# Low pass, high pass, frequencies and other dumb ?'s



## UNBROKEN (Sep 25, 2009)

Some if not most of the reading I do on here is geared towards the more knowledgable person in regards to tuning...so let's dumb it down for the beginners as far as real tuning is involved. 

Frequencies...specifically for a 3 way component set. 
Midbass....60 hz up to ?
Midrange...? up to ?
Tweeters...? up to 20khz

Explain high passing and low passing a certain driver. Midrange for example...low pass cuts out everything below the selected frequency and high pass cuts everything above?

The sub...I'm playing that 63hz and down. 

Now say you have it sounding great at average listening levels but you tend to get loud prett often. How do you tune it to not go to complete crap when you crank it up?
Lower the gains on the HU for the higher frequencies? Raise the low pass filters so nothing gets hurt?

Let's leave the technical stuff for the next forum down and speak in beginners terms up here. Everyone had to start their learning curve somewhere...


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

UNBROKEN said:


> Some if not most of the reading I do on here is geared towards the more knowledgable person in regards to tuning...so let's dumb it down for the beginners as far as real tuning is involved.
> 
> Frequencies...specifically for a 3 way component set.
> Midbass....60 hz up to ? *~200*
> ...


That should get you goin...


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## UNBROKEN (Sep 25, 2009)

Provided you have the capabilities...should the crossover points overlap of have one pick up where the other leaves off?
I was thinking about bumping my sub up to 80 and my midbass down to 70. 

With having my sub front firing in the front center console I'm not sure if imshould be playing it higher or lower though. I have very capable midbasses but I'm not sure how low I should push them since I do tend to get loud with some pretty aggressive music.


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## trojan fan (Nov 4, 2007)

This stuff is all subjective to one's own opinion ....let your ears answer some of your questions


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## UNBROKEN (Sep 25, 2009)

That's one way to put it....but knowing the baseline numbers to start with would save hours of trial and error and possible equipment damage. 
Obviously...my ears will be the final determining factor but they won't help much without knowing where to start.
And I could be wrong but I don't think crossover points and how to set high/low pass is subjective. Immpretty sure there's some tried and true science behind it somewhere.


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

trojan fan said:


> This stuff is all subjective to one's own opinion ....let your ears answer some of your questions



Are you ears going to determine the lower frequency of your tweeters, before you cook them?

Anyone could say what you just did, where did YOU start, last time you put together a 3way active front stage?


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

UNBROKEN said:


> Provided you have the capabilities...*should the crossover points overlap of have one pick up where the other leaves off?*
> I was thinking about bumping my sub up to 80 and my midbass down to 70.
> 
> With having my sub front firing in the front center console I'm not sure if imshould be playing it higher or lower though. I have very capable midbasses but I'm not sure how low I should push them since I do tend to get loud with some pretty aggressive music.


Ahh, HERE is where it gets subjective... 

IF you overlap the crossover points, you naturally boost in the overlap because 2 drivers are producing the same frequencies... So if you like the boost, go for it, some don't and it's hard to EQ out and RTA around...ect.. 

IF you GAP @the crossover point, you can cut "naturally" at the crossover point, should you want/need to...


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## UNBROKEN (Sep 25, 2009)

So there is no hard rule on overlap...gotcha. 
I'll start with them as close as I can then overlap them later and see what happens. 
It'll be nice to do all this from the HU instead of crawling around on the floor trying to see **** on the amps. lol


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## trojan fan (Nov 4, 2007)

Aaron'z 2.5RS/WRX said:


> Are you ears going to determine the lower frequency of your tweeters, before you cook them?
> 
> Anyone could say what you just did, where did YOU start, last time you put together a 3way active front stage?



