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21" ported horn (Othorn competitor)

Printed From: Speakerplans.com
Category: Plans
Forum Name: Other plans
Forum Description: Discussion / Questions about all the other plans
URL: https://forum.speakerplans.com/forum_posts.asp?TID=104751
Printed Date: 28 March 2024 at 5:39pm
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com


Topic: 21" ported horn (Othorn competitor)
Posted By: Matty309
Subject: 21" ported horn (Othorn competitor)
Date Posted: 26 January 2020 at 4:03pm
Hi all,

After spending much time thinking about building the othorn and spending £550 on a driver i thought i would design myself a ported horn with the RCF LF21n451. A £360 driver. 

my goals of the design are to have the extension that the typical reflex enclosure has whilst still preserving the impact and "throw" of a horn. might be worth noting i have previously designed and built 2 dual 15" folded horns to sit on top of these but im not sure if id even need them with this design.

Spending a short while on hornresp i came up with the following as shown in the images, performing similarly to the othorn whilst being significantly easier to build. I would design the enclosure on solidworks and it would probably be similar to the Void acoustics Nexus XL in terms of shape and layout.

Also with a bit of eq you can increase extension to have a f3 @ 30hz 

This is the results at Xmax, 1.25KW into 8ohms


it may be worth mentioning if you use a driver with a higher BL and Xmax (B&C 21) you can put about 2KW into the driver resulting it a 135db continuous output across its operating range. 

See what you guys think.

Thanks





Replies:
Posted By: VECTORDJ
Date Posted: 28 January 2020 at 9:12pm
A+


Posted By: VECTORDJ
Date Posted: 28 January 2020 at 9:18pm
Layout drawing???


Posted By: Matty309
Date Posted: 28 January 2020 at 10:07pm
haven't got a specific drawing yet as still deciding. but it will look like something similar to this..


Posted By: MarjanM
Date Posted: 29 January 2020 at 12:43am
According to that HR info you provided, the box should be about twice the size of the one you are showing there.



-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: Matty309
Date Posted: 29 January 2020 at 1:09am
I would like to know, where did you get the information from as your saying 900 litres for a single 21?

The total volume of the enclosure in the simulation is 450 litres . 240litre rear vented chamber plus a short horn approx 1.3m.

The drawing was crudely done just for a representation of my idea.

Thanks 


Posted By: MarjanM
Date Posted: 29 January 2020 at 1:00pm
The horn length on that box there is about 70cm. You need it to be 131cm, that is almost twice the length. Back chamber also is very small on that drawing. Probably about 70-80 lit. You need 240lit.



-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: Matty309
Date Posted: 29 January 2020 at 1:15pm
Yeah I know that why I meant it was for s rough representation. I will increase depth and height on box to extend horn and increase volume 


Posted By: VECTORDJ
Date Posted: 29 January 2020 at 1:59pm
A+  I always liked horn subs with ported rear chamber. More bass on the dance floor with punch compared to sealed chamber horn subs.  VECTORSONICS


Posted By: VECTORDJ
Date Posted: 29 January 2020 at 2:10pm
This horn should be able to fit in a CV Earthquake size 36 x 24 x 36 inch box???????? 


Posted By: cravings
Date Posted: 29 January 2020 at 3:38pm
kevin had a thread a couple of years back might be of interest to you

https://forum.speakerplans.com/21-ported-horn-design-idea_topic102437_page1.html?KW=othorn" rel="nofollow - https://forum.speakerplans.com/21-ported-horn-design-idea_topic102437_page1.html?KW=othorn


Posted By: MarjanM
Date Posted: 29 January 2020 at 3:56pm
Originally posted by VECTORDJ VECTORDJ wrote:

This horn should be able to fit in a CV Earthquake size 36 x 24 x 36 inch box???????? 

Horn mouth is quite small, so probably not that big. More like Martin WMX. 


-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: Matty309
Date Posted: 29 January 2020 at 3:57pm
yes should fit nicely, maybe even a bit smaller, whilst digging considerably deeper than a regular folded horn. Not only that it will be easier to build as the horn length is only 1.3m


Posted By: Matty309
Date Posted: 29 January 2020 at 3:57pm
hi yes thanks already been in contact!


Posted By: Matty309
Date Posted: 29 January 2020 at 4:16pm
Is there any benefits to using a baffle with a area cut out placed right up against the driver than using a  throat chamber as shown in the two images. Accuse me if that's not the correct terminology.

I Guess using a plate removes the need for a throat chamber and just starts with the beginning of the horn with the area to get a desired compression ratio ?

thanks


Posted By: VECTORDJ
Date Posted: 29 January 2020 at 9:48pm
The top drawing above shows a "standard" throat design and the photo shows a "turbosound turbo bass" throat design. Vary Vtc from small to large to see what this air volume does in the horn program????? VECTORSONICS


Posted By: Jo bg
Date Posted: 30 January 2020 at 11:28am
Have you considered port velocity? You can SIM It in hornresp selecting output/Port and then particole velocity. Your Port Is 1/4 of driver sd, seems  small.High Port velocityy Means noise and usually higher Port compression.
Once you consider that you Need a biggerr chamber, longer horn and smaller mouth than the design you showed, you Will realize that you need a different layout.
Take a look at Ricci skram and skhorn projects.
Posting only equalized response Is not so helpful....
Be aware that real tuning Will probably end up a Little lower than simulated, and the low corner Will probably have a downward slope (less low end ,take a lookat the semiinductance model.)


Posted By: Matty309
Date Posted: 30 January 2020 at 11:58am
Hi yes I have realised this soon after posting however I have redesigned the layout and changed it to an offset driver horn instead yeilding much better results. And a different port area thus reducing port velocity.

So you mean it will have a lower tuning frequency but it will roll off faster? 

Also will using the lossy le model more accurately represent what my driver will do? It it's of course quite a large voice coil so I suspect it while 

Thanks 


Posted By: snowflake
Date Posted: 30 January 2020 at 12:51pm
put large flares on both ends of your ports. it means you can reduce the port area a little and stop your ports getting stupidly long - which has it's own problems with pipe resonance, and fitting them in the box.


Posted By: exilegrant
Date Posted: 24 August 2023 at 10:32am
Don't suppose this project got finished? Got the same driver and looking for a nice build for it. This design sounds ideal


Posted By: smitske96
Date Posted: 24 August 2023 at 11:26am
Originally posted by exilegrant exilegrant wrote:

Don't suppose this project got finished? Got the same driver and looking for a nice build for it. This design sounds ideal

Build the scram from Josh Ricci, that driver should work with it.



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