# Unity V: The Midbass Strikes Back



## Patrick Bateman (Sep 11, 2006)

Over the past few years I've been refining what I believe to be the ultimate solution for creating a soundstage in a car, a Unity horn. These devices are hideously complex, which is why it's taken a few tries, and a lot of study, to get it right.

I'm documenting the process in order to document a few of the issues we face in the car, and also to discuss which solutions are going to work best.

Here's a brief history of the last three.









Here's the first Unity horn I built, in 2006. Like all Unity horns, the midranges are mounted on the same horn as the tweeter (compression driver.)








Here's a picture of the midranges from 2006. These are 2" midranges. Normally a two inch midrange wouldn't be sufficient, but three of them on a horn get quite loud.








The midranges are in bandpass boxes, and enter the horn through the ports on the bandpass.








Here's the measured response from the speaker in 2006. This looks a little ragged, but for a car, it's quite good. It's about +/- 3dB over most of it's range.​
My first try did a lot of things very well. The horn played down to 150hz, which is unheard of for such a small size. (I'll explain why in this thread.) The integration was incredible; I've never heard anything as articulate as a Unity horn.

But it had three fatal flaws:


I didn't know there was a specific formula for choosing the midranges. I could never eliminate the suckout at 1200hz without creating tons of distortion from the drivers. Basically, the midbasses are playing too low, and so is the compression driver.
The top end is too hot, because the midranges can't move enough air. They can play down to 150hz, but not with authority. They're displacement limited.
It's ugly as sin.

So back to the drawing board. It's documented here:

Twelve Inch Woofers In My Dash - CARSOUND.COM Forum

A year and a half ago I started my second Unity horn. This one was probably the worst of the bunch - the waveguide was built very carefully, but it didn't work right. On the bright side, the inventor of the Unity horn, and the world's best known expert on waveguides contributed to the thread. If you're interested in a technical discussion of the Unity horn, this thread is a good one.

Another Unity Horn - diyAudio















Here's a pic of the funky mold and waveguide I used a year and a half ago.

In 2009 I created a third Unity horn, and really gave this one 110%. This one was engineered to death, using everything I learned from the last two projects.























Here's a pic and a measurement of the third Unity horn that I put in a car. If you compare it to the 1st one, you can see it's a big improvement. The suckout at 1200hz is gone, and the response is falling slowly, which sounds more natural than flat response in a car. The third one worked really nicely.

The third one still had some flaws:


It sounded great, but it was too big. I had to chop up the waveguide a great deal to fit everything on the dash.
The F3 was 300hz or so, which meant that a midbass was required.

It's documented here : http://www.diymobileaudio.com/forum/diy-mobile-audio-sq-forum/60146-creating-perfect-soundstage.html

The third was the best one yet, but there was still room for improvement...


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## Patrick Bateman (Sep 11, 2006)

Six months ago I abandoned the idea of putting a Unity horn on the dash, since they're so big. I started a new system where the midbass was under the dash, the tweeters were in small waveguides on the dash, and the subs were in the trunk.

Basically a conventional car stereo setup, but with the midbasses and the tweeters on horns and waveguides.









Here are the midbasses and tweeter waveguides from last summer's project. You can see the waveguides are smaller than any of the three prior projects, and the midbass horns hide under the dash nicely.






Here's the tweeter waveguides up on the dash. They're not stealth, but they don't get in the way. The car is easy to drive, which is more than I can say for some under dash horns. Most importantly, the soundstage is wide and at eye level.

I spent a solid month trying to get the midbasses to work correctly in this project, with little luck. While they played fairly low, the response was ragged, and they never sounded "clean" to me. Out of sheer frustration, I slapped the midranges from the third Unity horn onto the waveguide. *(This project was never intended to be a Unity horn. It was dumb luck that the midbasses fit on the waveguide.*























At top is a pic of the fourth Unity horn. The second pic is the frequency response. In the second pic you can see that the response is better than the first, and very similar to the third.

The fatal flaw with the _fourth_ Unity horn was the midbass horns. You can't see it in the frequency response but in the polar response it's obvious that the midbass output is very peaky, and directional also.

The fourth Unity is documented here:

Creating a Soundstage with Waveguides and Psychoacoustics - Page 10 - diyAudio























In an attempt to fix the midbass problems of the fourth Unity, I spent a solid month building an measuring various midbass replacements. The pics above show a few things I tried. (sealed eights, front loaded horns, tapped horns, etc...)