Once you get in the ballpark your ears need to take over....so yes, SOME of his questions can be answered with his ears:laugh:


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## trojan fan (Nov 4, 2007)

Aaron'z 2.5RS/WRX said:


> Ahh, HERE is where it gets subjective...
> 
> IF you overlap the crossover points, you naturally boost in the overlap because 2 drivers are producing the same frequencies... So if you like the boost, go for it, some don't and it's hard to EQ out and RTA around...ect..
> 
> IF you GAP @the crossover point, you can cut "naturally" at the crossover point, should you want/need to...



x2...exactly


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

Another thing on crossover points, it all depends on your speakers. Make sure you know where your speakers are capable of playing. Some mids sign off around 3-4000, but some can easily play much higher as well, and may sound better doing so then tweeters playing too low. I think the lowest highpass your speakers can take is not subjective, its based on what your speakers can do. Everything else, low-pass wise, is more subjective.


For example, lets say you do the following crossovers.

Sub 20-63
Bass 63-200
Mid 200-3000
High 3000-20000

Now your tweeter could probably play that low, and it might sound ok. But if your mid can play higher, say to 5000, it would probably sound better at 3000-5000 than the tweeter would, if 3000 is close to the limit for the tweeter.


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## UNBROKEN (Sep 25, 2009)

Talk to me about infrasonic filters please.


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## trojan fan (Nov 4, 2007)

UNBROKEN said:


> Talk to me about infrasonic filters please.



Are you running a ported enclosure?


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## huckorris (Sep 2, 2009)

Infrasonic filters are exactly the same as a high pass filter. 

Ported boxes don't play well below the frequency the port is tuned to. Setting the infrasonic, or subsonic filter to around the box's tuned frequency keeps your sub from playing below that frequency. i'm sure there are more concise ways to explain that but I tried. 

As for hp/lp overlap or gap, it kinda depends on how steep the crossover slope is. A second order (12 decibels per octave) crossover (xo) will drop off twice as steeply as a 4th order, or 24 db/oct slope. So while 20hz or so might be a nice sized gap or overlap for a 12db/oct xo, that gap maybe too large for a 24 db/oct crossover.

Hope that helps. best of luck.


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## bmiller1 (Mar 7, 2010)

OP, thanks for a cool premise to start a thread on. I'm one of the ignorant so, I'm really interested to see how this thing flourishes. As a charter member of Club Noob, everyone's input and patience is seriously appreciated. 

So huck, is an LPF a must for any ported enclosure? I mean, I know it's not critical because I have one in my trunk with no filter. But, for managing the quality of your sound, it's a no-brainer? I wish i understood the slope/octave thing but, I haven't got to that chapter yet.


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## UNBROKEN (Sep 25, 2009)

So don't worry about an infrasonic filter with a sealed enclosure ?


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## trojan fan (Nov 4, 2007)

What size of sub(s) are you running?


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## UNBROKEN (Sep 25, 2009)

A single JL 10W7 off a JL 1000/1 in a 1.6 cu/ft sealed enclosure


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

UNBROKEN said:


> So don't worry about an infrasonic filter with a sealed enclosure ?


It can increase efficiency, being that it's cutting out frequencies the sub can't play anyway (but tries)


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## lithoman (Jul 21, 2011)

Help Another dumb question..... I have my amp's lpf set to 80 and my hpf at 80. I have no clue if those numbers are right. I just pulled them from reading posts of other peoples settings.
Now my HU has the same setting. what happens if i change the HU's LPF to 60 and HPF to 120 but leave the amp alone...which one rules out.. I would think that since the amp comes after the HU  the Amp settings rule... way to many duplicate settings. I dont know which ones to set.
I have a slope setting on my HU....1-3 what the heck is that??? I dont know so i set it in the middle 2.
I hope you guys go easy on my ignorance...


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## boogeyman (Jul 1, 2008)

One common practice is to use a highpass crossover frequency approximately 1 to 2 octaves above the resonant frequency. If the resonant frequency of the speaker is 850hz for example the lowest reasonable highpass crossover frequency expected would be between 1,700 hz and 2,550 hz.


