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Smallblock454 · 03-24-2018, 04:52 AM

Hello,

i have the 986 sound package (HAES speakers) with CD-R 23. My speakers were OK, but i wanted to improve the sound quality. And don't wanted to invest too much money.

First i analyzed the electronic circuit. Just a simple electrolytic cap with 4.7 uF. Hm, that would mean an incomplete -6 dB crossover only for the tweeter at around 8 Khz. Crap.

Next i've tested the cap capacity. One cap was within specs. The other way off. No wonder you can't hear them, when the crossover frequency is way above 8 Khz with a bad cap.

So i did some tests with different caps and coils. In the end i decided to use 6.3 uF MKP caps and 0,22 mH coils. To my ears that sounds much better, because the mid frequencies (higher voice frequency) are damped a bit. Still use the fader to reduce power to the dash speakers and give door speakers a little more power.

This is a comparison to the BOSE dash speakers. I preferred the HAES ones, because the are 10 cm in diameter while the BOSE ones are only 8 cm in diameter and didn't had enough lower mid power in this configuration. Tweeters seems to be the same:

This is the beta product (changed caps from 5.6 to 6.8 uF - see above). Didn't do a photo of the final product, but looks the same:

If you want to copy the idea, take care that the caps are enough on the inside, so you get the loudspeakers with the casing in the dash without problems.

03-24-2018, 04:52 AM	#1
Smallblock454 Registered User Join Date: Jun 2014 Location: LB, Germany Posts: 1,456	Dashboard sound system modification Hello, i have the 986 sound package (HAES speakers) with CD-R 23. My speakers were OK, but i wanted to improve the sound quality. And don't wanted to invest too much money. First i analyzed the electronic circuit. Just a simple electrolytic cap with 4.7 uF. Hm, that would mean an incomplete -6 dB crossover only for the tweeter at around 8 Khz. Crap. Next i've tested the cap capacity. One cap was within specs. The other way off. No wonder you can't hear them, when the crossover frequency is way above 8 Khz with a bad cap. So i did some tests with different caps and coils. In the end i decided to use 6.3 uF MKP caps and 0,22 mH coils. To my ears that sounds much better, because the mid frequencies (higher voice frequency) are damped a bit. Still use the fader to reduce power to the dash speakers and give door speakers a little more power. This is a comparison to the BOSE dash speakers. I preferred the HAES ones, because the are 10 cm in diameter while the BOSE ones are only 8 cm in diameter and didn't had enough lower mid power in this configuration. Tweeters seems to be the same: This is the beta product (changed caps from 5.6 to 6.8 uF - see above). Didn't do a photo of the final product, but looks the same: If you want to copy the idea, take care that the caps are enough on the inside, so you get the loudspeakers with the casing in the dash without problems. Last edited by Smallblock454; 03-24-2018 at 09:46 AM.