setting high pass filter..

[Etac 10+ year member]

ok yes i understand the concept on how a high pass filter works

i wanna set the crossover on my jbl amp as close to 80 as possible (and my HU doesnt have one)

but the problem is the dial on the amp has basically no indication on what it set at cept 32 min and 320 max

now since a filter has -3 db at the crossover point (or so im told)

i should use a voltmeter to detect when the power is approx. half using a 80 hz test tone (using the correct mathmatical forumlas)

correct?

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[Immacomputer 10+ year member]

You could do that but I would really set it by ear instead.

To do it using a VM, play an 80hz test tone and set the HPF as low as it can go. Read the voltage with a given volume input. Then take that voltage and multiply it by .707. The number you get there is going to be the new voltage you want the meter to read. So then roll the dial up until the meter displays the new voltage.

Example: Say when the filter is either off or set as low as possible, the voltage is 65v. Your new voltage will be 65*.707 = 45.95 or basically 46v. This will pretty much be 3dB down off by however much your multimeter is off by.

 

[Etac 10+ year member]

well the reason i wanan try to be really percise with it is cause the rainbow speakers tell me they *need* a 80 hz crossover pt and im running more than rated power so i wanna be careful - i know it can be higher than 80 but i wanna get as much from them as i can and im afraid if i do it by ear something bad might happen lol

thankyou btw

 

[nauc 10+ year member]

set your high pass as high as you can, turn up your deck the loudest you ever listen to it, then lower the hpf until it starts to sound like sh!t, then raise it a tad

test it out on a variety of music, make any changes and forget about it

 

[Etac 10+ year member]

well as i said

i got the rainbow cmx kicks and runnin 200w per side

the website and manual yell at me to use at least a 80hz crossover so i just dont wanna fry/break these things a week after i got em =) lol

 

[nauc 10+ year member]

youll only ruin them if you dont set your amp gain right and or set the hpf too low and overdrive them mechanically

 

[Etac 10+ year member]

which is exactly what im trying to avoid //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

i have the gains set right btw..

 

[jblayz1 10+ year member]

i'd say turn it 1/4 of the way up(should be around 100hz)@ 12db.