Is there a (relatively) simple method to selecting active crossover points & slopes?

2433 Views 17 Replies 12 Participants Last post by Holmz, Sep 17, 2021

hella356

Discussion Starter · Jun 14, 2021

I'm pretty green with this stuff. Have a Minidsp CDSP-DL 8x12 that I'm slowly learning to use. I keep seeing words to the effect of "set the desired crossover points and slopes" in setup guides, but how the heck do I determine exactly what those are? As of now, I've been pretty much arbitrarily picking points, while sticking with LR24 slopes. Beyond keeping the tweeter high pass well above Fs, and midwoofer low pass below beaming point, I feel adrift in a willy-nilly selection process. I'm just starting to learn REW, which I assume will play a role.

Anyone have quick & easy, tried & true steps to at least get in the proper ballpark? Not looking for instant perfection, and I realize it will take time to narrow it down to a "perfect" choice, but in the meantime it would be fantastic to get the stereo to, say, 80% fairly soon!

1 - 18 of 18 Posts

metanium

· #2 · Jun 15, 2021

This is only a recommendation to get you in the ballpark (as requested) so don’t take this a gospel. For tweeters high-pass at double the fs at minimum. Midranges high-pass at 1.5 the fs. and low-pass at the tweeters high-pass point. Mid-bass can be high-passed as low as their fs, but if you have a subwoofer, high-pass them at 80Hz. Let you subwoofer handle everything below 80Hz, though if you’re following most automotive house curves, you may want to underlap the crossover points between the subwoofer and mid-bass.

You’ll want to keep all of your low-pass point below beaming point if each driver, except the tweeter, which will play up to it’s limit.

I personally try to get all (most of) of the vocal range out if one driver (pair), so I’ll try to run miss from 250 - 3000Hz of so. By doing this, I don’t have lower vocals pull downward to where my midbasses are.

Reactions: 2

miniSQ

· #3 · Jun 15, 2021

For your 2 way set up...i would run it like this. ( all 24db LR)

Tweeter HP @2500
Mids 80Hz - 2500hz
subwoofer LP 60hz

Then you can adjust the XO between woofer and tweeter down to about 2200hz and see how it sounds.
The rest i think i would leave alone unless you hear things that don't sound right to you.
Report back those things and the tuning gurus here can help you out.

hella356

Discussion Starter · #4 · Jun 15, 2021

Thanks. It's a 2-way setup. I've basically been earballing the crossovers, but that has proven to be a bit maddening! I've been able to get it to sound good, although I feel like my lack of experience is leaving quite a bit out.

hella356

Discussion Starter · #5 · Jun 15, 2021

OK. Thanks for the starting points & "do it by ear for now" encouragement. I did some rudimentary measurements in REW, but not too sure what to do with that in terms of crossover settings. Optimistic I'll get there eventually - hard to be patient when I feel pretty close to the finish line, but patient I must remain.

miniSQ

· #6 · Jun 15, 2021

hella356 said:
Thanks. It's a 2-way setup. I've basically been earballing the crossovers, but that has proven to be a bit maddening! I've been able to get it to sound good, although I feel like my lack of experience is leaving quite a bit out.

in my experience level setting is more critical than XO settings. Its so easy to think something sounds harsh and blame it on XO settings when in fact your levels are off.

Reactions: 2

hella356

Discussion Starter · #7 · Jun 15, 2021

miniSQ said:
in my experience level setting is more critical than XO settings. Its so easy to think something sounds harsh and blame it on XO settings when in fact your levels are off.

Interesting. I did the "5 channel" initial Dirac run to get TA & levels, although my ears told me the right woofer was too loud. Is there a better way to ensure levels?

ckirocz28

· #8 · Jun 15, 2021

2

hella356 said:
I'm pretty green with this stuff. Have a Minidsp CDSP-DL 8x12 that I'm slowly learning to use. I keep seeing words to the effect of "set the desired crossover points and slopes" in setup guides, but how the heck do I determine exactly what those are? As of now, I've been pretty much arbitrarily picking points, while sticking with LR24 slopes. Beyond keeping the tweeter high pass well above Fs, and midwoofer low pass below beaming point, I feel adrift in a willy-nilly selection process. I'm just starting to learn REW, which I assume will play a role.

Anyone have quick & easy, tried & true steps to at least get in the proper ballpark? Not looking for instant perfection, and I realize it will take time to narrow it down to a "perfect" choice, but in the meantime it would be fantastic to get the stereo to, say, 80% fairly soon!

I believe these are from Helix.

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Reactions: 1

LBaudio

· #9 · Jun 15, 2021

one of the factors to determine x-o point is also beaming point for each driver, and MiniSQ gave you pretty good advice where to start including gap between SW and MB.
setting acoustical phase trough entire freq band is also crutial,....should be pretty close with 24 dB/Oct slopes...

SWRocket

· #10 · Jun 16, 2021

I've seen, and posted, this question many times and still I feel like it's confusing. The Helix chart above, as an example, is about the electric crossover points, I believe, not the acoustic ones.
I say this, because without an RTA, you can't gauge the acoustic crossover correctly.
The advice I've seen here many time, and have followed, is to set whatever electric crossover points (in the DSP) get you closest to the acoustic crossover points and then tune (EQ) to get it right. But I don't see how you do that by ear...

cathul

· #11 · Jun 16, 2021

You could always tune each driver flat to the target curve one octave below and above the desired acoustical crossover point and then set LR24db electrical crossovers.

