# 3-Way Active Crossover Points, where to start?



## Evl5150 (Jun 20, 2018)

I have this posted on another forum as well but it is known that this site is a little more knowledgeable on SQ things. I have a 2008 Pontiac G6 GT Coupe with 3-way factory mounting locations in the doors. I am doing an active build with the items listed below. It will be US Acoustics amp for the mids and midbass, RF 250A2 for the tweeters and US Acoustics for the Sub. Running the show is my 3Sixty.3.

Where should I set the crossovers initially? Before I do an RTA or anything like that... Literally the starting point with all EQ's flat and no enhancements. Here are the speaker sizes and locations:

Alpine 38mm Tweeter - High in the door, factory location, off axis. (Alpine says 800 - 45Khz [-10db]) (4ohm)

Digital Design 2.75" Midrange - Middle Lower door, Just above the woofer, factory location, off axis (160 - 20Khz) (4ohm)

SilverFlute 6.5" Woofer - Lower door, factory location, off axis (50 - 3... 4... 5Khz?) (4ohm)

NO REAR SPEAKERS

Dayton Ultimax 10" Subwoofer - Trunk, (25 - 1.5Khz) Dual 2ohm (1ohm)

I have read so many different post and there are so many crossover points... but where to start with a given speaker size?


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## Ifixtheinternet (Jan 29, 2016)

Silver flutes would be happy crossed at 2k or lower in my experience, and general rule of thumb is having a goal of covering 1 octave per driver if possible.

I would start with the following if you can choose 24db for your slope.


Sub: LPF: 60hz 
Woofer: 80hz - 2k
Mid: 2k - 4k 
Tweet: HPF: 4k

I think the one that merits the most focus is woofer to mid. It may sound better with that moved lower, like 1.5k rather than 2k.

Sent from my Pixel XL using Tapatalk


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## Evl5150 (Jun 20, 2018)

Ifixtheinternet said:


> Silver flutes would be happy crossed at 2k or lower in my experience, *and general rule of thumb is having a goal of covering 1 octave per driver if possible*.
> 
> I would start with:
> 
> ...


Thank you... this is going to get interesting.


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## SkizeR (Apr 19, 2011)

those posted frequency ranges are more marketing than anything. The low side is usually the drivers FS, the high side is usually the -3db )or even more) point in the rolloff after cone breakup. ignore all of that. dont cross any tweeter below 2k. Start at 80-300, 300-3k, 3k and up. All 24db slopes


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## Evl5150 (Jun 20, 2018)

I am most excited to see what these DD 2.75" mids do. It was a pain to find a speaker close to this size without a coaxial tweeter mounted to it and that wasn't crazy expensive and can handle some power.


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## gijoe (Mar 25, 2008)

Start with how low the particular speaker can play comfortably. 

I'd start with the midbass, don't go any lower than about 80hz, even the most stout 6.5" isn't going to be happy much lower than that. 

Next step is to find how low your midrange can play. There is a lot of vocal content around 2khz, so ideally you don't want to cross two speakers over in the area where we are most sensitive. If your midrange can play down to about 1khz or lower, use that as the next crossover point. You can probably play the midrange from 1khz to 5khz, and let the tweeter take over from there. 

Like SkizeR said, don't expect to go lower than 2khz for any tweeter, and since you are running 3 way, aim much higher than that. Even the best tweeters are pushing their limits at 2khz, let the midrange take those frequencies, and take the pressure off of the tweeter.


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## Evl5150 (Jun 20, 2018)

gijoe said:


> Start with how low the particular speaker can play comfortably.
> 
> I'd start with the midbass, don't go any lower than about 80hz, even the most stout 6.5" isn't going to be happy much lower than that.
> 
> ...


This is exactly what made sense in my brain. This may not be as hard as I think it should be.


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## Evl5150 (Jun 20, 2018)

Ifixtheinternet said:


> Silver flutes would be happy crossed at 2k or lower in my experience, and general rule of thumb is having a goal of covering 1 octave per driver if possible.
> 
> I would start with the following if you can choose 24db for your slope.
> 
> ...


Those Alpine tweeters in your sig, they from the SPX - 17Pro set? if so, alpine says 38mm, everywhere else says 28mm... can you verify the size?


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## SkizeR (Apr 19, 2011)

gijoe said:


> Start with how low the particular speaker can play comfortably.
> 
> I'd start with the midbass, don't go any lower than about 80hz, even the most stout 6.5" isn't going to be happy much lower than that.
> 
> ...


almost any midrange can cross below 1k. you also dont want to go to high with the low pass on it to the point where it starts beaming. Doing so will create cancellation in the off axis response.


