Hello,
I would like to explore the idea of a 8x12"horn sub (see attached sketch).
I don't know enough about horn theory, can someone help me where to start / proceed. Target is to make a super powerful horn and to go as low as possible in a group of 4 or more.
Some parameters I have:
* cabinet size 60x48x28 inch
* possible horn lenght 137 inch according the fold in the sketch.
* 1/4 wavelength of 25 Hz is 135,6 inch
* 8 cabinets in a row make for a circumfence of 544 inch (whole 25Hz wavelength is 542,4 inch)
What would be suitable drivers?
How to determine the flare of the horn?
Wil the drivers withstand the pressure at the beginning of the horn?
How to determine the size of that beginning?
How to get on?
these??
FaitalPRO - Professional Loudspeakers Made in Italy
or:
B&C SPEAKERS
thanks
best regards
Jan
I would like to explore the idea of a 8x12"horn sub (see attached sketch).
I don't know enough about horn theory, can someone help me where to start / proceed. Target is to make a super powerful horn and to go as low as possible in a group of 4 or more.
Some parameters I have:
* cabinet size 60x48x28 inch
* possible horn lenght 137 inch according the fold in the sketch.
* 1/4 wavelength of 25 Hz is 135,6 inch
* 8 cabinets in a row make for a circumfence of 544 inch (whole 25Hz wavelength is 542,4 inch)
What would be suitable drivers?
How to determine the flare of the horn?
Wil the drivers withstand the pressure at the beginning of the horn?
How to determine the size of that beginning?
How to get on?
these??
FaitalPRO - Professional Loudspeakers Made in Italy
or:
B&C SPEAKERS
thanks
best regards
Jan
Attachments
I would think you would want to search around the web for plans. The plans usually include what driver the cabinet is designed for.
The drawback I see in your design is that you will have to leave two panels removable to mount and access the drivers. Not terrible but a little tight to get your hands/tools in there to do the fastening.
The drawback I see in your design is that you will have to leave two panels removable to mount and access the drivers. Not terrible but a little tight to get your hands/tools in there to do the fastening.
This is not how tapped horns work. The mouth side tap contributes very little, it's only used to fill in normal tl nulls - it doesn't help at all in the lower bass. In fact, if the driver is mounted right at the beginning of the line (which is tough to do physically in the tapped horn but can be simulated easily) the results are exactly the same whether the driver is mounted on the outside (tl) or inside (tapped horn). Switch between Nd and TH in Hornresp and there's no difference at all.
Also, tapped horns are no more sensitive or loud (max spl) than front loaded horns. In fact, I can systematically beat tapped horns with front loaded horns of the same size (in simulation at least) using the same driver, tuning and low end rolloff. Every time. The front loaded horn might need to be unconventionally shaped for best response in order to compare with small tapped horns but I can always get the front loaded horn to beat the tapped horn.
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This is probably not a good project for your first diy horn. At this size there's a lot of things that even experienced horn designers don't usually have to consider. For example, if your mouth gets too big it's going to narrow your dispersion, so you have to be aware of that.
Having said that, since this is meant to be a full system with several modular boxes, personally I would design it as a single stack, like Danley did with the Labhorn, and then divide it up physically into several boxes instead of designing a small horn and just building a bunch of them.
It's absolutely essential to use Hornresp (or similar) software to help you design. There are no rules of thumb that will get you an acceptable horn. If you can't or don't want to learn proper horn design it's probably best to just build a stack of Labhorns, but I would recommend some modifications to the plans.
That's the easy part, just load your drivers into hornresp. For Nd, select the total amount of drivers to be used (32 in this case although that seems like a lot more than necessary). Set the Ang to the proper boundary loading and then select "system design - with driver". Select a desired bandwidth (but remember that hornresp has a mouth size limit so you might have to play around with that - you may need to select a higher tuning or more boundary reinforcement to get the simulation to run). Make sure the the throat is a reasonable size (so it won't destroy the drivers or cause tornado turbulence in the throat), the previously selected bandwidth may need to be reconsidered if it generates an undersized throat.
That will give you a proper full size classical horn. You can tweak it further from this point by simply exporting the flare dimensions as a txt document and reentering it with parabolic segments. When it's all tweaked out, simply divide the cross sectional area dimensions by the desired amount of cabs and you have the details of the individual boxes.
