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uxcell Film Capacitor can't find any info

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To avoid coupling the inductors should not be planarly positioned and should, instead, be orthogonally placed, maximizing the inter-inductor distance.

The field strength varies as r^2.

I refer you to the work of Troels Gravesen, the master on the subject:
 
"Frequency response of 38-24,000Hz, frequencies are crossed over and divided at 1750Hz in 12 Db per Octave segments" is all I know about this cross over


https://www.mavin.com/store.php/audio/boston-acoustics-dual-woofer-crossover-pair

https://www.ebay.com/itm/Pair-of-12db-Crossover-2-Way-300-Watt-8-OHM-TL-280-/362404964907

is there a prebuilt I can buy, I'm getting the feeling these old crossovers are not as good as the tweeter and cabinets deserve.

2 - 8" woofers and a peerless polk style tweeter.
 
Fsatsil said:
Have you traced it out to see what each component is doing?
Click to expand...
it "works" the tweeters are HARSH played loud for domes, and these are not kickingmy skirt up, and I know they could. I'm fine with trying a different crossover. I don't know 100% what I need though.
 
I wouldn’t expect good results from swapping in any prebuilt crossover. Maybe you just don’t like the speakers? Just because they look pretty doesn’t mean they have to sound pretty!
 
toxcrusadr said:
Electrolytics tend to have higher ESR which means they attenuate the signal a bit more than film caps. So replacing an old NPE with a film type can cause a higher output in that driver than was originally designed in. Some people don't mind it, some actually like it (many older speakers didn't have super highs anyway), while others find it too loud/shouty/harsh/edgy.
Click to expand...

What he said! It's not the capacitor itself that is harsh or bright... it's the change (reduction) in ESR compared to how the crossover was originally designed and voiced.

Throw a 1 ohm 5W resistor in series with the new capacitor and see if you subjectively prefer the sound.
 
pete_mac said:
What he said! It's not the capacitor itself that is harsh or bright... it's the change (reduction) in ESR compared to how the crossover was originally designed and voiced.
Click to expand...

Electrolytics have two problems which render them unsuitable for signal-path use:
(1) The NPE is two electrolytics inversely wired in series. The capacitor through which current passes acts as a rectifier, resulting in distortion.
(2) Electrolytics rely on ion movement through a liquid (electrolyte) instead of charge distribution across a plate, and are slow and consequently roll off the highs. The capacitance falls off above 1k Hz for this reason.
​
Electrolytics are designed, and best suited, for power-supply filtering which is very low frequency, down near DC. AC use is always problematic.

Adding series resistance affects damping factor and alters the impedance which shifts the crossover point. If a tweeter is too loud relative to the other drivers an L-pad may be used on it to reduce the volume without affecting the crossover point. Many times with degraded crossover capacitors the issue is a lack of familiarity with undistorted sound; listen for a week and see if you still hate the "new" sound. This is commonly called "break in", except it is for the brain, not the crossover components.
 
Retrovert said:
Electrolytics have two problems which render them unsuitable for signal-path use:
(1) The NPE is two electrolytics inversely wired in series. The capacitor through which current passes acts as a rectifier, resulting in distortion.
(2) Electrolytics rely on ion movement through a liquid (electrolyte) instead of charge distribution across a plate, and are slow and consequently roll off the highs. The capacitance falls off above 1k Hz for this reason.
​
Electrolytics are designed, and best suited, for power-supply filtering which is very low frequency, down near DC. AC use is always problematic.

Adding series resistance affects damping factor and alters the impedance which shifts the crossover point. If a tweeter is too loud relative to the other drivers an L-pad may be used on it to reduce the volume without affecting the crossover point. Many times with degraded crossover capacitors the issue is a lack of familiarity with undistorted sound; listen for a week and see if you still hate the "new" sound. This is commonly called "break in", except it is for the brain, not the crossover components.
Click to expand...

I don't disagree with anything that you've said above :) If the above attenuation trial works OK, then replacing a single resistor with a properly calculated L-pad is the way to go.
 
pete_mac said:
I don't disagree with anything that you've said above :) If the above attenuation trial works OK, then replacing a single resistor with a properly calculated L-pad is the way to go.
Click to expand...

If you agreed you would not suggest shifting the crossover point. Adding impedance alters the crossover point. That's just a fact. An L-pad maintains constant impedance device on one side. A T-pad maintains constant impedance on both sides. A series resistor does not maintain constant impedance.

You may trivially verify the effect of changing from R to (R + 1). For example, given a 8 µF capacitor and an 8 Ω driver the crossover point is 2,487 Hz. Adding your 1 Ω resistor changes the circuit to a 9 Ω driver and shifts the crossover point to 2,210 Hz. The points determined by the inductor similarly shift. Such shifts may not matter in practice, but it is altering the crossover in ways that may not be intended.

Consider the formulas:
Given:
R is Nominal Speaker Impedance (Ω)
C is Capacitance (Farad)
L is Inductance (Henry)
f is Frequency (Hertz)
​
Inductor Formulas:
L = R / (2π x f) (Henry)
f = R / (2π x L) (Hertz)
R = 2π x L x f (Ω)
​
Capacitor Formulas:
C = 1 / (2π x f x R) (Farad)
f = 1 / (2π x C x R) (Hertz)
R = 1 / (2π x C x f) (Ω)

NB:
L is inductance in Henry.
To convert from Henry (H) to milliHenry (mH) multiply by 1,000.
To convert from milliHenry (mH) to Henry (H) divide by 1,000.

C is capacitance in Farad.
To convert from Farad (F)to microFarad (uF) multiply by 1,000,000.
To convert from microFarad (uF) to Farad (F) divide by 1,000,000 or multiply by 0.000001.​
 
Retrovert said:
If you agreed you would not suggest shifting the crossover point. Adding impedance alters the crossover point. That's just a fact. An L-pad maintains constant impedance device on one side. A T-pad maintains constant impedance on both sides. A series resistor does not maintain constant impedance.
Click to expand...

I understand that... this isn't my first rodeo.

I was trying to help the OP with a simple way of taming the brightness inherent with swapping from the horrible black-bodied, red-ended ALCAP or COLLINS capacitors to new film capacitors due to large differences in ESR. The typical values have been measured before on this forum and others.

Yes, I should have known better and should have provided details of a proper L-Pad or T-Pad. Sorry I didn't have time to go into this kind of detail - I was posting from my phone at the time.

Seeing that you've got this under control, I will leave the OP in your hands.
 
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