Sony WH-1000XM4 teardown by 52Audio

I was not expecting a teardown so quickly of the Sony WH-1000XM4, but 52Audio.com has delivered once again, so time to dive in, see what is new and compare it to the WH-1000XM3. Warning a lot of photos coming up.

I will not focus much on the exterior changes, so if anyone wishes to compare the exteriors, check out the links here (XM4, XM3). All photos can be viewed in larger size by clicking on them, and most  comparison photos have the WH-1000XM4 on the left and the WH-1000XM3 on the right.

The first notable difference in the build is the inside plastic holding the driver and the sponge surrounding the driver. In the XM4, the plastic is one piece and the sponge does appear to be slightly bigger and fills out the space much more than the sponge in the XM3. This should help with passive noise cancellation.

Source: 52Audio.com - WH-1000XM4 sponge

Looking at the XM3 for comparison. The sponge has less material than the XM4 sponge.

Source: 52Audio.com - WH-1000XM3 sponge

Here we can see the interior plastic which holds the driver. In the XM4, it is made out of 1 piece, where as the XM3 has 2 pieces. Simplifying the design to 1 piece should help with rigidity, weight, and production. In addition, the design of the plastic is also quite different on the XM4 versus XM3. So while the XM4 and XM3 look almost identical on the outside, the interior is a different story it, as expected.

Source: 52Audio.com

Next up is the feedback microphone located inside the headphones. The FB microphone is now covered by a plastic piece instead of just tape. The plastic cover affixes to the main unit with clips. I wonder why this design change has occurred, perhaps the tape was peeling off and the NC microphone was coming free?

Source: 52Audio.com

Likewise the Feedback NC microphone has a different orientation on the XM4 than XM3. On the new XM4, the microphone is now perpendicular to the driver, where as on the XM3 it was parallel. I am not sure why this has been changed, perhaps this microphone is also involved for voice and noise cancellation during calls? Could this be the extra mic? Would love to hear Sony's reasoning for this change. If anyone has any ideas, please leave a comment below. Other than that, it looks like the microphone is the same.

Source: 52Audio.com

Opening the right side reveals the battery and touch sensor. The touch sensor looks identical but upon closer inspection is a bit different. Around the touch sensor cover is a rubber seal, same a before. A small change, but significant, is the use of a ribbon cable which connects the small battery/touch sensor PCB to the main board. This helps with production since on the XM3, the wires were soldered to the board which takes more time than just plugging in a ribbon cable. As well, repair's should be quicker.

Source: 52Audio.com

Another design change is the FeedForward NC microphone opening, now looking a lot better than on the XM3. This may not be something big, but it looks more premium and probably functions better.

Source: 52Audio.com

A close up of the Feedforward NC microphone, showing a slightly different design.

Source: 52Audio.com

Turning to the battery, it is identical in both models, the battery model is the LIS1662HNPC, rated at 1100mAh, 3.7V. While it would have been better if Sony used a slightly larger capacity battery, the fact it is not less is also a positive. 

For those interested in seeing the changes on the battery/touch sensor PCB, check out the links at the end of the post, but one change is the charging IC is now the MPS MP2625B on the XM4, compared to the MPS MP2625 on the XM3. I believe they are identical apart from the Operating Input Voltage, which is lower on the XM4 (4V to 10V, versus 4V to 14V on XM3). This is not my field, so if anyone wishes to post any other differences, please leave a comment below.

One area different is the USB type-C PCB, it looks like there are less parts on it, but again not my field, just pointing out what I can see visually. Anyone know the reason(s) for the differences?

Source: 52Audio.com

The NFC antenna on the inside on the left side is now smaller on the XM4. Reading a blog entry on NXP's site about antenna design, it seems that the smaller antenna would decrease the read range, but read range is also dependent on the chip inductor, which is identical on both models.

Source: 52Audio.com

Focusing on the call microphones, sorry to break the bad news, but the microphone array has the same amount of mics, 3, no more, no less. The only difference I can see is that microphones are closer together on the XM4 than in the XM3. So perhaps the tighter arrangement has slightly improved the voice call quality from the various hands on videos I have seen. But the voice quality is still not stellar it seems.

Source: 52Audio.com

So it seems that the amount of microphones has not changed, 5 on the left, 2 on the right. Perhaps Sony uses the NC mics now for the phone calls as well? But I have no idea if this is the case. It would have been great to see more microphones, perhaps 4 in the array or perhaps a similar array on the right side? Perhaps Sony does not really care to focus on call quality as much as sound quality and noise cancellation performance? This is my impression from the various interviewers I have read regarding the WH-1000XM3 an XM4.

Looking at the main PCB, there are some major changes, mostly for easier production/assembly/repair it seems, but also to newer components.

Source: 52Audio.com

The QN1 can be seen in the middle of both PCBs, but the XM4 has it orientated differently. Next on the left we can see a ribbon cable connector on the XM4, where it was just soldered on cables in the XM3. I pointed this out in the FCC WH-1000XM4 teardown post. The soldered on wires on the bottom of the boards in both are for the microphones (NC) and drivers.

 Close up of the Sony QN1, CXD90050.

Source: 52Audio.com

The other side of the PCB has the Bluetooth SoC (Mediatek MT2811), Q128JWYIQ memory chip, LATTICE ice40ul1k low power FPGA and sensor manager, and the Cirrus Logic CS48L32. The XM3 has the CSR8675, Q64FWY memory chip, Cirrus Logic CS47L15, and STM32L071CZT6. The majority of the changes in the WH-1000XM4 have been under the skin rather than the external design.

Source: 52Audio.com

Going back to the Cirrus Logic CS48L32 in the XM4, more can be found out here from Cirrus' website, the chip performs some the following functions:

• 24-bit audio processor with 104 dB signal-to-noise ratio
• supports up to four analog or four digital microphone (DMIC) inputs 
• “always on voice” (i.e., voice trigger)

I am sure it has more functions, again not my field of knowledge, so check out the link above from Cirrus to see the other features/functions.

Finally, let us look at the proximity sensor. The major new addition to the XM4.

 

Super close up of the proximity sensor. Not sure if the sensor also has the accelerometer built into it or if that is somewhere else on the device, either as a standalone chip or part of the other chips like the Cirrus Logic or LATTICE chip. The sensor is connected by a ribbon cable, so it will be possible to technically disconnect it from working, but I would not advise it.

 

Source: 52Audio.com

 

Source: 52Audio.com

 

Well that is all for the teardown. The teardown provides a nice insight into the new model. Most changes appear to be geared towards easier production, easier repair, less parts, more strengthening of parts and various quality improvements. This is evident with increased use of ribbon cables and connectors. 52Audio mention in their summary that more glue is used, additional rubber seals, thicker sponges and in general more tighter connections. This all should result in a more solidly built headset with better durability in the long term.

Of course, nothing is perfect, and Sony opting to keep the same 3 microphone array for calls is a disappointing decision. The battery capacity could have been slightly more, but thankfully there was no reduction.

If anyone finds anything of interest in the teardown on 52Audio, please post it in the comments. The links to both WH-1000XM4 and WH-1000XM3 teardowns are posted below.

Source: 52Audio WH-1000X4 teardown | 52Audio WH-1000XM3 teardown