Band & Olufsen tweeter retrofit

Band & Olufsen tweeter retrofit

Author
Discussion

Carbon_monkey

Original Poster:

11 posts

92 months

Sunday 20th November 2016
quotequote all
I thought I'd give this a go and it ended up working out quite well so I thought I'd share it.
I always fancied the B&O tweeters in the car. Why? well I'm a geek so tweeters that rise up out of the dash are just the coolest thing smile
There were a few issues with this little project which meant it didn't happen until now. Mainly is sourcing the tweeters. They are stupidly expensive. add to that the new leather 'hockey sticks' that will be needed made it an expensive job.
Fortunately, it seems all dashboards have the hole cut in them ready for the B&O, so no worries there.


Once I got hold of them, I found they dont do the party trick all by themselves. The amplifier is supposed to do all the electrickery. Not wanting to have to change out all the hifi system, I had to find another solution. Anyway, it's too much moneys worth of kit to let it beat me!
I didn't expect it would be a non-starter, designing some electronics shouldn't be a problem for me if required.
So, the tweeters.




As you can see, there are 5 wire contacts on the unit. Guessing two must be for the tweeter driver, that leaves three for the motor function. Guessing there would be one up, one down and a common was too much to hope for. Cutting to the chase, they operate much like a DC servo. Two contacts are for the motor, one is a pulse encoder. Obviously to tell the amp when they have travelled to the top or bottom.


Hmm. Much chin scratching ensued.... headache

Choices were either build a bespoke controller board (possible, I can do that) or find a simpler way. I didn't fancy a switch to drive them up and down, a manual option just seems like half a job so it needed to be automated.
I decided that because the speed of the rise and fall was constant, I'd go for a simple actuated timer system. Basically, two multifunction timers. One triggers on power on, the other on power off. For those that know, leading edge trigger and trailing edge trigger. All you need is a 12v source that stays on from key insertion and stays on a little after shutdown. Then a trigger when the engine or hifi is on.
Aston kindly have both built in. smile
The principle is simple. The system is powered up when the key is partially inserted. When the engine cranks, the second input triggers the 'up' relay for a pre-programmed time. When the engine is shut down, the removal of that input triggers the 'down' relay. Simple!

A quick check of this logic with a power supply to prove it.

The function test revealed the time for rise and fall and the important fact that the motor runs off 5VDC. I used a little 12v to USB power circuit. Yup, 5 volts. 12v will damage them. Be warned.

https://www.youtube.com/watch?v=jfK1qTZBDyg
Yup, works great!

So, automation.
Multifunction timers are handy little things. The circuit ended up quite simple. and you'll see it at the end of this post. Connecting to the tweeter in a neat and tidy manner is also important. I got some single pin molex connectors that worked great. Being individual pins means that when you have to do work on your car, disconnecting them will be a effing nightmare.



Supergluing the connectors together makes it nice, neat and plug and play when removing them in the future. You could always buy a 5 pin molex socket, but I had these handy from a developer board in the 'drawer of many bits'.



Once that was all wired in, it was time to test my little franken-tweeter.
https://www.youtube.com/watch?v=2SnGWYLIJ7s
Coolski!

Now put it all back in the car. The hockey stick is held in by three posidrive screws.


Refit the instrument cowl, don't forget the little retaining strap held at the front.


Here's the all important bit, the schematic.
For the geeks that want to know the way it works, here it is;
The motor is connected to the common terminals of both relays. The N/C contacts are both connected to -ve (negative). This basically locks the motor in position with both sides of the motor connected to -ve.
Changing one relay over will put power on one side of the motor and it will run. Change over the other relay, and it will run the other way.
So we have an 'up' relay and a 'down' relay. both relays at rest means no motion.
Having one relay (up) actuated by a leading edge pulse (Ignition on) for the required rise time will lift the tweeter. When the trigger (Ignition off) is released, the second relay will run for the down cycle and then stop.
That's it!

Apart from the tweeters and hockey sticks, parts were less than £50.
Enjoy and sorry for the pic heavy post.

dbs2000

2,685 posts

192 months

Sunday 20th November 2016
quotequote all
bowcoolbeer

JohnG1

3,471 posts

205 months

Sunday 20th November 2016
quotequote all
Carbon_monkey said:
Apart from the tweeters and hockey sticks, parts were less than £50.
Enjoy and sorry for the pic heavy post.
Do you have a fancy carbon fibre surround for the instrument binnacle? Photos please!

wotnoburgers

149 posts

100 months

Sunday 20th November 2016
quotequote all
Brilliant!! Love it!! Well done!!

