# Anyone Want Some HLCDs?



## Patrick Bateman (Sep 11, 2006)

I've been thinking about doing a 'modest' stereo project in the next few months. People seem to enjoy my projects, so I'd like to tailor this project so that it's more accessible than most. In other words, no crazy waveguides on the dash, no tapped horns that take up the whole trunk, no passive crossovers with sixty four components.

I think it will look a little something like this:









source : iPhone / iPod Touch / iPad









amplifier : any good 2-channel amp, in the range of 50w to 250w









sub : Alpine SWR 824D $110 (in a tapped horn, but not a big one, srsly)









midbass : dayton ns210 $170 (If this is too expensive or difficult to put in your car, I'll include other options as well.)









As usual, the midrange and highs will be covered by a unity horn. The unity horn offers some huge advantages in the car. First off, the articulation is unparalleled, particularly when you're sitting close to the HLCD, like we are in a car.

johnny cash on unity horn (in a corner).mp4 - YouTube
jbl control now.mov - YouTube

_here's a couple of videos I shot with my phone, comparing a well made JBL loudspeaker with a Unity horn. IMHO, the unity horn sounds more 'convincing' than the JBL, despite using a crossover that is complete crap. (one component in the whole xover, tuned by ear, using whatever I could find in the garage.)
_









The tweeter on the unity horn will be a Celestion CDX1-1425, available at Parts Express for $190 a pair. (was a much better deal last year, before the neodymium crisis, when they were $70 a pair.)

















The midrange on the unity horn will likely be the lowly Goldwood GT25, or else the Dayton RS75. Eight of the GT25s cost $40, four of the RS75s cost the $80.

Here's a summary of xover points and cost for the project, in case you'd like to do it:

sub - Alpine SWR 824D ≈ $110 delivered, covering two octaves from 20 to 80hz
midbass - dual Dayton NS210 ≈ $170 delivered, covering two octaves from 80 to 320hz
midrange - eight Goldwood GT25 ≈ $80, covering 2.5 octaves from 320hz to 2khz
tweeter - dual Celestion CDX1-1425 ≈ $190, cover 3.5 octaves from 2khz to 24khz

With the crossover, total cost will be ≈ $650, excluding source and amplifier.

I'm fairly flexible on these specs. If you guys want me to come up with a design that's different, let me know. I could probably get the cost down to $500 with a bit of work, or make it more expensive if these driver choices aren't compelling.

The Unity horns will go under the dash. One thing that will be strange about this setup is that I intend to have the entire front stage under the driver's side of the dash. *That's the reason I'm using an iPhone for a source - this will be an ambiophonic system*, using the software listed at ambiophonics.org. In an ambio setup you want the speakers right in front of you, so that's why I'm putting both on one side.


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## traceywatts (Jun 2, 2008)

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/111328-waveguide-horn-question.html

Waveguide/ horn question - traceywatts

Patrick, I think this is similar to what you are doing. I have revised my idea, since. I will add more after work.


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## thehatedguy (May 4, 2007)

I can make prices on the speakers cheaper than retail if using PE drivers...if people go foward with the idea.


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## Patrick Bateman (Sep 11, 2006)

traceywatts said:


> http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/111328-waveguide-horn-question.html
> 
> Waveguide/ horn question - traceywatts
> 
> Patrick, I think this is similar to what you are doing. I have revised my idea, since. I will add more after work.


Actually, in the car, you can hack away eighty or even ninety percent of the horn and it will still work fine. That's how you can cram two horns under the dash - you basically obliterated 80% of the horn, and use the boundaries under the dash to replace what you chopped off the horn. (Similar to the way a Klipschorn works.)

For instance, let's say you want to make a waveguide that works down to 2500hz, and works up to 20khz. The last three octaves we can hear. The waveguide doesn't need to be big at all - just a hair over 5" across.

Now let's say you want to get down to 270hz. To do that, you need a waveguide that's four feet wide(!)

The easiest thing to do by far is just build the high frequency part of the waveguide (the part that's 5" across) and cram it into a corner, then let the corner continue the curve.

Someone on the forum here has Image Dynamics HLCDs in his BMW that are setup like this - pressed right up against the firewall - and I'll bet they could play REALLY low with the right driver at the throat.

On a side note, this Scan Speak you're using looks like an excellent candidate for horn loading.









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## Se7en (Mar 28, 2007)

Patrick,

Please excuse my ignorance on the subject. What's the benefit of using a unity configuration, using drivers that in theory could play as low as 200hz, yet the horn itself, using your example of 5", only allows controlled directivity of frequencies down to 2.5k?

Thanks!


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## thehatedguy (May 4, 2007)

It would really increase system efficiency and lower distortion a whole lot.


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## DeanE10 (Apr 19, 2011)

as a starting MECA SQ Wanna be, I would love to get in on this


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## Se7en (Mar 28, 2007)

thehatedguy said:


> It would really increase system efficiency and lower distortion a whole lot.


I understand that of horns in general. I guess my question here is specifically of the unity horn. I understand how it works in principle, as a two way multiple driver horn, it would allow all of the benefits you listed, plus phase characteristics more in line of that of a point soure, across a broader frequency band.

The real question, is if the gating factor is the size of the horn, why use multiple drivers to cover frequencies that a single driver horn could. I,e If an off the shelf HLCD should be able to play down to 700-1.5k, why do this with a multiple driver solution?

Edit: excuse grammar, typing on a mobile device is balls.


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## fish (Jun 30, 2007)

Patrick Bateman said:


> For instance, let's say you want to make a waveguide that works down to 2500hz, and works up to 20khz. The last three octaves we can hear. The waveguide doesn't need to be big at all - just a hair over 5" across.
> 
> Now let's say you want to get down to 270hz. To do that, you need a waveguide that's four feet wide(!)
> 
> The easiest thing to do by far is just build the high frequency part of the waveguide (the part that's 5" across) and cram it into a corner, then let the corner continue the curve.



Patrick,

I'm sure you've posted it somehwere, but what's the mathematical equation to find out your lowest frequency response via your waveguide width?


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## Se7en (Mar 28, 2007)

fish said:


> Patrick,
> 
> I'm sure you've posted it somehwere, but what's the mathematical equation to find out your lowest frequency response via your waveguide width?


Speed of sound, 1126 ft/second, or 1126x12 to give you 13512 inches per second. Call it 13500.

Divide 13500 by the desired lowest frequency, let's say 2500hz, and you get 5.4".

If you wanted 200 hz, divide 13500 into 200 and you get 67.5".

Similarly, if you have a wave guide, you can apply the same formula. 13500/5.4 = 2500


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## asawendo (Nov 22, 2009)

Subscribed for PB latest experiment!


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## rawdawg (Apr 27, 2007)

Se7en,

Does the height factor into the equation? Say if you had a rectangular opening, like my USD's.


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## Se7en (Mar 28, 2007)

rawdawg said:


> Se7en,
> 
> Does the height factor into the equation? Say if you had a rectangular opening, like my USD's.


