Saturday, January 11, 2014

Plantronics M165 bluetooth headset teardown - Making a hole for the microphone to fix the low volume and make the other person hear you better

Some month ago I decided I should get a Bluetooth headset for my smartphone, mainly to get less RF to my head :-)
After some research and reviews reading activity I opted for a Plantronics M165 Marque 2 (I bought it on Amazon, they always have a fantastic customer service).
It looked nice, with a practical "hear plugging" system, and the reviews were good.

Effectively the headset is very nice, very light, and fit perfectly in my hears.

BUT, there is an issue, a big one (in my opinion).
The sensitivity of the mike is too low, if there is a bit of noise around me, the person I'm talking to hear the noise instead of my voice.
So, this Plantronics M165 Mk2 works nicely when I'm in a silent room, but if I'm outside near a road it is totally useless, I need to turn it off and recall the person without the headset. This happened to me so many times that I've stopped using this headset.

Just to be clear about the level of noise I'm talking about: when I'm in the office, in the outskirts of the city, then I go on the balcony: we are on the 4th floor, and the nearest road is at about 60mt. Here, the noise of the road is enough that I can't use the headset.

I asked myself why I can't use the headset with such a low noise... maybe that my headset is broken/defective? it is possible...
But I think there is a better explanation: this headset DOESN'T have a hole for the microphone.

Take a look at the following image, a photo of the frontal part of the headset.
There isn't any hole, it's all solid plastic, and the microphone is behind this plastic.
How can it hear my voice?

There is second mike (for noise reduction) that instead it's near some hole facing "the noise" on the opposite side of my mouth.
Here you can see an image of the hole near the "noise reduction" mike.
I've circled them in red because they are so tiny that even with a macro photo you can barely see them. They are very tiny, about 2-3mm x 0,5mm and are "trapped" between the plastic bezel of the headset.

In my opinion, this can't work well.
Any headset I've ever seen have a hole for the mike, why the Plantronics M165 doesn't have it?

Now, I think I understood the problem: no hole for the mike.
I have also decided that this headset is useless for me, because it can work only in a silent room, which is not the the typical situation where I want to use it.

So maybe I can find a way to fix it? If only I knew where exactly the mike is, then I could make a hole for it.
So, why not try to dismantle it? :-)

I always loved to dismantle things, and I know that try to dismantle a headset can be a one-way street. Sometime they are glued together, and they are so tiny that it's really easy to break something.
Anyway, I should at least try :-)

So here is my venture in dismantling and fixing my headset.
To dismantle it I've used some plastic opening tool and some mini screwdriver.

Typical plastic opening tool

After trying to put the opening tool in any spot I could find, I've been able to open my way into the headset.
In the following image you can see the partly opened headset.
In red I've circled the only existing opening on the headset, them are near the "noise reduction" mike. Through these holes the headset can listen for the ambient noise.
Circled in yellow there is one of the 5 clips that hold the headset together.

  Here are some other images of the partly dismantled headset.

After some more pulling and bending I've been able to open the headset.

In the following images you can see the external part of the headset.
Circled in Green there are the 5 clips that keep the headset together.
Circled in Red and Orange there are other 2 clips that hold the headset together.
These last 2 clips are very hard to "unclip" because them are very tiny, and you cant use the typical plastic opening tool to unclip them (because them are placed in the corer of the headset)

As you can see from the photo, the Orange one is missing, I  broke it during the opening procedure... :-(


Now we can take a look inside the headset.
Circled in red there are the hooks of the clips.
Circled in green the leds of the headset.
Circled in pink the switch of the main button.
Circled in yellow is the bluetooth antenna.
Circled in blue is what I suppose to be the "noise reduction" mike.

And where is the microphone for the voice?
Let's take a closer look...

 Look at the object circled in red, it looks very similar the the noise reduction mike (circled in blu)

Let me check better.. I can also slip a piece of paper under it, it definitely seem to be the voice mike.

Now I know exactly where I need to make a hole, on the external plastic of the headset :-)
So, let's drill a hole in this deaf plastic shell!
To make the hole I've simply used my old trusty Olfa Cutter


And after some hand drilling... Ta-daaaa!
Here is my modded version of the Plantronics M165 Marque 2, now with a hole for the mike, so that the person you are calling can hear you better :-)

Here you can see the voice-microphone through the hole :-)

I reassembled the headset, and I'm happy to tell you that it stay together perfectly, even with a broken clip.

Clearly the headset have now some sign of the surgery procedure it went over :-)


Now the headset works way better than before, and I can talk on the balcony of the office without any issue! :-)