Do you fancy doing the same in my car?

bogie

16,381 posts

272 months

Sunday 20th November 2016
quotequote all
cool project smile

bogie

16,381 posts

272 months

Sunday 20th November 2016
quotequote all
JohnG1 said:
Carbon_monkey said:
Apart from the tweeters and hockey sticks, parts were less than £50.
Enjoy and sorry for the pic heavy post.
Do you have a fancy carbon fibre surround for the instrument binnacle? Photos please!
carbon bits are here...tempted myself smile

http://www.divinatech.com/category-s/111.htm

Carbon_monkey

Original Poster:

11 posts

92 months

Sunday 20th November 2016
quotequote all
JohnG1 said:
Do you have a fancy carbon fibre surround for the instrument binnacle? Photos please!
I know, it's really pretty. A bh to make, great in matt. smile

wotnoburgers said:
Brilliant!! Love it!! Well done!!

Do you fancy doing the same in my car?
Thanks for the kind words.
Well, I'd be glad to help. It would be easy enough for me to make up the controller and plugs ready to go. Find yourself the tweeters and hockey-sticks.
If your'e happy to replace the hardware and connect up three wires, you'd be done.

Ken Figenus

5,706 posts

117 months

Monday 21st November 2016
quotequote all
Great effort smile I guess you have swopped the tach based 'power off' (when the pulses stop up or down) for a 3-4" power on timer? Good solution smile

You just have to tell me how much these tweeters are though - as if mine fail I sincerely hope they fail 'up'!

8Tech

2,136 posts

198 months

Monday 21st November 2016
quotequote all
Looks great, really cool, great project.

But.......does it sound any better? Are the crossovers for the original tweeters suitable for the new ones?

wotnoburgers

149 posts

100 months

Monday 21st November 2016
quotequote all
Carbon_monkey said:
Thanks for the kind words.
Well, I'd be glad to help. It would be easy enough for me to make up the controller and plugs ready to go. Find yourself the tweeters and hockey-sticks.
If your'e happy to replace the hardware and connect up three wires, you'd be done.
Hi
Great!
I thinkl I can do that.
Could you please send me an email to
d_watson@btinternet.com where we can carry on the conversation
Many thanks
Dave

LordBretSinclair

4,288 posts

177 months

Tuesday 22nd November 2016
quotequote all
bogie said:
carbon bits are here...tempted myself smile

http://www.divinatech.com/category-s/111.htm
Has anyone bought any of their "add on" bits????? Good??? Bad??? etc

AMDBSVNick

6,993 posts

162 months

Tuesday 22nd November 2016
quotequote all
LordBretSinclair said:
bogie said:
carbon bits are here...tempted myself smile

http://www.divinatech.com/category-s/111.htm
Has anyone bought any of their "add on" bits????? Good??? Bad??? etc
Very interested in this too. BTW Tim your two tone trim looks brilliant biggrin

Carbon_monkey

Original Poster:

11 posts

92 months

Tuesday 22nd November 2016
quotequote all
Ken,
Astonbits have them, but you only have two kidney's smile You might be wise to keep your eyes out for a breakers or fleabay advert.
If yours fail, don't panic. They aren't that complicated inside. If its electronics that fail, this system will sort it. If its mechanical, it's possible to repair or 3D print the parts.

Gerry (8tech),
The sound isn't that much better, but the soundstage is lifted and more defined. The original crossovers are spot on for them. The frequency response is almost exactly the same. If you leave the original tweeters connected, you might want to attenuate the originals with a resistor. I normally use a variable resistor on a flying lead and sit and listen. Turning up and down until it's balanced, then measure the resistor and put a fixed one in.
I just wanted them because they look uber-cool!

Dave,
Incoming email shortly buddy.

Tim, Nick, et all,
If you guys are ever in Northants, you're welcome to come in for a cuppa and fondle our bits smile
I'm not punting stuff on here, just joining in with the usual banter until Haymarket sort us out a good deal. We want to play fair and all that. But what I can say is that we refuse to disappoint anyone.

JOCKOO

2 posts

193 months

Wednesday 20th January 2021
quotequote all
Carbon Monkey I love the job you did. It looks great!
I just bought a set of tweeters myself. Do you know what timer you used to do the installation?
I've seen some on ebay but I dont want to try to hook up the wrong thing.

ReformedPistonhead

965 posts

137 months

Thursday 21st January 2021
quotequote all
LordBretSinclair said:
bogie said:
carbon bits are here...tempted myself smile

http://www.divinatech.com/category-s/111.htm
Has anyone bought any of their "add on" bits????? Good??? Bad??? etc
I bought their bonnet vents. They are identical to the factory ones so far as I can see. No issues at all and nice guys to deal with.