I'm no horn expert..keep this in mind. Yes, the height of the mouth is also a factor, but keep in mind that were only talking about the lowest frequency where the the horn or waveguide controls directivity. 

I need PB or Hatedguy to chime in here, but I believe that a unity horn with drivers that play below 2500hz (using the 5.4" horn described in this thread), lets say down to 200hz, could still play down to 200hz, but only frequencies above 2500 would have any sort of constant directivity. 

The nature of my original question, is what is the benefit of having these lower frequencies play through the horn? The only thing that I can think is that they would act more like a point source, all frequencies leaving the mouth of the horn, at the same time and from the same location. What am I missing?


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## thehatedguy (May 4, 2007)

Well the low frequency cut off depends on a few things...depth is only one thing, but is one of the main things for a conical horn.

Height just plays into the total area of the horn and expansion, which is another thing that can factor in. Plus a narrow height can help with the high frequencies in the car.

Horns generally have 3 degrees of freedom...tractrix horns have 2. Meaning the area dictates the length of the horn and visa versa in a tractrix. The other horns you can sort of juggle things around a bit more.

Plus you can use physical boundaries in the car like the bottom of the dash to extend the virtual size of the horn.

Nice little paper that explains a little bit about different horns:

http://folk.ntnu.no/bjorkol/hifi/Hor...troArticle.pdf


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## funkalicious (Oct 8, 2007)

Subscribed


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## The Baron Groog (Mar 15, 2010)

thehatedguy said:


> http://folk.ntnu.no/bjorkol/hifi/Hor...troArticle.pdf


linky no worky


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## thehatedguy (May 4, 2007)

I will fix that...sorry.


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## thehatedguy (May 4, 2007)

http://users.cms.caltech.edu/~ps/Horn1.pdf

http://users.cms.caltech.edu/~ps/Horn2.pdf

Same paper, same other, different formats.


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## The Baron Groog (Mar 15, 2010)

^some good reading for me there


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## danno14 (Sep 1, 2009)

Hatedguy- sorry to threadbomb, but did you get my PM? 
Thx


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## BMWTUBED (Aug 25, 2007)

Bateman, I have been thinking about trying a tapped horn sub as well. Is there a formula or calculator that you are going to use?


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## acidbass303 (Dec 3, 2010)

subbed


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## Patrick Bateman (Sep 11, 2006)

Se7en said:


> I'm no horn expert..keep this in mind. Yes, the height of the mouth is also a factor, but keep in mind that were only talking about the lowest frequency where the the horn or waveguide controls directivity.
> 
> I need PB or Hatedguy to chime in here, but I believe that a unity horn with drivers that play below 2500hz (using the 5.4" horn described in this thread), lets say down to 200hz, could still play down to 200hz, but only frequencies above 2500 would have any sort of constant directivity.
> 
> The nature of my original question, is what is the benefit of having these lower frequencies play through the horn? The only thing that I can think is that they would act more like a point source, all frequencies leaving the mouth of the horn, at the same time and from the same location. What am I missing?


Theoretically, to play down to 200hz, you need a humongous horn - literally the size of the whole dash.

BUT

You can use a corner as a horn. Simple as that. You just match the angle of your corner, and *voila*, you can eliminate 80 or 90% of your horn.

Watch these videos and you'll see what I mean.

First, here is a video of some cone tweeters playing without a baffle. Note how the high frequencies are present, but the frequency response is weird and nasal:

test SONY Made in 1975. Speaker unit 575-11 6.5cm Tweeter - YouTube

Now watch this video of a Unity horn using the same type of drivers (cone tweeters.) Listen how it plays down to 200hz? Even though the horn is small, the drivers don't care because the horn mouth is the exact same angle as the corner.

unity horn with cone tweeters - YouTube

The Unity above uses $10 worth of cone tweeters, no xover, and I made the horn using a handsaw. This is some seriously sloppy engineering here, nothing difficult 

The key to all of this is that it's in a corner; if you put this in the middle of the room it wouldn't sound much better than those little Sony tweeters.


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## thehatedguy (May 4, 2007)

Miscos showed up today.

Maybe I can get away with the DE5 as a tweeter...though the horns I'm working on are smaller than the one in the video. I am going to have a time physically fitting the drivers on the horn and keeping the magnets from sticking together.


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## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> Miscos showed up today.
> 
> Maybe I can get away with the DE5 as a tweeter...though the horns I'm working on are smaller than the one in the video. I am going to have a time physically fitting the drivers on the horn and keeping the magnets from sticking together.


Jason,

One thing you'll want to watch out for is the resonance peak of these cone tweeters. I stumbled across this rather accidentally.










If you look at the response graph of the Misco, there's a monster peak in the midrange - like 10dB!

If you listen to the video of the cone tweeters playing unbaffled, you can really hear the peak in the video. But if you listen to the video I posted of the Goldwoods, you don't hear the peak.

Here's what I think is happening here -

Basically the weight of the air in the horn dampens the cone of the tweeter. On the diyaudio Unity horn thread, I posted a quote from Danley, where he talks about this.

It's something you don't see often, because the mass of the cone has to be very very very very low. But we see it with the cone tweeters, because they really have no surround or suspension, and the cone is virtually weightless.










Anyways, you can see the effect in this graph. This graph compares the response of four of the Goldwood cone tweeters on two different horns. The first horn is a 60x90 horn; the second horn is a 30x45 degree horn. *Due to the second horn being 1/4 the size, the driver's response peak has been reduced. *

Or at least that's my best guess 

Hasquin or Danley or Sheerin would know how this works off the top of their head. It's definitely a bit strange; usually you need a BIG horn to get flat response, but these cone tweeters behave a bit strangely.


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## Se7en (Mar 28, 2007)

Patrick,

Most of the images of unity horns that I see, have a tweeter firing down the center of throat, and multiple mids mounted to the outside of the horn, firing off axis towards each other. Is phase cancellation not a concern here?

Thanks!


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## thehatedguy (May 4, 2007)

Phase is an issue, but not how you think it would be.

You have to think of the unity horns as a series of horns stacked on each other. Then the wavelengths of the mids are longer than the cross sectional area of the horn where they enter, so there are no issues as far as that is concerned.


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## The Baron Groog (Mar 15, 2010)

BMWTUBED said:


> Bateman, I have been thinking about trying a tapped horn sub as well. Is there a formula or calculator that you are going to use?


Hornresp


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## Se7en (Mar 28, 2007)

thehatedguy said:


> Phase is an issue, but not how you think it would be.
> 
> You have to think of the unity horns as a series of horns stacked on each other. Then the wavelengths of the mids are longer than the cross sectional area of the horn where they enter, so there are no issues as far as that is concerned.


That's kind of badass if you think about it..

I'm naively thinking of a configuration in the kick area of my car (more like the farthest corner where the firewall creates a corner), with a tweeter mounted dead center, and a series of mids creating a unity type configuration. You'd have to shape and smooth the hell out of the under dash and pedal area, but it's a fun concept...


