quality of crossover parts for budget speaker

[morbo]

Can anyone tell me if the inductors, resistors, and capacitors on this pages 103-104 of this catalog:

http://www.loudspeakers.ca/Qmedia/QCAT2003.pdf

are of sufficient quality for use in a budget (ie total cost per pair ~ $250USD) speakers? I am crossing in the 600hz neighbourhood, the woofer is a RS225, 'tweeter' is a Tang Band 871. The electronics used will be mass market receiver (Panasonic XR50 digital) fed optically by various cheap sources (phillips DVD player, Xbox, etc.) My other alternative is Solen, but everything there seems to be 2x the price or more (probably for good reason).

[ThomasW]

The resistors are generic so can't say. The poly caps are average. They have no air core inductors, and air core is what you should be using.

The fact that they show tables for building crossovers is troublesome, since those never sound good.

[morbo]

thanks Thomas, I appreciate the advice. Good to know that air core is what I need. Aren't these air core though:

Plastic bobbin air core inductors
Part No. Value Power AWG DCR Price ea.
MCL01 0.1 mH 180 W 20 0.24 ohm $2.53
MCL02 0.2 mH 180 W 20 0.32 ohm $2.80
MCL03 0.3 mH 180 W 20 0.39 ohm $3.06
MCL04 0.4 mH 180 W 20 0.44 ohm $3.36
MCL05 0.5 mH 180 W 20 0.50 ohm $3.65
MCL06 0.6 mH 180 W 20 0.53 ohm $3.95
MCL07 0.7 mH 180 W 20 0.61 ohm $4.48
MCL08 0.8 mH 180 W 20 0.64 ohm $4.54
MCL09 0.9 mH 180 W 20 0.68 ohm $4.84
MCL1 1.0 mH 180 W 20 0.73 ohm $5.14
MCL105 1.5 mH 180 W 20 0.90 ohm $5.44
MCL2 2.0 mH 180 W 20 1.08 ohm $5.75

Or is there a difference that I'm not spotting? I just called another local electronics store to see if they have air core inductors in the 2.0mH range, and they told me they have one in stock. I don't really understand why they would only have one, but now I'm wondering if this would even be a 'proper' air core or not... is there another parameter or descriptor that can tip me off to whether the inductor is suitable?

I agree about the crossover tables, though I think Parts Express and Madisound both sell 'generic' crossovers and have similar tables IIRC. That said, this place definately isn't aiming for 'hi-fi'. They are all about prosound products, it took a lot of prodding to even get them to list Xmax for their woofers... When I first went there several years ago, the salesman told me it was 'irrelevant'

[ThomasW]

Oops you're right, I missed that column. The wire is a little small, but they'll be better than the ferrite cores.

In the best case you want the wire to be 14 or 15 gauge, but those are expensive in air core.

I think that particular saleman is probably irrelevant :wink:

[morbo]

I tend to agree Thomas

[morbo]

Another question about the guague of these air core inductors - I have been modelling them in LSPCad, and it seems that going from an inductor with say a .5 DCR to a 1 DCR produces a relatively minor difference in the FR plot... I am just wondering if this is the only disadvantage of using the higher guage (18 or 20) inductors? Or are there other effects that don't show up on the plot? I can't tell if efficiency is affected because LSPCad for some reason is not giving me an 'absolute' predicted SPL curve (ie the Y axis is marked with -5, -10, -15 rather then 80, 85, 90).

[ThomasW]

It's the DCR and power handling capability. The smaller wire tends to saturate more quickly than the bigger stuff.