I tried a LOT of midbass options, and documented them here:

http://www.diymobileaudio.com/forum/diy-mobile-audio-sq-forum/69060-natural-bass.html


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## Patrick Bateman (Sep 11, 2006)

If you've followed these Unity projects for a few years, you've seen that I've made a lot of progress over the original design. Every single one of them had a soundstage to die for, and excellent dynamics, particularly in the midrange.

The price that you pay for this excellent soundstage is that the install gets progressively more ridiculous. If you look at my last set of underdash horns, they're totally insane.

*The goal of my fifth Unity horn is to get the entire stage, including the midbasses, up on the dash.*









Here's a pic of the Yorkville Unity horn, which is powerful enough to fill an entire club. Note there are three mids on one horn.[/img]






Most Unity horns use four woofers and four midranges, coupled to a single horn. In the car we're severely constrained by the dimensions of the dash. I have found that the waveguide increases efficiency to such a huge degree, we can get away with two inch drivers. For Unity V, I am going to use a single JBL midbass. While one midbass can't compare with four woofers, this midbass is very special. There are only a handful of midbasses this small than can handle tremendous amounts of power, and very few of them are this efficient. You can see the motor on this driver is big enough for a ten. _And it's neodymium!_ The giant motor raises efficiency, and it's 2" voice coil raises power handling. It's parameters are also quite good for horn loading. 







I believe the 400GTI which I am using is a relative of the midbass that Gary Biggs uses in his award-winning Regal. This is a scan of the magazine article on his car, the Regal's midbass setup is at the bottom left of the page. For my application the smaller size of my 400GTIs is better, because we're severely constrained by the dimensions of the dash. I should have an advantage in maximum SPL due to horn-loading. The directivity of the larger waveguide that I am using will definitely be superior to the small waveguide used by Biggs. (Theoretically, of course. Things get unpredictable once you put speakers in a car.)









Here's a mockup of the new waveguide. This is the first time I've done a three-way up on the dash. (Well, actually a 2.5 way.)









All three drivers radiate from a point in space thats about the size of a tennis ball. This is why the Unity works so well in car. It gives you the kind of articulation and soundstaging that you'd expect from a HiFi speaker at home. The only way to reach this level of performance in the car is to get the drivers very VERY close together. DSP and EQ are nice, but they can only fix things at one point in space. Physically moving the drivers together is the best solution.









Here are some waveguide molds. The center mold is my oblate spheroidal waveguide mold from 2006. All of my best projects use this mold. The OS curve used by Geddes is very good. The waveguide on the left was released by QSC this year. Look familiar? The mold on the right is my new mold. It's a clone of the QSC.









Here's a pic of the mold on the dash of my car. In the pic you can see that the mold is a near-perfect fit for the confines of the dash.









Here's the side view. Note the gentle transition from the edge of the waveguide to the dash and the windshield. That transition is the reason that we can put three drivers on such a small waveguide. The dash itself is horn-loading the drivers.









There's a big gap to the left of the new mold, on purpose. This is space for the big ol' JBL midbass.​
In a nutshell, the goal of this Unity is to deliver the articulation and soundstaging of my previous projects, along with power handling and dynamics that are competitive with the Biggs Regal. (My original target was the Clark Grand National, but I've backed off that goal. I'm sacrificing maximum SPL for point-source imaging.)


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## huckorris (Sep 2, 2009)

Wow. How epic. I love that Yorkville Unity horn.

Forgive my ignorance but how will that JBL midbass motor work without a cone?


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## thehatedguy (May 4, 2007)

It has a cone.


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## huckorris (Sep 2, 2009)

thehatedguy said:


> It has a cone.


Is it not attached yet or is it just hiding? It looks like just a motor, but there are no pics of the front so it's hard to tell.

:blush:


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## western47 (Nov 17, 2008)

Is the mid shown the one which will be used?
It doesn't seem to be the same candidate as before.


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## dcm220 (May 22, 2009)

Thanks for the summary. It helps me (and I'm sure others) understand the motivation for the crazy designs and multiple threads.


