redoing a crossover

[cowanrg]

i'm starting the project of redoing the crossovers in my main speakers. i like the sound of them in general, but there are just a few things that i don't like about them. they are BG radia 520i's. after opening the back panel and looking at the crossover, i can see that the crossovers are relatively complex, and full of the cheapest parts available. the high section has 2 bipolar electrolytics (so does the low section), so im sure those are doing wonders for the sound.

could i simply change out the cheap caps to auricaps or something similar and expect an improvement? basically im hearing a bit of ringing or smearing in the upper frequencies (cymbols, screeching guitars, etc), and the midrange isn't quite as lush as i would hope. could this be poor crossover components?

[sreten]

Hi,

The effect of the components depends on their circuit position.

http://www.stereophile.com/floorloudspeakers/1204bg/

It may be worth experimenting with some line level EQ ........

/sreten.

[auplater]

Since this uses the 50" version of the RD series planar, I'd suspect the notch filter section may be the problem. Should be a capacitor/coil/resistor parallel combo to lower the 5 khz or so frame resonance that occurs in these drivers. Here's a pic of the notch section in my homebrew RD 75 dipoles...

it's in the lower right corner, and I used all poly caps and open core inductors.

If it has an electrolytic and an iron core inductor, I'd definitely upgrade.

John L.

[cowanrg]

Originally posted by auplater
Since this uses the 50" version of the RD series planar, I'd suspect the notch filter section may be the problem. Should be a capacitor/coil/resistor parallel combo to lower the 5 khz or so frame resonance that occurs in these drivers. Here's a pic of the notch section in my homebrew RD 75 dipoles...

it's in the lower right corner, and I used all poly caps and open core inductors.

If it has an electrolytic and an iron core inductor, I'd definitely upgrade.

John L.

yes, it does have a notch filter. it appears to be an air core inductor, 10mfd cap, and resistor. the 'main' crossover consists of a 6uf and 4uf cap (in parallel), and a pair of bipolar electrolytics (47 and 68uf) next to an iron core coil.

so yes, it uses electrolytics and an iron core inductor. i dont have a way of measuring the inductor though. so, you think its worth at least replacing the iron core inductor and the bipolar elytics?

[cowanrg]

Originally posted by sreten
Hi,

The effect of the components depends on their circuit position.

http://www.stereophile.com/floorloudspeakers/1204bg/

It may be worth experimenting with some line level EQ ........

/sreten.

could you explain a little more what you mean?

[cowanrg]

here are some pics:

[cowanrg]

the notch filter:

[auplater]

The thinking goes that reactance in series with the driver crossed has the major effect on that drivers' sound. So in a second order low pass, the inductor primarily affects the bass and the bypass capacitor (the one paralleled across the driver) simply increases the slope (gross over simplification).

Likewise, in the tweeter circuit, a typical highpass network has the capacitor in series with the driver, so if it contributes to the sound (other than rolling off low frequencies) it will have the primary effect, with the inductor (in a 2nd order) increasing the slope as a parallel connection.

John L.