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## Patrick Bateman (Sep 11, 2006)

[


Se7en said:


> Patrick,
> 
> Most of the images of unity horns that I see, have a tweeter firing down the center of throat, and multiple mids mounted to the outside of the horn, firing off axis towards each other. Is phase cancellation not a concern here?
> 
> Thanks!












As Jason noted, it only works correctly if you visualize it as a horn on top of a horn on top of a horn. If you juggle all the parameters carefully, each segment of the horn doesn't 'see' the segment on top of it.

Weird huh?

For instance, let's say you want to cross your compression driver at 1200hz. 1200hz is 28.5cm long. Therefore, the mouth of your high frequency horn needs to be 64.64cm^2 or larger. Here's the math:

wavelength = 28.5cm
circumference of horn at midrange entry point = 28.5cm
radius of horn at midrange entry point = circumference / (2 * pi )
radius of horn at midrange entry point = 28.5cm / 2 * 3.14159
radius of horn at midrange entry point = 4.5359cm
area of horn at midrange entry point = 64.64cm^2

Now the MOUTH of your tweeter horn becomes the THROAT of your midrange horn. (Because it's a stack of pyramids.)

Let's say you want to cross your midranges at 300hz. 300hz is 114cm long. Therefore, the mouth of your midrange horn needs to be xxcm^2 or larger. Here's the math:

wavelength = 114cm
circumference of horn at midrange entry point = 114cm
radius of horn at midrange entry point = circumference / (2 * pi )
radius of horn at midrange entry point = 114cm / 2 * 3.14159
radius of horn at midrange entry point = 18.143cm
area of horn at midrange entry point = 1034cm^2

That works out to a square mouth that's 12.5" x 12.5"


















See why the horn above is that shape now? 

The mouth is actually 16" x 16", but you'll notice the angle changes in the last couple inches - the last couple inches are basically there to ease the transition into the room. Similar to the roundover on my Summas.

The rules change quite a bit when you stick them in the corner; if you use a corner to your advantage, you can eliminate a big chunk of the horn. All of the parameters are connected; for instance, if you raise the tweeter crossover from 1200hz to 2000hz, you have to move the midranges closer to the throat. (Because the tweeter mouth is the midrange's throat.)









The horn is a lot like giant version of the Vifa and Scanspeak ring radiators. (The 'ring' is around the horn, at the various taps.)

If any of this doesn't make sense, just ask, it took me a few years to 'grok' all of this, and I'm still learning.


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## Se7en (Mar 28, 2007)

PB,

Thanks for the insightful response. I'm pretty sure I'm grasping the concept, although I'll need to spend some time with the math to get it locked in.

I have two questions (semi related):

1. Maybe this is just semantics, but in your explanation, most of the objectives describing the design necessity of the unity horn, have mostly to do with controlling directivity of a given driver or frequency range. One of the advantages of a "horn" is increased efficiency as well as controlled directivity. If we were to remove efficiency as an objective, is also possible to have a Unity-Guide, which carries the same design principals, but in theory could be scaled down in its physical dimensions? Does that make sense?

2. What is the advantage of using a compression type tweeter in a horn/waveguide. vs. a conventional dome type tweeter. 

2b. I know that there's a lot of math having to do with mechanical resistance when dealing with horns, but I'm not sure if this is why compression drivers are proffered, and how much of this changes, when describing a wave guide vs. a horn?

Thanks and sorry for the lame-ass 3rd grade questions!


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## Se7en (Mar 28, 2007)

Although not a unity horn, this thread got me thinking about some AMT horns that Hawthorn has or had been developing for an OB system.

From their forum: "The horn is 16" wide and 11" tall. This cultured marble horn is approximately 3/4" thick minimum and about 6" deep." 

Apparently the diver has a usable range down to 500hz or so...


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## Patrick Bateman (Sep 11, 2006)

Se7en said:


> PB,
> 
> Thanks for the insightful response. I'm pretty sure I'm grasping the concept, although I'll need to spend some time with the math to get it locked in.
> 
> ...


The location of the taps is dictated by the speed of sound and the lowest frequency that the horn is going to play to. (The algorithm to figure out the taps is in my last post)

Since we can't change the speed of sound, that means *the only way we can make the horn smaller is by changing the xover points*.*

I didn't 'grok' this in 2006 - I was using 2" drivers simply because they worked best in the sims. But in 2012, I "get" that idea, that you simply can't shrink the horn arbitrarily.

Now you CAN shrink the horn by using a boundary; that's why I'm always trying to cram these things into a corner, and it's the reason all these videos I've uploaded are recorded in a corner. If you pull the horn out into the room, it sounds completely different, and the corner is factored into the design.









If you tweaked the angles on this horn, you could remove everything foward of the midrange ports. Of course you'd have to chop a hole in the wall for that big compression driver, but that's one of the reasons I use these tiny ones, they enable me to push the horn all the way into the wall.



Se7en said:


> 2. What is the advantage of using a compression type tweeter in a horn/waveguide. vs. a conventional dome type tweeter.
> 
> 2b. I know that there's a lot of math having to do with mechanical resistance when dealing with horns, but I'm not sure if this is why compression drivers are proffered, and how much of this changes, when describing a wave guide vs. a horn?
> 
> Thanks and sorry for the lame-ass 3rd grade questions!


These aren't lame questions at all. 

I could fill up a few pages on the "compression driver vs dome" question. It's actually very complex.

Basically, if you put a dome at the apex of a horn, the response goes to hell. Check out the graphs on Zaphaudio, where he loaded a waveguide with a dome. *As long as the waveguide isn't large, the results are pretty good.* But as the dimensions get larger, it gets ugly.

Compression drivers can sound pretty sweet if you get a good one. I'm always looking for excuses to NOT use them, but I keep coming back to them because they work so well. I have a couple of ribbons and some ring radiators here, and none of them have worked as well as the Celestion CDX1-1425













* Note that you CAN make the horn longer or shorter; the volume won't change by much, but you could make the thing 8 inches deep instead of 16" if you were so inclined. (Since the location of the taps is determined by *area*, not by depth.) As you make the horn shorter, the woofers get closer and closer to the apex, and eventually you reach a point where there's simply no room for them. That's a big part of the reason the pyramid is sixty degrees.


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## whoever (Nov 21, 2008)

Patrick I didnt understand this part:

" (Since the location of the taps is determined by *area*, not by depth.)" and this: 
"That's a big part of the reason the pyramid is sixty degrees."

would you mind touching on that a bit...

By taps I assume you mean the entry point for the midranges, what are the determining factors for size of the entry point's?


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## thehatedguy (May 4, 2007)

IMO, you would want the compression driver on the top end. In my sims using two Misco 3" tweeters, I am 115 dB sensitivity in the pass band of the midranges...and at the extremes, it peaks at 120 dB. Yeah it's going to be padded down...and I'm going to take care of a lot of that in the crossover. But that 115 dB is from about 600-6k. That's with 2 3" tweeters getting 10 watts and moving half of their xmax. I doubt these things will ever see a real 10 watts even padded down to 100-105 dB.