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## 2fast4thelaw (Jul 5, 2009)

wow! you appear to have waaaay too much time on your hands. This is totally insane but I kinda like it. :wacky:


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## thehatedguy (May 4, 2007)

http://bmsspeakers.com/fileadmin/bm...ssion_drivers/neodymium/bms_4592nd_t.data.pdf

Under the dash= done= mondo expensive


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## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> http://bmsspeakers.com/fileadmin/bm...ssion_drivers/neodymium/bms_4592nd_t.data.pdf
> 
> Under the dash= done= mondo expensive


The cost really isn't too bad. The 1.4" version is $1200 a pair. I considered it, but opted against it because I'd have to go back to waveguides under the dash.

One nice thing about compression drivers and horns is that they're like having money in the bank. For instance, if I used a $1500 set of Focal components, and grew bored with them, I could probably get about $750 for them on Ebay.

OTOH, a well cared for set of BMS coaxes will easily fetch $800-$1000. This is because they're very uncommon - you can only buy them from two companies in the US.

Even better, you can uninstall a compression driver in less than five minutes. Try doing THAT with a set of 2-way components.


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## Patrick Bateman (Sep 11, 2006)

2fast4thelaw said:


> wow! you appear to have waaaay too much time on your hands. This is totally insane but I kinda like it. :wacky:


Actually I spend more time writing about it than doing it. It took me all of an hour to make the new mold. I spent three hours photographing it, uploading the pics to Picassa, summarizing the last few speakers, etc...

On the plus side, it's 30 degrees in the garage and 70 degrees at my computer.


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## thehatedguy (May 4, 2007)

I wish my Beymas held their value like that...I would be getting a set of BMS coaxes.


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## req (Aug 4, 2007)

interesting. i just wish your projects looked as nice as i imagine they could with some more finishing work. if it were me, i would take a garbage bag (with a lot of care mind you) and fill it with expandable foam and shove it into the corner of the dash, then let it fill up. after its a solid block, do some precise measurements to get the size for the passenger \ driver side the same relative size. then get the transitions to the dash at the correct spots\angles, and then work on chiseling out the lens shape... or cut a hole out and put your mould into the back, then fill the two together with more foam and chisel that back, and make this whole thing into a mould.

if i were to do something like you are doing - id need to be able to have it totally finished you know? you go through tons of work to make theory into practicality - but unless i can look at it every day and smile at such a fine job (especially when i cant NOT look at it lol) id need it to look nice.

i mean no disrespect, because it takes a lot of courage to do something like this and spend years working it out... i certainly dont have the motivation to do a project like this hahha.

well, ill keep an eye on this - good luck, i hope this one turns out better for ya! dont ruin your dash too, haha.


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## SSSnake (Mar 8, 2007)

The problem with the bag approach is expanding foam needs moisture in the air to cure. You end up with a bag of goo.


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## T3mpest (Dec 25, 2005)

thehatedguy said:


> http://bmsspeakers.com/fileadmin/bm...ssion_drivers/neodymium/bms_4592nd_t.data.pdf
> 
> Under the dash= done= mondo expensive


Wouldn't the horn under the dash need to be huge to keep directivity at those lower frequencies?


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## DanMan (Jul 18, 2008)

SSSnake said:


> The problem with the bag approach is expanding foam needs moisture in the air to cure. You end up with a bag of goo.


I have thought about doing this for other purposes. Now that I have been made aware that it won't work, I don't feel so bad about procrastinating and not doing it.

Thanks.


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## thehatedguy (May 4, 2007)

Yeap.




T3mpest said:


> Wouldn't the horn under the dash need to be huge to keep directivity at those lower frequencies?


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## Patrick Bateman (Sep 11, 2006)

req said:


> interesting. i just wish your projects looked as nice as i imagine they could with some more finishing work. if it were me, i would take a garbage bag (with a lot of care mind you) and fill it with expandable foam and shove it into the corner of the dash, then let it fill up. after its a solid block, do some precise measurements to get the size for the passenger \ driver side the same relative size. then get the transitions to the dash at the correct spots\angles, and then work on chiseling out the lens shape... or cut a hole out and put your mould into the back, then fill the two together with more foam and chisel that back, and make this whole thing into a mould.
> 
> if i were to do something like you are doing - id need to be able to have it totally finished you know? you go through tons of work to make theory into practicality - but unless i can look at it every day and smile at such a fine job (especially when i cant NOT look at it lol) id need it to look nice.
> 
> ...


A couple of years ago I read an article in the WSJ about a meeting at Sony. In the meeting a group of engineers were proudly demonstrating their new product, which was a Walkman. One of the executives took the prototype, and DUNKED IT IN A BUCKET OF WATER. When a few bubbles of air rose to the surface, he told them to go back to the drawing board.