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## SkizeR (Apr 19, 2011)

Evl5150 said:


> Those Alpine tweeters in your sig, they from the SPX - 17Pro set? if so, alpine says 38mm, everywhere else says 28mm... can you verify the size?


99% sure they are 28mm. 28mm is a standard size (1 inch) for a tweeter.


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## Evl5150 (Jun 20, 2018)

SkizeR said:


> 99% sure they are 28mm. 28mm is a standard size (1 inch) for a tweeter.


I am still waiting for mine to arrive.


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## tjframe (Jun 17, 2015)

Wow Ive been running my woofers at 80 to 350. The rationale being that I'd get better performance and loudness from them by limiting the range they are being asked to deliver.

I'm going to fire up the laptop tonight and play around a bit with my 3 way setup. if only it wasn't so damn cold here in Arizona lately (31 degrees outside).. We have to endure unbearable heat most of the year, at least give us super balmy winter plz


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## Evl5150 (Jun 20, 2018)

tjframe said:


> Wow Ive been running my woofers at 80 to 350. The rationale being that I'd get better performance and loudness from them by limiting the range they are being asked to deliver.
> 
> I'm going to fire up the laptop tonight and play around a bit with my 3 way setup. if only it wasn't so damn cold here in Arizona lately (31 degrees outside).. We have to endure unbearable heat most of the year, at least give us super balmy winter plz


Exactly my point... I searched and searched for crossover points per given speaker sizes and I kept coming up short. Hopefully this thread can point others in the right direction too. 

I still think a chart would be cool to show what frequency ranges are best for most common speaker sizes.


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## SkizeR (Apr 19, 2011)

tjframe said:


> Wow Ive been running my woofers at 80 to 350. The rationale being that I'd get better performance and loudness from them by limiting the range they are being asked to deliver.
> 
> I'm going to fire up the laptop tonight and play around a bit with my 3 way setup. if only it wasn't so damn cold here in Arizona lately (31 degrees outside).. We have to endure unbearable heat most of the year, at least give us super balmy winter plz


this is the most common passband for a midbass in a 3 way setup. also, limiting its bandwidth wont exactly make it louder or give you better performance. If you raise the high pass itll increase mechanical power handling, thats about it


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## Ifixtheinternet (Jan 29, 2016)

Evl5150 said:


> Those Alpine tweeters in your sig, they from the SPX - 17Pro set? if so, alpine says 38mm, everywhere else says 28mm... can you verify the size?


Ya they are 28mm.
Thanks for reminding me to update my sig.
Much happier with my mids now 

Sent from my Pixel XL using Tapatalk


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## Evl5150 (Jun 20, 2018)

I plan to use the SilverFlutes because I know they fit in the G6 factory speaker pods... If they sound good, great. If not, I will try the Satori 6.5" Egyptian Papyrus cone speakers as the mounting depth is almost identical. Here is a pic I found with some SilverFlutes in G6 speaker pods. The DD 2.75" speakers will be where this guy mounted the tweeters. They come with 3.5" mounting brackets which will fit exactly in the hole.


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## tonynca (Dec 4, 2009)

This may be useful. I found it in the Audiofrog tune guide written by Andy. It's on their website: https://testgear.audiofrog.com/wp-c...Process-and-Some-Notes-About-Why-it-Works.pdf

It's a great read. 

You don't want to cross over at any of the red or orange if it can be helped. When you start getting into the red or orange, beaming occurs and you will end up not hearing the direct sound if you are not on axis.


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## Evl5150 (Jun 20, 2018)

tonynca said:


> This may be useful. I found it in the Audiofrog tune guide written by Andy. It's on their website: https://testgear.audiofrog.com/wp-c...Process-and-Some-Notes-About-Why-it-Works.pdf
> 
> It's a great read.
> 
> You don't want to cross over at any of the red or orange if it can be helped. When you start getting into the red or orange, beaming occurs and you will end up not hearing the direct sound if you are not on axis.


Outstanding!!! Thank you!!!

I bought some tweeters. Went with the Alpine's. Only Paid $37.98 with free shipping.


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## maybebigfootisblurr (Nov 4, 2011)

Are they the Ebay Alpine's?


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## Evl5150 (Jun 20, 2018)

kfinch said:


> Are they the Ebay Alpine's?


