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Horn Plan

Printed From: Speakerplans.com
Category: Plans
Forum Name: New Projects Forum
Forum Description: Forum for new speakerplans projects, in memory of Tony Wilkes, 1953 - 2014
URL: https://forum.speakerplans.com/forum_posts.asp?TID=97431
Printed Date: 29 March 2024 at 8:54am
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com


Topic: Horn Plan
Posted By: Mikkel
Subject: Horn Plan
Date Posted: 03 January 2017 at 10:00pm
Hey

I've been looking at moving on to a fully hornloaded system for a while now and have finally finished tweaking (I can never seem to stop).

I want to get some wood cut to size at b&q asap so any help with regards to glaringly obvious mistakes or problems with sims that i might have missed is greatly appreciated.

The external dimensions are 122x80x52cm and is designed around the fane colossus 18b

If want any more info or more detailed drawings just let me know.





Replies:
Posted By: cookie-dj
Date Posted: 03 January 2017 at 10:31pm
B&Q wont cut angles. And they don't have any decent ply in stock either

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You can't polish a turd!


Posted By: mobiele eenheid
Date Posted: 03 January 2017 at 11:06pm
If I copied you input parameters carefully your simulated internal volume is 540 litres. The external dimensions of your cabinet are giving about 500 litres, say about 70 litres for wood panels, meaning your internal volume present is 440 litres.


Posted By: Mikkel
Date Posted: 04 January 2017 at 12:12am
Thanks for the reply's guys.

cookie-dj - Thanks yea i know they don't do angles, im just getting all the 'straight' panel edges cut to size and cutting the rest on my own. and the first batch will be made from mdf. if it all pans out okay i will sell them and remake out of ply. (plus its cheaper with mdf if make any mistakes at first)

mobiele eenheid - yes sorry i should have mentioned that my sim takes into account the exit behaviour of FLH's (i.e. the air immidiately in front of the mouth is still coupled to the horn). discounting this the horn volume is approx 400L according to hornresp.

I gotta say though Johan that i've had 4 cubos 18's for a while now and they have always put a smile on my face, so many thanks for that wonderful design. I just felt like a change and a challenge so this designing my own seemed the obvious next step.




Posted By: Mark James
Date Posted: 05 January 2017 at 10:02pm
looks like a larger simplified 186 at first glance,
be interesting to see how these get on. what are
you intending them to be used with/range etc?
be nice to see more drawings etc too .
looks good so far :-)


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me so horny me love you long throw
horn loaded for her pleasure


Posted By: Mikkel
Date Posted: 07 January 2017 at 8:22am
Thats exactly what i was going for, the 1850/186 horns are just a tad too short for my taste. Intended usable freq range 35 - 120 hz with a 65 cm 12" horn on top (again another of my own designs).

Hornresp puts the -3db point around 38hz with a 35hz (12db bw) highpass and im guessing it wont really play nice above 100 because of the two sharp bends.

Will post more plots and drawings as i progress.

Would people say the bracing is adaquate on the drawings? They are the white pieces on there.


Posted By: mstep77
Date Posted: 11 January 2017 at 9:41pm
You're modelling in 0.5pi space which will flatter the response a lot! I guess you're doing this to simulate a stack of 4 horns coupled together?

I'm not sure your horn length will be enough to get down to 38/35Hz. Can you post the hornresp plot for the excursion of the cone? I have a feeling this might be quite high at reasonable power levels and also considering your rear chamber is pretty big.

I think 120Hz should be fine on the high side although a 12 on a 65cm horn will be pushed to get down to 120hz so maybe you'll want to extend that around 70cm.

Looks decent though :-)


Posted By: Mikkel
Date Posted: 13 January 2017 at 12:19am
Yea modelling in 4pi to simulate 4 horns stacked together.

The horn length is circa 215 cm give or take. Im not sure how to manually calculate so can only really go with what hornresp is telling me.

Here's some plots with excursion, and you are right xmax is reached fairly soon. The top sim in picture are with 450w and the bottom is 300w. As you can see i've had to move the highpass up to accomodate for the extra power to keep within xmax.



Im not entirely certain what im doing with the mid horn just yet as it is still in the tweaking phase but thanks for the suggestion.

Im currently trying to piece together some cut lists to take to B&Q next week. Will post them up when i've finished them.

EDIT: if you want the raw excursion plots at various power levels just let me know and will upload them when get a moment.

Also quick question. Has anyone found hornresp overdoes the power a bit. 300w in 4 cabs shouldn't be giving me 135dB surely? would have thought double that be a more realistic. (i know its to do with more than just wattage, but as a general standpoint it seems a bit off)

Cheers!