The horns in the doors are small, like 4x6" and about 2" deep. They won't hold directivity below where I am going to bring the HF in at...they are barely big enough to fit the 2 3s and a DE5 for the top end. Keep in mind this is for the fronts in a L7 system...and one edge is butted up to the dash edge while the other edge is butted up against the door, so it will extend the size of the horn some. 

The horn for the center will be much much larger...and probably 3 way. I think I can get a pair of Dayton RS100s up to 105 dB sensitivity between 100-600 hertz and run the 3s from 6-800 up to, well I want to go 3-4k or a little higher on them.

If I can get one driver playing that 1-4k hz "snap and impact" with high efficiency, I will be happy.

John Hasquin has dropped me a few hints on the crossover for the Unity/Synergy, and I have been dissecting the Unity crossover in LspCAD to see what all everything does.

And if you think the horns are pretty trick...Danley is doing some interesting stuff in the passive crossovers as well. And we haven't even seen what he is doing on the new Synergy horns.

I am learning a whole lot about this stuff. I commited to finally doing a unity setup...I played around with some sealed back mids on my ID horns probably 5-6 years a go with some good results, but never went full monty on/with it yet.


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## thehatedguy (May 4, 2007)

That is a whole nuther can o'worms...lol.

First, the location of the ports. They are in the corners of the conical horn because they are more invisable to the compression driver/HF there.

Second, it's not only the size of the ports, you have to factor in the depth of the ports too. And that is all related to how big of speakers you are using for the mids...as you have to factor in the area and volume of the chamber between the cone and the horn. That will tell you about the ports entering the horn.

If it sounds like you are desiging a bandpass enclosure, you are. You are firing that bandpass's output into the horn.

Strictly speaking on the area of the ports. You want to keep them large enough to get you good flat output, but you don't want them to be too large too close to the HF driver because you will/could mess up the HF driver's FR.

There is a lot of juggling going on in making one of these horns.

Then you have the placement of the ports as mentioned before...you want them to be 1/4 wavelength away from the HF driver at your desired XO point because there will be a certain amount of energy traveling up to the HF driver...and doing this you create a null point in the mid's output to turn the bandpass off.



whoever said:


> Patrick I didnt understand this part:
> 
> " (Since the location of the taps is determined by *area*, not by depth.)" and this:
> "That's a big part of the reason the pyramid is sixty degrees."
> ...


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## whoever (Nov 21, 2008)

WOW! A miniature bandpass! I laughed when I "got" that, only one of the walls is completely moving! sorry, it's kind of funny in my head...anyway, thank you for the explanation. I researched and saw this:
Suitable midrange cone, for bandpass mid in Unity horn. - Page 27 - diyAudio post 264 by Tom Danley


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## Patrick Bateman (Sep 11, 2006)

After spending the last few weeks evaluating various options, I've decided to resurrect this thread. I'm going to build a small pair of underdash horns.


























It will look fairly similar to the picture above.

Prior to starting this project, I tried a few things. First, I tried a pair of NEO 8s up on the dash. That sounded alright, but the imaging was terrible. This is because the NEO 8 is very directional. Basically you can only hear the speaker that's close to you.

I also tried the speaker in the picture above, and it worked pretty well, but some research I've done indicates that I can improve the phase response. Which should make it sound more 'articulate' and realistic.

So...

Stay tuned!


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## DeanE10 (Apr 19, 2011)

Looking forward to seeing more on this Patrick!!


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## Patrick Bateman (Sep 11, 2006)

DeanE10 said:


> Looking forward to seeing more on this Patrick!!


Thanks!

I'm hoping I actually finish this one. It's going to incorporate a lot of the tricks I've learned in the last few years, but it will still look a lot like the horns from this thread:

http://www.diymobileaudio.com/forum...vanced/60146-creating-perfect-soundstage.html

A lot of the projects that I've done over the past few years have been fairly experimental. IE, I'd throw something together really quickly to explore something that I hadn't seen done before.

But this project will be different - I really intend to collect a series of things that I *know* work. So it won't be as zany as most, but it will probably actually work. Which is more than I can say for a lot of my projects (cough cough such as my Triple8 subwoofer, which really didn't work.)


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## Patrick Bateman (Sep 11, 2006)

Here's some info on how to build the horns.










First, here's a diagram of the horn. It's a pyramid, just like the Danley Unity horns. Danley uses a symmetrical horn with a coverage of 50 degrees by 50 degrees for his flagship. I'm using a coverage of 60 degrees by 22 degress. The reason that my coverage is different is that it needs to fit under the dash.

Ideally I'd use something closer to Danley, but if I did that it would have a mouth that's 20cm tall. And that won't fit under the dash.




























Here's some pictures of the horn. To make the sides, I drew a cut sheet in Xara Xtreme, then simply printed it on my printer. It's *that* simple.

Getting the shapes correct is pretty important. If one side is half an inch too long, or the angle is wrong, the pyramid will be lopsides. Acoustically, a couple of degrees won't make a huge difference, but it will look funky. Also, it's a lot easier to assemble the pyramid if all the shapes are correct.

*If anyone wants to make one of these, I can post the cut sheet. It's four pieces per horn. Literally assembled a pair in under an hour.*


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## ErinH (Feb 14, 2007)

I've been really reading on horns, arrays, and planars a lot lately and I was honestly thinking last night that I'm surprised I've not seen anyone try ribbon/planars paired with a waveguide. At least _try_ it, I mean.


That said, Patrick, if you happen to have any horns you're not using, would you be willing to ship them to me and let me put them on my test baffle and test them out? There's just not much data on horns, in general. The problem is that people mix and match the compression drivers with various horns, but it might be cool to see how a single driver in various horns behaves. FR, HD and raw impulse measurements are what I'm looking at.


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## Mic10is (Aug 20, 2007)

bikinpunk said:


> I've been really reading on horns, arrays, and planars a lot lately and I was honestly thinking last night that I'm surprised I've not seen anyone try ribbon/planars paired with a waveguide. At least _try_ it, I mean.
> 
> 
> That said, Patrick, if you happen to have any horns you're not using, would you be willing to ship them to me and let me put them on my test baffle and test them out? There's just not much data on horns, in general. The problem is that people mix and match the compression drivers with various horns, but it might be cool to see how a single driver in various horns behaves. FR, HD and raw impulse measurements are what I'm looking at.


email me your address dood, i'll send u one or a pair that im not using, but youre on your own for compression drivers


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## ErinH (Feb 14, 2007)

will do.

i have zero compression drivers so if anyone feels like making a donation (that may take a while to get back) then LMK.


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## ErinH (Feb 14, 2007)

bikinpunk said:


> I'm surprised I've not seen anyone try ribbon/planars paired with a waveguide.



I take that back...

Overview


Shows my nooB'ness.


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## Patrick Bateman (Sep 11, 2006)

bikinpunk said:


> I've been really reading on horns, arrays, and planars a lot lately and I was honestly thinking last night that I'm surprised I've not seen anyone try ribbon/planars paired with a waveguide. At least _try_ it, I mean.