Before you get too far you need to consider dispersion. If the mouth gets too big dispersion will become increasingly narrow. Also, the further away from round the mouth gets, the faster dispersion will narrow. The mouth needs to be large enough to support the tuning frequency but small enough to allow the higher frequencies to be distributed properly.
Then it needs to be folded, which is a huge topic by itself. I don't even want to get into folding right now. This is the hard part, although it gets exponentially easier if you plan ahead.
I'm sure epa knows all about all of this, I'm just posting to let the OP know what is involved here. (And note this is only one way to proceed.)
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Hello epa and just a guy thanks for you're input
Designing it as a single stack is what meant, indeed exactly like danley did with the Labhorn. but it takes 8 cabs in row to get the circumfence of the mouth opening to be approx 540 inch (25hz wavelength)
I would prefer max performance in a 4 block but that would give a much to small circumfence of the hornmouth 320inch??
epa if you would like to assist me with a sim / model that would be great!
for now i dont know how to proceed? do i need to choose a driver first? or model the horn first? I downloaded hornresp it asks for both?
I don't know what driver parameters make for a good horndriver especially in this horn since the beginning seems to become pretty small so high pressure.
As for the horn the size of the mouth opening is known, but how to start the horn is a mistery to me? Can it start like in my scetch or does it need a chamber first like the labhorn?
thanks
Jan
Designing it as a single stack is what meant, indeed exactly like danley did with the Labhorn. but it takes 8 cabs in row to get the circumfence of the mouth opening to be approx 540 inch (25hz wavelength)
I would prefer max performance in a 4 block but that would give a much to small circumfence of the hornmouth 320inch??
epa if you would like to assist me with a sim / model that would be great!
for now i dont know how to proceed? do i need to choose a driver first? or model the horn first? I downloaded hornresp it asks for both?
I don't know what driver parameters make for a good horndriver especially in this horn since the beginning seems to become pretty small so high pressure.
As for the horn the size of the mouth opening is known, but how to start the horn is a mistery to me? Can it start like in my scetch or does it need a chamber first like the labhorn?
thanks
Jan
I just told you exactly how to do it - in detail - in post 9.
The Labhorn uses the LAB12 driver which is available everywhere. I'd start with that if I were you, it's very good for horn subs. Enter the specs for the driver and follow the steps in post 9. The program will design the horn for you. All of it, the chambers, the flare, everything. But you still have to know enough about horns to determine if the result is reasonable, practical, and overall a good idea or not.
The Labhorn uses the LAB12 driver which is available everywhere. I'd start with that if I were you, it's very good for horn subs. Enter the specs for the driver and follow the steps in post 9. The program will design the horn for you. All of it, the chambers, the flare, everything. But you still have to know enough about horns to determine if the result is reasonable, practical, and overall a good idea or not.
Here's a different way to do it. (There are a bunch of different ways to do it.)
It seems like you know a bit about the Labhorn. It's unlikely that you will come up with anything that will beat the Labhorn so (especially since this is your first diy horn) it makes sense to study the Lab a bit before getting too far. Here are the details of the original Labhorn design that you can enter right into Hornresp.
St = throat area = 80 sq ins (40 sq inches per driver)
Vb = rear chamber volume = 1530 cu in per driver (separate rear volumes for
each driver)
Vf = front chamber volume = 170 cu in per driver (volume between cone & throat)
Flare = 26.4 Hz, hyperbolic t = .5, path length = 126 inches (inc front volume).
(Please note that while it uses a 26.4 hz flare, this horn really doesn't do much below 35 hz, this is a big misunderstanding about the Labhorn. There's lots of info about the Lab around the internet, at least half of it is untrue, misinformed or outright ingnorance.)
It's even easier to enter this info than to do the design routine in post 9. Then you can play around with this simulation a bit (change it to an offset driver model with parabolic segments). I can tell you that this is a very good design.
But the Labhorn went off track when it was folded, the rear chambers are too small. I'm not sure this can be fixed without completely refolding the horn.
Anyway, studying the Labhorn you can learn a lot of things, for example how many drivers - and which drivers - to use in a full size classical 30 hz sub horn. The drivers were actually designed for the Labhorn to be the best they could be to cover the intended bandwidth. Using more drivers than the Labhorn uses isn't necessarily going to help - it might make some things considerably worse.
To be honest, I think the best thing you could possibly do (considering your experience level) is just refold the Labhorn original design properly and build that. It's going to take a lot of work (or a lot of money) to beat that design.
I really don't want to discourage you from designing your own but without at least a couple of years of horn study in your free time I can't imagine this project turning out well.