<Edit>Great project above you have my respect! </Edit>

EVR

1,824 posts

60 months

Thursday 21st January 2021
quotequote all
What a huge project, from my point of view at least. Congrats on tackling it!

shinjuku

476 posts

81 months

Friday 22nd January 2021
quotequote all
This indeed is superb, and I would love to fit this in my car. Almost don't want to know the cost of the tweeters, though.

carmutt

16 posts

35 months

Tuesday 8th June 2021
quotequote all
Carbon_Monkey,

If u r still on this forum, i would appreciate connecting with you about this. Ddlehmann1@gmail.com is email. Thanks!

Dave


Carbon_monkey said:
I thought I'd give this a go and it ended up working out quite well so I thought I'd share it.
I always fancied the B&O tweeters in the car. Why? well I'm a geek so tweeters that rise up out of the dash are just the coolest thing smile
There were a few issues with this little project which meant it didn't happen until now. Mainly is sourcing the tweeters. They are stupidly expensive. add to that the new leather 'hockey sticks' that will be needed made it an expensive job.
Fortunately, it seems all dashboards have the hole cut in them ready for the B&O, so no worries there.


Once I got hold of them, I found they dont do the party trick all by themselves. The amplifier is supposed to do all the electrickery. Not wanting to have to change out all the hifi system, I had to find another solution. Anyway, it's too much moneys worth of kit to let it beat me!
I didn't expect it would be a non-starter, designing some electronics shouldn't be a problem for me if required.
So, the tweeters.




As you can see, there are 5 wire contacts on the unit. Guessing two must be for the tweeter driver, that leaves three for the motor function. Guessing there would be one up, one down and a common was too much to hope for. Cutting to the chase, they operate much like a DC servo. Two contacts are for the motor, one is a pulse encoder. Obviously to tell the amp when they have travelled to the top or bottom.


Hmm. Much chin scratching ensued.... headache

Choices were either build a bespoke controller board (possible, I can do that) or find a simpler way. I didn't fancy a switch to drive them up and down, a manual option just seems like half a job so it needed to be automated.
I decided that because the speed of the rise and fall was constant, I'd go for a simple actuated timer system. Basically, two multifunction timers. One triggers on power on, the other on power off. For those that know, leading edge trigger and trailing edge trigger. All you need is a 12v source that stays on from key insertion and stays on a little after shutdown. Then a trigger when the engine or hifi is on.
Aston kindly have both built in. smile
The principle is simple. The system is powered up when the key is partially inserted. When the engine cranks, the second input triggers the 'up' relay for a pre-programmed time. When the engine is shut down, the removal of that input triggers the 'down' relay. Simple!

A quick check of this logic with a power supply to prove it.

The function test revealed the time for rise and fall and the important fact that the motor runs off 5VDC. I used a little 12v to USB power circuit. Yup, 5 volts. 12v will damage them. Be warned.

https://www.youtube.com/watch?v=jfK1qTZBDyg
Yup, works great!

So, automation.
Multifunction timers are handy little things. The circuit ended up quite simple. and you'll see it at the end of this post. Connecting to the tweeter in a neat and tidy manner is also important. I got some single pin molex connectors that worked great. Being individual pins means that when you have to do work on your car, disconnecting them will be a effing nightmare.



Supergluing the connectors together makes it nice, neat and plug and play when removing them in the future. You could always buy a 5 pin molex socket, but I had these handy from a developer board in the 'drawer of many bits'.



Once that was all wired in, it was time to test my little franken-tweeter.
https://www.youtube.com/watch?v=2SnGWYLIJ7s
Coolski!

Now put it all back in the car. The hockey stick is held in by three posidrive screws.


Refit the instrument cowl, don't forget the little retaining strap held at the front.


Here's the all important bit, the schematic.
For the geeks that want to know the way it works, here it is;
The motor is connected to the common terminals of both relays. The N/C contacts are both connected to -ve (negative). This basically locks the motor in position with both sides of the motor connected to -ve.
Changing one relay over will put power on one side of the motor and it will run. Change over the other relay, and it will run the other way.
So we have an 'up' relay and a 'down' relay. both relays at rest means no motion.
Having one relay (up) actuated by a leading edge pulse (Ignition on) for the required rise time will lift the tweeter. When the trigger (Ignition off) is released, the second relay will run for the down cycle and then stop.
That's it!

Apart from the tweeters and hockey sticks, parts were less than £50.
Enjoy and sorry for the pic heavy post.

melhuishjames

161 posts

273 months

Friday 11th June 2021
quotequote all
Has anyone done this recently, curious to costs/if anyone is doing this aftermarket?

Thanks

JonnyCJ

1,309 posts

54 months

Friday 11th June 2021
quotequote all
Divinatech are the people to call. The owner is the OP. A pair of used tweeters will set you back about £800 on eBay, so factor in what Divinatech would charge for the circuit board and I reckon you could do it for £1k all in.