Yes...


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## maybebigfootisblurr (Nov 4, 2011)

If you end up with a DOA, or some issue, I'll send you mine. No need to wait from China again.


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## Evl5150 (Jun 20, 2018)

kfinch said:


> If you end up with a DOA, or some issue, I'll send you mine. No need to wait from China again.


Normally I don't have issues ordering from China... I know it's a crap shoot but so far no real issues to speak of. I am keeping my fingers crossed. Thanks for your offer though... I am gonna cry like a baby if they are DOA and hit you up quick lol


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## Evl5150 (Jun 20, 2018)

Going off the Audiofrog chart above, how does this rudimentary illustration I did look to you all? Still generic starting points but closer to what the speakers ask for based on the Fs of each speaker and trying to stay green on the Audiofrog chart. It's not an accurate representation but you get the idea. Imagine they are 24db crossovers.


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## maybebigfootisblurr (Nov 4, 2011)

Yeah. 2.5k is the lowest those tweeters stay composed.


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## Evl5150 (Jun 20, 2018)

I have an email into DD to find out the Fs of the EX2.75 speakers as they don't have it listed anywhere. Once I have that I can finalize my starting points.


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## 04quadcab (Dec 31, 2017)

Evl5150 said:


> I am most excited to see what these DD 2.75" mids do. It was a pain to find a speaker close to this size without a coaxial tweeter mounted to it and that wasn't crazy expensive and can handle some power.


How much power can they take?

I would argue that the number provided is just marketing. Power ratings are strange things. Is it based on cone excursion or on heat dissipation? If it is cone excursion, then at what frequency? If they are measuring that at 80hz I bet it can take a lot more power if you cross it over at 1,000. At those frequencies there is less energy, so less heat.


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## Evl5150 (Jun 20, 2018)

04quadcab said:


> How much power can they take?
> 
> I would argue that the number provided is just marketing. Power ratings are strange things. Is it based on cone excursion or on heat dissipation? If it is cone excursion, then at what frequency? If they are measuring that at 80hz I bet it can take a lot more power if you cross it over at 1,000. At those frequencies there is less energy, so less heat.


25 - 75w rms and 200w max
160hz - 20Khz
87 dbspl


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## Evl5150 (Jun 20, 2018)

Well here are the speakers I will be crossing over...


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## openglcg (Jun 23, 2018)

start with the sub below 60hz and move it up to find out where it starts to sound bad. proabably keeping it below 70hz is a good idea but it depends on the interference pattern. you wont have to push any of those speakers into beaming given that you have a 3 way. start somewhere where the lower freq speaker is below beaming and the higher freq speaker is above fs. if you have sealed enclosures for woofers then the total system resonance will be higher than fs. model it.

look at ib frequency response measurements to see where any drivers may have issues that you want to avoid. if you see a peak or null or inductance spike that you want to avoid then adjust accordingly.

then its on to the long process. i usually spend a few months playing with the crossovers to get the best feel. just making adujstments, listening for a few days to a week, and then trying a new setting. and then sit down for an hour or so fine tuning each one to get the phase /frequency response as good as I can.


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## Evl5150 (Jun 20, 2018)

Here I am with two days off and it's raining. I may still pull the door panels and mount the woofers and mids. The tweeters wont be in the doors. I am going to use aluminum pods and aim them at the listening position.


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## Evl5150 (Jun 20, 2018)

I am going to try something different. I am going to install my 2.75" mids into my door pods, readjust the crossovers in the DSP then add my JL crossovers to run the 2.75" mids and the tweeters. Both drivers are 4ohms... I hope it doesn't destroy the amp running the rear channels of the amp at 4ohms and the fronts at 2ohms.


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## Frank JANSZ (9 mo ago)

tjframe said:


> Wow Ive been running my woofers at 80 to 350. The rationale being that I'd get better performance and loudness from them by limiting the range they are being asked to deliver.
> 
> I'm going to fire up the laptop tonight and play around a bit with my 3 way setup. if only it wasn't so damn cold here in Arizona lately (31 degrees outside).. We have to endure unbearable heat most of the year, at least give us super balmy winter plz


I prefer the Lixman A2003 3 way Variable active all tube Crossover Network, for my Klipsch LaScala Speakers set at 450 Hz for my woofers and 6 DB roll of Low bass filter High cut filter 12 Db Roll off at 450- KHz therter to take off from 4500 to infinity.


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