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-   -   Need expert help with first DIY car audio 3-way design (http://www.diyaudio.com/forums/car-audio/106405-need-expert-help-first-diy-car-audio-3-way-design.html)

nola000 5th August 2007 04:24 PM

Need expert help with first DIY car audio 3-way design
 
Hello all. Attached is a diagram I drew up of a system I am pondering for use in my car based on my very limited knowledge of crossover design. Even though I've done much research on the subject I still have many questions since this is my first crossover and DIY 3-way for car audio and I want to be sure everything is correct before I proceed to the purchasing stage of my endeavor.
I based my decisions on these drivers from the comparisons made at Zaphaudio.com

1. Are these speakers compatible?

2. In your opinion, would they sound good together with this crossover design or are there any concerns with the overall frequency response?

3. Is there any advantage at all to going with this 3-way design with a 5.5 inch and a 4 inch involved? Or should I lose one and just do a 5.5 with a tweeter? (I was limited to a 5.5 inch midbass because I drive a 2002 Honda Civic Coupe and I didnt want to modify the look or function of the interior door panel. Otherwise I would have used a 7 or 8 inch midbass.)

4. I have a subwoofer in my trunk. Does that mean that I will actually have a 4-way? Or because the subwoofer isnt involved in the crossover design is it still considered a 3-way?

5. I plan to put the tweeters in the a-pillars or further down in the little plastic panels behind the side view-mirrors. I plan to place the midranges in kickpods and the midbasses in the door. Is this good speaker placement? If so, then should the tweeter go in the a-pillar or in the piece on the inside of the side-view mirrors like I mentioned? Should I put both the midranges and the midbasses in the kickpods and forget about using the doors?(midbass would be playing at about 90 degrees off-axis inside the door)

6. Does the design of this crossover appear correct for the crossover points I selected?

7. Are these good crossover points for these drivers?

8. Are the crossover component figures correct? Remember, I have TWO NARROW pass-bands in the design.

9. Would you consider this setup in YOUR car? Why or why not?

Just trying to pick the brain of some experts with experience.
Thanks for all that respond to help an audio noob brighten his life with beautiful music in his ugly little car. :)

nola000 5th August 2007 05:28 PM

2 Attachment(s)
Sorry

zigzagflux 5th August 2007 09:03 PM

Sounds like this should belong under 'Car Audio', instead of here, but I can respond to an extent.

In the dozen or so systems I have built in cars, nothing has beaten a 6 1/2" woofer plus tweeter in the door. Unless you are looking for a serious competition-level system with more emphasis on SPL and frequency response than sound quality, you will be best off putting in a two way up front with a subwoofer in the rear. The three ways I have heard (with similar drivers as my systems) were all confusing to the brain. Sure, they had "blink your eyes" snappy midbass, but overall subjective quality was not as good. I suspect this had to do with the difficulty of selecting crossover points more than anything.

That being said, I would suggest putting in the largest woofer you can fit in the door, which is tyipically a 5.5" or 6.5". The bigger the woofer up front, the better your midbass will be, albeit at maybe a little midrange sacrifice. Pick a tweeter that will mate well with this woofer, and go 2-way. If you insist on 3-way, I would say it is pointless if you cannot fit a 6.5" in the door. Coupling a 4" with a 5.5" isn't the best solution, IMO; drivers are a little too similar.

sdclc126 6th August 2007 04:13 AM

I agree with Zig 100%. The "third" part of a car 3-way should be the sub(s).

Save money and crossover complexity (thus money again) by ditching the Vifa mid and keep the SEAS & Dayton drivers - this will be an excellent combination IMO; I have the aluminum version of the SEAS in my car and they are superb. They are combined with the sale Peerless 5" woofers from Madisound. I'm only running caps on the tweeters for XO. This week I will be installing the 6.5" Silver Flute 4 ohm woofers in my rear channels for bass. I have the 8 ohm Daytons in my home system, with the SEAS 27TBFC/G tweeters and they sound like Heaven, so I have experience with both drivers in your system, only not combined with eachother.