Sony's new Walkmans are a good example of this philosophy.

I'm taking that approach this time around. I am going to try and use every last inch of space in the corner of the dash, so that I can reduce the size of the waveguide to the smallest depth humanly possible.

In my measurements I've found that the size of the waveguide is virtually irrelevant if the termination to the dash is done very VERY well. In other words, you can chop the size down by 50 or even 75%.

At that point, the biggest obstacle to making them look good is to use very small drivers, and push them as far back as possible.







If you look at the overhead pic, you can see that the waveguide isn't symmetrical. This wasn't accidental; I did this because the midbass and the midrange are different sizes. Since I'm keeping the waveguide footprint as small as humanly possible, I hacked a big hunk of foam off the mold to reduce the footprint. The waveguide will be *just* big enough to mount the drivers, and then I'll let the windshield take over. Again, you CAN'T do this if it's under the dash, there's no boundary that will continue the waveguide. But it *does* work on the dash. It also works if you're mounting a waveguide into the corner of your music studio or your home theater. (Or in the kick panels for that matter. Check out my measurements of the QSC waveguide in the kick panels. It's the flattest measurements I've ever seen in a car, thanks the to boundary reinforcement.)

Once all that's out of the way, a decent baffle and some careful finishing will preclude the need to do what you described.

This isn't a knock against your idea - just trying to "sketch out" one of the goals for Unity V. I don't want ANY wasted space at all on the dash.


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## Patrick Bateman (Sep 11, 2006)

In the last post, I mentioned that minimizing wasted space was going to be a big goal for the Unity V. I want this thing to play lower and louder than Unity IV, but I also want it to be smaller.







This is a pic of the mold, along with the three drivers. (I plan on using four BTW.) The pic illustrates where everything will be mounted, and how the waveguide is *just* big enough to mount the woofers, and no bigger.







Here's a pic of the bandpass enclosure for the JBL midbass, sitting on the dash of my car. The pic is dark because the sun sets about 5pm here, so the pic quality kind of blows. Can you see the problem though? The enclosure is about 1/4" too wide. The thing that sucks is that I can't do anything about this - I'd literally have to grind down the woofer's basket to get it to fit. The instrument console is in the way.







Here's a pic of the waveguide mold, on the dash, during the day. In this pic you can see that there's *just* enough space by the waveguide to squeeze the woofer in. It's a tight fit.







To illustrate the absurd lengths I've gone to in the pursuit of midbass, here's the new midbass enclosure. Note the *entire enclosure* is slanted now! *That* wasn't easy to do...







Here's a close up. The angle of the enclosure is an exact fit for the A-pillar.







Here's a pic of the enclosure, but with the bandpass chamber removed.







Here's the back of the sealed chamber. I literally filed down the PVC so that it's flush with the basket. The enclosure isn't finished, obviously. I intend to add standoffs so that the venting from the voice coil will still work. (IE, we don't want to seal off the vent in the basket.)







Front view







To get the angles consistent for both woofers, I built a jig. Basically take a piece of pine, screw the PVC to the pine, and then set your saw appropriately. This insures that the two are symmetrical.


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## Patrick Bateman (Sep 11, 2006)

The vertical angle of the previous waveguide was calculated to match the windshield. Due to a bit of serendipity, I noticed that the *horizontal* angle of the new waveguide happens to mate with the A-pillar quite nicely. Just dumb luck really.

The vertical angle is basically the same, and is practically a perfect match for the windshield of the car.























Here's a couple pics of the new waveguide, along with the old one for comparison's sake. Like all of my waveguides, it's constructed with a sandwich of fiberglass, aluminum foil, and more fiberglass. At this point the last layer hasn't been applied, which is why it's shiny.


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## Patrick Bateman (Sep 11, 2006)

_(This is a cross-post from diyAudio. I hate to spam both forums but it touches on topics from two threads.)_

I gave up on using domes in waveguides a few years ago, but I think I'm ready to take another crack at it. I personally believe that a compression driver is a better solution, but I have a unique problem, and I can't find a way to solve it that doesn't involve a dome tweeter. Here's the situation:

I've built a ton of horns and waveguides, primarily for automotive use. When I first started, I built them full size. We're talking huuuge ol' horns that make the car basically undrivable. This is back in the 90s. As I began building waveguides, I found that you could use boundaries to extend the waveguide. And I don't mean an inch or two. I'm talking about removing over 75% of the waveguide.