Good luck though, I love to see large horn projects.
It seems like you know a bit about the Labhorn. It's unlikely that you will come up with anything that will beat the Labhorn so (especially since this is your first diy horn) it makes sense to study the Lab a bit before getting too far. Here are the details of the original Labhorn design that you can enter right into Hornresp.
St = throat area = 80 sq ins (40 sq inches per driver)
Vb = rear chamber volume = 1530 cu in per driver (separate rear volumes for
each driver)
Vf = front chamber volume = 170 cu in per driver (volume between cone & throat)
Flare = 26.4 Hz, hyperbolic t = .5, path length = 126 inches (inc front volume).
(Please note that while it uses a 26.4 hz flare, this horn really doesn't do much below 35 hz, this is a big misunderstanding about the Labhorn. There's lots of info about the Lab around the internet, at least half of it is untrue, misinformed or outright ingnorance.)
It's even easier to enter this info than to do the design routine in post 9. Then you can play around with this simulation a bit (change it to an offset driver model with parabolic segments). I can tell you that this is a very good design.
But the Labhorn went off track when it was folded, the rear chambers are too small. I'm not sure this can be fixed without completely refolding the horn.
Anyway, studying the Labhorn you can learn a lot of things, for example how many drivers - and which drivers - to use in a full size classical 30 hz sub horn. The drivers were actually designed for the Labhorn to be the best they could be to cover the intended bandwidth. Using more drivers than the Labhorn uses isn't necessarily going to help - it might make some things considerably worse.
To be honest, I think the best thing you could possibly do (considering your experience level) is just refold the Labhorn original design properly and build that. It's going to take a lot of work (or a lot of money) to beat that design.
I really don't want to discourage you from designing your own but without at least a couple of years of horn study in your free time I can't imagine this project turning out well.
Good luck though, I love to see large horn projects.
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Sorry to misrepresent how they work.
Carry on.
Hey, no problem, the actual purpose of the tap is the biggest misunderstanding about tapped horns.
Hi jan1, I got your message. I prefer to answer here so that others can check the technical accuracy of anything I say. I find this interesting as an intellectual excercise but I don't want to be responsible for errors on a project of this magnitude.
I have a better understanding of what you are trying to do now that I know you already own Labhorns but I still have a few questions. Are the Labs not loud enough, not low enough, or both? Are you using a high pass filter to protect them below tuning? How much power are you giving them? Is this a permanent setup or do you move it to different locations? Are you consistently taking advantage of boundary loading? (Do you always put the subs stacked together in a corner when possible, and when there are no available corners do you always set them up so it can have at least single wall loading?) What is your average audience size and room size that you need to fill?
It's hard for me to believe that a stack of 4 Labs isn't enough, once we are sure you are using what you already have to extract it's maximum potential we can begin to talk about how to proceed. Things like budget, desired tuning, who is going to fold the design, etc.
I have a better understanding of what you are trying to do now that I know you already own Labhorns but I still have a few questions. Are the Labs not loud enough, not low enough, or both? Are you using a high pass filter to protect them below tuning? How much power are you giving them? Is this a permanent setup or do you move it to different locations? Are you consistently taking advantage of boundary loading? (Do you always put the subs stacked together in a corner when possible, and when there are no available corners do you always set them up so it can have at least single wall loading?) What is your average audience size and room size that you need to fill?
It's hard for me to believe that a stack of 4 Labs isn't enough, once we are sure you are using what you already have to extract it's maximum potential we can begin to talk about how to proceed. Things like budget, desired tuning, who is going to fold the design, etc.
Took what I had read, extrapolated, and ran with it. A dangerous thing to do.
Hi jag.
The labsubwoofers are verry powerful and go pretty low.. but remeber the labsubwoofer is approx. 10 years old, modern productions dance/dubstep is a different story, than the labs can be not powerful and low enough at the same time.... yes they are highpass filtered. It is for a permanent setup with one wall behind the stack of 4. Audience size approx 750. I have Crown Itechs8000 and lab gruppenfp10000q. to power them Budget: 4 labs cost me approx 5000 euro I expect this cab (with 4 times the drivers) wil almost cost around that a piece. Disired tuning: 25/26 hz if the cabinat size allows for that... Folding: if i have a good cross section of the horn i would like to give it a shot... but what makes me wonder here is: hornresp gives a 2D cross section, but what about the 3D expansion??
Jan
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