# Can we get some horn modification pics?



## TheScottishBear (Feb 3, 2011)

As the title says. I would like to see the modifications you made and hear any thoughts on the improvements that they made. Are any of you sealing the gap between the horns and the adapters? Now that I have them eq'd to a point I am happy with I would like to see if there is anything else I can use to step my game up. Deadener, modeling clay, dynaglass?
Also; anyone using foam in the mouth of the horn still? I have only seen Patricks' pictures. Is fluval foam the best or is there others that will work?


----------



## ariko81 (Dec 15, 2008)

I'd sure like to see some pics of these mods as well.


----------



## Patrick Bateman (Sep 11, 2006)

TheScottishBear said:


> As the title says. I would like to see the modifications you made and hear any thoughts on the improvements that they made. Are any of you sealing the gap between the horns and the adapters? Now that I have them eq'd to a point I am happy with I would like to see if there is anything else I can use to step my game up. Deadener, modeling clay, dynaglass?
> Also; anyone using foam in the mouth of the horn still? I have only seen Patricks' pictures. Is fluval foam the best or is there others that will work?


Reticulated foam, like the Fluval, works and the attenuation is predictable.

But you could get the same effect using fiberglass batting or even open cell foam. Fiberglass batting wouldn't be ideal because it's hard to get the consistency correct. Having said that, car horns are so small, I have a hunch that the difference between the left and right horn would be relatively benign.

Only way to know for sure would be to measure it.

Open cell foam would work also, but the attenuation would be much greater than reticulated foam.


----------



## TheScottishBear (Feb 3, 2011)

Patrick Bateman said:


> Reticulated foam, like the Fluval, works and the attenuation is predictable.
> 
> But you could get the same effect using fiberglass batting or even open cell foam. Fiberglass batting wouldn't be ideal because it's hard to get the consistency correct. Having said that, car horns are so small, I have a hunch that the difference between the left and right horn would be relatively benign.
> 
> ...


I think I will try out the fluval foam first. I seem to a remember a thread in which you said the entire volume of the horn needed to be filled with it? Also mention of needing an RTA to bring back the high freq. response? All I have is my tablet, RTA app, and my ears for that. How difficult will it be? I am mainly interested in attenuating the midrange area to take a little of the bite out of the horns. At normal volume it isn't as noticeable but I am predisposed to listening to my stereo very loud. lol I have done some heavy cuts between 1-6k but feel there is something I can't get at. It doesn't really cause listening fatigue per-say but rather a sharpness or "shoutiness" I could do without. It's hard to articulate but you guys probably get the idea.


----------



## Patrick Bateman (Sep 11, 2006)

TheScottishBear said:


> I think I will try out the fluval foam first. I seem to a remember a thread in which you said the entire volume of the horn needed to be filled with it? Also mention of needing an RTA to bring back the high freq. response? All I have is my tablet, RTA app, and my ears for that. How difficult will it be? I am mainly interested in attenuating the midrange area to take a little of the bite out of the horns. At normal volume it isn't as noticeable but I am predisposed to listening to my stereo very loud. lol I have done some heavy cuts between 1-6k but feel there is something I can't get at. It doesn't really cause listening fatigue per-say but rather a sharpness or "shoutiness" I could do without. It's hard to articulate but you guys probably get the idea.


^^^ what you are describing is basically the sound of higher order modes

And as you noticed, EQ doesn't work.
If you try to reduce the level, it sounds 'dark', even if it measures well.

So, yeah, check out all the research that Geddes did. The reticulated foam and a roundover underneath the horn, like in the Homster thread on diyaudio, is a great start.

If you do it, let me know what you think of the results.

One thing that the foam and the roundover *can't* fix is pattern flip, but that's another geometry problem with car horns.


----------



## oabeieo (Feb 22, 2015)

Patrick Bateman said:


> ^^^ what you are describing is basically the sound of higher order modes
> 
> And as you noticed, EQ doesn't work.
> If you try to reduce the level, it sounds 'dark', even if it measures well.
> ...


What is pattern flip? I've been reading a ton of old posts and trying absorb as much as I can but this question is itching at me badly???????


----------



## thehatedguy (May 4, 2007)

It is the frequency that all non symmetric horns change dispersion patterns.

I don't recall the math off of the top of my head, but Keele talks about it in his paper, "What is so sacred about exponential horns?"

AES Papers -- Official website of D.B.Keele


----------



## lsm (Mar 11, 2009)

I have three layers of sound deadener on my large mouth horn bodies but that doesn't make for a very interesting picture. The mini-horn bodies are pretty thick so they don't need anything extra.


----------



## oabeieo (Feb 22, 2015)

thehatedguy said:


> It is the frequency that all non symmetric horns change dispersion patterns.
> 
> I don't recall the math off of the top of my head, but Keele talks about it in his paper, "What is so sacred about exponential horns?"
> 
> AES Papers -- Official website of D.B.Keele


Boring read , but I pushed myself through it and tried to follow what the author was saying and trying to relate it to a car horn . But I got the jist of tho, thank you !!! So what is a car horn a exponential tractrix?? I definitely need to do a lot more reading to fully understand even how my horn disperses sound and coverage angles etcetera


----------



## Patrick Bateman (Sep 11, 2006)

oabeieo said:


> What is pattern flip? I've been reading a ton of old posts and trying absorb as much as I can but this question is itching at me badly???????


