Corner horn subwoofer

Hey guys,

Does anyone know how to model a corner horn in Hornresp? It is so deeply reliant on room modes and geometry that it seems like there must be some trick to it. I wan't to get at LEAST 20Hz extension, depth extension is valued far above max SPL because I would rather hear very low notes than annoy the neighbors at 2:30 in the morning :D

I am designing my college system, I was going to make 2 16Hz tapped horns for the corners but I figure those would be too hard to store in the summers, so I want to make something smaller and I thought 2 corner horns would fit the bill. Btw I won't have a room mate hence the awesome sound system

Luckily the dorm I will be in will most likely be just a standard dorm sized rectangle roughly 10'x15' (or thereabouts) so there won't be any funky room geometry things going on. The walls (I think) are concrete or brick or something like that.

Budget wise I would prefer to stay under $100 per woofer, so that after finishing and everything the cost for the two of them is around $300.
 

Xoc1

Member
2008-11-08 8:25 pm
Devon UK
Hey guys,

Does anyone know how to model a corner horn in Hornresp? It is so deeply reliant on room modes and geometry that it seems like there must be some trick to it.
Just set the Ang setting to 0.5 X Pi
Free Space 4 x Pi is speaker in the air.
Half space 2 x Pi is speaker on the floor My favourite setting for a PA sub.:)
Quarter space 1 x Pi is speaker on the floor and against the back wall.
Eighth space 0.5 x Pi is speaker in the corner.
 
Hmmm I've used that before and I thought it pretty much just increases output over the whole range not use the wall as a part of the actually horn expansion. Aka if I just simulate the throat part of the horn it doesn't take into account that the mouth of the horn actually is the room if that makes sense.
You are correct, better to use the room wall corner expansion as the final horn segment.
A room corner is a tetrahedron,(not a pyramid) you will need to do a little math to figure the expansion area and which expansion type (probably Par) fits best.
 
A low-freq horn is an exceedingly complex bit of woodworking and big as a refrigerator, even down to "just" 35 Hz (where the justifiably famous Klipschorn disappears).

Down to where it disappears, nothing fills a room with woofing like a horn. But I'd have trouble figuring out any other advantages exception that you get training in woodworking.

Ben
 
A low-freq horn is an exceedingly complex bit of woodworking and big as a refrigerator, even down to "just" 35 Hz (where the justifiably famous Klipschorn disappears).

Down to where it disappears, nothing fills a room with woofing like a horn. But I'd have trouble figuring out any other advantages exception that you get training in woodworking.

Ben
Ben,

Low frequency horns for use as subwoofers don't need to be near as complicated to build as the Klipshorn, which was designed to sound good up in the vocal midrange.

That said, the Klipshorn would be a good plan to use as a model, but scaling up the size for 20 Hz response will use a lot of plywood.

And more than enough SPL to get kctess5 kicked out of the dorm room quite quickly even using a 10 watt amp.
 
I don't think it needs to be all that complex, considering that I basically just have to build the rear chamber and the throat. I am thinking of using a pretty high compression ratio. I don't even think it will have to be that large considering that the room IS the horn, which will be the majority of the size of it, it just has to be the rear chamber and a bit more.

Basically it will just be a sealed, corner loaded box, with a bit extra in front of the woofer to provide a higher compression ratio than normal.

And size wise the tapped horns I was planning were something like 10 cubic ft each so it can be pretty large and still be RELATIVELY small.

I was thinking something like this:
[IMGDEAD]http://www.bianchidelaroche.co.uk/Marco/Subwoofers/eckhorn11.jpg[/IMGDEAD]

I need it to go from about 60Hz down, preferably with output at 15Hz. I want to use either two 25w plate amps or two 50w plate amps, even if it could handle a lot more than that just to prevent excessive SPL levels.

What should the final segment length be? The distance from the corner to the listener?

And then should the size of the mouth be the cross sectional area normal to the corner from the listening position? I would guess that it won't matter too much what it specifically is as long as it is in the ballpark because the mouth will be so large.

I will probably make them look like little tables and put a couple of lamps on top of them or something to make them "disappear"
 
kctess5 - easy to make a box that kind of looks like a horn. But even the Klipschorn (35 - 400 Hz) is at the very limits of "cutting [theoretical] corners" and even cutting those corners leave a lot to be desired in performance. And this big box goes NOWHERE anything under 35 Hz.

Just forget this idea of a horn concept. Inconceivably unfeasible in light of everything you've said that matters to you.... unless for no good reason what so ever you think a "tapped horn" is a some kind of horn?

BTW, there are people on this forum who pop up just to argue just because.... I don't know why... maybe they couldn't get into Mensa.