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

lithoman said:


> Help Another dumb question..... I have my amp's lpf set to 80 and my hpf at 80. I have no clue if those numbers are right. I just pulled them from reading posts of other peoples settings.
> Now my HU has the same setting. what happens if i change the HU's LPF to 60 and HPF to 120 but leave the amp alone...which one rules out.. I would think that since the amp comes after the HU the Amp settings rule... way to many duplicate settings. I dont know which ones to set.
> I have a slope setting on my HU....1-3 what the heck is that??? I dont know so i set it in the middle 2.
> I hope you guys go easy on my ignorance...



The highest high pass filter wins, no matter where it is in the signal chain. If your amp high passes at 80hz, and your head unit high passes at 120hz, the speakers effective high pass is at 120hz.

Opposite for low pass, the lowest low pass wins. If your amps low pass is at 80hz, and your head units is at 60, your speakers effective low pass is at 60hz.

As far as your slope settings, I'm going to guess 1, 2 and 3 mean first order, second order, and third order, which means 6db, 12db, and 18db per octave.


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## huckorris (Sep 2, 2009)

bmiller1 said:


> So huck, is an LPF a must for any ported enclosure? I mean, I know it's not critical because I have one in my trunk with no filter. But, for managing the quality of your sound, it's a no-brainer? I wish i understood the slope/octave thing but, I haven't got to that chapter yet.


Generally you want both a lpf and hpf on ported box.


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## bmiller1 (Mar 7, 2010)

huckorris said:


> Generally you want both a lpf and hpf on ported box.


Thanks. Yeah, I've got both on my HU and amp. I'm an idiot but, at least the guy that put it in wasn't.


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

lithoman said:


> Help Another dumb question..... I have my amp's lpf set to 80 and my hpf at 80. I have no clue if those numbers are right. I just pulled them from reading posts of other peoples settings.
> Now my HU has the same setting. what happens if i change the HU's LPF to 60 and HPF to 120 but leave the amp alone...which one rules out.. I would think that since the amp comes after the HU the Amp settings rule... way to many duplicate settings. I dont know which ones to set.
> I have a slope setting on my HU....1-3 what the heck is that??? I dont know so i set it in the middle 2.
> I hope you guys go easy on my ignorance...


Use one or the other, not both... that's really the best way to know... knobs on amps aren't "acccurate" so your 80hz could be 86 or 90 even... 

If you can't defeat the amp crossover, use it, if you CAN, use the HU, that way you have real time control up front... 

IF you can hit both crossovers on the same frequency, you can double your slope, one cutting 12db/oct, the other doing the same... creating a 24db/oct slope.. but again, that's IF you can hit the same on both, which would be difficult.. 

One or the other..


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

TOOSTUBBORN2FAIL said:


> The highest high pass filter wins, no matter where it is in the signal chain. If your amp high passes at 80hz, and your head unit high passes at 120hz, the speakers effective high pass is at 120hz.
> 
> Opposite for low pass, the lowest low pass wins. If your amps low pass is at 80hz, and your head units is at 60, your speakers effective low pass is at 60hz.
> 
> As far as your slope settings, I'm going to guess 1, 2 and 3 mean first order, second order, and third order, which means 6db, 12db, and 18db per octave.


This...


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## UNBROKEN (Sep 25, 2009)

Here's one.....can you set up a bandpass configuration using both your head unit and your amps crossovers ?

On my HU I'm using the "standard" setting, not the "multi" which is the active setting.
I use front high, front low, rear and sub.
Here's the chart:









Now...given those standard settings can I use the head unit for one end and the amps for the other end to come up with a bandpass like the multi mode has ?

I'm lost on how to get my midbasses to play from 60-70hz up to 2-300. Right now I think they're playing down too low and I can't figure out how to bump it up.

At this point I think it would be easier to use one of the amps pass through RCA's and add another amp for rear fill that way and use the DRZ 4 way active. If I did that it's very obvious how to set each speaker how you want it.


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

UNBROKEN said:


> Here's one.....can you set up a bandpass configuration using both your head unit and your amps crossovers ?
> 
> On my HU I'm using the "standard" setting, not the "multi" which is the active setting.
> I use front high, front low, rear and sub.
> ...