Posted By: Lili
Date Posted: 13 January 2017 at 2:15am
Originally posted by Mikkel Mikkel wrote:

yes sorry i should have mentioned that my sim takes into account the exit behaviour of FLH's (i.e. the air immidiately in front of the mouth is still coupled to the horn).

You may not do this, because hornresponse does this already.

Besides
In your drawing the port (Ap1, Lp) between speaker and horn throat is missing


Posted By: Marko
Date Posted: 13 January 2017 at 8:56am
Originally posted by Mikkel Mikkel wrote:

Yea modelling in 4pi to simulate 4 horns stacked together.

The horn length is circa 215 cm give or take. Im not sure how to manually calculate so can only really go with what hornresp is telling me.

Here's some plots with excursion, and you are right xmax is reached fairly soon. The top sim in picture are with 450w and the bottom is 300w. As you can see i've had to move the highpass up to accomodate for the extra power to keep within xmax.



Im not entirely certain what im doing with the mid horn just yet as it is still in the tweaking phase but thanks for the suggestion.

Im currently trying to piece together some cut lists to take to B&Q next week. Will post them up when i've finished them.

EDIT: if you want the raw excursion plots at various power levels just let me know and will upload them when get a moment.

Also quick question. Has anyone found hornresp overdoes the power a bit. 300w in 4 cabs shouldn't be giving me 135dB surely? would have thought double that be a more realistic. (i know its to do with more than just wattage, but as a general standpoint it seems a bit off)

Cheers!


Mikkel, which simulation software is this?



Posted By: Mikkel
Date Posted: 13 January 2017 at 12:12pm
Lili - I see, i wasnt aware of that. Do you have any litterature supporting that, as I have read quite extensively on Hornresp and have never seen such a function. In regards to your second point, the drawings arent very clear on here but if you zoom in there are two lines on the top panel (i.e. where the obvious horn beginning is) denoting where the aperture is supposed to be.

Marko - The software im using is called Hornresp. You can download it for free online, just search for it in google. Its an excellent program made by a guy called David Mcbean.


Posted By: Mark James
Date Posted: 13 January 2017 at 1:39pm
i missed the porting bit, this is a ported horn then? 
cant work out how its ported tho lol
i might have to sim this with a few cheap drivers see if it miht be an option for a small free party stack, block of four with semi cheap ish drivers and a proline running them should do nicely


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me so horny me love you long throw
horn loaded for her pleasure


Posted By: Mikkel
Date Posted: 13 January 2017 at 2:46pm
It's not supposed to be ported, its just a normal flh. I think what he meant is that he couldn't find the 'hole' for the letterbox throat on the plans. They are there but not very easy to see. Im gonna upload a better picture of the plan with all the measurements. The one i posted at top was really just for perusal purposes.


Posted By: Mikkel
Date Posted: 13 January 2017 at 3:29pm




Posted By: Mikkel
Date Posted: 13 January 2017 at 3:31pm
Im new to making plans and such so hope these are okay. Will upload cutlist when they are finished.

Edit: Made a tiny ajustment on these new uploads, as found a mistake on the originals.

Also the braces in white are just for illustrational purposes. Can obviously be changed to suit whatever.


Posted By: Mark James
Date Posted: 13 January 2017 at 9:55pm
looks good to me
be good to see/hear how they get on


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me so horny me love you long throw
horn loaded for her pleasure


Posted By: tv00
Date Posted: 14 January 2017 at 8:55am
This is really interesting to me.
I've been playing around with the idea of modding the invader bin to fit pallet (120x80)
I suggest you take a look at that thread, lots of sims & experiments with porting.
What I prefer about the invader is that it has no 180 degrees bends, should smoothen response upwards. Also u could take a look at the Amano verion WSX.


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www.facebook.com/babysoundsystem


Posted By: Mikkel
Date Posted: 14 January 2017 at 11:12am
Hi tv00. Ive read through the invader thread several times and definitely remember seeing amanos wsx somewhere, thanks for the suggestions, both have influenced my learning curve with horn designing.

Anyways i dont mean to be rude but there are plenty of ported horn designs out there. Designed up from the bottom specifically with that concept in mind, and i think it would be a shame porting this horn. Also i think -3dB @ 38 hz is plenty, and if you need more you need a bigger horn!

The reason i used the s - style bin is because it has added length compared to the c - shape bin.

At the heart of this design process was simplicity. Im no good in the workshop so wanted to have a nice easy box with a decent response down to 40hz. They were the princibles in mind when i started this.


Posted By: nickyburnell
Date Posted: 14 January 2017 at 11:23am
Looking forward to pics, this looks so simple and good


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It's everything, not everythink!


Posted By: gen0me
Date Posted: 14 January 2017 at 1:36pm
Originally posted by Mikkel Mikkel wrote:

The horn length is circa 215 cm give or take. Im not sure how to manually calculate so can only really go with what hornresp is telling me.

