folded horn subwoofer for single 10" driver - diyAudio
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Old 26th February 2010, 04:41 PM   #1
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Default folded horn subwoofer for single 10" driver

Hello, my name is David. I've spent some years in mobile audio, but lately I've been taking on quite a few home audio projects. I recently built my first folded horn for my moms car (attached pictures). Designed for a single 10" driver I just kind of guessed on the dimensions of the horn end, and
was quite impressed it out performed her previous 2X12" ported box. My dilemma is I expected more and it had a nasty dead spot below 40Hz or so.

Now it's time to build one for my living room about 20'X20' (6 X 6 meters) using another single 10". The driver requires just .8 cubic feet (.022 cubic meters) for the sealed end of the box. I'd like to put it in a corner standing as upright as possible. I am willing to go as high as 6-8 feet (2-2.5 meters) and 24-36 inches (600-900mm) deep but The problem is, just as the first project, I cannot find any plans for single 10" folded horn woofers, I luckily found your site and would greatly appreciate any assistance you could offer.

P.S. Don't even bother with conversions of measurements, I can do all of that, I'm more than thankful for your time and wouldn't want to further complicate the situation.

Sincerely appreciative, David.
djdaveysprocket@yahoo.com
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Old 26th February 2010, 06:14 PM   #2
jbell is offline jbell  United States
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Horns are VERY driver specific.

A. can you post the driver model and/or the T/S parameters of the driver you want to use.

B. have you downloaded HORNRESP to simulate the horn you are looking to build

C. Do you have SPL and frequency response requirements? (aka, 120db@1m@30hz, in a corner)

D. are you looking to build a Front loaded horn, Rear loaded horn, or Tapped horn.

The above info should be enough for others to help you.
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Old 27th February 2010, 12:07 AM   #3
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+1. Nice box tho'!
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Old 27th February 2010, 08:15 PM   #4
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[QUOTE=djdaveysprocket;2100054] David: .... "My dilemma is I expected more and it had a nasty dead spot below 40Hz or so...."

Hi there: The enclosure pictured seems to be a hybred front loaded horn/ported reflex box where the port exits at the convergence of the twin horn mouths. You may want to read the FLH explanation by Martin L. King: "Design of front loaded exponential horn, section 6", ( about paragraphs 5 through 7 ) where he describes correctly designed and the effects of incorrect design. If you plug the port, your design would be a FLH as defined by MLK. As stated above by others, horns take a lot of work using software such as "Hornresp" to get good results and you need the driver T/S parameters. Cetrainly a longer path length, as you propose for a home system, would produce a lower cutoff. Also there are other easy to build tall bass reproducers, check out "BIB" enclosure on this DIY. Hope you will continue to enhance your design and report the status listening results. ...regards, Michael
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Old 27th February 2010, 10:33 PM   #5
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[QUOTE=j.michael droke;2101398]
Quote:
Originally Posted by djdaveysprocket View Post
David: .... "My dilemma is I expected more and it had a nasty dead spot below 40Hz or so...."

Hi there: The enclosure pictured seems to be a hybred front loaded horn/ported reflex box where the port exits at the convergence of the twin horn mouths. You may want to read the FLH explanation by Martin L. King: "Design of front loaded exponential horn, section 6", ( about paragraphs 5 through 7 ) where he describes correctly designed and the effects of incorrect design. If you plug the port, your design would be a FLH as defined by MLK. As stated above by others, horns take a lot of work using software such as "Hornresp" to get good results and you need the driver T/S parameters. Cetrainly a longer path length, as you propose for a home system, would produce a lower cutoff. Also there are other easy to build tall bass reproducers, check out "BIB" enclosure on this DIY. Hope you will continue to enhance your design and report the status listening results. ...regards, Michael
LOL!

It seems a little confusing to me as well.

Where are the test graphs?
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Old 8th March 2010, 05:40 AM   #6
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Quote:
Originally Posted by jbell View Post
Horns are VERY driver specific.

A. can you post the driver model and/or the T/S parameters of the driver you want to use.

B. have you downloaded HORNRESP to simulate the horn you are looking to build

C. Do you have SPL and frequency response requirements? (aka, 120db@1m@30hz, in a corner)

D. are you looking to build a Front loaded horn, Rear loaded horn, or Tapped horn.

The above info should be enough for others to help you.

A. you're all going to laugh at me but, the driver is an Alpine SWR-1021D intended for mobile audio, I'm pretty certain it's not ideal but I'm working with a limited budget and happen to have this one sitting around. I am however open to sugestions on purchasing something better if it's affordable.

B. I've been trying to find a version of HORNRESP I can run on my Linux OS, but have yet to find anything.

C. The only specs I can find on this driver are from the factory (attached PDF)

D. I'm not familiar with the different types of horns but this is a visually appealing driver and was hoping to put it at the top of my box facing down, I don't even know if thats possible or ideal for efficiency.
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File Type: zip OM_SWR-1021D.PDF.zip (393.9 KB, 102 views)
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Old 8th March 2010, 01:15 PM   #7
jbell is offline jbell  United States
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I think an up and back tapped horn ala cowan Tapped Horn Experiments is exactly what you are describing, and actually works with your chosen alpine driver.

This is the hornresp sim for an 8 foot tall up and back, 70cm2 throat and 700cm2 mouth.
You'll need to face the driver 'into' the throat, so the magnet is visible in the mouth.

I think that is workable and would do what you want. It's good down to 25hz, and 300 watts, coils in series for 4ohm.

I believe others have made hornresp work correctly under WINE.

hope this helps.
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File Type: jpg alpineth.JPG (86.8 KB, 745 views)
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Old 8th March 2010, 04:05 PM   #8
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Thank you so much jbell, I really like the design you suggest.
I'm super excited to start building, it's my favorite part (besides listening to the finished result). I will post pictures of the process, construction, and finished results.

P.S.
Am I correct to assume that I should be using 3/4" plywood and internal bracing on such a large box?

Thanks again, David
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Old 9th March 2010, 05:58 AM   #9
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Quote:
Originally Posted by jbell View Post
I think an up and back tapped horn ala cowan Tapped Horn Experiments is exactly what you are describing, and actually works with your chosen alpine driver.

This is the hornresp sim for an 8 foot tall up and back, 70cm2 throat and 700cm2 mouth.
You'll need to face the driver 'into' the throat, so the magnet is visible in the mouth.

I think that is workable and would do what you want. It's good down to 25hz, and 300 watts, coils in series for 4ohm.

I believe others have made hornresp work correctly under WINE.

hope this helps.

I'm still a little confused, I've successfully acquired WINE and HORNRESP but I don't understand it one bit.
Also not sure about the 8 foot bit. Is the box 8 feet tall (16 feet of horn), or is it an 8 foot horn folded in half to make a 4 foot box
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Old 9th March 2010, 06:25 AM   #10
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8 foot tall box, with a single fold inside, for 16 feet of horn.

I've used Hornresp under WINE without problems.

Understanding Hornresp can be a challenge. This may help.

Last edited by littlemike; 9th March 2010 at 06:33 AM.
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