Please help me fold my horn!!

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Moring all,

I've been playing with hornresp and while I'm getting there with the programme I'm still not making good progress with the folding of a design. I'd been working on a folded tapped horn for 2x KEF B139 and Bjorno very kindly helped with an 18Hz design (home theatre and music) to fit the volume I have

Computers are my nemesis and I've tried to design it on sketchup and gotten nowhere. So I've bought some graph paper and drawn it out, worked fine until I tried to transpose this into reality and started sketching out the horn on some MDF-I spent 5hours yesterday just trying to get the design off paper and onto the MDF, trying to juggle the dimensions so they fitted properly!

Lines on graph paper have no physical dimensions, so while the plan works on paper by the time you make it out of 18mm MDF the internal volume is all wrong and the length has changed-undoubtedly this will adversely affect the performance.

I've seen some of you are exceptionally skilled when using CAD programmes-any chance anyone could get this design into a working CAD drawing for me? The gross dimensions available to me are: 46.5"w x 16.5"h x18.75"d though depth can be increased-which I'm sure it will have to be to accomodate the volume.



diyAudio
 

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Hi TheBaronGroog,

I have a few questions:

1. Why have the T/S parameters changed from earlier attempts? (It doesn't seem to matter, just interested.)

2. Can the enclosure be taller? (Even a double fold will be in the 51" tall range.)

3. Do you have a sketch for the side view of these speakers? (What I have so far I have not been able to verify, e.g.: Magnet dia, height from mounting flange,.... The width-210mm-seems to be well documented.)

Regards,
 
Hi TheBaronGroog,

I have a few questions:

1. Why have the T/S parameters changed from earlier attempts? (It doesn't seem to matter, just interested.)

2. Can the enclosure be taller? (Even a double fold will be in the 51" tall range.)

3. Do you have a sketch for the side view of these speakers? (What I have so far I have not been able to verify, e.g.: Magnet dia, height from mounting flange,.... The width-210mm-seems to be well documented.)

Regards,

Hi Oliver, thank you for your assistance:)

The T/S changed as Bjorno found the "correct ones"

The enclosure must fit under a a pre-existing piece of furniture. Two of the dimensions are limited so that it can fit under, the depth can be changed as I can bring the furniture out into the room some more (currently in a bay window). So
Height: 16.5" or 419.1mm and FIXED
Width: 46.5" or 1181mm and FIXED
Depth: I could probably get to 25" or 635mm and still keep my crown jewels, a bit more if needed!

I'll get full dimensions of the driver for you tonight. There are some links on here that won't open on my pc-might work on yours? Technical Details of KEF Drive Units

The enclosure you have designed looks great, however I would orientate the drivers the other way, increasing the box height and hopefully allowing the depth and width to be reduced. Less the top and bottom panel there is 383mm or 15.08" height to play with-which will just allow the drivers to be squeezed in vertically:)

I mailed Bjorno about this and he has said if he gets 5 he'll try and re-model it to fit, so you might want to hold fire before re-drawing again.
 
Hi TheBaronGroog,

Is this what you're talking about (if bjorno doesn't substantially change the simulation, the volume will stay similar, should fit w/ less than 25").

Also, do you want the box to vent forward (as in the drawings so far), or sideways (which would be in the drawing from Post #3: straight down)?

Regards,
 

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I was initially looking at in isobaric design-but for different reasons; there was an old CRT above where the enclosure is being fitted and mounting the drivers mag2mag got rid of the stray gauss issue. There's now a nice new 3D LCD (I know, 3D will be gone again soon-seems to come round once a generation-but the missus wanted to make sure our 10month old doesn't feel deprived when she gets to school and everyone else has 3D!) that myself and my partner got each other for Christmas.

There's plenty of space for a ported enclosure, isobaric or not, that would give very good results, same for a sealed-but I'm interested in the enclosure design as much as the response and thought I'd have a go at cutting my teeth with horns and TQWT etc. I work in car audio so have designed plenty of sealed and vented enclosures-so the prospect of another doesn't really float my boat! Ok, I'm getting a lot of help with my design-but I'm hoping it's more of the "teach a man to fish and he can feed himself forever" scenario then the "give a man a fish and he can feed himself once".
 
