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Old 12-01-2018, 02:17 PM   #1
JGood
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What are the specs of the OEM premium sound tweeter capcitors?

I am in need of capacitors for the OEM tweeters used in the premium sound system (typically mounted on the 5-1/4" woofer). Can anyone tell me either the specs of the factory capacitors, or suggest a suitable replacement?


I had installed a set of OEM tweeters many years ago, without the matching 5-1/4" woofers, and just noticed both are blown (probably for some time now). I just installed another set I had laying around, but realized the same thing will likely happen without a high pass filter. I know I should probably just get the OEM woofers with the capacitors mounted on, but until I stumble upon a reasonably priced set, I just want to throw a capacitor in there.
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Old 12-01-2018, 08:28 PM   #2
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Old 12-02-2018, 12:43 PM   #3
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I found an old set of shitty home theater speakers in my garage, and took them apart. They had a small high pass filter circuit board with a 1.5uf capacitor and an inducer. I figured, why not? Yanked them off and wired them up to the e30 tweeters. It actually sounds pretty good, although I don't have the stock woofers/capacitors to compare it to. 1.5uf at 8 ohms is like 12000 hz, and if stock is 3.3uf at 8 ohms, that's ~6000 hz. Oh well, this was free and easy.

Anyone know how the inducer impacts the speaker and/or amp load? I don't know anything about that, and it's not an easy subject to research without being overwhelmed.
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Old 12-02-2018, 07:58 PM   #4
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IF you have just the CAP wired in series with the tweeter it makes it a first order electrical high pass crossover. If you then add a coil in parallel with the tweeter you end up with a 2nd order electrical high pass crossover. And so on.

OEM config is cap is used in series with the tweeter to block the lower freq, and the coil is used only with the midrange to block the higher frequencies from it.

input --||----tweeter (this is 1st order highpass)

input -^^^^----woofer (this is 1st order lowpass with coil in series)


You can go really deep into crossover design and pros and cons of each, but the basics of it is 6db/octave 1st order is fine if you cross is high enough to protect the tweeter. Every tweeter and midrange and woofer is different, some can play higher or lower than others.

Also, impedance of the tweeter or midrange or woofer needs to be accounted for when you design or wire a cap. Same value 3uf CAP for example will not result in the same crossover frequency for 4ohm and 8ohm driver.

Let me know if this helps
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Old 12-02-2018, 11:37 PM   #5
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Quote:
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If you then add a coil in parallel with the tweeter you end up with a 2nd order electrical high pass crossover. And so on.
Thanks Jean. What I was asking is basically what does this mean? Is it just the dB/octave? 6 vs 12? So by adding in the coil with the 1.5uf cap, I not only increased the cutoff frequency compared to OEM, but I increased the drop off curve as well?
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Old 12-03-2018, 06:45 AM   #6
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Correct , using a coil and cap vs a single cap Increases the cut off slope (from 6db to 12)at the minimum. To answer if the crossover point was changed you’d need to know the exact value of both components, caps uF and inductors mH
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Old 12-03-2018, 06:47 AM   #7
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Quote:
Originally Posted by Jean View Post
Correct , using a coil and cap vs a single cap Increases the cut off slope (from 6db to 12)at the minimum. To answer if the crossover point was changed youíd need to know the exact value of both components, caps uF and inductors mH

I suppose there isnít a way to determine that inductors mH if itís not labeled?
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Old 12-03-2018, 07:23 AM   #8
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It can be measured with LCR meter I wouldn’t worry about it, if it sounds good to you and tweeter isn’t crackling you probably won’t blow it like you did with one running full range sound to it .
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Old 12-05-2018, 05:53 PM   #9
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I ended up picking up a full set of premium speakers locally from a friends old parts car, front and rear, basically free.

I installed the fronts tonight, in place of my prior cobbled setup. At first, they seemed to lack in bass compared to what I had, and I was a bit upset. But I let them hammer away while I reinstalled the trim pieces, and played with the crossover and equalizer on the head unit. Eventually settled on a flat equalizer and 65hz high pass on the head unit, and it seemed like the speakers got better as time went on. Now I'm extremely impressed with them, the sound quality is significantly better than the old ones. I don't think there was a huge difference in bass, but the overall quality is significantly better.

I have a pair of 6.5" Pioneer ts-a1780r speakers on the back deck, and they actually sound great as well, but they overpower the front when I set the fader to zero, both in bass (which isn't a problem) and highs (which is a problem). It's easy to fade to the front to balance it, but I lose a ton of bass. I'd love to just filter out the highs and be able to keep it centered (basically, more bass), so I'm thinking about ordering some low pass filters from parts express, maybe 800hz? And just use the rears as bass/low mids?
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Old 12-06-2018, 04:33 AM   #10
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Nice. Yes there are two easy ways you can keep the soundstage or sound more upfront vs back . One cheap and easy way is to simply disconnect the rear tweeters , see how easily you can do that on the pioneers. That’s a preference with many that get more into hifi , concentrate more on a solid front stage and use rears as “fill” to not over power the front .or even no rear fill at all. I personally only run mids in the back with no tweeters and it keeps the sound more upfront.

Another option is add a low pass filter, 800hz is probably too low. I would shoot for 3-5khz myself and see how you like that first . Also crossover parts for higher frequency will cost you less than for lower (inductors and good non electrolytic caps get expensive with bigger values )

For the low pass of 3khz you can simply add an inductor in series with rear speakers . Find one around 0.4-2.0 mH and see how you like it. Putting a non polorized cap in parallel with the rear speakers can also help cut down on high frequencies.
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Old 12-06-2018, 05:59 AM   #11
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I remembered that my Pioneer head unit has an option to switch the rear speakers to subwoofer mode, and then I could operate the rear speakers based on the subwoofer controls (built in low-pass crossover and level control) So I did that, and set it to the highest crossover (200hz). It definitely worked to get rid of mids/highs and sound much more balanced, but the speakers couldn't handle the lows. I have a high-pass on the head unit that had previously prevented them from seeing anything below 60 or 80hz. So that got me thinking, why not put a pair of 6-1/2" dedicated woofers back there?

I have a few pairs of Dayton B652's (they use a 6-1/2" driver). I'm going to pull one out and install it, see how it does. That's a $6 driver. If it's good enough, I'll order a pair. If I think I want more, they have these for $25/each:

https://www.parts-express.com/dayton...eaker--295-309

I bet they'd rock, and probably wouldn't need an external high pass filter at all, I'm sure they could handle any lows my head unit puts out? I could just run them with the head unit crossover set to 200hz (the max). Basically just small subwoofers in the back, mids/highs up front.

It might be better to run them up to a higher frequency, but the max is 200. And if I change the rear speaker mode back to 'speakers', then the high pass filter would apply, and limit them to 60-80hz, which would limit bass. And if I drop the low pass, then the fronts start breaking up down low.
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