Excellent question! It took me years to understand what it was, and why it's a problem.


















Here's a pic of a couple studio monitors. *See how the waveguide and the woofer are the same size?* The reason that's done is because it matches the wavefront shape at the xover point. For instance, if you have a 6.5" woofer and a 1" tweeter, *you can use a 6.5" waveguide to generate a wavefront that's 6.5" wide at the xover point.* The same size as the woofer.

Run down to a place like Guitar Center and you can listen to these; notice how there isn't an obvious transition from woofer to tweeter, it sounds (fairly) seamless.









When the width of the waveguide is very wide, but the height is very narrow, *you get pattern flip.*

It's not the end of the world; there are things you can do about it. For instance, making the depth shorter and getting a very close match to the dash helps. Basically the dash extends the waveguide.

By far, the easiest way to fight pattern flip is to simply use a waveguide that's symmetrical, or close to it, along with a woofer that has a horizontal width that's about the same as your WG.

For instance, with a 8" woofer you'd want a waveguide that's about 8" wide and 8" tall. Of course, it's hard to figure out where to put a WG that's 8" tall, which is why we depend on the dash to extend that curve.


----------



## oabeieo (Feb 22, 2015)

Patrick Bateman said:


> Excellent question! It took me years to understand what it was, and why it's a problem.
> 
> 
> 
> ...


Thank you that makes sense, so the shape of the dash and the angle/distance height etc. from the listener can factor what xo, polarity, phase you would need for any given horn install for optimum sound, and of course distance and size and axis the midbass is but that's not what I'm referring to just the shape of the wave from the horns at different angles, or diffrent types of cars. I immagine the angle of the lower dash plays a part would be nice to know what a optimum shape would be , maybe a re shape of lower dash to get things to move up


----------



## Bmxnick101 (Dec 1, 2009)

I'm in, I've read so much, but have yet to mess with horns. Thinking of trying it in a build soon.


----------



## subterFUSE (Sep 21, 2009)

I have a bunch of reticulated foam which I would like to test out, but not really sure how to stuff? Any suggestions?

Using Eric Stevens full sized bodies.


----------



## Patrick Bateman (Sep 11, 2006)

subterFUSE said:


> I have a bunch of reticulated foam which I would like to test out, but not really sure how to stuff? Any suggestions?
> 
> Using Eric Stevens full sized bodies.


1) measure the frequency response
2) fill the horn with foam
3) Use EQ to replace the high frequencies lost due to the foam. Basically make the response curve look the way it looked before you put the foam in.

That's it!


----------



## subterFUSE (Sep 21, 2009)

Patrick Bateman said:


> 1) measure the frequency response
> 2) fill the horn with foam
> 3) Use EQ to replace the high frequencies lost due to the foam. Basically make the response curve look the way it looked before you put the foam in.
> 
> That's it!


How far into the horn should the foam go?

Should the foam be packed into the horn tightly, or loosely?

Does it need to be cut to fit the horn perfectly? Like a glove?


----------



## oabeieo (Feb 22, 2015)

I used this cause I don't know what reticulated foam is not can I find a link anyone has posted for it not does my local fabric store know what it is but this works fantastic for edginess around 3-4khz Parts Express Speaker Cabinet Grill Foam 19" Wide x 31" Long x 3/8" Thick Black

It's probably the wrong stuff but it does the job great it also makes the horns have a better psychoacoustic responce I just cut strips and shoved back near the diffraction slot


----------



## nadams5755 (Jun 8, 2012)

reticulated cell foam is a type of foam that's blown then 'cut' open. it has different properties than open cell foam or closed cell foam. the last time i bought some was from Welcome to Foam Factory, Inc. (since they were across town)

your speaker grill foam may be the same stuff.


----------



## oabeieo (Feb 22, 2015)

nadams5755 said:


> reticulated cell foam is a type of foam that's blown then 'cut' open. it has different properties than open cell foam or closed cell foam. the last time i bought some was from Welcome to Foam Factory, Inc. (since they were across town)
> 
> your speaker grill foam may be the same stuff.


Thank you, !!!


----------



## subterFUSE (Sep 21, 2009)

So I just finished a first tune with the horns stuffed with 30 ppi reticulated foam. There was definitely some attenuation, especially at the higher end above 10,000 Hz. I used a high shelf EQ on my DSP to bring the response back up.

I was also able to bring up the gain in the DSP for the horns slightly. Without the foam, I had to keep the horns at -8dB in the DSP. Now I'm running them -6dB.

I can't decide if I like the horns stuffed or not. Listening to them, I feel like they might be a bit smoother. I have been turning up the volume higher than usual, which I'm sure has to do with the attenuation from the foam.


One thing I have been thinking about is maybe turning up the amplifier gains on my midbass a bit. I set the midbass and horns using -5dB overlap sine wave signals. The subs were set with a -10dB overlap.

I'm beginning to think maybe I should keep the horns where they are, but set the midbass against a -10dB overlap? That should boost the midbass some and help lessen the SPL gap with the horns. They are crossed from 50Hz - 800Hz, and they are handling it very well.


----------

