# Use Alpine F1 Crossover for Home Speakers?



## jimbno1 (Apr 14, 2008)

I am hoping someone here has attempted something similar. I am going active with my F1 Alpine SPX-Z18T I was wondering if I could use the Alpine 3-way crossovers to build some home speakers. I have been testing them in my basement in cardboard mockup enclosures and I must say they sound amazing. Probably as good or better than my Newform research ribbon main home speakers. 

I previously had purchased the 12M/4631G00 and 18W/4531G00 Revs before I got my hands on the F1 set. They are both 4ohm like the Alpine versions. I hate to see them go to waste. The woofer specs are different but I would imagine that would affect the cabinet design more that the crossover. 

There are thousands of adjustments that can be done on the crossover but the one that sounds most likely to work in a home environment is the following:

Type-1A: Pathlength to the listening position is considered to be basically equal in this case (ideally 2-3m away), with relative on-axis positioning of all drivers. Phase linkage
is accomplished with a low Q 2nd Order high-pass filter on the tweeter, 1st Order lowpass and 4th Order high-pass on the midrange, and a semi-4th Order low-pass on
the woofer. This results in acoustic crossover points of 3.8kHz and 700Hz respectively.

The only 4ohm tweeter I have on hand is a BG Neo3, which I could use as a prototype before investing in a more appropriate tweeter. 

Does anyone think this is worth attempting or am I goofball for considering it? I have never built home speakers but I do have some friends who do some cabinet making as a hobby who may help with the construction.


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## [email protected] (Jun 12, 2008)

most likey your ht reciever wont handle a 4ohm load, are you planning on using a rack mount amp or something?


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## jimbno1 (Apr 14, 2008)

I use separate amps so 4ohm load is not a problem.


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## Aaron D (Jul 14, 2008)

jimbno1,
No reason it won't "work". It could be a good learning process for you. If the woofer Qt isn't too high you can also play w/ box tuning too. The only thing you won't be able to compensate for w/ the crossover is baffle step compensation or BSC. I would not consider this a deal breaker though, I'm working on a similar project using an old Kenwood din sized active crossover. I'm not too worried about BSC but I would like to learn how to design a passive circuit that I can run on the woofer and possibly midrange (3-way system). Good luck.

Later,
Aaron D


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## TXwrxWagon (Sep 26, 2008)

I would disagree.

If you use the Alpine or the ScanSpeak drivers that are matched to the crossovers, the crossovers have a nearly infinity adjustable "focus"... included is inline/direct on axis... just go to www.alpine-usa.com & hit "support" type in the F1 product code... download the manual...

I have a set of 2-ways I built using the SPX-17M's (same as in my car) & LOVE them... the crosovers are on the outside/back of my cabinets & I can adjust them between a "tailgate" situation & in my garage & my joke of a listening room (aka living room/breakfast nook/Kitchen cavern)... LOL

If your set up is 4 ohm friendly (mine is also)... go for it... just pay attention to driver matching.... 

Rob


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## Aaron D (Jul 14, 2008)

I can agree w/ you disagreeing, no big deal. BSC is rarely an issue in a car environment. I’ll admit that I have not looked at the “focus” capability that you referenced but I’m guessing that it is nothing more than an adjustable pad for the tweeter (commonly used). Adjustable BSC is very rare even in home apps as it generally affects several crossover components at a time. I’m sure your project sounds good but BSC can make the difference between sounding good and sounding “professional”.

I will admit that I neglected to mention that BSC is not required if placing the speakers against a wall. This is an acceptable approach but can degrade other characteristics, primarily stage depth/imaging.

Regardless, I was not in any way trying to discourage the project. Quite the opposite actually. I was just trying to state that it is viable w/in given limitations. I’m in the same boat with my project as well and I find it acceptable until I get bored and want to take it to the next level.


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## TXwrxWagon (Sep 26, 2008)

Aaron... its all good... no worries...

Alpine's crossover design is actually quite unique. Instead of pads or traditional jumper-type circuits, they use a series of small gold plated (pretty.. lol) little bars that snap in & out of up to 8 different locations (depending on the 2-way/3-way &/or Bi-amped).

Its very interesting. Worth checking out Alpine's support section & downloading th manual. You can choose anything from coincident mounted, door mounted woofer, kick tweeter, high door tweeter, vertical array tweeter with the woofer etc... 

Rob


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## GlasSman (Nov 14, 2006)

No reason it won't work...just go for it.

Only way to fail is if you _*never*_ try.

If it doesn't work...you just_* learned*_ something.


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## jimbno1 (Apr 14, 2008)

I have compatible woofers and mids (4ohm Revs) not an exact match but close enough I think. I will have to figure out the box volume for the woofer. I am searching for a suitable tweeter. I don't want to spring the bucks for 7100. I noticed Zaph uses Vifa X25 Ring Radiator in his Rev tower. I figured that or the Peerless HDS are my most likely choices at 4ohms.


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