Help With Tweeter Crossover


Jun 9, 2018
89
2
Washington
Hi everyone,

So I'm trying to finally install tweeters in my 1994 Bronco. So far I have the following:

1X 12" Rockford Fosgate 750W sub in the back powered by a 1200W Rockford Fosgate amp
2x 7" Denovo Audio Anarchy 7" Midbass woofers in the doors powered by a Pioneer GM8604 Connected for 2 channel output (so each speaker gets 200W @4ohms)

Anyway, herein lies the issue: I have another GM8604. This is a 4 channel, 100W per channel amp. 2 channels are already powering two Alpine 6x9 speakers in the back seat area, and I'd like the other two channels to power my tweeters. The tweeters I have are these:

https://ebay.to/3usUrxe

These are the 100W Alpine HiEnd 28mm tweeters that I heard great reviews about.

Now the issue starts at the headunit. I'm willing to spend up to $600 on a double-dine head unit, that has crossover capabilities, but most I've seen have only 6 channel outputs (front, rear, sub). So my idea was to obviously run the front to the 7" Woofers, sub to sub in the back and then split the rear channel with a y-splitter and run both through the second GM8604. One channel would go to the 6x9s and other other would go to the tweeters.

Now this may be a stupid question, and forgive me for it, but that would mean I couldn't apply a high-pass filter in the head unit crossover, because both the 6x9s and tweeters would be restricted to the high pass filter, correct? So how do I mitigate this, since tweeters HAVE to have a HPF applied so I don't blow them out. The amps come with a built-in HP and LP filter per channel, but that's only adjustable from 40-500Hz.

I was thinking of just putting some micro-farad capacitor in series to work as a HPF to cut off all the frequencies under ~2kHz (I determined this value by doubling the resonant frequency from the Ebay page's bode plot, where it appears to have a resonant frequency of about 800Hz.), but I'm worried that may not be enough or I may not get a quality High-pass filter.

Sorry for the long post, but in short my question just boils down to: how can I apply a High-pass filter to JUST my tweeters if their signal comes from a single input that is also going to the 6x9 speakers in the back? I know I could get a DSP but with the 3 amplifiers I'm already running out of space in my car haha!

Any help appreciated!

-BND
 

hispls

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Sep 10, 2009
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Delete the rears, use active crossover between the Anarchy and tweeters. Be mindful here, those Anarchys start breaking up much lower than most dedicated midranges so you'll want to cross your tweeters low-ish. Best pairing I've had for mine as 2 way system has been with some 4x6" planars. Also just a capacitor for crossing over is 3dB per octave which may not do so hot protecting your tweeters (or blending into the mids). IF you want to DIY passive crossovers consider spending up into 2nd or 3rd order. Poly caps and air core coils for preference (ribbon coils are supposedly best but I doubt you'd hear the difference). It will turn into an expensive project.
 
Jun 9, 2018
89
2
Washington
  • Thread Starter Thread Starter
  • #5
Delete the rears, use active crossover between the Anarchy and tweeters. Be mindful here, those Anarchys start breaking up much lower than most dedicated midranges so you'll want to cross your tweeters low-ish. Best pairing I've had for mine as 2 way system has been with some 4x6" planars. Also just a capacitor for crossing over is 3dB per octave which may not do so hot protecting your tweeters (or blending into the mids). IF you want to DIY passive crossovers consider spending up into 2nd or 3rd order. Poly caps and air core coils for preference (ribbon coils are supposedly best but I doubt you'd hear the difference). It will turn into an expensive project.
Ha, the entire car has been an expensive project since day 1! :D
On a serious note, thank you for the info! Could you elaborate on the Anarchy speakers? What do you mean by "breaking up much lower"?
I also got a few oscilloscopes so whatever tweeter crossover I end up designing, I can check the frequency response.

Thanks again for the help!
 
Jun 9, 2018
89
2
Washington
  • Thread Starter Thread Starter
  • #6
Delete the rears, use active crossover between the Anarchy and tweeters. Be mindful here, those Anarchys start breaking up much lower than most dedicated midranges so you'll want to cross your tweeters low-ish. Best pairing I've had for mine as 2 way system has been with some 4x6" planars. Also just a capacitor for crossing over is 3dB per octave which may not do so hot protecting your tweeters (or blending into the mids). IF you want to DIY passive crossovers consider spending up into 2nd or 3rd order. Poly caps and air core coils for preference (ribbon coils are supposedly best but I doubt you'd hear the difference). It will turn into an expensive project.
So I may have just found a solution to all my problems:

https://amzn.to/3vUnBW8

From the reviews, this seems to be a pretty good DSP, with the only caveat being that some people experience noise issues with it, but from the forums I've read, it appears to be a power issue and the provided power supply and cables being junk, but that's not a problem, since I can diagnose these issues easily with all the equipment I have.

But anyway, I can run this DSP, and set the crossovers on IT instead of on the head unit, which is great, this will help with the tweeter situation. The other thing this helps with is purely practicality. This DSP has a physical knob for volume control, which the head unit I'm looking at doesn't, and the knob can also be used as a preset selector.