Ben
 
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Hey guys,

Does anyone know how to model a corner horn in Hornresp? It is so deeply reliant on room modes and geometry that it seems like there must be some trick to it. I wan't to get at LEAST 20Hz extension, depth extension is valued far above max SPL because I would rather hear very low notes than annoy the neighbors at 2:30 in the morning :D

I am designing my college system, I was going to make 2 16Hz tapped horns for the corners but I figure those would be too hard to store in the summers, so I want to make something smaller and I thought 2 corner horns would fit the bill. Btw I won't have a room mate hence the awesome sound system

Luckily the dorm I will be in will most likely be just a standard dorm sized rectangle roughly 10'x15' (or thereabouts) so there won't be any funky room geometry things going on. The walls (I think) are concrete or brick or something like that.

Budget wise I would prefer to stay under $100 per woofer, so that after finishing and everything the cost for the two of them is around $300.

Forget fully horn loaded 20 hz in a dorm sized room. The room will most likely be smaller than a real horn
Either
1. Plan for a 20 hz vertical tapped horn ( several plans on this forum) and plan on crossing fairly early - say 60hz or so
2. Aim for a 30 hz horn loaded design such as the table tuba or other designs (tapped or otherwise ) and plan on crossing 80-100hz
3. Design a 20hz t-twqt. These tend to have less dynamics than a horn but can sound better than the usual reflex sub- and are the smallest of all the 3 options

I'm speaking from personal experience with options 2 and 3
 
Hi kctess5,

Does anyone know how to model a corner horn in Hornresp?

Simply set Ang = 0.5 x Pi.

It is not necessary to include the corner walls as part of the horn design.

I wan't to get at LEAST 20Hz extension, depth extension is valued far above max SPL

A conventional corner horn capable of working down to 20 hertz (a wavelength of 17.2 metres) would need to be significantly larger than a Klipschorn bass horn.

Luckily the dorm I will be in will most likely be just a standard dorm sized rectangle roughly 10'x15' (or thereabouts)

A 20Hz bass horn is unlikely to perform particularly well in such a relatively small room.

Kind regards,

David
 
Hmmm I've used that before and I thought it pretty much just increases output over the whole range.

Hi kctess5,

Not so.

At very low frequencies there is a theoretical +6 dB improvement in SPL response each time the solid radiation angle is halved. 3 dB is due to improved acoustical loading conditions (enabling twice the power to be radiated), and the other 3 dB is due to the doubled power radiating into half the space. Going from free space to eighth space therefore gives an 18 dB increase overall.

At very high frequencies (assuming constant directivity) there is only a +3 dB enhancement - the acoustical loading conditions do not change when the solid radiation angle is halved. Going from free space to eighth space therefore gives a 9 dB increase overall.

The attached example shows the difference going from free space (4 x Pi) to eighth space (0.5 x Pi). The low frequency response is improved by 18 dB and the upper frequency response by 9 dB, as expected.

Kind regards,

David
 

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kctess5 - easy to make a box that kind of looks like a horn. But even the Klipschorn (35 - 400 Hz) is at the very limits of "cutting [theoretical] corners" and even cutting those corners leave a lot to be desired in performance. And this big box goes NOWHERE anything under 35 Hz.

Just forget this idea of a horn concept. Inconceivably unfeasible in light of everything you've said that matters to you.... unless for no good reason what so ever you think a "tapped horn" is a some kind of horn?

BTW, there are people on this forum who pop up just to argue just because.... I don't know why... maybe they couldn't get into Mensa.

Ben

Hi Ben. You've been arguing against tapped horns for several years now, but I'm betting you've still never actually heard one.

Here's an example of a tapped horn (using a 6 inch driver - tang band w6-1139) I did way back in 2009, back when we were still fumbling around trying to figure tapped horns out. Total cost was about $75 (in 2009 dollars) including driver and wood.

[IMGDEAD]http://i41.tinypic.com/w9wvhx.jpg[/IMGDEAD]

[IMGDEAD]http://i42.tinypic.com/11juh3k.jpg[/IMGDEAD]

[IMGDEAD]http://i42.tinypic.com/opz9yc.jpg[/IMGDEAD]

[IMGDEAD]http://i41.tinypic.com/2075jk3.jpg[/IMGDEAD]

Pic 1 shows it's not very large at all, the missing dimension (width) is 8 inches.
Pic 2 shows groundplane response (outside in my driveway at about 7 meters away).
Pic 3 shows same as pic 2 but with a bunch of stuffing crammed in the mouth hole.
Pic 4 is the same horn in the corner of my room, measured at the listening position (no stuffing, and the null is worse due to floor/ceiling cancellation).
SPL is not absolute in any of these, the mic is uncalibrated and these were taken at different distances under different conditions.