Here's the problem I'm running in to: The size of the compression driver itself is really becoming an issue. I can't find compression drivers small enough to fit into corners. The best solution that I've found so far is to bend the throat of the waveguide, so that the compression driver enters at a 45 degree angle. But it's tricky, because the bend creates a dip in the frequency response, and the dip gets deeper as the bend gets bigger. (IE, if the compression driver enters the waveguide at a ninety degree angle you get a big fat dip due to a reflection off the wall of the waveguide.)















Here's the best waveguide I've built. It's an elliptical oblate spheroidal loaded by a BMS 4540ND. It has a horizontal coverage of 108 degrees, vertical of 72, and an average of 90. You can see that the compression driver enters at an angle. This allows me to push it as far back as possible on the dash of my car, which better mates with the angle of the dash and the windshield.







So here's what I'm thinking. If you a neodymium tweeter at the apex of a waveguide instead of a compression driver, you can push that waveguide almost all the way back. By pushing it back further, you can reduce the mouth of the waveguide even further. Basically, you let the windshield and the dash do more of the work.

Again, not saying that this is a good solution for the home, where depth isn't a problem. But my application is rather unique, and I simply can't think of another way to solve this.

By using a dome tweeter I will lose a great deal of efficiency, reduce power handling, and increase distortion. On the upside, it's smaller, looks better, and costs less. I have a hunch that a phase plug could be built to improve the high frequency polar response. Basically get the dome to behave more like a compression driver, and less like a dome.







As I see it, a compression driver is a big dome tweeter with an extraordinarily powerful motor, and a carefully designed phase plug. Here are two compression drivers that I've used. JBL 2470 on the left, back when I was into huge horns in the car. BMS 4540ND in my hand, once I switched to Unity horns.






Here's a TAD compression driver cut in half. They had this laying around their demo room when I was there, a rather amazing paperweight if you ask me. In the cross section you can see that this isn't much different than a dome tweeter, except they've added a very carefully designed phase plug in front of the diaphragm, and the dome is inverted.






To give you a sense of scale, here's the compression driver that I'm using in my car, mounted on a conventional horn. (woodhorn.com btw.) You can see that the TAD absolutely dwarfs it.







Here's a pic of JBL's top of the line components, which use a waveguide that looks suspiciously like an elliptical oblate spheroidal. My design would be similar to this, but using the windshield to bring the soundstage to eye level, and to extend the curve of the waveguide. (In other words, my waveguides will have a narrower coverage angle than JBL's.)

So I would end up with a waveguide that uses the oblate spheroidal curve, but with a footprint that's about 75% smaller than the waveguides I am already using. I haven't decided yet if it will be a Unity. There *is* enough room to mount a couple of midranges to extend the response. The primary goal will be to reduce the waveguides size to the smallest footprint possible, and use the existing boundaries to extend the curve.

Anyone care to comment on these plans?


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## lycan (Dec 20, 2009)

Patrick is asymptotically approaching a solution we'll all recognize : a dome tweeter clipped onto the A-Pillar  

Just playin'. And yes, i'm quite sure the JBL waveguide is an elliptical oblate spheroid ... they even call is EOS


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## Patrick Bateman (Sep 11, 2006)

lycan said:


> Patrick is asymptotically approaching a solution we'll all recognize : a dome tweeter clipped onto the A-Pillar
> 
> Just playin'. And yes, i'm quite sure the JBL waveguide is an elliptical oblate spheroid ... they even call is EOS


lol i know

i'm going to finish my car, only to find out it looks exactly like Andy Wehmeyers

(I have my five channel processor arriving this week... That's why I need to dramatically reduce the foot print of the waveguides... There's going to be at least three, possible five.)


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## lycan (Dec 20, 2009)

Seriously for a moment, Patrick , for what it's worth ...

I have done _nowhere near_ the experimentation that you've done on controlling directivity in a car. But I have thought, and analyzed for a long, _long_ time. And the conclusions i've come to are quite simple :

1. _Mount_ the tweets up high, since we recognize height only in the treble. No need to put the midrange drivers up there, though, since we can't recognize height in the midrange. Midrange & midbass drivers deserve their own attention, of course (covered in kickpanel pros & cons), but L/R concerns dramatically outweigh height concerns in the midrange & midbass. Use parallel time alignment to make sure primary wavefronts from treble & midrange arrive simultaneously ... and, to first order, your ears won't hear the vertical displacement of midrange & tweeter.