Wait.... you're running a DRZ and you are running "4way" and you aren't running the DRZ full active from the HU in the first place.... 

Why do you own a DRZ.... :laugh:


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## UNBROKEN (Sep 25, 2009)

It's a learning curve thing. Figured I'd use the standard setting to learn the art of tuning _then_ move into an active set-up.
I have enough channels to go active now I'd just lose my rear fill which I do like in a truck this size.


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

I'm jus playin man... I know the feeling with my 701.. lots to re-learn..


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## lithoman (Jul 21, 2011)

Aaron'z 2.5RS/WRX said:


> Use one or the other, not both... that's really the best way to know... knobs on amps aren't "acccurate" so your 80hz could be 86 or 90 even...
> 
> If you can't defeat the amp crossover, use it, if you CAN, use the HU, that way you have real time control up front...
> 
> ...


Thanks for the reply....just to confirm, I should turn off the LPF and HPF on the amp and use the LPF and HPF on the HU? I will give that a try.


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## BuickGN (May 29, 2009)

I'm pretty new to this thing but when I went active I started somewhat close to what the factory passives were set at.

After reading hours worth of posts on the subject I kept lowering my crossover points on the midbass, mids, and tweeters. I could never get it to sound as good as it did on the passives. So finally, just this week I started all over and raised the crossover points on every driver and I was rewarded with the best sounding system to date.

I ended up with everything higher than the majority run but it sounds so good this way.

Subs go from 20hz/6db (only because the MS8 won't let it go any lower) to 100hz/24. 

Mid bass go from 100hz/24db to 900hz/24db

Mids go from 900hz/24db to 5,000hz/24db 

Tweeters play from 5k/24db and up.

The system as a whole sounds 10x better than it did. So I would start with some fairly conservative points and use the forum as a rough guide but use your ears for the final result and don't be afraid to try something that's not so popular.


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## huckorris (Sep 2, 2009)

lithoman said:


> Thanks for the reply....just to confirm, I should turn off the LPF and HPF on the amp and use the LPF and HPF on the HU? I will give that a try.


A big reason to do that is because it's hard to hear a clear difference when you have to go back to your amp, adjust the settings, then get back in the drivers seat for a listen. It would be much easier and more convenient to just sit in the drivers seat and adjust it WHILE you listen to it from the listening position. I hope that made sense.


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## lithoman (Jul 21, 2011)

huckorris said:


> A big reason to do that is because it's hard to hear a clear difference when you have to go back to your amp, adjust the settings, then get back in the drivers seat for a listen. It would be much easier and more convenient to just sit in the drivers seat and adjust it WHILE you listen to it from the listening position. I hope that made sense.


Understand..i was not sure if an amps filters were better then the HUs filters.


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## huckorris (Sep 2, 2009)

lithoman said:


> Understand..i was not sure if an amps filters were better then the HUs filters.


Actually now that I think about it more, sometimes the pots (knobs) on an amp are not all that well marked, and sometimes not even linear.

For example it will have a little dot at 80 hz, and one at 120 hz, and you kinda guess exactly where to put it in between. But a difference of 5 hz or so wouldn't really make that big of a difference. It's more about what sounds good.

Head units will tell you exactly what frequency it is.


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## kevin k. (May 5, 2005)

Aaron'z 2.5RS/WRX said:


> IF you overlap the crossover points, you naturally boost in the overlap because 2 drivers are producing the same frequencies... So if you like the boost, go for it, some don't and it's hard to EQ out and RTA around...ect..


Not necessarily "boost" as one or both of the drivers may have a dip in output or decreasing output and overlapping could actually smooth to a flat response. An example would be the Hiquphon OWII tweeter that has a shelved down response of 2 - 3 db's from 2 kHz to approx. 4.5 kHz that could be smoothed to flat with a mid overlap in that region.