This is something I literally figured out a few weeks ago. It's part of the reason I've been posting like crazy, because it was a real 'Eureka' moment.


Geddes has stated vehemently and repeatedly that compression drivers are what should be used to feed a waveguide. He's argued that compression drivers are the only devices that produce a wavefront that's correct for a waveguide.

Yet, cryptically, he's also mentioned that flat diaphragmed drivers are ideal. Such as the ones from TangBand, and Geddes messed around with some flat diapragmed tweeters that Panasonic used to sells nearly 30 years ago. (You can also get some flat tweeters from E-Speakers and Parts Express. I can't remember who makes the former, but the latter is a flat circular ribbon from Hi Vi.)

Further confusing things, John Krutke (Zaph) has had good results with domes in waveguides.

So the 'Eureka' moment was when I realized it's not the shape of the diaphragm or the horn that's so critical. *It's the distance from the driver.*

For instance, if you have a dome tweeter that's 2.54cm in diameter, the tip of the dome is about 1.27 closer to the listener than the edge of the diaphragm. And a difference of 1.27cm seems absolutely meaningless in the grand scheme of things. But high frequencies wavelengths are VERY short. And to get the radiation from two radiators to sum properly, the radiators need to be within about 1/4 wavelength. *Anything above that will start to comb filter.* So in the case of that 1" tweeter, the tip of the dome will start to interfere with the edge of the dome at about 6692hz. (34000cm/s / 1.27cm / 4)

Of course, you might wonder then -

Why did John Krutke get good results with domes?

And

If domes suffer from an interference pattern from 6692hz and up, then why are there domes that play to 20khz?

And the answer to both questions is simply. The diameter of the dome (2.54cm) causes it to beam, and that begins about 13500khz.

So you have this octave from 6692hz until 13500khz, where the edge is starting to interfere with the apex, but the beaming is starting to focus the energy at the apex so that it *doesn't* interfere with the edge.


To make a long story short, shallow waveguides should work with domes, as long as you stick with an angle that's wide enough. As the walls get narrower and narrower the 'incorrect' geometry will become a problem, because the energy will get focused in front of the tweeter, where it might cause a problem.

If those paragraphs above made any sense whatsoever, you'll realize a couple things:

#1 - the ideal driver for a horn or waveguide is a point. Smaller the better.
#2 - a flat diaphragm is better than a dome because the energy radiated from the apex of a dome will interfere with the edge
#3 - an inverted cone or sphere, similar to the shape of plain o' cone drivers is good. But the problem with cone drivers is that you start to get standing waves that travel from side to side. For instance, a 10cm cone will have a standing wave that travels from side to side that occurs at 325hz, 975hz, 1625hz, 2275hz, etc...




bikinpunk said:


> That said, Patrick, if you happen to have any horns you're not using, would you be willing to ship them to me and let me put them on my test baffle and test them out? There's just not much data on horns, in general. The problem is that people mix and match the compression drivers with various horns, but it might be cool to see how a single driver in various horns behaves. FR, HD and raw impulse measurements are what I'm looking at.


Sure! I'll see what I can dig up.


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## thehatedguy (May 4, 2007)

I'll donate a BMS 4540Nd/JBL 2407H for the compression driver. It's a screw on so it would need an adapter purchased....I have a few adapters but no 1" bolt on to 1 3/8-16 screw on adapters.


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## thehatedguy (May 4, 2007)

And Hygeia Electric makes those flat circular ribbons...can find them on e-Bay from a guy out in Utah.


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## Patrick Bateman (Sep 11, 2006)

Patrick Bateman said:


> After spending the last few weeks evaluating various options, I've decided to resurrect this thread. I'm going to build a small pair of underdash horns.
> 
> 
> 
> ...




It was a sunny weekend, so I managed to throw one of these together in a couple days.

In this post, I am going to show a couple videos of the device.

The first video is one of my past Unity horn experiments. The old device uses a compression driver and a sealed pair of 12cm midranges.

The new device (the second video) uses a ribbon and a semi-sealed triplet of 5cm midranges.

In the video, look for the following:


The new device has a better transition from the ribbon to the midranges. It's more seamless. This is basically the hardest thing to get right in a Unity horn.
In the old device, you can hear a 'depression' in the midrange, which is due to the fact that the midranges can't play high enough to mate with the tweeter.
The new device sounds 'hotter' in the treble. The crossover is a single component, so the frequency response isn't sorted out at all. I literally guessed.
Perhaps the biggest improvement is in the lower midrange. Listen to Johnny Cash in the clip, and note how his voice sounds too 'chesty' in the second clip.

Here's the new device (the one I built this weekend)

under dash unity apr 10 2012.mp4 - YouTube

Here's the old device (similar size and angle, but using different drivers. I built this about three months ago.)

unity with phase plugs-1.mp4 - YouTube

In a nutshell, the very small sealed enclosure used by the first horn causes that 'chestiness', that resonance in the lower midrange that you hear on the Johnny Cash track. It's a similar situation as when you put a subwoofer in a sealed box that's way too small. The lower frequencies sound slow and sluggish.

This is due to the fact that when there's a resonance in a loudspeaker it causes the sound to be delayed in time at the frequency of resonance.

In other words, the sealed midranges in the second video have a big resonant peak at 500hz, and that peak makes them sound 'sluggish.' The sealed midranges in the first video are using a much larger enclosure, so the resonance is lower in frequency, where it's smaller and also less audible.


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## mosconiac (Nov 12, 2009)

Thanks for continuing to share your audio adventures "Patrick". It's fun to read & I've learned a lot!

I can't leave this post without a question, so are you building another unity or prototyping a "sunshine" horn? I thought (maybe) you were transitioning to a "sunshine" unit for this system.


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## DeanE10 (Apr 19, 2011)

Looks like your well on your way to creating a very nice and effective horn Patrick! Definitely looking forward to seeing this one completed. I am also very curious to see how the staging is going to work out from under the dash.


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## SSSnake (Mar 8, 2007)

Pat,

What is the height of the horn? I couldn't tell from the pics but it looks larger than 1" tall but smaller than 13" which would put the pattern flip in a fairly audible portion of the passband for most applications. 

The reason I ask is that I have been trying to find good material on the audibility of pattern flip. Intuitively it would seem like something to be avoided but i haven't seen concrete evidence. Any ideas concerning good reference material?


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## thehatedguy (May 4, 2007)

I've only seen it mentioned briefly on the Renkus Heinz website.


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## SSSnake (Mar 8, 2007)

Thanks jason I'll check it out. I'm struggling with a high freq horn design. I would like to add some directivity but I am worried about getting it to couple to some physical boundaries which makes the overall shape smaller than desired and puts the pattern flip in a bad spot. Too many variables to just build and test. Looking to apply what others have discovered.


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## Patrick Bateman (Sep 11, 2006)

DeanE10 said:


> Looks like your well on your way to creating a very nice and effective horn Patrick! Definitely looking forward to seeing this one completed. I am also very curious to see how the staging is going to work out from under the dash.