Hi TheBaronGroog,..Is this what you're talking about (if bjorno doesn't substantially change the simulation, the volume will stay similar, should fit w/ less than 25")..Also, do you want the box to vent forward (as in the drawings so far), or sideways (which would be in the drawing from Post #3: straight down)?..

Hi Oliver,TheBaronGroog

Thank you for helping me out. IMO:You have the done a good work with TheBaronGroog's sub...So far I have not yet done any work..Gremlins are lurking in my computer making it very difficult to do a quick descent job.:(

b:)
 
Hi TheBaronGroog,

Is this what you're talking about (if bjorno doesn't substantially change the simulation, the volume will stay similar, should fit w/ less than 25").

Also, do you want the box to vent forward (as in the drawings so far), or sideways (which would be in the drawing from Post #3: straight down)?

Regards,

Hi Oliver,

That looks spot on:) I'm not really too concerned with where the vent exits-front or side my 10month old will probably work out how to get her hand and various other goodies into it;) As it's being fitted into a bay window I'd guess it would benefit me to have the vent into the corner-but again side or front wouldn't make difference-would it?

For simplicity and lack of woodworking tools/skill;) I'd like to keep the vent as a slot.

Which of these does anyone think would work better:
 

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Hi TheBaronGroog,

The attempt by pinkmouse was a tapped horn. The T-TQwT is not a horn, more like a tapped transmission line. By the way, did you see Post #7?

Regards,

Greg is fine if you can't be bothered with my username!

Yes, I saw post #7-looks like some of the derivations(abortions-no offence pinkmouse!) of Bjorno's design that I came up with while trying to adjust his design.

Differentiating between the various designs is proving quite entertaining/frustrating (depending on mood) is there a link anywhere that pictures the various designs for me to get my head round?

Hi Oliver,TheBaronGroog

Thank you for helping me out. IMO:You have the done a good work with TheBaronGroog's sub...So far I have not yet done any work..Gremlins are lurking in my computer making it very difficult to do a quick descent job.:(

b:)

Thank you both, and everyone else for your input-without it I'd be up a certain creek without a rowing impliment..
 
Hi Y'all,

I second the motion, point the vent towards the room. Bye the way the round port may actually be easier on the woodworking skills than the slot (it doesn't matter much in the design/drawing); anyway, I'll be taking a look at the drawing tonight.

Regards,
 
I was actually thinking of mounting the isobarik arrangement in the TL enclosure...

That was what my 1st attempted "design" was! http://www.diyaudio.com/forums/subwoofers/195672-thoughts-my-isobaric-tl-horn-box-design.html
What benefit would there be in the isobaric mounting-I know the benefits of isobaric mounting for sealed/vented/bandpass boxes, but have no knowledge in it's benefits for TLs/horns and all their derivatives

Setting the mouth close to a solid surface, firing into a wall, would retune the design.
I'd go with the front firing since you won't be able to use a corner to aid in loading. see pic :)

Hi Y'all,

I second the motion, point the vent towards the room. Bye the way the round port may actually be easier on the woodworking skills than the slot (it doesn't matter much in the design/drawing); anyway, I'll be taking a look at the drawing tonight.

Regards,

Looks like that's the best solution-will need to make a grill to keep the little fingers out!

Thanks Oliver, slot is one bit of wood cut in half-round = jigsaw trying to cut a perfect circle and I'm no Da Vinci;)

That looks spot on, what do you use to design it?

With the void at S4 could the port be moved to that end/further down for any gain in output/extension? Also the small section voided in at S1-could that be removed to any gain? Aprt from the gross and S* dimensions how do I work out the figures for the values 1-11 on the unfolded horn so I can transpose them to the build?

Also any comment on what the output would be like if I'd gone ahead with this, it's Bjorno's unfolded horn, "folded" by me:http://www.diyaudio.com/forums/atta...4039-entering-info-into-hornresp-plans1.2.jpg
What enclosure would it actually be? I'm still trying to work out what's what in terms of designs-any useful links?

I quickly measured the driver dimensions, look like they should fit fine-though was hoping to invert one driver-but if there's no space there's no space:
 

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