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My "value" 991 tweeter upgrade

Old 01-28-2019, 06:36 PM
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Default My "value" 991 tweeter upgrade

I haven't been very impressed with the Sound Package Plus system in my 2015 C2, and I've been doing research on what I want to replace it with. There are lots of threads about the tweeter being the Achilles heel of the SPP and Bose systems, so I thought I'd try to find a better tweeter that I could swap directly into the standard tweeter grills on the dash. And, I found one.

Dayton Audio ND20FB-4

This Dayton Audio tweeter has a diameter of 35.7 mm from edge to edge at the top of the casing. That's almost exactly the same size as the stock SPP tweeter.

The specs are pretty good for a $15 tweeter as well. It's 4 ohms. The stock tweeter has a 4.7uF, 50V cap in series with the speaker. I went with a 10uF, 160V for the Dayton Audio tweeter.

You can see how to remove the dash trim/vents, remove the grills, and unhook the speakers in other threads, so I won't cover that ground here. Once I got the grills off, I took the front clip off all the way & didn't reinstall it - they went straight into the proverbial ****et bucket. That way, next time, you don't have to remove the dash parts to get the grill off. It doesn't rattle in my car at all, and if does, a little felt tape around the tab should solve it.

So after the grills & original tweeters were out, I decided to burn the boats, cut off the connectors, and replace them with a different connector. Soldering in a Porsche is fun! You could also crimp, but hey, we didn't get to ripping apart our Porsche dash without a bit of courage. I went blue and green shrink wrap because I'm the sort of person that bucks tradition. Also, it was the stuff I had in a garage toolbox close at hand.

I also took the time to solder connector ends onto the standard Porsche connectors, so I can easily put the stock tweeters back in (I won't, but I could).

After that, I started playing around with installation options, trying to make everything fit well. The tweeter is the easy part. It's a bit tight, but it fits directly into the same tweeter hole as the stock one. It's a bit shorter than the stock too, so if you want to use the stock mounting bracket, you'll need some weather stripping or something to fill the gap.

Now we just have to wire it up, right! And here's where I took some time. First, I bought some 8.2uF Dayton Audio polypropolene caps when I ordered the speaker. They're huge. I don't care how you mount them, or where, they won't go into the hole you have to work with.
Failure 1 (too deep for hole, didn't pass mock up):

Failure 2 (too stiff & long & wide for the wire routing channel):

I thought the second one would work. I couldn't make it fit even after shrinking the wire bits down. I looked at the stock tweeter again, and decided I'd just go with a cheap electrolytic cap like what Porsche used. It's small, which is basically what it has going for it.
4.7uF, 50V cap on the stock tweeter:

I went to my local Fry's and bought two different style caps; an inline one, and one with the legs on the same side. Both are 10uF, one rated at 50V, one with 160V. I ended up going with the 160V ones, just because of where I chose to mount them.
Check out the size difference:

I had two mounting options. One was inline with the wiring, and the other, I could mount under the weather stripping & bracket to hold it in place. I went with the weather stripping/bracket option. This seemed the most secure, and let me keep the leads for the connector short.


How do they sound? Much better than the stock ones, IMO (but of course I'd say that, I did the work, and none of these audio threads have data in them). I think it's a huge improvement. I can listen to The Crystal Method's Busy Child and not cringe! You can hear detail in the highs, and the clarity is much, much better. It cost me $30 for the tweeters, $2 for the caps that I used, some stuff I had around the house from other projects, and an afternoon. This should also work directly in the 981 Boxster/Cayman with SPP or Bose as well. In fact, I think the 987/997 cars used the same tweeters too, but I'm not 100% sure on that one.

I had big plans to use REW and my miniDSP Umik-1 microphone to benchmark the performance of the stock tweeter vs the Dayton Audio one, but it's not super easy to do that. Biggest PITA is that because of the radio/amp setup, in order to benchmark one speaker at a time, you have to unplug some door speakers. And I really didn't feel like taking my door apart. Maybe I'll do this if there's interest, and I decide to upgrade some other speakers or my amp.

Have fun!

Edit: forgot to add the speaker wiring diagram, in case people need it. I can confirm that wire coloring on the tweeters, at least, is correct.

edit 2: if you open in a new tab, you get a bigger image. right click -> open in new tab. Odd.

Last edited by flgfish; 01-28-2019 at 07:02 PM. Reason: I forgot the speaker wiring diagram!
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Old 01-29-2019, 07:51 AM
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Super job!
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Old 01-29-2019, 01:37 PM
12v Nick
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Nice job! Always love to see a well-executed DIY like this.

Also, it's probably for the best that you didn't RTA the before and after to see a performance benchmark. With this type of upgrade, the improvements are rarely seen in data points and it takes more of an audible experience to gauge the difference.
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