever had. I eventually sold it, then regretted it, so I found one last year with one side not working. I eventually sent it in to Audeze for a driver replacement (thanks Audeze, they sound fantastic), but before doing so I thought it would be fun to learn about how they're constructed, and to see where the failure was. I thought it was fascinating, so I wanted to share.

The following post is a photo dump of the insides of the left driver. In short, the diaphragm had torn near the bottom edge and went through a few trace paths, which you can readily see in the photos of that piece.

Here was the process, for those interested:
Pulling off the pad leaves some glue and residue on the driver assembly. That came mostly off eventually with isopropyl alcohol and scrubbing. Next I started unscrewing the brass screws/nuts. I thought some of them were really difficult and couldn't figure out why. Turns out the magnets are very strong (as advertised!) an in that orientation, the two plates were repelling so hard that when I was down to one or two screws, they were forcing each other open like a clamshell, jamming the screws up. I pressed the plated together while unscrewing the last ones, and then let go, which was a bit of a mistake. The plates turned and slammed together with their magnetic pull. Thank goodness I had confirmed prior that Audeze would be replacing the whole driver unit, including the magnets, wave guides, etc, basically everything that is functional (so not including wood rings, etc). Bacon saved.

You'll see in the photos, but 6 of the magnet pairs came unglued from the assembly and stuck to other magnets. I was able to (difficultly) pull them off and glue them back in their plces, but mostly that was just for later reassembly. One of them broke as well, they seem to be ceramic magnets. I knew I'd mess something up, haha, but I got to learn things!

At that point the tear in the diaphragm was immediately visible. I'm not certain, but I believe this was the original membrane that Audeze sent these out with (I think it was nominally 100ohms), but eventually swapped over to a more robust one (happened to be 200 ohms I think). This unit was manufactured on 2016 so that would fit.

After this, I took my sweet time photographing, it's just such a cool and effective design. I also made a CAD drawing of the whole assembly. I have zero ambition of ever using that for anything, but it was a fun exercise to practice drawing. If anyone would have use for those drawings, let me know, I drew it in Rhinoceros 3D but imagine it would import to other programs. Also if anyone would like higher resolution photos or the original RAW files, let me know.

For those curious, the sandwiching of the plates is like this:

Fazor wave guides
Wire mesh
Metal plate
Magnets and frame to hold then in place
Paper barrier/gasket
PCB frame for diaphragm
Diapragm (this is in the center, everything after is just mirrored)
PCB frame for diaphragm
Paper barrier/gasket
Magnets and frame to hold then in place
Metal plate
Wire mesh
Fazor wave guides

Thanks if you've read this far, and please let me know if you have any questions! Huge thanks to Audeze for making some of my favorite headphones!

Edit: Oops, I didn't realize I can't double post, nor post more than 25 photos at a time. I'll post the first 25 here, then the last few if someone happens to reply to this thread. Thanks!

 

[2leftears]

I think the rule about no double posts already existed informally, but is now being enforced. That will mess up many threads in the Music forum as often there are only a very limited number of posters for specific music genres. And editing a previous last post I don't think will flag the thread as having new post(s), so many threads will go dead from now on...

 

[LuthierJeff]

Thanks for chiming in about that! I hadn't really realized, since I don't often make posts, but it's good to know. That's too bad about those threads you mentioned, although I can understand the reasoning about double/multi posting.
Alrighty, here are the last few photos. Interesting to note, but I always wondered why sometimes the input jacks get loose, and it looks like it's due to being set in place with something like Bondo, which just breaks loose after a while. They remedied that with their more recent headphones, but interesting to see here. Thankfully they don't fall out, just are a tad wiggly.