Identify Crossover?

[neddyboy]

I have a pair of 2-way crossovers from a Pair of DCM Light Frame speakers. They seem pretty good quality but I'd like to replace the caps with better ones and use them in an old pair of Paradigm Phantoms. The Paradigm crossovers are pretty poor.

Could someone take a look at the attached schematic (I drew it and it's my first) and identify what kind of crossover this is and what caps I need to put in to change the crossover frequency to 2500hz?

I can't find any crossover diagrams online that match these and I don't recognize the circuit.

Thanks in advance,
Neddyboy

[Jonathan Bright]

I can see why you're a bit puzzled. My first reaction is that you may not have got the drawing down accurately. I can imagine a circuit where those components would work but as it stands it doesn't make a lot of sense. Is it possible that you need to redraw it? Perhaps sleep on it first..... as circuits sometimes make more sense in the morning!

Here's some suggestions. You've got the ingredients there for a 12db per octave unit (also known as second order) and maybe some attenuation for the tweeter. If that is the case then the big cap is likely to be across the teminals of the woofer with the larger inductor (coil) feeding the woofer. The tweeter would have the reverse.
Good luck, Jonathan

[neddyboy]

I'd say the chances of my drawing being wrong are pretty high! I think maybe I'll just take a photo of the front and back of the crossover and post it later. Not sure my ability to draw a schematic are going to improve much.

Thanks,
a Jonathan too
(neddyboy)

[sreten]

Hi,

Generally speaking you cannot take a crossover from a "good"
speaker and use it in a "bad" speaker. The "bad" speakers
crossover is highly likely better than any "good" replacement.

/sreten.

[neddyboy]

I'm not sure I followed that one, sreten.

"Generally speaking you cannot take a crossover from a "good"
speaker and use it in a "bad" speaker. The "bad" speakers
crossover is highly likely better than any "good" replacement."

Do you mean that the DCM is a "good" speaker and the Paradigm is a "bad" speaker, but the crossover in the Paradigms is still better than the DCM? I actually don't think much of either set. However, the crossover in the Paradigm seems particularly cheesy and the crossovers in the DCMs seem pretty decent. Both sets are (or were) pretty bargain-basement. I only have the crossovers from the DCMs left. Three offour drivers were blown when I was given them and I chose to pull out the good bits and chuck the rest.

I mostly wanted to figure out which caps to replace to be sure that I don't blow up the tweeters in the Paradigms.

[Cloth Ears]

Originally posted by neddyboy
Do you mean that the DCM is a "good" speaker and the Paradigm is a "bad" speaker, but the crossover in the Paradigms is still better than the DCM?

What he means is that crossovers are (in almost all cases) not interchangeable. If the drivers used in both speakers are the same make and model, then you could probably do this. But even then you may not get the results that you're looking for.

When you said "I have a pair of 2-way crossovers from a Pair of DCM Light Frame speakers. They seem pretty good quality but I'd like to replace the caps with better ones and use them in an old pair of Paradigm Phantoms." did you mean
i) that you were going to remove the crossover from the DCMs (rendering them inoperable) and put them in the Paradigms?
ii) that you were going to copy the crossover from the DCMs and use this in the Paradigms?
iii) that you were going to replace the caps in the DCM crossover with better caps and use the old caps from the DCMs in the Paradigm crossover (but without making any other changes)?

Is the schematic from the Paradigm crossover or from the DCM crossover?

Your first post is a little ambiguous, thus all the questions.

P.S. Jonathan also

P.P.S. I just had a look at the attached picture, and it looks like the woofer runs full-range, with a notch filter (small inductor/2.6R/.47mf) to smooth out something. The tweeter is a 1-st order with resistor padding (3.3mF/2.6R) with a series notch filter to dampen tweeter resonance (47mF/large inductor). BUT, I would have expected a resistor as a part of the series filter.

[sreten]

Originally posted by neddyboy

However, the crossover in the Paradigm seems particularly
cheesy and the crossovers in the DCMs seem pretty decent.

Hi,

You do not know this at all. Paradigms are well engineered (to a price),
the "cheesy" c/o may be all that is required to do the job properly.

/sreten.