If I were to do this again today it wouldn't have that nasty dip and I could easily get the full 3 octaves out of it just by moving the driver a few cm back from the mouth. For that matter, I could change it from a tapped design to front loaded and still get the same bandwidth in the same size package.

As you can see, it hits 20 hz no problem in a very small package. When used below 80 hz it's the best sounding sub I own - which includes front loaded, ported, tl and sealed. That's a subjective judgement but it's true as far as I'm concerned.

You could easily argue that it's not a full sized horn, but most aren't. With the fingers on one hand, I can count the number of properly designed full sized bass horns I've seen in my lifetime. A stack of 8 Labhorns being one of them.

You could easily argue that tapped horns are not really horns, but then again, most front loaded horns are not horns either, by the classical definition. The vast majority are quarter wave resonators, front loaded and tapped.

Just because a classically defined horn won't fit inside a dorm room doesn't mean you can't hit 20 hz easily in a small enclosure with a flare that expands from throat to mouth in a package that 1 man (or woman) can easily carry; will easily get loud enough to get you evicted, and sound great at the same time. You don't even have to use the room's corners as part of the design.
 
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I am unworthy of the care just a guy puts into his post. True, never heard one - and that should mean something to this forum which is the world's sole repository of posts favourable to "tapped horns."

You have shown (and I have always believed) that you can hand-configure through good design and luck excellent small frequency range speakers with a "tapped horn, BR, or Karlson. But those systems feature a tactic I find repellant as a concept: trafficking in resonances as a principal means of boosting bass. Footnote: luck (as in choosing a TH driver) not a big factor in other designs.

My real problem is that I find it appalling to call these boxes horns. The part that kind of looks like a horn is just a distance spacer, no different than the volume of a BR or length in a TL; maybe the taper has some minor benefit but it does no horn transformations worth fussing about much.

I believe calling it a horn (a high-status name) arose from discreditable commercial motivations rather than from anything in the patent(s).

TH can be just right, I suppose, for many church halls and maybe on a good day for home systems, like BRs and Karlsons.

Ben
 
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1. Plan for a 20 hz vertical tapped horn ( several plans on this forum) and plan on crossing fairly early - say 60hz or so

That was the original plan. I am just thinking about different options as the full sized 16Hz tapped horn I designed is pretty large and would be hard to move for the summers. The good part about that horn though is it is (theoretically) ruler flat from 16-70Hz and is sensitive enough that I wouldn't need a large amp.

The attached example shows the difference going from free space (4 x Pi) to eighth space (0.5 x Pi). The low frequency response is improved by 18 dB and the upper frequency response by 9 dB, as expected.

Thanks for the info! :cheers: I will work with hornresp a bit tomorrow if I get a chance. I am not so much going for a "true horn" as a sealed enclosure that is designed around the fact that it will be corner loaded, taking as much advantage of that as possible.

Just forget this idea of a horn concept. Inconceivably unfeasible in light of everything you've said that matters to you.... unless for no good reason what so ever you think a "tapped horn" is a some kind of horn?

Ok thanks for your input but could you think of a more obnoxious way to put this? I don't even know how that bit about tapped horns is relevant to this :confused: I'm not asking about tapped horns. If you are just here to argue against tapped horns or terminology please start your own thread.

BTW, there are people on this forum who pop up just to argue just because.... I don't know why... maybe they couldn't get into Mensa.

Such as you? What does MENSA have to do with this again?
 
That was the original plan. I am just thinking about different options as the full sized 16Hz tapped horn I designed is pretty large and would be hard to move for the summers. The good part about that horn though is it is (theoretically) ruler flat from 16-70Hz and is sensitive enough that I wouldn't need a large amp.



Thanks for the info! :cheers: I will work with hornresp a bit tomorrow if I get a chance. I am not so much going for a "true horn" as a sealed enclosure that is designed around the fact that it will be corner loaded, taking as much advantage of that as possible.



Ok thanks for your input but could you think of a more obnoxious way to put this? I don't even know how that bit about tapped horns is relevant to this :confused: I'm not asking about tapped horns. If you are just here to argue against tapped horns or terminology please start your own thread.



Such as you? What does MENSA have to do with this again?

A gently dropping response from high to low end may be better than a flat response wrt room modes
 

freddi

Member
Paid Member
2005-08-16 4:21 pm
I've got badly resonant walls - they ruin whatever can be had from a K-horn. Mine sound terrible. Here's the response of a late 1970's Khorn in that ~18' x 27' x 8' room

20 years ago I had plans for Ben Drisko's corner horn which may have gone somewhat lower (?)

[IMGDEAD]http://imageshack.us/a/img402/3406/khornchokeeffect.jpg[/IMGDEAD]