Capacitor recomendations for a cross over

[ricardo]

This was decades ago so maybe modern low Z electrolytic caps are better

If you are a major Speaker maker, you get into bed with a Capacitor maker and he will make you some really good Bipolar Electrolytics with low ESR & other good stuff.

Never met a cap rep i would bed, but at Peavey we were a large capacitor customer.

Ha ha!  You need to be on good terms with the Tech VP and Production VP of the Capacitor maker.  Definitely not just the cap rep.    ;D

But you are right about active xovers.  I think the frequency below which its sensible to be active is about 1kHz.  Today DSP allows much more if you are going active.  Pity most makers hardly do anything that can't be easily done with analogue electronics.

 

[JohnRoberts]

Ha ha!  You need to be on good terms with the Tech VP and Production VP of the Capacitor maker.  Definitely not just the cap rep.    ;D

But you are right about active xovers.  I think the frequency below which its sensible to be active is about 1kHz.  Today DSP allows much more if you are going active.  Pity most makers hardly do anything that can't be easily done with analogue electronics.

The real cap engineers rarely visited MS, and my typical exchanges with them were on urgent phone calls dealing with some significant cap problem that had a line shut down. One small cap distributer actually tried to hire me to be his cap engineer, after I explained to him what was wrong with his caps. (I declined).

There is some pretty serious DSP crossover work being done by guys like David Gunness (Fulcrum Acoustic). Generally dealing with big dog PA speakers, throat distortion in horns  etc.

JR 

 

[usekgb]

This was decades ago so maybe modern low Z electrolytic caps are better

If you are a major Speaker maker, you get into bed with a Capacitor maker and he will make you some really good Bipolar Electrolytics with low ESR & other good stuff.

Never met a cap rep i would bed, but at Peavey we were a large capacitor customer.

They don't sound the same as good films but can often be preferred in DBLTs.

The ESR/ESL no doubt factors into passive crossover design and can shift actual crossover frequency.

Right until the end of the last Millenium, NONE of the Bipolars available to DIY were anyway near these specials.  Dunno about today.

Modern electrolytic caps do deliver lower ESR/ESL driven by switching supply use. 

If you can afford the size & cost, use good films.

I've told this story too often, but i once approved an engineering change to use a film cap in a crossover, because the speaker engineer's actual boss refused to sign it. I don't recall the exact cost increase but it was not much. 

If the values force you to use Bipolars, buy the physically largest you can find for the same value & voltage.  This isn't a guarantee of good performance but physically smaller Bipolars are guaranteed to have poorer ESR bla bla and sound worse.

It's a looo.oong time since I bodged up Bipolars with 2 Polars but if you do, use MUCH higher voltage rating, good ESR and CHECK THE FINAL VALUE.

I would never bother bypassing Bipolars with films.  I'd just use a better Bipolar.

This is why I prefer active crossovers and bi/tri-amping. Capacitors are doing pretty heavy lifting in passive crossovers.

JR

I prefer the active stuff these days as well.  You can achieve better time alignment, steeper slopes, less phase shift, and more intricate frequency correction.  Slap a small amp on each driver, and you can have a much more accurate loudspeaker system than you could using passive networks.

 

[gswan]

I've always used film caps, usually 100V rated ones.
Buy a big bag of 2.2 or 3.3uF and parallel them up to get the required capacitance.
For the very large ones, use 4.7 or 6.8uF ones in parallel.

 

[pucho812]

I've always used film caps, usually 100V rated ones.
Buy a big bag of 2.2 or 3.3uF and parallel them up to get the required capacitance.
For the very large ones, use 4.7 or 6.8uF ones in parallel.

I would but the crossovers are in a box and space is premium.  I ordered the daytons and one solen as the solen had the right value the daytons didn't have. I should be good

 

[CJ]

Solen Fast Caps are supposed to be good for crossovers,

can't vouch for that, never used them,

a Peavey amp that came in had a crossover selection switch which varied the freq,

could be interesting,

 

[Moby]

Looking for the following capacitors to recap a pair of crossovers in some old urei's.

8uF
12uF
16uF
20uF
32uF

minimum 50Vdc on all of those. 

What do people like in capacitors these days? Anyone?

Hey, I used Mundorf's and they are good but best results I had with good old Philips 1u/100v 344 22105 polycarbonate in parallel. If u need a help with them let me know I have a great local source with good price

 

[pucho812]

I went with the daytons and one solen as they had all the values I needed except for the 32uF which got a bump to 33uF big change in the speakers as they are now behaving  more evenly. They sound great. but At least I get even frequency responce between both monitors.  As feared space was an issue as the crossover is in a box inside the cabinet so I had to not close the box all the way. It has not effected performance. Now to blast my neighbors away as  these 815's are big.  8)