As many of you know, I've been working on a custom component set for my kick panels for quite a while now. I've finally made some progress and thought I'd update.

I got all of the drivers a couple weeks ago, and finished a set of kicks for myself (finally). Late last week I soldered up my first set of crossovers and installed everything.

The crossovers use 4th order acoustic slopes for both drivers, with a crossover frequency centered around 2.1khz. I developed this crossover based on published frequency response plots of the drivers, which are not always the most accurate. They certainly don't give insight as to what their in-car response is, but it's the best I have to work with for now.

So anyway... they're installed, and here are my opinions of what I've got right now:

The overall sound quality, while showing a lot of promise, basically sucks. I find them to be a bit fatiguing, vocals have a "tin-can" sound to them, especially male vocals, and there's an awful upper midbass boost that makes certain things sound overbearing and distorted. At higher volumes, the sound degrades rapidly. However, some of these characteristics exist with multiple component sets in my car, so that shifts the blame to the installation and not the speakers. However, judging by what I'm hearing, I believe that my crossover is the biggest source of the problems, and since this is just my first cut at the crossover, I never really expected perfection.

There are definately a lot of good things about this component set though. These woofers have a lot of detail. The tweeters seem to be very clean in the top couple octaves. I can't tell about the lower end of their spectrum yet, because I have yet to determine whether the fatiguing issue is from the woofers or the tweeters. Dynamics are very impressive. Percussion is very dynamic with a lot of impact, and a very realistic sound. This holds true from bass drums right through cymbols.

The Soundstage is outstanding. The height of the soundstage is above the dash board in the center, and almost as high at the extremes. Vocals are very stable with minimal drift from the driver seat. I haven't listened from the passenger side yet, but my 2nd set of ears (my fiance) reported that the vocals drifted slightly.

The extreme high frequencies might be a bit soft, especially from the speaker on the listener's side (driver speaker for the driver, passenger speaker for the passenger). This is due to the tweeter aiming of my kicks. My kicks were basically designed with swivel-mount tweeters in mind, since this is how the majority of flush-mount tweeter cups work. My tweeters don't have this type of mounting configuration. However, this may not be such a bad thing. Because of the interior in a car, most highs seem to be unnaturally bright, which is why a lot of component sets come with multiple tweeter attenuation options. When listening to these components outside of the car in an extreme off-axis configuration, the highs are disappointing. In the car, while still a bit soft, they still have a very natural sound. Since it's generally difficult for the human ear to build an accurate soundstage at extreme high frequencies in a car environment, you tend to get a polarization effect where the extreme high frequencies seem to come from the extreme outer edges of your soundstage regardless of your tweeter positioning. This is because you get so much reflected high frequency energy, that at those tiny wavelengths, what actually gets to your ears is a mess. So anyway... on to my point. Although my tweeters are in a non-ideal setup, I don't feel that the actual imaging suffers when compared to other more ideally aimed tweeter configurations that I've used. Once I get the crossover optimized, I'll decide whether this is an important enough issue to warrant a kick panel redesign.

So, what is my next step? I really need to buy the rest of the necessary equipment to do my own frequency response and t/s measurements so that I can find out exactly what the frequency responses of the speakers are. This will help me design a crossover that has a known flat frequency response, rather than the "guess" I'm working with now. I also will take in-car measurements so that I can correlate what I think I hear with what is actually going on. Also, I need to listen to the drivers individually to determine if the fatiguing sound I hear is from the woofer's high frequency breakup or if it's from the tweeter's low frequency distortion characteristics. Once I figure that out, I'll know what changes might be necessary to the crossover topology. I also know that I need to construct a notch filter for the range from aproximately 200-500hz that's getting boosted due to the kick panel design, but I'm going to wait for measurements before I tackle that.

I've still got a ton of work to do, but overall, I'm very happy with what I've heard so far. Certain songs already have some phenominal characteristics. The guitar and percussion in Dire Straits Money For Nothing is incredible. Resolution of detail and the ability to hear specific instruments in Mary Jane's Last Dance from Tom Petty is very impressive, though his vocals still leave a lot to be desired. Hotel California from the Hell Freezes Over cd is still a disappointment to me, though I have extremely high standards when it comes to this song. Henley's vocals are distant and tin sounding, and I'm getting a nasty boomy resonance in one of the guitars. This will be helped when I build my notch filter, but I'm also exciting a panel resonance in the car's floor, so some sound deadening will be needed. I also expect the sound deadening to eliminate the distortion issues I'm experiencing at higher listening volumes. I get this distortion with all of the speakers I've used in the car, so it's not an indication that the speakers themselves are causing the problem. I think that the higher volumes are causing enough panel resonance for it to be audible. Deadening the floor and the dash panels will be a necessity.