The preset selector is what sold me, because I'll probably keep the 6x9s in the back, just because they're already there and hooked up, but I can set presets where the signal going to them is blocked, so they'll essentially be off. This is excellent, since I get that from an audiophile perspective, it's better they weren't there, and I'll probably appreciate it when I'll listen to more calm music, but I often just listen to thrash / speed metal and the rear 6x9s provide an extra "thump" in the music at the expense of actual sound quality, so being able to switch between the two presets would be excellent.

Then again, I am fairly new to all this, what is your opinion on my proposed solution?

BND
 

hispls

CarAudio.com Veteran
5,000+ posts
10+ year member
Sep 10, 2009
11,858
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Central Maine
Then again, I am fairly new to all this, what is your opinion on my proposed solution?
I haven't used that unit but Dayton is a good brand in general and I haven't seen anything bad posted about them. Also I think a lot of DIY guys use them so I'd imagine common troubleshooting issues are all just a google search away.

Consider buying direct from PartsExpress and you may get better support/service if it doesn't just work out of the box.

Could you elaborate on the Anarchy speakers?
In layman's terms, the heavier the moving mass is of a loudspeaker, the worse it performs at high frequencies. ANYTHING with big power handling and excursion will by necessity be (comparatively) heavy moving mass.
Notice the 2 way kit they sell for these crosses over at only 1400hz . From my own experience I can confirm that you'll have best results crossing off there or not much higher. Again, consider a large format tweeter if you're trying to go 2 way with those.

 
Jun 9, 2018
89
2
Washington
  • Thread Starter Thread Starter
  • #8
I haven't used that unit but Dayton is a good brand in general and I haven't seen anything bad posted about them. Also I think a lot of DIY guys use them so I'd imagine common troubleshooting issues are all just a google search away.

Consider buying direct from PartsExpress and you may get better support/service if it doesn't just work out of the box.


In layman's terms, the heavier the moving mass is of a loudspeaker, the worse it performs at high frequencies. ANYTHING with big power handling and excursion will by necessity be (comparatively) heavy moving mass.
Notice the 2 way kit they sell for these crosses over at only 1400hz . From my own experience I can confirm that you'll have best results crossing off there or not much higher. Again, consider a large format tweeter if you're trying to go 2 way with those.

[/URL]
Would 1500-1600Hz be good? I looked at the tweeters again and the resonant frequency is ABOUT 750Hz. I may actually get the JL Audio TWK 88 as a DSP and that allows a 48db/octave slope which is nuts so would the tweeters and the Anarchys crossed over at roughly 1500Hz with 48db slopes be good? I'm comfortable running the tweeters as low as 1500-1600Hz if the slopes are that steep so sub-1k frequencies won't creep in as they would with a 6 or 12db slope.

Again, very much appreciate the help!
 

hispls

CarAudio.com Veteran
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Sep 10, 2009
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Would 1500-1600Hz be good? I looked at the tweeters again and the resonant frequency is ABOUT 750Hz. I may actually get the JL Audio TWK 88 as a DSP and that allows a 48db/octave slope which is nuts so would the tweeters and the Anarchys crossed over at roughly 1500Hz with 48db slopes be good? I'm comfortable running the tweeters as low as 1500-1600Hz if the slopes are that steep so sub-1k frequencies won't creep in as they would with a 6 or 12db slope.

Again, very much appreciate the help!
That's where I'd aim for for crossover point, and yes you will want to take care of your tweeter and don't try to push it to max rated power crossed that low.

I've been using those Adire knockoff 6.5" woofers for a long time now and really like them, but the Anarchy version is definitely the most challenging for mounting and pairing into 2 way system.
 
Jun 9, 2018
89
2
Washington
  • Thread Starter Thread Starter
  • #10
That's where I'd aim for for crossover point, and yes you will want to take care of your tweeter and don't try to push it to max rated power crossed that low.

I've been using those Adire knockoff 6.5" woofers for a long time now and really like them, but the Anarchy version is definitely the most challenging for mounting and pairing into 2 way system.
This is going to be quite a challenge, including mounting these massive speakers into my door, but should be a fun project! Thank you for the help, I'll be working on this for the next few days and I'll keep this thread updated.

Thanks,

BND
 
Jun 9, 2018
89
2
Washington
  • Thread Starter Thread Starter
  • #11
That's where I'd aim for for crossover point, and yes you will want to take care of your tweeter and don't try to push it to max rated power crossed that low.

I've been using those Adire knockoff 6.5" woofers for a long time now and really like them, but the Anarchy version is definitely the most challenging for mounting and pairing into 2 way system.
12

You weren't kidding about crossing over at ~1500Hz. I installed the speakers yesterday and actually tried them, hooked up to the amplifier and all.. Man, it's like having two more subwoofers! Well, not quite, far more midbass than my Image DynaMICS 12", but still. I'm excited to finish this project! I'm instlling tweeters tomorrow and then picking up the DSP this week hopefully.
 
Jun 9, 2018
89
2
Washington
  • Thread Starter Thread Starter
  • #12
That's where I'd aim for for crossover point, and yes you will want to take care of your tweeter and don't try to push it to max rated power crossed that low.