You're on the right track with excellent drivers that will give you awesome mobile fidelity - just put subs in the rear channels and I think you will be very happy!

nola000 6th August 2007 06:31 AM

sdclc126 great! Thanks for the opinion. Right now I have 2 15" Dayton Quatros in sealed boxes 50% stuffed at Qtc .78 running off a Zapco 750.2. Overkill, I know. Im going to put one of them in my truck when I get another amp.
Where should I cross the Dayton RS if I drop the Vifa and should I put the RS in the door or in a kickpod?
What is your opinion in putting a Zobel on these drivers?

sdclc126 6th August 2007 08:35 PM

I honestly can't comment on a Zobel for your combo - I have never used one and I don't have one on my home speakers - hopefully someone else can chime in on this, but let me ask - where are you going to put the crossovers? You'll need some room for them, as you will want to cross steeply on both sides - 4th order would be ideal, no lower than 2000 Hz as that's about the limit for the tweeter. Ideally you should notch the woofers also, to deal with their significant breakups.

I think you should put the woofers in your doors - kick panels are way too low and forward IMO, where a lot of curved surfaces and sharp edges can get between the speakers and your ears. They will also be very far away from the tweeters in this location, and that may compromise good cohesive sound.

One possible advantage of kick panel placement, if done properly, is less vibration than what can occur in doors. But some sound absorbing material should greatly help with that, so given that you are investing in high end drivers I'd do a thorough job of best driver placement and vibration damping.

nola000 7th August 2007 11:01 PM

2 Attachment(s)
I think you are saying you would put some 6.5s or the 5.5 Dayton RS in the doors as part of a 2-way system with the Seas tweeter still in the original placement i mentioned? If that is the case then...I was concerned about putting them in the doors since they would be like 90 degrees off axis. I wanted to go in the kickpods with whatever speaker would be playing in the midrange frequencies because I could crossfire them to the middle of the car giving a less off-axis placement. From what I read (and always correct me if im wrong, since im a noob) lower frequencies suffer less from off-axis response since your ear cant really tell where lower frequencies are playing from. Im not sure where this threshold begins in the frequency range but that is why (if I was going to do a 3-way system) I was going to put the 100Hz-300Hz 5.5 Dayton RS150-4 in the door and put the 4 inch Vifa PL11WH09-04 300Hz-4kHz in a kickpod and the 4kHz Seas 27TFFNC/G tweeter in the a-pillar or maybe in the kickpod with the Vifa.
But if you are suggesting I go 2-way then maybe I should put the Daytons in the kickpod instead of the Vifa since I would be moving the Daytons range from 100Hz-300Hz to 100Hz-4kHz.
Is this not a good idea? I would much rather it in the door to avoid a kickpod altogether but im worried about playing my mid frequencies so far off-axis in the door. If it would help I could move the crossover frequency down to 2.5kHz if you think that would help the off-axis response. That way the Dayton in the door wouldnt be playing as many frequencies off-axis. What do you think?
Also. I have read a bunch about this and Ive come to the conclusion that 2nd order is the best slope. But you mentioned using 4th order for my setup. I chose 2nd order as a general rule not specifically for my drivers. I dont know enough yet to determine the slope based on a particular set of drivers. I was wondering why you suggested 4th order? Is there something you saw in the HD or FR of these drivers that made you suggest that slope? I dont really have a preference but Im curious to know if there was a specific reason you chose that slope that way I can make a better descision next time.

zigzagflux 7th August 2007 11:46 PM

You could certainly try putting the midrange in the kickpod, though you may be lowering the SPL of your bass as a result. The benefit of a door installation is the pseudo-box you create behind the woofer, providing nice midbass.