2. _Aim_ the tweeters so as to minimize reflections : aimed equally away from the windshield, side window, and dash. This direction will also approximate an acceptable compromise to combat side bias, crudely exploiting off-axis response to do so.

Waveguides do look like a promising "enhancement" to me, though, _especially_ in terms of exploiting off-axis response to combat side bias. I see tweet waveguides as attenuating the lower treble off-axis, while boosting the upper treble off-axis, thereby creating an _off-axis_ response that looks like a frequency-independent attenuation of the _on-axis_ response ... in sharp contrast to what you get from default beaming. Just what we'd like to see in the IID (inter-aural intensity difference) frequency range for _both_ front seat listeners


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## fastlane (Apr 6, 2009)

So are you stating; the aformentioned recommendations in the past of keeping the tweet and woofer as close together as possible, were possibly overstated? 

After reading through your numerous posts; it seems the soundstate will benefit more by getting tweeter up and away from as many reflections as possible.


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## ryan s (Dec 19, 2006)

What about mounting them high...almost up to the top of the A pillar? The headliner is there, so a soft material is nearby...

Or is that too high?


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## SSSnake (Mar 8, 2007)

Patrick,

I'm glad you are coming over to the dark side (non compression drivers on waveguides). Take a look at the Zaph site for some typical results. As I mentioned in a previous thread I have duplicated those results. I am building a dash waveguide right now using domes. It will be quite some time before I get in car measurements but they looke promising on the bench. 

BTW - I switched to small neo domes for the same reason you are contemplating... compression drivers are BIG


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## SSSnake (Mar 8, 2007)

Fastlane,

Most agree that the most critical frequency band is 1000 to 5000hz. I personally would like to see reflections minimized down to 500 hz but because of wavlength this is tough.


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## vactor (Oct 27, 2005)

any news on this project PB? i am looking for more info before i plan my next setup


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## Patrick Bateman (Sep 11, 2006)

vactor said:


> any news on this project PB? i am looking for more info before i plan my next setup



I'm leaning towards cloning a Beolab 3 and putting it up on the dash

Cloning a $3200 Speaker for $400 - diyAudio

The Unity horns sound good. But there's two big drawbacks. If you use the same 2" midranges that I used, you end up with a hole in the response between the subwoofers and the waveguides. About 100hz to 400hz is AWOL.

That was the inspiration for the "Natural Bass" thread, and I tried a LOT of things to solve that problem. But coming up with a midbass that can "keep up" with the waveguides isn't easy. If I was willing to chop up my car it might be easier, but I haven't removed a single screw from my car - it's 100% stock. I don't plan on owning this car forever, and I want to preserve it's resale value.

Another option is to put the midbass AND the midrange on the waveguide. A true three-way Unity. But as you can tell from this thread, I never finished that. As the pieces started to come together, it was obvious that the finished product would take up half my dash.

It might sound good, but it would look inexcusably ugly.

Let's hope the B&O clones don't.


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## diebenkorn (Jan 3, 2009)

Twelve Inch Woofers In My Dash - CARSOUND.COM Forum

Thought this thread may be of interest (haven't read the whole thing and apologies if it has already been talked about) Enjoying your posts Patrick, thank you. Just realized that majestik is from washington state is that Patrick Bateman's alter ego if so DOH!


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## Patrick Bateman (Sep 11, 2006)

diebenkorn said:


> Twelve Inch Woofers In My Dash - CARSOUND.COM Forum
> 
> Thought this thread may be of interest (haven't read the whole thing and apologies if it has already been talked about) Enjoying your posts Patrick, thank you. Just realized that majestik is from washington state is that Patrick Bateman's alter ego if so DOH!


Yep, I wrote that


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## Torquem (Jun 27, 2009)

You could have made 100% of this up and I would never know :laugh:


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## freemind (Sep 11, 2008)

Man I have boat-loads of respect for every thread you have posted.

You do not keep your mind.in.a.box

Keep on keeping on.


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## razholio (Apr 15, 2008)

lycan said:


> Seriously for a moment, Patrick , for what it's worth ...
> 
> I have done _nowhere near_ the experimentation that you've done on controlling directivity in a car. But I have thought, and analyzed for a long, _long_ time. And the conclusions i've come to are quite simple :
> 
> ...