I've been using those Adire knockoff 6.5" woofers for a long time now and really like them, but the Anarchy version is definitely the most challenging for mounting and pairing into 2 way system.
I just remembered I forgot to ask, what should my crossover point be for my subwoofer and midbass? I have an Image Dynamics 750W sub in a ported box with a 1200W Rockford Fosgate amp.

Thanks!
 

hispls

CarAudio.com Veteran
5,000+ posts
10+ year member
Sep 10, 2009
11,858
636
Central Maine
I just remembered I forgot to ask, what should my crossover point be for my subwoofer and midbass? I have an Image Dynamics 750W sub in a ported box with a 1200W Rockford Fosgate amp.

Thanks!
Very dependent on how much power you're running into them, but probably no lower than 40hz unless they're in a box.

Dial in your gains first,, then turn off the sub, play some bass heavy tracks and turn the high pass crossover down until you start running into excursion. Bear in mind if you overlap a lot you may wind up with some phasing issues causing cancellation around the crossover points so once you've found your sweet spot for crossover points it would be worth testing running the sub reverse phase to see which blends in better.
 
Jun 9, 2018
89
2
Washington
  • Thread Starter Thread Starter
  • #14
Very dependent on how much power you're running into them, but probably no lower than 40hz unless they're in a box.

Dial in your gains first,, then turn off the sub, play some bass heavy tracks and turn the high pass crossover down until you start running into excursion. Bear in mind if you overlap a lot you may wind up with some phasing issues causing cancellation around the crossover points so once you've found your sweet spot for crossover points it would be worth testing running the sub reverse phase to see which blends in better.
They are in a box, technically. I sealed off the doors to the point where they're practically sealed tight, and air can't move out. I just installed the TWK 88 and connected everything today, everything works great except the midbass woofers in the doors. I did a bandpass from 100-1400Hz and not sure if the gain was set wrong or something but there was almost no addition from them. They produced sound, but nothing more really...

Going to try and figure it out tomorrow. Any advice?

BND
 
Jun 9, 2018
89
2
Washington
  • Thread Starter Thread Starter
  • #15
Very dependent on how much power you're running into them, but probably no lower than 40hz unless they're in a box.

Dial in your gains first,, then turn off the sub, play some bass heavy tracks and turn the high pass crossover down until you start running into excursion. Bear in mind if you overlap a lot you may wind up with some phasing issues causing cancellation around the crossover points so once you've found your sweet spot for crossover points it would be worth testing running the sub reverse phase to see which blends in better.
Nevermind, the Pioneer has a weird Gain scheme. It tells you what the input should be not what the output will be. Since I;m running this from a bluetooth output, the output voltage is roughly 500mV, not the 4V it usually is from pioneer head units, and that's what I set my gain to haha! I will have a friend come over tomorrow to help me set my gain with my oscilloscope. I tried to today but it was too late to blast 1kHz test tones through the neighborhood.

BND
 

hispls

CarAudio.com Veteran
5,000+ posts
10+ year member
Sep 10, 2009
11,858
636
Central Maine
They are in a box, technically. I sealed off the doors to the point where they're practically sealed tight, and air can't move out.
For all intents and purposes that's like running those infinite baffle. I meant a box like some of the DIY bookshelf or subwoofer cabinet projects for these where they'd be in like 1/4 cubic foot or some small airspace that would control the cone.
 
Jun 9, 2018
89
2
Washington
  • Thread Starter Thread Starter
  • #17
For all intents and purposes that's like running those infinite baffle. I meant a box like some of the DIY bookshelf or subwoofer cabinet projects for these where they'd be in like 1/4 cubic foot or some small airspace that would control the cone.
Hm... so for some reason I still can't get my midbass woofers to sound any good. the rest of the system is great but right now all I can really hear is the sub and tweeters. I double checked all connections, I am running a bridged Pioneer GM8604 amp to the speakers (the 7" anarchys), so they're getting 200W per speaker with very thick copper wire cables going to them. I am crossing over from 100Hz-1500Hz but it just still all sounds very muddy. I listen to modern metal songs for testing and I was expecting these speakers to carry the low end guitars and kicks but right now it's not doing any of that.

Any ideas?
 

hispls

CarAudio.com Veteran
5,000+ posts
10+ year member
Sep 10, 2009
11,858
636
Central Maine
Hm... so for some reason I still can't get my midbass woofers to sound any good. the rest of the system is great but right now all I can really hear is the sub and tweeters. I double checked all connections, I am running a bridged Pioneer GM8604 amp to the speakers (the 7" anarchys), so they're getting 200W per speaker with very thick copper wire cables going to them. I am crossing over from 100Hz-1500Hz but it just still all sounds very muddy. I listen to modern metal songs for testing and I was expecting these speakers to carry the low end guitars and kicks but right now it's not doing any of that.

Any ideas?
Well, you want to run the HPF lower than 100hz for starters.

Keep in mind XBL^2 drivers trade efficiency for low distortion so you may have to put some power to them.
 

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