Black Walnut Wooden Shell Headphone With Hi–Fi 40 or 50mm Sennheiser Drivers

This post is my 4th instructables. As I find the community is more interested on big and Hi-End over-the-ear headphones, guess you might be more glad to hear this. Quality of this build is comparable with any $300+ commericial headphones, while the budget is 50% or less. An additional benefit is, the wooden house is strong enough to withstand multiple MODs, e.g，upgrading drivers, than plastic shells.

This post is to share my experience building a genuine wood headphone with a pair of Hi-End 40 or 50mm dynamic drivers and a replaceable cable. See above for my final result. This design has 3 advantages to me that:

1. Comparable sound quality with hundreds $ Hi-End earphones, where I put Sennheiser HD650 as benchmark. Both genuine wood shell and the open end design help a lot on the he low frequency band performance for drums and cellos, which are most critical to me.
2. The ear pads must be big, soft and comfortable for hours wearing.
3. 16 or 32-Ohm and high sensitivity to be easily driven by my cell phone and the USB DAC with embedded AMP.

My son was so happy and volunteered to be a model ? I am also planning to DIY a sound measurement system so I can fine tune it objectively. See attached Frequency Response measurement of Sennheiser HD650. Also see my other Instructables:

1. Make a Sound Isolation Earphone With Sennheiser IE80 Drivers

2. Build an “Aladdin's Lamp”, Gold Plated Copper In-ear Earphone

3. Build a Headphone With Beats Studio 2.0 Drivers

See the figure for all components:

1. Item 1: wooden headphone shell and housing
2. Item 2 (optional): 40mm-50mm adapter, only needed when using 40mm dynamic drivers.
3. Item 3: a pair of ear pads
4. Item 4: a pair of front cover for dynamic drivers
5. Item 5: a pair of dynamic drivers

Items 1/3/4 can be bought from here. And Item 2/5 can be bought from here.

Some basic tools are needed to put everything together. See the figure of everything I bought for this project and all work well. But don’t misunderstand the DIY being too easy. Although the headphone worked amazingly, there are a lot of additional fine tune works can be done, which need sound measurement instruments and extra materials.

Dynamic drivers are very fragile and better to be installed in to the housing first. See the pair of drivers before installation.

Apply glue (highly recommend E8000 or silicon glue, and do NOT use any instant glue like 502) evenly around the outer of drivers, stay 1min till the glue becoming sticky, and insert it to the housing. Notice the direction of the soldering panel. Wait for another 15min until the glue strong enough.

The headphone shell comes with internal wires ready, so the work is to connect (solder) wires correctly with the dynamic drivers. Please be very careful and quick (<2s) in soldering. Also notice the driver is with polarity – positive is at the right hand side.

As all wires having been connected in the last step, the headphone actually can work! So you may want to connect it to your cell phone and verify if all wirings have been done correctly.
Screwing the housing (with driver) to the shell firmly, and then put on the ear pad – you almost done! You can also add some sound-absorbing cotton which could be sponge or even real cotton (not recommend if you leaving in a wet area). I tried but not seeing significant gain, as the powerful wooden shell perfectly absobs most echos.

if you have done everything correctly, the headphone shall already working perfectly. The most common error is connecting wires in wrong orders. Please read this article Understand 3.5mm jack to understand how.

About how to pick between 40mm or 50mm drivers, I tried both and here are my subjective experience:

1. if you are a big fan of supper bass, go for 50mm. The drum or bass could blow up and your skip can actually feel the vibration. However, the side effect is distortion, as the coil moving out best working position.
2. 40mm driver gives you a very balanced performance and bright/clear sounds. See the figure for the 40mm driver I tested with this shell. Note as the house is 50mm, a aluminum ring 40 to 50mm adapter is needed.