I've had really good success with just this setup. It's amazing how good the soundstage is with tweeters and midrange so far apart.


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## Juanhanded (Apr 3, 2010)

diebenkorn said:


> Twelve Inch Woofers In My Dash - CARSOUND.COM Forum
> 
> Thought this thread may be of interest (haven't read the whole thing and apologies if it has already been talked about) Enjoying your posts Patrick, thank you. Just realized that majestik is from washington state is that Patrick Bateman's alter ego if so DOH!


Wow...that is a 26 page thread.This Bateman dude has a saga going wayyyyy better than Star Wars. I bet he is a swashbuckling Harrison Ford type in real life.


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## Patrick Bateman (Sep 11, 2006)

I kind of lost interest in car audio since I bought my Summas. But I'm really getting sick of my (stock) stereo.

I had an idea, curious if anyone else is interested.

Basically I'll take the traditional under dash horns, like the ones sold by USD and Image Dynamics, and I'll improve on them in a series of ways.

Here's what I would do:


The first problem with underdash horns is that they don't play low enough. That's why dudes in the 90s would tear up their cars and put hyooooge compression drivers in there. I can fix this one easily, by simply using a Unity horn. That's a lot cheaper, and it's smaller too.
The second problem with underdash horns is that they don't play high enough. Conventional compression drivers drop like a rock around 16khz. The solution to this is easy too. Just use a small neodymium compression driver, like the BMS 4540ND or the inexpensive Celestion that Brandon tested.
The waveguide would be similar to the conventional underdash horns, but about 50% larger. It would also be straight. This eliminates a notch in the response.
The waveguide would be stuffed with foam, like Geddes uses.
The waveguide would have diffraction treatment. Might look a bit like this:















The finished design wouldn't require active EQ. All of the EQ would be in the passive crossover. This makes it a lot more accessible to regular folks. Remember in the 90s when people would run Rane EQs because they needed that last bit of resolution?

Obviously this isn't something I can sell, since it uses patented technology from Geddes and Danley. If I'm not mistaken that's OK as long as the product isn't for sale. (Does anyone know?)

Anyways, just throwing this out there. Is anyone interested?


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## western47 (Nov 17, 2008)

I for one would be quite interested as I have the same car and my home gear is by the same designer as yours which means I know you have a good reference

Tell me more...


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## Hernan (Jul 9, 2006)

Patrick, I take caraudio as a hobby. I live far away from the US. Here there is a interesting market for car horns. Nowdays very little knowledge lead in awefull inplementations of the concept. It would be fun and perhaps profitable to offer an alternative solution in this market. 
Regards. Hernan. 
Feel free to PM me if you like this game.


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## rawdawg (Apr 27, 2007)

Yes sir!


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## fish (Jun 30, 2007)

Hell yeah, I'm in! Always interested in your projects.

One thing that concerns me from the get-go is the whole 50% larger than conventional horns. The sheer size of horns is one of the reasons I haven't tried them by now.


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## BigRed (Aug 12, 2007)

rawdawg said:


> Yes sir!


don't you need a working radio first rawdawg?


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## Patrick Bateman (Sep 11, 2006)

western47 said:


> I for one would be quite interested as I have the same car and my home gear is by the same designer as yours which means I know you have a good reference
> 
> Tell me more...


In the car, I like the Unity concept better. The Gedlee speakers have a huge center-to-center spacing. That requires one to sit very far from the speakers for them to integrate properly.

At home, I notice a distinct improvement when I sit reeeeeeeally far back.

When I listen up close, they still sound great, but nowhere near as good as they do at a distance.

I can't remember where I read this, but I've read that one should sit five to ten times the CTC distance of a loudspeaker. (Doesn't matter if it's a horn or a direct radiator, the formula is the same.)

So for my Summas, I should sit 6.25' to 12.5' away. (15" center-to-center spacing.)

With a Unity horn, the CTC spacing is about 4". So that distance shrinks to 1.67' - 3.33'. Which is no problem at all in a car.


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## Patrick Bateman (Sep 11, 2006)

fish said:


> Hell yeah, I'm in! Always interested in your projects.
> 
> One thing that concerns me from the get-go is the whole 50% larger than conventional horns. The sheer size of horns is one of the reasons I haven't tried them by now.


I'll explain why I had to use a horn size that's bigger than USD and Image Dynamics here:

Audio Psychosis • View topic - Unity VI: Crossover

I'm going to document this project on my own forum this time around.


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