Poor Bluetooth audio at other end? A fix

FireOne

Hi,
I want to share this as it will probably help many people as frustrated as I was with people on the other end not being able to make out what I was saying at any kind of speed.
I used to have an Octavia with a Parrot kit installed, mic clipped high by door pillar, pointed at my mouth, had no problems. got a Hyundai IX35 recently. I love it but the bluetooth is factory installed and the mic is overhead in the ceiling. No longer could I chat away as I drove, my voice was blurred into road noise being picked up and conversations were irritating for both sides. Stopped it was fine, but slightly muffled.
Googling forums and chatting to car-kit companies revealed this is a common problem with may cars, many makes. People had had microphones changed, stereos changed, and no improvement (and some people reported no issue). People just live with it.
In the following posts I will explain my solution and hopefully post pictures.

FireOne

I first bought a Besign BK01 on Amazon, a surprisingly effective bluetooth kit with built-in mic that used the AUX audio-in and USB plug for power and worked very well with my smart phone. Not as good as a proper installed bluetooth system but it left me free to tinker with the factory system. I also recorded some messages on my own voicemail for comparison purposes.

I prised the mic holder out of the bezel using a small screwdriver.
there are three small recesses around it for this purpose. Be gentle.

FireOne

The mic holder will hang on a couple of inches of cable. It is composed of two parts. This cable isnt that flimsy but I could not seem to locate the plug at the end of the cable that would allow replacement of the mic.
The two halves of the holder can be separated by gently levering the clips as shown in the picture. The cable inside is flimsy so be careful.

FireOne

The front part will come away. This reveals the actual sensing element of the mic. There is a small cylinder with two tiny pieces of foam packing holding the actual microphone in place, see picture 3.
But in the front part of the mic I found a piece of material glued over the inlet holes. See Pic 4.
I have no idea what this is for. Is it to stop wind noise as air passes over the ceiling from the winscreen outlet vents? Is it to prevent the mic being damaged by cleaning products at valeting? Is it to cushion the mic sensing element if it is too far forward?

FireOne

I removed the material and before re assembling the microphone holder I carefully pushed the mic itself back a little bit, just touching the outer metal edge with the tiny screwdriver, seating it well just in case there was a chance it would touch the other plastic front cover.
I then re- assembled the holder, pushed it back in place and tested it. It worked an awful lot better. I think that material was muffling my voice, blending it in with the road noise, and the audio system amplified both.
I made further improvement by putting a small soft cylinder over the mic as shown in the final picture. This further eliminated road noise and also any echo. I found a windscreen ice scraper in a pound shop (Mr. Price in Annacotty, Limerick) which had a grey foam rubber hand grip. Twist off the end of the handle and the foam grip slides off. Cut to an inch or so and stick on with Pritstick. (Its important to use something that wont hurt anyone in a crash).
(You could try cutting an inch off your garden hose and experimenting). Ordinary sponge or foam will let sound through but the grip above has a thin solid rubber inner surface.
By the way I cut it at a slight angle to ensure it leaned right a little, and down a little, to point at my mouth.
Between the two there was an amazing improvement, 80% due to removing that black disc, 20% due to the foam 'funnel' and now I can drive at 120k/hr on the motorway and have normal conversations. At low speeds people don't even think I am on a hands-free.
If your bluetooth audio is terrible at the other end I hope this helps you.