OEM tweeter wiring on UK Yaris

[Paul Evans]

Hi Guys.
This is a bit of a long shot, but I'll ask anyway. I live in the UK and have a 2009 model Yaris SR, which has inbuilt tweeters and airbags in the A pillar.
I don't think US-spec models have OEM tweeters, but I know some other markets do, not just the UK.

I am thinking of replacing the headunit and the front door speakers and tweeters (with component speakers). Lots of threads on these forums about replacing headunits and door speakers, but I can find nothing about replacing the OEM tweeters. If possible I would like to put my new tweeters behind the existing grilles for a stealth look. However, reading the Yaris manual I am nervous of messing with the A pillars since there are airbags there. There is nothing in the Yaris manuals or wiring diagrams which explains how the OEM tweeters are wired, or how they can be accessed.

So - anyone done this? Is it possible to get the tweeter grills and/or tweeters off the A pillars without removing the entire A pillar inside trim? If I take the A pillar trim off, the manual says there are airbag-related clips I need to replace before reassembly. I have tried (gently) to remove the tweeter grilles (sort of rounded off triangles) and they don't seem easy to remove - didn't want to break anything.

And does anyone know how the OEM door speakers and tweeters are wired? Just wondering whether to remove the existing wiring or re-use it, is there a crossover somewhere? (I would need to replace it with the one from the new speakers if so).

Any and all input would be much appreciated!

Thanks

Paul

[Paul Evans]

And in case anyone else wants to know, I have now answered my own question, via a circuit diagram from a "usually reliable source".
In a 2009 UK Yaris with the 6 speaker setup (2 front, 2 back and 2 tweeters) the front door speakers and the front tweeters on each side are wired in parallel. The wiring seems to go from the HU to the tweeters on each side and then down into the doors.

This means -
- that the tweeters at least must have a cap mounted on each tweeter to roll off the low frequencies
- that the front door speakers may have a choke mounted on the back to filter out the high frequencies (different part number to the normal 4 door speakers)
- that putting component speakers with crossovers into such a system is going to be tricky using the existing wiring!

Not rushing into action now, having a bit of a think!

Paul

[TOLMACH]

And in case anyone else wants to know, I have now answered my own question, via a circuit diagram from a "usually reliable source".
In a 2009 UK Yaris with the 6 speaker setup (2 front, 2 back and 2 tweeters) the front door speakers and the front tweeters on each side are wired in parallel. The wiring seems to go from the HU to the tweeters on each side and then down into the doors.

This means -
- that the tweeters at least must have a cap mounted on each tweeter to roll off the low frequencies
- that the front door speakers may have a choke mounted on the back to filter out the high frequencies (different part number to the normal 4 door speakers)
- that putting component speakers with crossovers into such a system is going to be tricky using the existing wiring!

Not rushing into action now, having a bit of a think!

Paul

Not sure about yaris.. with couple of my previous toytas, tweeter was crossed exactly in a way you describe.. 1st order filter.. tiny (inappropriate type) capacitor.. and woofer working in the full-range mode.. you can use similar crossover type to replace the tweeter using the capacitor of appropriate value.. you might also need to attennuate your new tweeter (quality tweeter is likely to have higher sensitivity) using resistance or L-pad (if you are using a resistance in series the crossover point will shift downward.. keep this in mind.. L-pad is a bit more predictable).. the problem with 1st order filters is that most likely you would have to experiment with different caps.. like 4.7 / 5.6, etc.. to find the one that serves the task best depending on tweeter location and orientation/angling.

IMO opinion replacing the tweeters might be a good idea (stock tweeters usually suck) keeping the OEM door woofers - they are of a good quality.. you might as well need to build the custom podium for tweeters (lots of examples how this is done can be found here on YW) or place them somewhere on the dash (some tweeters come with nice looking mounting hardware/podium)

if you want to continue with this project you might want to read some on-line stuff on filter types - (not a rocket science)

http://www.the12volt.com/caraudio/cross.asp#hp
calculator (you want something like 3500 or 4000 hz as your crossover point)
http://www.the12volt.com/caraudio/crosscalc.asp

good store for parts
decent tweeter (lots of other stuff to consider)
http://www.madisoundspeakerstore.com/sb-acoustics-soft-dome-tweeters/sb-acoustics-sb26stcn-c000-4-tweeter-4-ohms/

capacitors.. bennic - inexpensive but quality stuff (you have to buy several values.. like 4.7 / 5.6/ 3.9 each one is 2-4 bucks.. of course you need them in pairs - one for each channel)

http://www.madisoundspeakerstore.com/xxp-poly-cap-250vdc/bennic-poly-5.6-mfd/

you re also gonna need some resistors (you can use cheap stuff like this)
http://www.madisoundspeakerstore.com/resistors/

[TOLMACH]

I am hoping the above helps, if not.. ask questions

Your major problem now seems to be lack of installation experience and fear to break something.. well.. we all started with something

Before you proceed, please, also keep in mind, that once you start, there is no turning back... your car-audio illness will only progress ))

[DRAGONHEAD_NZ]

Hi there, this might be a long shot as I know this post is quite old, but what was the outcome of this? I have a situation where I have the same set up, and the two tweeters are working fine but the front speakers in the front doors are not working anymore, doesn't sound as simple as just swapping the speakers for new ones if tweeters and door speaker are connected in parallel. Would love to know how it worked out for you!