I've only listened to it for about two hours, but I'd say it sounds better in the kicks than placed up high.

This wasn't by design; the only reason I put it down low was for cosmetic reasons. But it seems to sound 'smoother' in the kicks than up on the dash.

I haven't done any measurements yet, but I'm guessing it sounds smoother because the carpet absorbs a lot of stray reflected energy.

In other words, a fraction of the horns energy is projected forward, but another fraction 'leaks' to the sides. When the horn is up on the dash the glass is rigid and reflective, so it efficiently reflects that stray energy. Down low, the carpet isn't, so most of what you hear is unreflected energy.

Just a guess though.

As far as directivity goes, the trick is to get the throat as small as humanly possible.

































Here's some pics of what I am talking about. The ribbon in the Fountek is .85cm wide, or less than a third of an inch. That means that it won't start to beam until about 40000hz(!)

Unfortunately, there's a waveguide built right into the magnet. This is fine if your baffle is flat, but won't work for a waveguide or a horn. (Well it will work fine as long as the coverage is 90 degrees or larger.)

So...

Here's how I dealt with the problem.

First, I applied some clay into the gap to narrow the dimensions so they're an EXACT match for the horn. This was way scary, I was 110% certain I'd kill the ribbon, and stupid Madisound doesn't even stock replacements. (You can make your own BTW, but it's a p.i.t.a.)

Then I stole an idea from Geddes, and used a plexiglass mounting plate. This is a GREAT idea - and this is the first time I've ever used it. It really makes it easy to line up the mouth of the driver and the throat of the horn easily.

Now please don't complain that the clay isn't perfect, my work is always half-assed and sloppy 

If I actually made good looking speakers I'd finish one a year 



Anyways, here's the main point of this post. The vertical directivity is narrow, but it is even. It should be consistent from 40000hz and down. So basically when you aim both of them up a bit, the left is *consistent* with the right. This is critical for a wide and solid stage. In other words, CONSISTENCY is more important than beamwidth. This is because our high frequency cues are dictated by *level*. If one side is too 'hot' then the soundstage falls apart.

It would be great if I could figure out a way to do 50x50 on both sides but the horn just gets too big. You wouldn't be able to drive the car.

You *can* do 50x50 on the dash, but it's ugly as hell.

Another option would be to do what Image Dynamics does, which is that it's basically omnidirectional in the vertical dimension. This doesn't work for my horns because the diameter of the horn would be too small where the midranges tap in.


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## Patrick Bateman (Sep 11, 2006)

SSSnake said:


> Pat,
> 
> What is the height of the horn? I couldn't tell from the pics but it looks larger than 1" tall but smaller than 13" which would put the pattern flip in a fairly audible portion of the passband for most applications.
> 
> The reason I ask is that I have been trying to find good material on the audibility of pattern flip. Intuitively it would seem like something to be avoided but i haven't seen concrete evidence. Any ideas concerning good reference material?












horn directivity isn't something that just falls off a cliff; it's a gradual process. For instance, if you want a horn or waveguide to control directivity down to 900hz, it needs to be 37cm in diameter, or about 15".

The thing is, the directivity changes in a wide band that begins a full octave above that point, and continues about an octave below. The graph above shows the response of my reference speakers (Gedlee Summas) and how the waveguide actually works well below the 'cutoff.' In fact, Geddes is averse to using the term 'cutoff' at all.

We can use this to our advantage in our cars, and it's the entire reason I jump through so many hoops to jam these devices up against a boundary. And it doesn't have to be a full 360 degree corner; even 180 degrees goes a long way, or even 90 degrees!

You can test this out yourself really easily.

Take your phone, and play some music over it. Now place the phone on a table. It will get louder, noticeably.

Now jam it into a corner, and it will get louder still.

So, fundamentally, that's how all of my horn projects work. I'm lopping off a HUGE chunk of the horn, but I'm really jamming it into car boundaries so that the car continues the curve. *And it doesn't have to be four sides.* Even two or three will significantly increase efficiency and directivity.

Check out the video I posted yesterday, with the Notorious B.I.G. track. That's playing with a sing 5uf cap on the ribbon, and no crossover whatsoever on the midranges. If you played those drivers on a flat baffle they'd explode at these levels.


Long story short - pattern flip is a very real problem for Danley, who has his devices mounted five or ten meters above the floor. For car audio? Just use a boundary. Dash is good, under the dash is good too.


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## Elgrosso (Jun 15, 2013)

PB, in your many horn projects, have you already tried to extend two sides only of the horn like you just described in this last post?
I mean extending the upper and external sides of the flare for example.
I know the dash and door themselves already act like an extension, but what if it was really optimized and smoothed out to perfect, like a real huge exponential horn in this case, but cut in diagonal. Like a skin extending, filling holes by covering the facial dash and the door. If it makes sense.

I ask because I could probably easily optimize my actual upper side to the dash, with fiberglass for example. Not to just something clean without mini steps, but to a perfect curve from throat to edge.
The door will be harder though (especially if it still needs to be opened ).
Thx!


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## Patrick Bateman (Sep 11, 2006)

Elgrosso said:


> PB, in your many horn projects, have you already tried to extend two sides only of the horn like you just described in this last post?
> I mean extending the upper and external sides of the flare for example.
> I know the dash and door themselves already act like an extension, but what if it was really optimized and smoothed out to perfect, like a real huge exponential horn in this case, but cut in diagonal. Like a skin extending, filling holes by covering the facial dash and the door. If it makes sense.
> 
> ...


Here's how this works:










Picture a horn or a waveguide as a pyramid. (Ignore the text in the pic above, I'm just using the shape of the pyramid for this example.)

Here's the thing, *each segment of the pyramid covers a segment of the audio bandwidth.*

At the top of the pyramid is the very highest frequencies, and then lower, and lower and lower.

At very high frequencies, the shape needs to be PERFECT.









That's why the surface around this Kef tweeter is OBSESSIVELY smooth. Nothing less than perfect will do, it must be flawless or you'll have issues above 10khz.

But as you start to move down that pyramid, the wavelengths get long, and as the wavelengths get long, you don't have to be so obsessive about how smooth or perfect the waveguide is.

That's why underdash HLCDs work. Although it's true that the dash and the door only continue two of the four sides of the waveguide, we can get away with that because the wavelengths are getting longer and longer as you get closer to the mouth.



Long story short: I don't think there's a huge benefit to doing what you suggest, the biggest 'bang for the buck' is getting the first few inches of the waveguide correct. That is also why I almost never use reflectors any more. Though it IS possible to have a reflector that causes nearly no problems, but it's very difficult to get right.


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## Elgrosso (Jun 15, 2013)

Patrick Bateman said:


> Here's how this works:
> 
> 
> 
> ...


Ok thank you!
So can we say that surface irregularities that are smaller than the wavelength (or maybe than 1/4 or 1/2 of it) are of secondary importance?