Anyway, I know some people are interested in my progress, so I wanted to let people know where I'm at. Overall I'm very happy with where it is right now, but I still have a lot of work to do before I let anybody else hear it.

EDIT: Oh, and I'll have a couple pictures shortly. If all goes well tonight, I might finally be able to get online with the computer that all of my pics are on rather than burning them all to cd and bringing them to work to upload.

 

Thanks for the update on the progress, Jim. Given your perfectionism, I am sure you'll have that system fine tuned beautifully by the time you are ready to market it. I know I want to be kept informed, so keep the info coming.

 

you're the man. send me a set to test out once you're finished, i can put em up against my alumapros, some rainbow vanadium pros, and a set of ology's components, and give you a comparison.

 

While you haven't stated what kind of speakers your using but imo the crossover point is a bit low unless your tweets have a FS of around 1k or so. How familiar are you with builing and designing xovers? I only ask because you are by far an advanced designer/installer and there is no point in me pointing out what you already know. What kind of network are you using?

 

The F3 on the tweeter is a bit higher than 1k (1.3k to be exact) but I'm hoping to get away with it with the steep slope. The tweeter is a fairly robust tweeter with a large x-max. The tweeter can handle the low crossover, but my listening is still trying to determine just how good it sounds doing it.

The crossover is pretty straightforward. The woofer uses a traditional 2nd order electrical to achieve a 4th order acoustic, and the tweeter is currently using a 3rd order electrical to achieve a 4th order acoustic, but I've got a 2nd order electrical design that I need to try. The 2nd order gives the same 4th order acoustic slope, but has a better phase relationship with the woofer.

Of course, all of this is just a stab in the dark until I take my own measurements. My goal with this filter was just to be able to start identifying the various driver characteristics so that I can take them into account with my next filter.

 

So far the limited amount of xovers i have done I have never been happy with running my xover points 90* out of phase. But alot of my problem is most likely the same as yours Im stuck using published speacs. What are you getting for test equipment? i've seen the woofer tester that PE sells and have been tempted to check it out.

 

I'm buying Sound Easy. It's far more advanced than the woofer tester. It can take frequency response and impedance plots, measure all t/s parameters, and can even do distortion analysis and CSD (cumulative spectral decay) plots. In other words, it gives you everything you need except for ears.

http://www.partsexpress.com/pe/showd...number=500-912

 

Pics!



Installed:


Passenger side with the woofer grill on:


I haven't made the tweeter grills yet.

 

i need a pair of those and the frame you have for your tv in the console

 

yeah the screen is sweet, more details please.

 

Even fits with the clutch pedal nice...that was what I was concerned about for this kind of idea. Nice

 

If you click on the link in my sig and follow the sounddomain link to my IROC, you'll see a step-by-step description of what I did.

 

awesome update Jimbo. You know I have been waiting for your kicks for a looong while.

my only question now is since I swapped to a 4thGen dash how much of a difference do you think it would make in the sound stage and final results compared to the stock dash?

I would think it would make some kind of diff. but would it be anything to worry about? I'm sure my ears arnt as particular as yours when it comes to this.

 

I would expect the differences to be minor, but I really can't say for sure. The overall dashboard shape is different than a thirdgen's (obviously), but its overall size and location really isn't different. How much would a new coffee table effect the sound of your home stereo? I would think this would be a similar effect. Sure, it'll be different, but I can't think that it would be drastic.

I'd be more concerned with how well the kicks would fit. I don't know if the 4th gen dash would cause any fitment issues. The passenger side kick is shaped specifically to avoid fitment problems with the stock under-dash panel. If the 4th gen panel is different, who knows how they'll fit. :shrug:

 

true.. Im sure it would be minimal diff.

kicks fit just fine...

 

I'm sure the stock kicks fit fine, but that doesn't mean that mine will. On the passenger side, I had to notch the new section because the factory kicks slide up behind the lower dash panel. There's not enough room for my kicks to slide up behind the panel because they're much thicker, so I had to notch my part so that the stock portion can still slide up behind the dash panel, but my new part still doesn't interfere.

At the most, you'd have to notch out the lower dash panel, so it wouldn't be anything major, but there could be some minor fitment issues.

 

I know exactly what Jim is talking about from first hand experience – even with a factory dash the passenger’s side kick is still a fairly tight fit. To put it really simply: the plastic kick is taller than what is visible within the car (ie it goes behind the lower trim piece on the dash). If that trim piece is even lower on a 4th gen then Jim's kicks won't fit without modification. If you're willing to run outside and measure the distance from the floor to the bottom of the dash in front of the kick panel I will be able to tell you how that compares with what I have.