Center dash speaker mod

[Gearbox]

Just wanted to share a neat easy project I had just finished up. Went to find a replacement speaker for the center dash on my 71S and found that no one really made a high quality 4"x8" speaker that would fit. During my search, I came across a set of two stage 3.5" Blaupunkts on e-bay for 10 bucks, new. Since they were only going to be driven by my stock OEM mono Blaupunkt Frankfurt, I took a shot. Built the housing out of 4"x8.25" hardboard, mounted the speakers and popped them in. I have to admit, sound quality was 100 times improved. All in all, it took about 1/2 an hour and totalled 20 bucks. Not bad for a rainy day project. Merry Christmas Allan

[Zithlord]

Thats great, I will copy your job if I can find the right speakers.


John

[rvdv]

Alan, if you want them to sound even better get some duxseal or dumdum and seal the speakers around the edges to the baffle board that you made. You will notice a big improvment in the bass response, those 3.5" Blaupunkts need all the help you can give them. What is happening is that the air that is coming from the back of the speaker is leaking through the baffle board around the edge of the speakers. This is 180 degrees out of phase with the air movement from the front of the speaker, when these 2 waves interfere or collide with each other there will be a decrease in the amplitude of the original waveform, this is called destructive wave interference which results in less bass to your ears.

Rudy

[gulf908]

Allan,

This is what I did with my speakers as I was reluctant to make holes in the virgin waffle door panels.
I have two Alpine 4" speakers connected to a Blaupunkt Bahama setup - I needed an MP3 player in the unit !
The sound hasn't been all that good but I usually listen to the motor instead
Thanks for the extra info Rudy - I will get my mechanical Einstein to follow this tip through soon.
Every little bit helps !

Cheers,
Dennis.

[Gearbox]

Hey Dennis, I'm with you, in all my "toy" cars, I leave the OEM radio for originality. I enjoy the sound of the engine much more. The flat six song at speed beats anything on the radio IMHO. But sealing the speakers is a good idea, plus it gives me more things to do on the Porsche, and that makes me happy . Merry Christmas Allan

[JimR]

Great job! Maybe another winter project for me.

[daepp]

I have installed a similar setup. However, after doing so I questioned why I used two speakers. The little guys have little bass response, and there is no provision for stereo on my Blaupunkt Frankfurt for 72. That being the case, wouldn;t the sound quality improve with one large 2-way speaker?

[denson]

I did this about one year ago. Did not find a difference in sound when using the stock Blaupunkt radio. So, I pulled them out bought the correct size single speaker from a guy on ebay. Took his speaker out of the mount he provided which has a black screening cloth over the speaker. I still had the original speaker, mount and tan cloth that covers the speaker and which was installed by the factory. I then installed the replacement single speaker into the factory mounting board and re-used the factory tan screening cover.

I did this to keep it 100% original and because I stayed with the factory Blaupunkt radio. I suppose if you change the radio that the dual speaker set up may sound better.

BTW, anyone aware of the proper installation of the mp3 player?

John

[kilodawg]

Maybe you guys can help. I just acquired a Blaupunkt Frankfurt and I have an early '73. The radio is a stereo radio. So the question I have is should there be two speakers or just one in the dash? What would have been correct for an early '73.

I'm sticking with the Frankfurt regardless but I'm wondering if I should be going with the 2-speaker dash mod or something else.

Thanks!

[Gearbox]

The only Stereo radios as OEM for the 73 model year was the Blaupunkt Bamberg or the Becker Mexico. The Frankfurt was also offered but as a Mono AM/FM/LW/SW. The center speaker on all 911's was a single 4x8 speaker. I'm not quite sure where the stereo speakers were located from the factory, if any. But there are two 6" speaker cut outs built into the door frames. The sound from the twin speakers is much improved and would be the only way to make the radio you have work while keeping the OEM look of the car. Good luck, it's an easy project, Allan