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Is this Capacitor the right one ?
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sicoroots View Drop Down
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    Posted: 19 March 2019 at 11:23pm
Hello everyone,

I'm about to buy some capacitors to be added into a few mid-top custom boxes I have built. ( on the compression driver wiring path ).

I've been discussing this topic sometime ago but since then I have changed a few thing in the set up so before buying these caps I'd like an opinion from the community...

I have the signal going into the mid top speakers split with Behringer DCX2496, there is no crossover inside the speaker boxes.

Xover point for the Compression Drivers is at 1.5 Khz. Based on my calculations I need a capacitor of 26.5 uF...I was going to go with a 250V capacitor like this one :


Am I looking right ?

Also...pardon if it's a dumb question but are the wires on the capacitor polarized ? from the picture on the webshop I can't see any + or - sign on the capacitor body...

thanks !
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Conanski View Drop Down
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Yes that is the right capacitor and no it is not polarized but.... you need more than a single cap to protect a compression driver at 1.5khz you need a 3rd order crossover minimum and preferably a 4th order.

Why aren't you biamping these boxes using the DCX? You don't need a very big amp to power CDs.. something capable of 100-150w is plenty so even a cheap paw shop find will do it.

To do this with a passive crossover you need a real 2 way crossover like the Eminence pxb-1k6 and then you also need to build an L-pad to bring the output level of the CD down to match the mid driver. All tolled you might spend $100 on these parts for a pair of boxes.
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I think he is bi-amping the mid-top but wants a cap for added protection. He started a similar thread in September, so not really sure why he's asking the same question.
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Originally posted by Conanski Conanski wrote:

Yes that is the right capacitor and no it is not polarized but.... you need more than a single cap to protect a compression driver at 1.5khz you need a 3rd order crossover minimum and preferably a 4th order.

Why aren't you biamping these boxes using the DCX? You don't need a very big amp to power CDs.. something capable of 100-150w is plenty so even a cheap paw shop find will do it.

To do this with a passive crossover you need a real 2 way crossover like the Eminence pxb-1k6 and then you also need to build an L-pad to bring the output level of the CD down to match the mid driver. All tolled you might spend $100 on these parts for a pair of boxes.

Hi Conaski, thanks fro the reply, yes I am bi amping the mid top boxes. I have a 2 CH amp dedicated to them, so one channel power the mids in parallel at 4 OHM and same thing for the CD horns..

so what I'm really doing here is to add an additional protection to the CD in case of power surges and unexpected signals peaks that may damage them.
I did discussed this on an earlier thread but since then I was not able to get to work on them and I have slightly changed the xover settings. I have some time now to add the caps to the CD and just wanted to make sure I was buying the right one.

Based on the discussion thread stated back in September ,as another user poited out, I thought I was going to need only one capacitor per each CD box ( 4th order )...I guess that when you mentioned in your message is if I needed to make an internal xover for the mid/highs where you need more than one capacitor.
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sicoroots View Drop Down
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Originally posted by markie markie wrote:

I think he is bi-amping the mid-top but wants a cap for added protection. He started a similar thread in September, so not really sure why he's asking the same question.


I'm asking again because I didn't get to work on it back then and changed some of the settings on my soundsystem so I just wanted to make sure I was going to buy the right capacitor at this time...
the thread back then was also discussing other topics...I think I got the situation understood I just want to avoid buying the wrong items
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Conanski View Drop Down
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Points: 2537 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Conanski Quote  Post ReplyReply Direct Link To This Post Posted: 20 March 2019 at 9:07pm
After refreshing my memory with your old thread it seems you have all concerns covered so ignore what I stated above, the cap you selected will do just fine as protection.

Edited by Conanski - 20 March 2019 at 9:09pm
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studio45 View Drop Down
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If you're really worried about signal peaks though, you want a Polyfuse or protective lightbulb in there. The capacitor will protect against low frequencies/DC accidentally getting to the CD, but won't really do anything about high power peaks (apart from eventually blowing up if the high power persists). 

A 20 watt, 12v lightbulb in series is a good start. If you position it in a place where you can see it illuminate, you will have visual feedback to let you know you're about to blow your tweeters ;) If it illuminates before you feel like you've got to maximum safe output, go up in wattage.

Alternatively, a 2 amp Polyfuse would do a similar job. However, you won't get any warning - they just open up, so your tops will cut out, and you might think you've blown them. But, they last longer than a bulb and are much more rugged.
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Conanski View Drop Down
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Points: 2537 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Conanski Quote  Post ReplyReply Direct Link To This Post Posted: 21 March 2019 at 3:42pm
Originally posted by studio45 studio45 wrote:

If you're really worried about signal peaks though, you want a Polyfuse or protective lightbulb in there.
The processor being used has limiters so that shouldn't be a problem. I have used lightbulbs in a passive crossover, they work well enough but when driven hard alter the tonal character of the signal so I'm not a hugh fan, if it's all ya got for protection by all means but when there is a DSP limiter available I don't see the need.
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