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Old 24th September 2012, 01:57 PM   #21
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Analog crossover can be better sounding than digital, if done right. The big, big advantage to the digital crossover is its flexibility. You can easily have different slopes and frequencies for the different sections. Fine control of phase (delay) is also possible.

To get the best out of your speakers, stock crossover points will not be the choice. They can work, but won't be ideal.
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Old 24th September 2012, 02:40 PM   #22
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If you are going fully active, the cap as tvrgeek suggested is for protection not for influencing the slope of the crossover you actually want it to not be having any effect for probably at least an octave below the crossover frequency otherwise it may mess up the slope of your active crossover. I'd be guessing a cap of at least 50uF but I could be way off (just simmed that with 6.5 ohms and it is down 3db at about 500Hz.

I'm not sure about the question about putting the cap in the +ve or -ve leg. The norm in passive crossovers is to put it in the positive. I would think that it is better to block the DC before it gets to the driver than after the voice coil though when used as a protection device.

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Old 24th September 2012, 04:51 PM   #23
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Thank you! I'm learning a lot here!
All right. I understand that the frequency where the cap cut's off has nothing to do with the minimal cross-over frequency of the driver. The cap has to cross at least an octave below the active cross-over frequency. (so for a 4500hz active cross-over for the tweeter, I could take any cap that starts cutting off at 2250hz? But why a cap of 50F that is 3db down at 500hz? Because the slope is more steep then the slope of a crossover at e.g. 2250hz? Or because 500hz is safe area that doens't influences the active cross-over slope? Just asking )

According to the spec sheet, the DC impedance of the midrange electrovoice drivers is 4 ohms (it' the DC impedance that matters, right?). I'd like to cross it at about 500hz. So, If I understand right, I'll have to look for a cap that starts cutting of at least an octave below that frequency. Let's say: 250Hz.
Calculated: 4ohms impedance, Cross-over at 250hz --> value cap: about 160F
Or should I get a lower frequency cross-over point for the cap to not influence the active cross-over point?

One last question: do I need a cap for the woofer too, or can this 'coil' handle some DC of the amp? Or just to avoid phase problems?

PS: As I spent already a lot of money for the speakers, I think I'll go analog for the active cross-over.
Found two of them for a reasonable price (about 80€) in my region. Costed about 300€ new.

- Inkel DIV 23 Cross-over (3-way stereo cross-over, costed about 300€ new. In good condition. XLR inputs. But you have to choose between about 10 predefined cross-over frequencies for each active cross-over)
- Unika PX23S cross-over (made in china, more advanced then the Inkel DIV 23 cross-over, jack 6.3mm inputs, 4-way cross-over (there is also a subwoofer cross-over))
PX-23S - Products, ????(?)??
http://www.hdaudio.com.tw/file/unika/px/px-23s.pdf

any thoughts? Are they worth its money?

Last edited by vandevoordekoen; 24th September 2012 at 05:13 PM.
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Old 24th September 2012, 07:25 PM   #24
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There are two approaches to the protection cap in an active crossover. The first is to as wintermute says, make its influence negligible by moving it's cut-off out of the passband. This calls for a big cap though. The second is to use its cut-off as part of the crossover. This doesn't need the cap to be as big but you do suffer from a loss of damping around the crossover frequency, which is one of the benefits of going active in the first place.

It is your choice which route you take. I bought some 40uF motor run caps to use as protection caps, but they are almost the size of coke cans and I never bothered fitting them as my amps are all relay controlled/protected.
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Old 24th September 2012, 07:54 PM   #25
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Coke cans??? Ok... :s

As I would not like to influence the active x-over point, I'd take the first approach. I'll think about it and ask prices at the local electro-shop.

Another (completely different) question: I'm not very happy with the horns on the ev-1823M drivers. The horns are bolt-on horns that are fitted to the drivers with a bolt-on/screw-on adapter https://reconingspeakers.com/product...nscrew-driver/). Not very pro. I don't find any specs of the horns (bought used for 15$), and the dispersion isn't great.

Someone had an idea for a good but acceptably priced horn that fits the midrange screw-on driver?
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Old 25th September 2012, 03:44 AM   #26
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good quality polyprop caps in big values (that aren't quite as big as coke cans) and won't break the bank, can be had at partsconnexion AXON True Cap Metallized Polypropylene Capacitors

I used Axons in my passive crossover and have no complaints at all. The biggest I have are 51uF which is still completely manageable Pic of one of my crossovers attached The coils are much bigger than the 51uF cap (it measures 53mm long with diameter ~38mm)

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Last edited by wintermute; 25th September 2012 at 03:45 AM. Reason: add won't break the bank comment.
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Old 25th September 2012, 03:11 PM   #27
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Ok, thank you!
So I'd need 2 x 50F caps for the tweeters, what do you suggest for the mids?
ev1823M have a DC impedance of 4 ohm and I'd like to do an active cross at about 500hz.
(I guess it's better just to ask, because I can't simulate those X-over slopes and define good values )

Any thoughts about a good midrange horn?
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Old 25th September 2012, 03:29 PM   #28
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If you are going to spend time and money on crossovers, you owe it to yourself to measure, measure, measure. Your speakers look very nice, they deserve a good crossover.
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Old 25th September 2012, 03:36 PM   #29
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But the caps aren't for cross-over, just for DC protection. Crossing over will be active, and then I'll start measuring with mic and program. I just need te know what type of cap I can use to protect the drivers but without influencing the cross-over slope ^^
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Old 25th September 2012, 04:20 PM   #30
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Big ones.
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