About the shorter and longer sides on asymmetric horns, I wonder where is the final central axis of the directivity pattern.
Is it always orthogonal to the driver or is it always the bisector (is it the right word in english?)
Just to get an idea of the soundwave propagation on an horns like these:
http://www.diymobileaudio.com/forum/4747233-post607.html

And indirectly to get the idea for car horns, with door & dash "extension".
Or maybe this central axis is FR dependant? (bisector for long FR and driver axis for HF)


I must say I got really intrigued recently by the horn behavior, in relation to its shape and dimensions etc.
I've read many of your threads between here and on diyaudio, and learned a lot. It's incredible the amount of knowledge we can find there, between you, your trials and errors, and other contributors like Gedlee, Danley, JMLC etc 
And impossible to not find a photo of one of your tests on an image search 

I think you already covered almost everything, but I still have a lot of questions.
I got the theory around mouth dimensions, angle and directivity.
But would like to find something more visual, a heatmap in 3d would be cool, like:
Understanding Horn Directivity Control


It's kind of easy to understand what happens on a square or round horn for each frequency.
But on our car horn, flat rectangle, asymmetric and with different flare angles in the middle, it's harder to get the whole picture.
Seems there's no visual to represent everything at once. 
This would be really cool, do you know any?


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## Patrick Bateman (Sep 11, 2006)

It's really bizarre hearing my name in the same sentence as those guys

If I was as well known in my day job I'd be a billionaire. (You can't throw a rock without hitting a billionaire in my field, they're everywhere.)









When the diameter of a waveguide is wider than the wavefront that's moving down it, it doesn't 'see' the sides of the waveguide. That's one of the challenges with wide angle waveguides, it's the reason the JBL M2 looks like this:









The phase plug in the M2 waveguide basically takes the radiation of the compression driver, which is a ring, and turns it into a "X" shaped radiator. I've built a few of these and I think it's a little bit of a gimmick, a plain ol' oblate spheroidal curve seems to work better but YMMV. The JBL design was specifically to address the need for wide beamwidth. (And I wager that the marketing team liked the look.)

In regards to your first question, yes you are correct. When sound encounters something that's a small fraction of it's wavelength, it's basically invisible. You can test this for yourself; wave your hand in front of a speaker while it's playing. You'll hear an impact on the very high frequencies but anything below the midrange is unimpeded. (1khz is 34cm long.)

Here's where I sourced the ABEC sim from:
http://www.diymobileaudio.com/forum...horn-loading-full-range-itll-end-tears-2.html


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## Patrick Bateman (Sep 11, 2006)

As far as the "center axis" of a horn is concerned, that one is tricky!

Here's why:

The center axis can vary with frequency!

That sucks huh?

Here's why:

If you look at the pyramid pic from last week, you'll understand that a horn is basically a series of horns stacked on top of each other. *Each segment of the horn works over a different bandwidth.* 

For instance, if your compression driver is mounted to the horn and it's 'tilted' ten degrees, then the very very high frequencies will be tilted ten degrees, and the rest will not. (Because the very very high frequencies are controlled by the compression driver itself.)

JBL has done some work to fix this. For instance, if you disassemble a JBL 2408H-1, you'll see that the phase plug is designed so that the apparent source of the sound is NOT the compression driver, it's at the throat of the waveguide.

This is kind of a fun trick, you can leverage this to make it seem like the loudspeaker is closer than it really is. This is particularly useful in car audio, it means you can put a loudspeaker under the dash of the car but make it behave like it's closer to the edge of the dash. This is useful to achieve wider vertical beamwidth, which moves the soundstage UP.

Here's how I do that: Ultra Shallow Waveguides - diyAudio


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## Elgrosso (Jun 15, 2013)

Patrick Bateman said:


> It's really bizarre hearing my name in the same sentence as those guys
> 
> If I was as well known in my day job I'd be a billionaire. (You can't throw a rock without hitting a billionaire in my field, they're everywhere.)
> 
> ...



Yeah I remember this great thread!
I finally managed to play with hornresp, took me few days to figure out we could just draw something on the sim window.
I still have to learn how to properly use it, especially about the scale to get something realistic.
But it's already super easy to test different things and understand the reaction of the waves.
Simulate the dash, the doors, different flare angles, vertical or horizontal, it explains a lot, I play with it all day 


About the M2, I've searched a lot on these, but couldn't find real good informations, details on why it is exactly like that.
Found some interesting stuff on the Progressive Transition Waveguides but not enough (patent pending).
You might be one of the few that started to explain.
But I really doubt it's a gimmick.
Sure marketing probably loved it too, but it really looks like the shape just came out during research for the solution and not the other way around.

I have this in mind since I have my LSR305, very similar.
The first thought when I saw the M2 was that it's a surface with constant or close to constant "radius".
Radius might not be the right word here IDK, I mean distance throat to edge for every angle.
In a way they found the quadrature of the circle, fit a circle in a rectangle while keeping equal sound wave paths.
This must have a strong effect on the wave shape per FR (from round to star to square), with different directivity effect per X/Y and diagonals axis.
Kind of hard to explain so here's a quick illustration:



Of course it must be also based on their history like the bi-radials and more recent evolutions like the progressive transitions ones.
Maybe the "beaks" allow some sort of loading and minimize HOMs? The LSR have these beaks too, but smaller and farther from the throat, probably because they're domes.
Maybe the low FR sound wave are as close as possible of a rectangle once they leave the mouth. 
No flat or parallel surfaces, all smooth in one piece, less diffraction less distortion

In fact I always wanted to ask one of my buddy 3d expert in nurbs to try something like that.
And simulate in ABEC but it will take more time for sure.


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## Elgrosso (Jun 15, 2013)

I watched the video on the M2, the one you talked about somewhere in one of your thread :thumbsup:
https://www.youtube.com/watch?v=CDmzfpf3fCk&app=desktop

Really cool, they don't go really deep in details but it confirms a lot of stuff.
One thing surprised me, the «beaks» are protruding a bit into the throat:



I had no idea, I haven’t seen them in real yet.
But that’s interesting, they say it helps to diffract/widen the angle a bit more over 10Khz.
10Khz wavelength = 1.356 inches, since it's a 1.5'' CD/throat diameter, it looks like it matches the pic here, beaks going slightly inside.

Seems to work in a similar way than the EON waveguide, but for 1.5'' instead of 15''


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## Patrick Bateman (Sep 11, 2006)

How did you do that?!


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## Elgrosso (Jun 15, 2013)

Do what?


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## Patrick Bateman (Sep 11, 2006)

Can you explain how you created this waveguide?


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## Elgrosso (Jun 15, 2013)

Ok, well this is just a 2d, on illustrator. So not usable as this it's just a drawing.
I played with this to better understand how it’s built.
At that time I really thought the m2 had a constant radius so I wanted to check if I could re-create it. Now I’m not so sure I think it's just a direction, not an absolute constrain.