Con (S1S2)+Con (S2S3)+Con (S3S4)+Con (S4S5)+ Lp



Posted By: gen0me
Date Posted: 14 January 2017 at 1:39pm
Why my hornresp is telling me 193cm LOL?


Posted By: Mikkel
Date Posted: 14 January 2017 at 2:17pm
you forgot to add the Lp, hornresp doesnt do it for you. But to clarify what i meant was I dont know how to manually calculate how low the horn can go, mstep77 said the length probably wasnt long enough to support 38hz, I have no way of verifying hornresp's simsulations so can only go with that.


Posted By: DMorison
Date Posted: 14 January 2017 at 3:00pm
Originally posted by Mikkel Mikkel wrote:

you forgot to add the Lp, hornresp doesnt do it for you. But to clarify what i meant was I dont know how to manually calculate how low the horn can go, mstep77 said the length probably wasnt long enough to support 38hz, I have no way of verifying hornresp's simsulations so can only go with that.

First rule of thumb is the horn has to be at least 1/4 of a wavelength long to provide decent loading.

Therefore if you want 38Hz, you want a length of at least 226cm.

Obviously, lots of other factors affect the final shape of the response curve, but that's one key thing anyone can look at when evaluating a potential design to see if it's at least "in the ballpark".


Posted By: Mikkel
Date Posted: 14 January 2017 at 5:02pm
Excellent, thanks for that Dmorrison!

So being circa 218 cm it should support down to 39 hz, assuming there is sufficient mouth area to support that too.

Which brings me to another question - I remember reading that a rule of thumb for mouth area is that the circumference needs to be same length as the lowest wavelength. now 870cm would be something like 12 horns stacked together! Is this correct or am I barking up the wrong tree?


Posted By: odc04r
Date Posted: 14 January 2017 at 5:19pm
Yes that is the correct idea. 39Hz at 345ms = 8.8m to terminate the horn semi-ideally (must check expansion length vs area too for idealness).

But you're presumably ground stacking them so that will double the effective mouth area if you assume the floor is an ideal reflective boundary and not a vibrating stage. You;d need to have a stack 3-4 bins wide I think assuming they are ~2ft wide. Which is pretty common for that sort of cutoff.



Posted By: Ruggeddave
Date Posted: 14 January 2017 at 5:27pm
Horn resp has a built in function for simulating multiple cabs, simulating in .5pi space is not the same as having 4 cabs!

Simulate it in 2pi for a more realistic response, check excursion graphs again also.

Another point is don't forget to check the clearance of the driver between the cone and the letterbox throat, you will most likely need a separate driver baffle rather than mounting the driver flush on the letterbox its self.

Hope this helps.  


Posted By: Mikkel
Date Posted: 14 January 2017 at 5:33pm
52cm wide (1.7ft) so not quite but should still get me fairly close with 4 stacked together. I forgot about the boundry loading of the ground, so in 2pi, effectively half the circumference is needed (in laymans terms).

Thanks for clearing that up!

Ruggerdave - I've checked this as I thought the same but all the graphs come out identical if simulating one cab in .5pi or actually using the multible cabs function to get 4 stacked together. God knows if this is correct but I assume that its so similar it doesn't matter.

With regards to the cone excursion maybe hitting the baffle, i intend to router out a 4/5mm deep circle around the inside edge (maybe a bit wider than the surround) instead of adding a baffle 'ring', if that makes sense. Saves wood and seems easier.

Thanks for suggestions!


Posted By: tv00
Date Posted: 15 January 2017 at 10:03am
Are u in Huddersfield? -Your name sounds danish:-)



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www.facebook.com/babysoundsystem


Posted By: Mikkel
Date Posted: 15 January 2017 at 10:49am
Im originally from Denmark but live in England, lived her most of my life. Though with all this brexit nonsense dunno how long that'll last. Ouch


Posted By: Mark James
Date Posted: 18 January 2017 at 2:52pm
im not a fan of ported horns either usualy, im liking this design idea so far

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me so horny me love you long throw
horn loaded for her pleasure


Posted By: tv00
Date Posted: 18 January 2017 at 6:13pm
I find the dimensions perfect! -just for an EU pallet.
Size & fane driver was the things that got me to think of invader (b600)
But the 18b is only available on special order now isn't it?
I'd love to put my col18-1500s in some real horns one day...
Gotta fix some other speakers now...


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www.facebook.com/babysoundsystem


Posted By: Mikkel
Date Posted: 28 January 2017 at 6:13pm
Hi

Apologise about the belated response about this. Unfortunately due to personal reasons ive had to shelve this project for the forseeable future.

If anyone else is wanting to build some prototypes, drop me a pm and ik happy to help however i can.

Will if course update if this comes back on track but dont hold your breath.

Thanks



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