Crossover Components: How much does it REALLY matter?

[TheLaw117]

Hi,

I'm starting a project from Parts-Express called "Sophomores". You can find the project here: “Sophomores” writeup.... - Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com


I already have the 2 HiVi M4Ns and I will start ordering the rest of the parts very soon. There seems to be a lot of controversy on using x-parts in crossovers and how it affects sound etc.

For the resistors. Can I use a standard wire-wound? (Not "audio-grade"?) Something like this: 280-CR25-7.5-RC Xicon Wirewound Resistors - Through Hole


Just out of curiosity...What would happen if I used some 50W thick film resistors instead of the wirewounds?


Secondly. As far as capacitors go, how much better do poly-film capacitors sound in comparison to non-polarized electrolytics (NPEs). Films start to get reaaaally expensive...and I'm trying to be as economical as possible.

I appreciate any input. After doing some preliminary planning for the crossovers, the xovers wind up being almost 1/3 of the cost of the entire project...and that sure says something. So I'd like to make some cost cuts...

Thanks.

Yours truly

[PeteMcK]

re:'resistors. Can I use a standard wire-wound?' - as long as they are non-inductive; an alternative is to parallel several lower rated metal film resistors to get the value & power rating you want
re: poly-film capacitors in comparison to non-polarized electrolytics - electrolytics degrade over time (years), but big poly caps are expensive.... I use electrolytics for values over ~ 10uf

[Jim Leach]

Well... I had some old Advents a few years ago and these benefited greatly when I changed the crossover caps to Wondercaps (no longer made AFAIK)

As to resistors, I think non-inductive wire wound are a good choice for a crossover unless you have a way to monitor actual inductance of the assembly and can tailor the inductors accordingly. (generally you can't, so why risk adding some inductance from resistors?)

So, I guess the crossover will sound as good as you are willing to make it sound. You could always build them up and then change components later if cost is a huge concern for you now...

[TheLaw117]

Alright thanks everyone. This cost of this project just keeps on growing, and I'm trying to cut back a little bit. I'm no "audiophile" by any means, though I still want it to sound decent.

[TerryO]

Originally Posted by TheLaw117

Hi,

~~~~~~~~~~~~~~~~Snip~~~~~~~~~~~

There seems to be a lot of controversy on using x-parts in crossovers and how it affects sound etc.

For the resistors. Can I use a standard wire-wound? (Not "audio-grade"?) Something like this: 280-CR25-7.5-RC Xicon Wirewound Resistors - Through Hole


Just out of curiosity...What would happen if I used some 50W thick film resistors instead of the wirewounds?

As others have already pointed out, just make sure they're non-inductive and you'll probably be OK.

Secondly. As far as capacitors go, how much better do poly-film capacitors sound in comparison to non-polarized electrolytics (NPEs). Films start to get reaaaally expensive...and I'm trying to be as economical as possible.

We've actually done listening tests and most people couldn't tell which of two identical pairs of speakers had electrolytic caps and which had poly caps. Just a note, all the caps in both pairs had small value poly (fairly cheap) bi-pass caps in parallel. Let your budget be your guide.

I appreciate any input. After doing some preliminary planning for the crossovers, the xovers wind up being almost 1/3 of the cost of the entire project...and that sure says something. So I'd like to make some cost cuts...

Thanks.

You're welcome and good luck on your project, it should sound very nice!

Best Regards,
TerryO

[Ed LaFontaine]

Maybe Wolf will pay a visit...

[Pano]

1/3 of the project cost for the crossover is not out of line. Especially with the cost of copper these days. Almost any of the budget items at Parts Express will serve you well.

[davidsrsb]

Wirewound inductance in crossovers is not that important. Typical values between 2R and 22R are not going to shift much at 20KHz

The place where it matters is the ~0R2 emitter resistors in amplifier output stages, where the inductance causes stability problems

[TheLaw117]

Thanks again. I'll just get most of the items from Parts Express and the NPEs from Mouser.

Tomorrow, hopefully I will have everything sorted out and will make an order.

Thanks again.

[TheLaw117]

Just a quick question which I'm pretty sure I know the answer to...but I just want to be certain of. If the X-Over schematic calls for a 6.45uF capacitor, using 6x 1uF films + 1x 0.47uF film would give me 6.47uF. 6.47 is close enough to 6.45 is it not? Capacitors have a pretty big tolerance anyway so a capacitor labeled 6.45uF can be +/- 5-10%?