But I want to ask a friend to work on a real 3d surface.
Like putting a constant radius, square outside/round inside, and see what kind of surface could appear by itself when moving the throad on the orthogonal axis.
I feel like we’ll get the m2, just without some of their post-adjustments for molding or driver specs.

If she’s ok to work on this, I could share the file for you to print it!


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## Elgrosso (Jun 15, 2013)

Did you see that? 

Bose Professional Introduces EdgeMax In-Ceiling Premium Loudspeakers with PhaseGuide Technology










It’s like half a horn!
Hard to see, there’s something at the throat, some kind of reflector or what?
And what are all those mini steps, like frequency related size.
The right one seems to have some flat translucent cover, but maybe it’s a light effect.

https://www.proacousticsusa.com/media/wysiwyg/tds_EdgeMax_EM90_prelim.pdf


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## Patrick Bateman (Sep 11, 2006)

Wow, VERY nice catch!

I don't have time to dig up the patent, but I'll bet this is how it works:

A horn can be segmented; the pyramid I posted last week shows how that works. Small pyramid for the very high frequencies, on top of a bigger pyramid for the next octave, on top of an even bigger pyramid. And on and on. The big Danley Jericho horns take this concept all the way down to about 250Hz.

If that makes sense...

What if you took that horn and segmented in into a bunch of straws?

So it's still a pyramid, but the pyramid is full of straws?

Like this:










*Then bend those straws.*

Voila! You get the sound from point A to point B, while making a 90 degree bend, but keeping a very low profile.

BTW, the reason you don't want to simply bend the horn 90 degrees is because you get waves that won't bend perfectly. Basically the ones that don't bend perfectly, they'll follow a path that's unequal to the ones that DO bend perfectly. And that turns your response shape into a sawtooth and just sounds like ****. (Our ears are VERY sensitive to small differences in arrival time, that's why CD jitter was such a problem in the 90s.)

So the 'straws' get you from point A to B, but keeps everything following a rigid path. It's also the type of thing that would be super easy to 3D print.


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## Elgrosso (Jun 15, 2013)

Wow you’re spot on, it’s even crazier than I thought!
Searched some patents too, must be based on these:

https://patents.google.com/patent/US20170006377A1/en?q=waveGuide&assignee=Bose+Corp&sort=new
https://patents.google.com/patent/US9451355B1/en?inventor=Joseph+A.+Coffey
https://patents.google.com/patent/US20160295337A1/en?inventor=Joseph+A.+Coffey
https://patents.google.com/patent/US20170006377A1/en?inventor=Joseph+A.+Coffey


















Reminds me a bit the jbl in-ceiling stuff too.


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## dcfis (Sep 9, 2016)

Something like this? I always wondered why JBL never went back to the 8 cell waveguide after casting and thermo plastics would make this so much easier and cheaper than hand made 
















Patrick Bateman said:


> Wow, VERY nice catch!
> 
> I don't have time to dig up the patent, but I'll bet this is how it works:
> 
> ...


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## Elgrosso (Jun 15, 2013)

PB, did you study all these patents?
Maybe something crazy cool to create in the corner windshield/pillar/dash?


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## Patrick Bateman (Sep 11, 2006)

Elgrosso said:


> PB, did you study all these patents?
> Maybe something crazy cool to create in the corner windshield/pillar/dash?


Yes, I'm implementing some of those innovations here:

Image Dynamics HLCD Clone - diyAudio

I have a three day weekend so I'm hoping to make some progress on this


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## Elgrosso (Jun 15, 2013)

Very cool!
Is it adapted in any way to your actual car/dashboard or something more standard?

I see you used a curve shape only for the top side.
Could it be useful to use some kind of curvature at the bottom surface too?
A concave inferior face that could accentuate the neck effect, for a natural vertical tilt.
Or maybe it would cause too much internal reflections?

Pretty cool, please keep us updated!


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## Elgrosso (Jun 15, 2013)

So how productive was this long week end?


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## Elgrosso (Jun 15, 2013)

Pretty cool dynamic horn/lens shape on the beolab 50!

For narrow & wide mode:

B&O Tech: BeoLab 50’s Beam Width Control – earfluff and eyecandy

Says they have a dynamic filter to compensate the change in magnitude per angle 


















Or here in the middle of the vieo:
https://www.bang-olufsen.com/it/collection/speakers/beolab-50#


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## Elgrosso (Jun 15, 2013)

Been a while I searched for patents, I was still looking on the m2 style since they say patent pending, and found that (what a pain to read through to try to find the real deal):

I found this on the eon:
https://patents.google.com/patent/US9693141B2/en?inventor=Charles+M.+Sprinkle

And this on the m2:
https://patents.google.com/patent/USD783570S1/en?inventor=Charles+M.+Sprinkle
And new synthesis:
https://patents.google.com/patent/U...allow+horn&q=Horn&q=Waveguide&assignee=Harman

And more global this one:
https://patents.google.com/patent/US9386361B2/en?inventor=Charles+M.+Sprinkle

Didn't read everything and I don't know much about Us patents (I don't care) but the description seems volontary unclear so it could cover the maximum of designs.
Nothing on sound waves behavior but more about how to design it.
But so far I feel like it could confirm some intuitions, like:
- it's a mix of horn and waveguide, the beaks could have a certain load effect
- transformation of a round wave into a square and flat one, with almost constant length/radius (from throat to mouth)

What do you think PB?


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## Focused4door (Aug 15, 2015)

Elgrosso said:


> Been a while I searched for patents, I was still looking on the m2 style since they say patent pending, and found that (what a pain to read through to try to find the real deal):
> 
> I found this on the eon:
> https://patents.google.com/patent/US9693141B2/en?inventor=Charles+M.+Sprinkle
> ...


I was impressed enough after hearing the M2 to price out the waveguide and drivers.

Everything Harman makes is available as non warranty replacements, and frequently available by many third party vendors as repair parts as well.

I don't recall what the waveguides cost, but it was obviously enough that I didn't impulse purchase them.


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## Elgrosso (Jun 15, 2013)

I didn't have this chance yet, only heard the scl2/3/4 and yes they were impressive!
Also the whole system was great, the room etc.

During my last visit there I was told that many fancy parts go directly to speakerexchange in FL: JBL M2 Horn Lens 5025594 - Speaker Exchange

I often check and there's not much stock, don't know if it's controlled or not I don't have more details.
I think I remember a price not that expensive once.

But if I want to go there for the car I think I will try first the lsr series or scl they're smaller, or the new 705. Either through the part list or just used once they will get cheaper.
The waveguide could be cut, and the CD must be great! (2409h)


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## Patrick Bateman (Sep 11, 2006)

Elgrosso said:


> Been a while I searched for patents, I was still looking on the m2 style since they say patent pending, and found that (what a pain to read through to try to find the real deal):
> 
> I found this on the eon:
> https://patents.google.com/patent/US9693141B2/en?inventor=Charles+M.+Sprinkle
> ...


Great stuff. I did a massive brain dump on the JBL patents here: JBL M2 for The Poors - Page 49 - diyAudio

Those new JBL waveguides really make me want to learn ABEC


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