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Setting crossovers accurately


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Hey everyone, I'm trying to set my crossovers but I don't have a CC-1 or an RTA... Is there a trick for doing it "by ear"? 

My head unit is a Sony MEX-XB120BT and has settings for 1st, 2nd, and 3rd order at multiple set points all 20hz apart (though I don't know if it uses Linkwitz or Butterworth crossovers... if anyone knows please chime in), and my amp is a Kenwood Excelon 501, and has a continuously variable x-over knob. 

I'm not trying to match frequencies perfectly like when you're running multiple bass amps... I just want my lows and highs to blend nicely at the selected frequency. I know it's going to be quite a bit of trial and error, but are there any tricks to help me along the way, and maybe speed up the process? 

Any help is greatly appreciated! 

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If you want to do so scientifically, set amp to full pass, play a tone you want to set to, measure the voltage coming out of the amp, divide that number by the square root of 2, then adjust crossovers until the voltage matches your calculated number

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  • 2 weeks later...

You'll need a DMM.

amp All pass, play desired test tone frequency, measure voltage, now set either low pass or high pass. Play tone again with your frequency dial well below setting for high pass and above for low pass.

With meter hooked up, slowly turn dial on frequency up torwards the desired setting (hp) or down towards setting (lp) until you see the same voltage that was given when tone was played in all pass mode. 9 times out of 10 it will be pretty close to the numbers written on the dial if a quality amp is  used,  but could be off by a good bit as well. Trust the meter not the marked indicators on dials. Also front and rear channels on same amp most of the time won't match up perfectly to where it is visually shown on the marked numbers on dial. This is just the nature of tolerance with components used to build the Amps.

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6 hours ago, AaronT said:

You'll need a DMM.

amp All pass, play desired test tone frequency, measure voltage, now set either low pass or high pass. Play tone again with your frequency dial well below setting for high pass and above for low pass.

With meter hooked up, slowly turn dial on frequency up torwards the desired setting (hp) or down towards setting (lp) until you see the same voltage that was given when tone was played in all pass mode. 9 times out of 10 it will be pretty close to the numbers written on the dial if a quality amp is  used,  but could be off by a good bit as well. Trust the meter not the marked indicators on dials. Also front and rear channels on same amp most of the time won't match up perfectly to where it is visually shown on the marked numbers on dial. This is just the nature of tolerance with components used to build the Amps.

You missed a step.  After you measure your voltage with the amp set to all pass you need to multiply that number by .707 and write down/remember the calculated value, then you adjust your high/low pass until you see the voltage you calculated.  If you set your filters so they show the same voltage as your original measurement your low pass will be set a lot higher and your high pass will be set a lot lower than you intend.  

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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33 minutes ago, Triticum Agricolam said:

You missed a step.  After you measure your voltage with the amp set to all pass you need to multiply that number by .707 and write down/remember the calculated value, then you adjust your high/low pass until you see the voltage you calculated.  If you set your filters so they show the same voltage as your original measurement your low pass will be set a lot higher and your high pass will be set a lot lower than you intend.  

I messed up post above.

I always wondered what does the .707 account for?

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2 hours ago, AaronT said:

I messed up post above.

I always wondered what does the .707 account for?

So when setting a crossover, the frequency it is set for isn't the point where rolloff beings, it where the output is reduced by 3 dB.  This makes sense when you have crossovers set between two different speakers, a 3 dB reduction is half as much output.  So if you cross between your mids to your highs at 3 kHz, for example, right at 3 kHz half the output is coming from the mid, and half is coming from the high so there is a smooth transition.  All filters, whether they are low pass or high pass are measured at their -3 dB point.    

Now the reason you multiply your voltage by .707 is because that's how much voltage reduction you need to cut your output in half.  (.707 is 1 divided by the square root of 2, FYI).  

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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