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-   -   Who wants to explain how to set high pass and low pass? (https://maxima.org/forums/audio-electronics/257306-who-wants-explain-how-set-high-pass-low-pass.html)

my99maxisnice 10-16-2004 06:08 PM

Who wants to explain how to set high pass and low pass?
 
I have separate dials on my amp for high pass and low pass, and I just have this gut feeling they aren't set correctly. Anyone want to help me out? Amp is in sig, they're powering my front components.

*EDIT* I'm dumb.*EDIT*

darrick 10-16-2004 06:58 PM

i cant see your sig :smash:

my99maxisnice 10-17-2004 02:51 PM

bump there we go.

jmal 10-18-2004 08:26 AM

A high pass will filter out low frequencies....
A low pass will filter out high frequencies....
therefore...
say you set your high pass (for fronts, rears, tweeters...smaller speakers) at 1000 mhz, the speakers connected to these outputs won't play anything lower than 1000 mhz.

Vice-versa for the low pass...

If you're using your amp for your subwoofers (bass), you should be using the low pass. If its for the rears, fronts or tweeters (mid/highs), you would use the high pass.

The way I had my stereo set up in my Jeep went like this.
Infinity Kappa 5.25" separates, front (built in crossover) high pass around 300/350mhz
Infinity Kappa 6.5" separates, rear (built in crossover) high pass around 100/150mhz
Kicker Comp 10" subs, low pass around 80/60mhz.

I had a little bit of an 'underlap' in the mhz there, but its somewhat hard to really tell when you're missing a few mhz in that range...especially when the volume is cranked all the time....might have something to do with my slight hearing loss in my left ear....what?
I wish I had an 8" sub with that system to compliment the 2 10"s....oh well, maybe I'll do that with the Max :chuckle:

Obviously the right way to set up a system is so that the intended speakers only play the sounds in the sound range they were intended for...you don't want your subs playing guitar/voice sounds, and the tweeters playing drums/bass sounds. :Party:

Feel free to PM or Email me if you have any questions about anything car-audio-related...I've done tons of research for my multiple stereo installations :happyface

Micah95GLE 10-18-2004 10:52 AM


Originally Posted by my99maxisnice
I have separate dials on my amp for high pass and low pass, and I just have this gut feeling they aren't set correctly. Anyone want to help me out? Amp is in sig, they're powering my front components.

*EDIT* I'm dumb.*EDIT*

I don't know how low those CDTs play, but you want to high-pass the fronts as low as your speakers can handle (60-70Hz) so you get plenty of up-front bass. Then low-pass the sub (if you're using one) at about the same frequency. You can overlap or underlap the mid and sub crossover points to EQ the midbass response. For the rears, I would high-pass them at 140-170Hz (I've done that in the past with good results).

friendhasmax 10-18-2004 01:20 PM


Originally Posted by jmal
A high pass will filter out low frequencies....
A low pass will filter out high frequencies....
therefore...
say you set your high pass (for fronts, rears, tweeters...smaller speakers) at 1000 mhz, the speakers connected to these outputs won't play anything lower than 1000 mhz.

Vice-versa for the low pass...

If you're using your amp for your subwoofers (bass), you should be using the low pass. If its for the rears, fronts or tweeters (mid/highs), you would use the high pass.

The way I had my stereo set up in my Jeep went like this.
Infinity Kappa 5.25" separates, front (built in crossover) high pass around 300/350mhz
Infinity Kappa 6.5" separates, rear (built in crossover) high pass around 100/150mhz
Kicker Comp 10" subs, low pass around 80/60mhz.

I had a little bit of an 'underlap' in the mhz there, but its somewhat hard to really tell when you're missing a few mhz in that range...especially when the volume is cranked all the time....might have something to do with my slight hearing loss in my left ear....what?
I wish I had an 8" sub with that system to compliment the 2 10"s....oh well, maybe I'll do that with the Max :chuckle:

Obviously the right way to set up a system is so that the intended speakers only play the sounds in the sound range they were intended for...you don't want your subs playing guitar/voice sounds, and the tweeters playing drums/bass sounds. :Party:

Feel free to PM or Email me if you have any questions about anything car-audio-related...I've done tons of research for my multiple stereo installations :happyface

lol mhz?

i dont think anyone would hear any frequencies in that range ;)

Micah95GLE 10-18-2004 01:36 PM


Originally Posted by friendhasmax
lol mhz?

i dont think anyone would hear any frequencies in that range ;)

:laugh: I wasn't gonna say anything.

Maxima Dan 10-18-2004 01:51 PM


Originally Posted by friendhasmax
lol mhz?

i dont think anyone would hear any frequencies in that range ;)

Sure you can...it's called channel 2 :chuckle:

friendhasmax 10-18-2004 01:58 PM


Originally Posted by Maxima Dan
Sure you can...it's called channel 2 :chuckle:

sure with the aid of a tv...lol...but 1000mhz coming from a speaker? hehe

my99maxisnice 10-18-2004 03:03 PM

Ok, so my amp is powering the components, and it's currently set on both, not just high pass or low pass. I thought this would be correct, since the components play both highs and lows. Currently my high pass is right below 1.5 Khz, and my low is at 250 Hz. Judging by what you guys are saying, this sounds wrong.

And also, for the gain, I thought it was supposed to be high to keep from blowing speakers, but I read somewhere that some guy set his at 1/4th as a fact that the speakers are still good. So is mine wrong?

Thanks for your help.