Reactions: 2

SWRocket

· #12 · Jun 16, 2021

cathul said:
You could always tune each driver flat to the target curve one octave below and above the desired acoustical crossover point and then set LR24db electrical crossovers.

For sure. There are several techniques to achieve this. But even this technique would require an RTA and Mic no?

Reactions: 1

hella356

Discussion Starter · #13 · Jun 16, 2021

Thanks, guys. I do have a UMIK-1 that came with the miniDSP and have REW on the laptop, although I'm just barely learning how to use it. It seems that RTA is the way to zero in, but my lack of experience with it has me going by ear for now. So the idea is to measure the individual drivers without crossovers (except a safety high pass for the tweeters), determine where they naturally roll off, and set the crossover points to more or less match those points? And I suppose use my ears to fine-tune the points once RTA has gotten them in the ballpark?

bills72sj

· #14 · Jul 7, 2021

This is only a recommendation to get you in the ballpark (as requested) so don’t take this a gospel. For tweeters high-pass at double the fs at minimum. Midranges high-pass at 1.5 the fs. and low-pass at the tweeters high-pass point. Mid-bass can be high-passed as low as their fs, but if you have a subwoofer, high-pass them at 80Hz. Let you subwoofer handle everything below 80Hz, though if you’re following most automotive house curves, you may want to underlap the crossover points between the subwoofer and mid-bass.

You’ll want to keep all of your low-pass point below beaming point if each driver, except the tweeter, which will play up to it’s limit.

I personally try to get all (most of) of the vocal range out if one driver (pair), so I’ll try to run miss from 250 - 3000Hz of so. By doing this, I don’t have lower vocals pull downward to where my midbasses are.

Thank you for sharing this info. I am not as far along as the OP but I am at the same point with my new RF DSR1 connected to my existing amps and speakers. You have given me a place to start. Below is my long winded thread.

Old guy, old car, been upgrading it with cheap gear for...

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Reactions: 1

bobgodd

· #15 · Sep 17, 2021 (Edited)

I might get flamed for this, but I have a similar setup to you, and I let the Dirac tune handle it all. I set my crossovers based on arbitrary points starting off, then adjusted while playing some music I’m very familiar with until it sounded best to my ears. I downloaded REW but haven’t used it for one second. If Dirac can match the house curve pretty much perfectly, I don’t think I can do any better.

I did a rough (as precise as reasonably possible) time alignment with metric tape measure, then followed this post I found here about nulling that made a lot of sense to me. So I used nulling to fully dial in time alignment, however Dirac also adds delay, so if you’re going to use Dirac, you’re going to have to live with its results, or else you’re just correcting something that’s already trying to be a correction.

dumdum

· #16 · Sep 17, 2021

bills72sj said:
This is only a recommendation to get you in the ballpark (as requested) so don’t take this a gospel. For tweeters high-pass at double the fs at minimum. Midranges high-pass at 1.5 the fs. and low-pass at the tweeters high-pass point. Mid-bass can be high-passed as low as their fs, but if you have a subwoofer, high-pass them at 80Hz. Let you subwoofer handle everything below 80Hz, though if you’re following most automotive house curves, you may want to underlap the crossover points between the subwoofer and mid-bass.

You’ll want to keep all of your low-pass point below beaming point if each driver, except the tweeter, which will play up to it’s limit.

I personally try to get all (most of) of the vocal range out if one driver (pair), so I’ll try to run miss from 250 - 3000Hz of so. By doing this, I don’t have lower vocals pull downward to where my midbasses are.

Thank you for sharing this info. I am not as far along as the OP but I am at the same point with my new RF DSR1 connected to my existing amps and speakers. You have given me a place to start. Below is my long winded thread.

Old guy, old car, been upgrading it with cheap gear for...

That’s not really how it works, if the timing and phase matches well at the crossover points you can cross above that and you won’t get the vocals pulling down, the same way as your midbass should come from eye level and the sub bass also

If the midbass pulls down or the sub bass pulls back your levels and/or timing is off

DoubleCrown

· #17 · Sep 17, 2021

Learn to use the RTA in REW first, there is so much info on the minidsp site, YouTube, diyma etc. Tuning by ear for us amateurs is a total waste of time.

Holmz

· #18 · Sep 17, 2021

hella356 said:
I'm pretty green with this stuff. Have a Minidsp CDSP-DL 8x12 that I'm slowly learning to use. I keep seeing words to the effect of "set the desired crossover points and slopes" in setup guides, but how the heck do I determine exactly what those are? As of now, I've been pretty much arbitrarily picking points, while sticking with LR24 slopes. Beyond keeping the tweeter high pass well above Fs, and midwoofer low pass below beaming point, I feel adrift in a willy-nilly selection process. I'm just starting to learn REW, which I assume will play a role.

Anyone have quick & easy, tried & true steps to at least get in the proper ballpark? Not looking for instant perfection, and I realize it will take time to narrow it down to a "perfect" choice, but in the meantime it would be fantastic to get the stereo to, say, 80% fairly soon!

Well if you know where the speakers play well…

1 - 18 of 18 Posts

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