Aaron'z 2.5RS/WRX said:


> IF you GAP @the crossover point, you can cut "naturally" at the crossover point, should you want/need to...


Same as the above, but inversely... having a driver, e.g., mid, with a rising response can allow you to take advantage of that rise and underlap x-over points to sum to a flat response. A couple great examples of such a mid are the AudioTechnology C-Quenze 15 cm and 18 cm drivers that rise up 6 db or more as they approach 4, 5, and 6 kHz.


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

so same thing but different... my post was just a generalization.. lol.. but thanks...


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## Vital (Feb 23, 2010)

I have SR5250 and SR6500 and was looking into some possible 3-way set ups using some of what i have. Here's reply i got over at Polk's forum. Might not be exactly what OP asked but good info for beginers (which IS what op asked for) made a lot of sense to me:



> There are two things you have to look at. The physical capability of the drivers and driver placement. If I was going to run a 3 way here is what I would look at doing. Again there's no right or wrong, just different ways.
> 
> I would want my midbass, deep in the floorwell. Either in kicks or by cutting some metal and mounting them free air. Mounting them as far forward as possible would give better depth perception. For me this would be very important since my stock locations are high on the door just about where the dash starts. If your stock location is low on the doors and a bit forward, thats an edge to start with. I would use the midbass for the 50~400 range.
> 
> ...


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## val69 (Apr 7, 2011)

Can someone explain 6db, 12db, 18db, and 24db on my crossover choices?

Should they match on amp, speakers, headunit?


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## BoomHz (Apr 20, 2007)

OP, would you mind stating what your setup consist of? I see your sig, but can't make it all out. But as somewhat stated earlier, "your running a DRZ"? You have ample room to do minimal setting on the amps and do tons from the deck. 

Give us a little run down of whats up


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## thomasluke (Jun 10, 2011)

From what i just read your trying to figure out what xovers are "better".
The thing is neither is really better.
I went back and forth between the xovers on my hu and amp for awhile myself.
The conclusion i came to was that it sounded somewhat the same. 
The only diff is the hu is easier to use and you know exactly were your at.
I suggest setting it with the hu only using the amps as amps no boost set to all or fullpass listen for a while i tihnk went like two or three days.
Then bring your amps into play just playing with diff xover point for a while.
If you like what you hear then leave it if not you can always go back to just the hu.
Oh and 6/12/24 is how quickly the sound with drop after the xover freq.
The 24 will drop off much quicker than the 6 lets i would say about 4 times as much.


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## UNBROKEN (Sep 25, 2009)

BoomHz said:


> OP, would you mind stating what your setup consist of? I see your sig, but can't make it all out. But as somewhat stated earlier, "your running a DRZ"? You have ample room to do minimal setting on the amps and do tons from the deck.
> 
> Give us a little run down of whats up


Sorry for not posting sooner...I hate leaving a thread and leaving people hanging. I was doing some travelling and didn't have time for net access.

Anyway....

Obviously the DRZ to start.

I'm running a Focal 165KRX3 set up front.
Front mids and tweeters are in the a-pillars.









Midbasses are in fully sealed and deadened doors, mounted solid on over 2" of MDF, which was also sealed from water.









Rear components are in the stock locations behind the rear seat.

Front mids and tweeters run off the fron half of a JL 300/4, front midbass runs off a 300/2, rear comps run off the rear half of the 300/4 and the 10W7 runs off a 1000/1 in a sealed enclosure in the front center console.










I'm using the standard mode on the DRZ right now but I'm seriously considering dumping the rear fill and switching to multi mode and 4 way active up front.


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## lithoman (Jul 21, 2011)

thomasluke said:


> From what i just read your trying to figure out what xovers are "better".
> The thing is neither is really better.
> I went back and forth between the xovers on my hu and amp for awhile myself.
> The conclusion i came to was that it sounded somewhat the same.
> ...


Trying this right now. ty


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## BoomHz (Apr 20, 2007)

Nice.......few more things and we'll hook you up to the best of your possible set up (not physically being there)................


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