Chitwista 10-18-2004 03:12 PM

For setting the gains.. I would do the following..
1 - Turn the gain on the amp all the way down
2 - Put all of your bass and treble on the deck to 0 or flat
3 - Turn your headunit up to about 80% volume
4 - Slowly turn up your gain until you notice some distortion

Not sure if this is the exact way of doing it, but it will set your gains fairly well..

MannyNJ2k2max 10-18-2004 03:45 PM

Just play around with it- your speakers will perform differently depending on music also- so if you dont have the crossover adjustabily in your HU- play it by ear
Subs should be anywhere between 55hz-200hz(some like to crossover their SQ subs in the 100-200hz range) and the high pass according to how well your mids play to those frequencies at your optimum listening volume level- generally mine like between 80-125hz

jmal 10-18-2004 07:02 PM

Doh!...yeah, I get computers and stereos mixed up sometimes...sorry

joebangaa 10-18-2004 09:41 PM

geez we're getting some really bad xover input

whoever said to set your fronts at something absurdly high and your backs low, disregard that. if you want your car to sound sh!tty like jmal go for it, lol.

set your speaks to 80-120 and low pass the subs at HIGHER than 80 or whatever stupid number he said. it will hit much better if it's up even as high as 200

darrick 10-18-2004 09:49 PM

I agree i set all mine at 120 go i get all my music

5 spd 10-18-2004 10:19 PM

I am with chitwista. in my hardbody, I turned up my alpine to 3/4 volume, then adjusted the gains on my amp to where I wanted it to sound at that volume. I dont listen to my stereo that loud, but when I do, I want it to sound nice. once you get your gains on your amp set, then mess with the crossover points. everything is subjective, and only your ears will know what sound you like.

slickrick 10-18-2004 11:08 PM


Originally Posted by ighettoboyi
geez we're getting some really bad xover input

whoever said to set your fronts at something absurdly high and your backs low, disregard that. if you want your car to sound sh!tty like jmal go for it, lol.

set your speaks to 80-120 and low pass the subs at HIGHER than 80 or whatever stupid number he said. it will hit much better if it's up even as high as 200

i think their point was so that you basically get midbass from the rear speakers...apparently its beter for sq. anyway i have my fronts and back at 80 and call it a day.

Maxima Dan 10-18-2004 11:50 PM

Here's how I normally set mine up. Subs low passed anywhere from 80-100Hz, I wouldn't go too much higher than that but if your mids suck you might have to. If you are running a passive comp set you just need to high pass at something slightly less than where you have your subs set to. I really wouldn't want much overlap since you just end up with a bump in the response at that point. The other thing I do is actually band pass my rears so that they are high passed like my fronts but than cut off so they don't pull my image back and toward the passenger side. Then again those with rear shelf speakers might have different opinions.

We have so many odd responses to this question because there is no "right" way to set this up. It is highly dependant on equipment and speaker positioning.

Oh yeah as for gains, the setting up by ear method ahs never failed me. Pretty much the same way the other guys were doing it. Set you HU to 3/4 volume and start turning the gain up, etc.

Micah95GLE 10-19-2004 09:20 AM


Originally Posted by ighettoboyi
set your speaks to 80-120 and low pass the subs at HIGHER than 80 or whatever stupid number he said. it will hit much better if it's up even as high as 200

But it won't sound very good. All of the low bass, midbass, and low midrange will be coming from the back of the car. The music will jump back and forth from the front of the car to the rear.

jmal 10-19-2004 01:15 PM


Originally Posted by ighettoboyi
low pass the subs at HIGHER than 80 or whatever stupid number he said. it will hit much better if it's up even as high as 200

As high as 200? Ouch! :gotme: Maybe if you're using 6.5s as your subs....

jmal 10-19-2004 01:24 PM

Its all dependent on what you have for the rear midrange speakers. In my case I'd go with some Infinity Kappa 6.5 separates, set the high pass between 80/120Hz, and set the sub's low pass at whatever my separates were set at.

friendhasmax 10-19-2004 04:31 PM

i like to set my gains with my oscilloscope :)

my99maxisnice 10-19-2004 06:01 PM

I don't have a sub, I'm talking about the low pass on my amp for my speakers. I think they're correct now, thanks to slick rick, but this has nothing to do with subs.

Maxima Dan 10-19-2004 06:06 PM


Originally Posted by friendhasmax
i like to set my gains with my oscilloscope :)

Just curious, did it matter if there was a load on the amp or not? I've got an O-scope at my disposal but I've been doing them by ear for so long that I've never tried it any other way. Creature of habit I guess.

slickrick 10-19-2004 06:10 PM


Originally Posted by my99maxisnice
I don't have a sub, I'm talking about the low pass on my amp for my speakers. I think they're correct now, thanks to slick rick, but this has nothing to do with subs.

glad i could be of assistance.

friendhasmax 10-19-2004 06:32 PM


Originally Posted by Maxima Dan
Just curious, did it matter if there was a load on the amp or not? I've got an O-scope at my disposal but I've been doing them by ear for so long that I've never tried it any other way. Creature of habit I guess.

actually never tried it with the load because it would be too annoying to the neighbors lol. i would assume that the output voltage would theoretically be independent of the load, or it would actually decrease the voltage. you would be safe to do the O-scope test with the load disconnected because the load would never cause the voltage to increase and therefore clip. i would think it would be hard to mimmic the load with a dummy load (like a power resistor) because of voice coil inductance and frequency effects. first thing first is to hook up the head unit's preamp ouputs to the o-scope to test for clipping on the head unit at some maximum volume and then do the gains on the amp.


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