I think I am going to wait and save up for a couple plate amp's,will give me time to research them.mybe there is one that will do 2.5 ohms,altough I dont think 10 ohms is bad neither,but I am a rookie at this.
You should at least try and find a published impedance curve for your speakers, or better, measure their impedance curve.
The Crossover component values need to be designed using the speakers impedance at the crossover frequency.
The impedance of most speakers varies quite a bit dependent on frequency.
Impedance could be half or double the nominal at the crossover frequency depending on the speakers and what frequency you choose.
This is especially important because of the component values (cost) of the inductors and caps.
Most people would figure a way to do an active (electronic) crossover before separate amps for the sub and the mains (Bi-amping)
Good luck with your build,
Dave
I have decided to go with a active setup ,any thoughts on this rig.
Technics REQ0207 100W Subwoofer Plate Amplifier | 309-047
Technics REQ0207 100W Subwoofer Plate Amplifier | 309-047
I was going to say that when you see the price of those inductors and caps, you might want to look at going with the active approach. It sounds like you have.
Just for the record, here's a relatively simple way to measure a drivers impedance at a particular frequency:
Put a 50 ohm pot (variable resistor) in series with the driver, which will be driven by a sinewave generator driving a poweramp. Get it going just loud enough to hear it. Set the frequency where you want it (the proposed crossover frequency). Adjust the pot such that an AC voltmeter shows that the voltage drop across the driver is equal to the voltage drop across the pot. Disconnect the pot and measure it, and that will be the driver impedance at that frequency.
Just for the record, here's a relatively simple way to measure a drivers impedance at a particular frequency:
Put a 50 ohm pot (variable resistor) in series with the driver, which will be driven by a sinewave generator driving a poweramp. Get it going just loud enough to hear it. Set the frequency where you want it (the proposed crossover frequency). Adjust the pot such that an AC voltmeter shows that the voltage drop across the driver is equal to the voltage drop across the pot. Disconnect the pot and measure it, and that will be the driver impedance at that frequency.
OK thanks ,I probaly wont need it,I dont think I am capable enough for the speaker building crowd.,I failed miserably in this endeaver.
I started building speaker systems in 7th grade (1967) and didn't know the math for several more years (and speaker systems), but they still sounded good enough just doing it by ear. I copied part values from existing speaker systems to get started. You don't necessarily have to be an expert to get reasonable results. Remember the words of Thomas Edison, "The most important ingredient of success is failure." One of Zaphs speaker kits might be a good place to start. He has a great website with tons of relatively accurate info on tons of drivers and his kit systems. I think you can buy one of his kit systems from Parts Express or Madisound, if not directly from him.
Zaph|Audio
Zaph|Audio
OK I just found info on a inline filter called a f-mod can I run a signal into the f-mod and into a power amp to the subs.will that work.
my friend has a crown power amp I can get real cheap I think it is 300 wats.
my friend has a crown power amp I can get real cheap I think it is 300 wats.
I had never heard of these before, so I had to google it.
I came up with the second hit being Amazon.
Amazon.com: FMOD Crossover Pair 70 Hz Low Pass: Car Electronics
These things look very useful, especially the 20 Hz hipass one.
This all assumes that your amp has a 22 K input impedance.
or, if it is a little different, say 20 K you get a slightly different frequency.
.
They are still not quite a Driverack or any good active X-over, but if it works😉
All that said I have never seen one let alone used one so they could be crap for all I know.
I believe that they would work for your situation if the amps input impedance is right.
What model Crown amp.
The XTS line of Crown are 10 K on the unbalanced (RCA input).
The XTi line (I have an XTi 1002 for subs) only have balanced 3 wire inputs, but are 20 K ohm.
Thanks for that reference,
Dave
I came up with the second hit being Amazon.
Amazon.com: FMOD Crossover Pair 70 Hz Low Pass: Car Electronics
These things look very useful, especially the 20 Hz hipass one.
This all assumes that your amp has a 22 K input impedance.
or, if it is a little different, say 20 K you get a slightly different frequency.
.
They are still not quite a Driverack or any good active X-over, but if it works😉
All that said I have never seen one let alone used one so they could be crap for all I know.
I believe that they would work for your situation if the amps input impedance is right.
What model Crown amp.
The XTS line of Crown are 10 K on the unbalanced (RCA input).
The XTi line (I have an XTi 1002 for subs) only have balanced 3 wire inputs, but are 20 K ohm.
Thanks for that reference,
Dave
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the crown power amp is already sold so back to the drawing board,still gonna try and find a good power amp and try the fmods or maybe there is a active pow pas filterin a kit form,any way something will turn up.I was looking at the pyle power amps there are some good looking ones but they seem to be cheaply built and way under powered from what they state.
for a subwoofer I would think a good middle of the road amp would do since low frequnecies are just power hungry and not into detailed sound like mids and highs,the search goes on,,a little help please!
for a subwoofer I would think a good middle of the road amp would do since low frequnecies are just power hungry and not into detailed sound like mids and highs,the search goes on,,a little help please!
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