When designing these crossovers i realised that i had to have a completly different set of goals when compared to the typical home audio envirnoment. I spent some time thinking about what problems that would arise when a simulated crossover was placed in an ambiguous setup such as one found in most typical car stereos. Unfortunately i havent had any experience (until now) in doing car crossovers, my views and opinions may or may not change after this attempt.

Firstly nearly all car audio installation's are different. Woofers when mounted in doors trims (like my install) can be over 50 deg's off axis, so often manafactures design their X-overs with that in mind, but what happens if these components are placed in door pods? Typically the frequency response has an undesirable peak in the crossover passband. One way to reduce this problem is with either 3-ways and/or low crossover points. Basically the steeper the slops of the crossover the lower you can X-Over the tweeter. A general rule to follow is that the tweeter is 20Db's down at its resonant frequency.

Another problem is tweeter placement. When the tweeter is moved around the phase relation between the drivers change, although this can be offset somewhat be reversing the phase of the tweeter, the results are often unpredictable. By using a very steep slope with the driver's slightly out of phase this problem (in this case anyway) is almost eliminated, the only effect an out-of-phase tweeter placement is slightly worsend off-axis response. The only negative effect would be a loss in imaging, i just dont know how much.

Another goal in all passive X-Overs is flat impendance phase (how much it varies), generally a flat inpendance will sound more dynamic than one that is not. That impendance of this system is very linear that would be considerably better than most stystems. A linear phase impendance X-Over is very easy for amps to power and does make a dn auditable difference.

I think i have found a good compormise between all the factors of X-Over design that would lead to clean predictable sound in this envirnoment

After several attempts at this crossover i finally have something im finally happy with.

Here are some graphs



This is the raw response of the drivers. The woofer response is NOT what Peerless have stated in their PDF files which sucks... The woofer does have 5.5mm of X-max though, which in an infinite baffle car door makes the driver fairly linear, they need an X-Over of about 80-100Htz at 12dB's an octave.


This is the overall frequency response of the system, very flat over the entire frequency range, although i would have likes the woofer to play down to 100Htz its still only 3db's down. Note the very steep slopes and low crossover points, this will help bring the soundstage up to dash level.


This is the response of the Tweeter with its phase reversed, remember the phase changes as you move the tweeter about, the worst case the phase would change is that its reversed, BUT in this case the response is still flat, therfore tweeter placement realistically does not affect the frequency response. Only inaging. No need for pod installs here.


This is the overlay of the off-axis system response, its VERY good therefore any placement of the woofer within reason will result in the same response. Again no need for pod installs.


Here's the impendance graph, the dotted line is the phase and is very flat accross the entire spectrum, in some systems this is ignored and dynamics suffer.


This is the crossover for the drivers and is unconventional because it uses elliptic X-Overs which are magic for most car installs. It has very steep slope when compared to its component count. I have never seen this used in a commercial car system.


This is the Mid-Bass crossover.


And here's a pic of my Woofer.

And a PDF file for my Tweeter


The X-Overs are wired in parallel. The tweeter is crap and sounds IMO really bad (i regret buying them and should of got the more recent design with its silk dome but it was at the time i had no money . The woofer is 7" and wont fit in stock location's, i made an MDF baffle the shape of my grill and mounted it that way.

If you want to build this X-Over i wont stop you BUT, i havent tested it and im going to design a more compatable and better sounding design with the Silk dome tweeter and Peerless 6.5" Car woofer. Which will be done when i make evaluations of this design. This design cost about $300-$350 .

Nice work...

Is there any particular reason you chose to drive these passively rather than with an active setup? Cost?

And what did you use to design your crossover, XOver Pro?

The cost for active crossovers dont justify their peformance difference and dont have slopes steep enough for my application and they didn't have the flexilibity you need when using difficult drivers. I used Speaker Workshop to design them.

My objective was to get the best possible price to peformance ratio possible in virtuallty any install

I know of a couple of active crossovers that give you adjustable slope... one of the main reasons i got my headunit is because i can choose crossover points from a massive range, and select a rolloff from 6dB thru 36dB per octave... it only works for a 3 way setup (2 way front stage plus sub) which is a little bit of a downer, but the flexiblity is wonderful, and its a massive bonus being able to toggle through slopes with a touch of a button and instantly hear how it affects the sound

there are Xover design programs?
i do it manually! :oops:

whilst the output is relatively flat... it will probably end up rather differently in the car. have you RTA'd it?

I havent got my parts yet, Its definately not intended as a competition vechicle, just a set of quality sounding cheap 2-way components.

I ordered the parts this morning and expect to have them by Webnesday, my amp has been down a channel so i order a the 2x150 response amp a few days ago. When i get them both ill give an honest review.