Mounting speakers in the kickpod was a preference from years back, before the advent of easy-to-buy delay processing. The goal was to, as much as possible, equalize the path lengths from left to right for the off-axis listener (both driver and passenger). The method to do this was to mount the drivers as far away from the seats as possible; hence the kickpod location.

Further, most component sets provided as a package come with the intent of door installation, and the drivers are designed with this in mind. The axis of each driver should be mounted in the same plane, aligned as such. Putting one in the kickpod violates the dispersion pattern, potentially, unless you have verified your drivers to operate better with them off axis.

IMO, with current, affordable head units with DSP, you can select both crossover frequencies, as well as delay, all in the digital domain. A nice feature, and as far as I have heard, produces a much improved soundstage. Only for the driver, of course; passenger suffers with confusion. In those instances where you want to please the driver, I would simply turn the delay off and settle for a compromise.

So, my advice would be to go for the door installation, even without a DSP head unit. At some point in the future, you can upgrade the head unit with ease, and the system is prepared for your delay programming.

As far as crossover slopes, I am preferential to a 2nd order or 3rd order electrical, with a likely 3rd or 4th order acoustic. It is mostly dependent on the tweeter, and where you plan to cross it over. Tweeters hate low frequency, and if you plan to go for a 2.5 kHz frequency, a 3rd or 4th order electrical might be better than a 2nd. Again, a DSP head unit gives you the ability to actively cross over, and experiment with various slopes.

tinitus 8th August 2007 12:00 AM

Just a comment to your xo layout... you should place L1 between C2 and L2
And why do you have high pass components on your woofer ... do you cross your sub that high ?

Regarding a 2way, a driver like this would do, apart from not being 4ohm ... is it ok to use paper cone ?

http://www.partsexpress.com/pe/showd...number=264-850

nola000 8th August 2007 10:31 PM

Maybe I haven't been clear up to this point.
Right now I have 2 (soon to be just one) Dayton Quatro 15 inch SUBwoofers in my trunk playing 100Hz down off of my Pioneer DEH-P880PRS being pushed by a Zapco 750.2. This setup will stay this way. No passive crossover on the Dayton sub.
I need to add some highs and mids as Im still crying over my crappy factory 5 inchers up front in my doors and the factory 6x9s in the rear deck in my 2002 Honda Civic coupe. Im was contemplating the setup that is attached with the original post. However Im looking for feedback as this is my first crossover and DIY build. Im open to going 2 way. I chose these specific drivers based on the info provided at Zaphaudio.com. And my crossover was designed with the info I learned off of this website...http://www.the12volt.com/caraudio/cross.asp
This website didnt say anything about placing L1 between L2 and C2. So im not sure what that would do. I used the component calculators provided on the website which suggested I follow the narrow band pass chart for configuring the component values for my dayton rs150-4 playing between 100Hz-300Hz and my Vifa PL11WH09-04 playing between 300Hz-4kHz. Im not sure if those are the correct values or not. I just followed what the 12volt.com website (www.the12volt.com/caraudio/crosscalc2.asp) gave me when I punched in the crossover figures that I chose based on the FR chart of the drivers attained from Zaphaudio.com. If it looks wrong to you then tell me why and suggest something else.
So...I think I might go 2-way. But no one has yet to give me a good reason why I shouldnt (in a 2-way system) put my midbass/midrange (Dayton RS150-4) in a kickpod...I mean...what ABOUT the off-axis response? Wouldnt 90 degrees off-axis sound horrible in the midrange frequencies that would be handled by this driver? I would much rather put it in the door and much rather go 2-way as this would make installation a breeze and be alot cheaper. But please, someone make me feel better (using facts and statistics and/or experience) about going 90 degrees off axis in a car door and the sound difference between the 3-way presented in the attached file at the start of the thread and the same drivers minus the Vifa in a 2-way design crossed 100Hz-2.5kHz (the crossover would put the Dayton RS150 at 100Hz-2.5kHz and the Seas tweet 2.5kHz up while my Dayton Quatro 15" still handles 100Hz down off the head unit).


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