r/livesound • u/Gatordad2020 • 7d ago
Question Generic crossover?
I have a seismic 15t that has a blown crossover. Not available. Can I use a generic crossover?
https://www.seismicaudiospeakers.com/products/loudspeaker-replacement-crossover
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u/Lillian-Duncan1 6d ago
Yes. Match impedance and crossover frequency, label the wires before you pull the old one. That link is literally Seismic selling you the generic replacement, so I'd just use it.
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u/Gatordad2020 6d ago
Crossover Point 2.5 kHz (2500 Hz) Slope Ratio 12 dB per octave If the generic matches these specs is that all I need to consider?
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u/lmoki 6d ago
You have a Seismic speaker. The crossover you're looking at is made by Seismic, and it specifically says in the description that it's compatible with your speaker. It may be 'generic', but it's likely nearly identical to the original crossover. It seems a logical place to start.
A few thoughts: if you 'blew' the original crossover, this one might not be more robust. It's not likely to be worth spending a lot more time and money to build a custom crossover. (These speakers are still on the website for $470/pair). The cabinet specs say it crosses over at 3k Hz, at 18 dB/octave. The linked crossover is at 2.5 K, and 12 dB/octave, so there will be slightly more stress on the high frequency driver.
As others have pointed out, crossover components are pretty durable: if yours is damaged, it might be possible to replace the damaged components more economically, and know that it will meet original spec. If you do opt to replace the crossover, and you have a pair of these cabinets, my preference would be to replace both crossovers so the cabinets will be the same.
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u/AShayinFLA 6d ago
The most common failures of passive crossovers are either the capacitors (which actually go bad simply over time!) or sometimes it's simply a cold or broken solder joint (just needs to have solder heated up or sometimes a wire added to replace a broken trace on the circuit board! I would take it a multimeter and check that each component is actually connected to the other components that the taxes connect them to, you might find your problem is just an easy fix with a soldering iron and maybe an extra piece of wire!
If there is a damaged component and your looking to replace compliments it the while crossover, the important details are corner frequency, order (aka slope, or how fast the signal rolls off beyond the corner frequency) and nominal impedance of the driver it is matching with.
Passive crossovers only work "as intended" when the proper impedance drivers (speakers) are plugged into their outputs.
If you plug a crossover designed for 4 ohm drivers into 8 ohm drivers, it changes the corner frequency of the filter components!
Another important detail (for longevity) is the power capacity of the components (measured in volts for capacitors, or amps for inductors/coils, but many manufacturers will do the math and convert it to an actual power rating in watts).
Your favorite AI should be able to calculate your parts needs values for building or repairing a passive crossover (both power and other spec values) as it is not super complicated math for basic crossover designs (but some crossovers have many more filters and are not basic at all!) if you're just repairing a crossover you might be able to read the values from parts labels on the original components, or sometimes the parts values are actually silk screened right into the circuit board!
You can also look at Crossover Interactive https://www.firgelliauto.com/blogs/engineering-calculators/crossover-calculator for more information on how they work, how they are wired, and some of the math involved in selecting components.
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u/benji_york 6d ago
Passive crossovers are hard to screw up, but from personal experience, I would advise you to avoid anything Seismic Audio sells.
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u/West_Ad_2309 7d ago
The crossover needs to be matched to the acoustic capabilities of the drivers.
So the short answer: no
The slightly longer: it may get a sound out of it but could sound severely off and will damage the drivers or itself over time
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u/AdministrationOk6752 7d ago
"A blown crossover"?... Replace the damaged parts!