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18Hz Infinity Offset Horn Tower

post #1 of 42
Thread Starter 
I have been enjoying my 8" tapped horn up to this point as seen in this thread. While it has great output for an 8" sub it does not play terribly low. http://www.avsforum.com/avs-vb/showthread.php?t=1240371

Lately I've been looking for a bit more output and lower frequencies to enjoy in my living room. I also had an Infinity Perfect 12VQ sub sitting around from my car audio days. I decided to put it to work.

Having already built several of Bill Fitzmaurice's designs such as the TLAH, Tuba 30, THT, and AutoTuba I have really enjoyed the sound of a properly designed offset horn sub.

I chose to build an offset horn and make it as slim and tall as possible to minimize floor space. The requirements were that I needed output down to about 18Hz in as little floor space as possible. I built it as tall as possible to fit in my room with 7'4" ceilings. The external dimensions of the enclosure being constructed of 1/2" Arauco ply are 16x16x84.



Here is the output with 2.83V of input.


And the output at 44.72V or 500W.


Cone Excursion at 500W. The excursion can easily be controlled with a subsonic filter as many plate amps use. Keep in mind that this sub has an Xmax of 16.75mm but this is not yet Xlim.


Group Delay


Phase


Schematic-Less than 300 liters!!


I drew up the sub using AutoCAD. Here is a jpg of the dimensions. If anyone is interested I can send out a much better pdf of the dimensions.


Here is the cutlist. It uses less than 2 sheets of the aforementioned 1/2" Arauco ply. As a side benefit it was on sale at my local Menards for $21 a sheet.


Here are a few pics of the construction stages.










Of course I had to bring it in my house and try it out before finishing it. For reference that is a 50" Samsung plasma and my Mini Ewave speakers in this pic.


Currently I am powering it with a Crown XTI2000 I had sitting around. I set the limiter to -3db and a high pass at 20Hz. This will provide around 400W of power and protect the driver from overexcursion.
After listening to it for a couple of days I am extremely happy with the build. So far it really only cost me $50 for the wood and PL to assemble the enclosure. The next step will be to take some measurements and then to finish the enclosure and apply Duratex. I may even paint it the same color as the walls to help it "blend" in.
post #2 of 42
Very nice! What mains?
post #3 of 42
Thread Starter 
The mains are one of Zilch's later designs using the Beta 8a and the Eighteen Sound XD120 compression driver/horns. I bought the horns when they could be had for $30 each. They make for great sounding and efficient mains. They are part of the reason why I had to upgrade the sub.
post #4 of 42
Nice build from start to finish =]

You should take some in room measurements
post #5 of 42
Great build! Love the footprint and slimness. Can't wait to see measured results.
post #6 of 42
it would be great to see either ground plane or close mic measurements too
post #7 of 42
Looks good tad. That 8" mcm horn is just great but I kinda want it deeper though. Hell I threw the 8" epic in the model and the mcm was still more efficient. That liitle horn just gets so loud most don't believe its a 25 dollar 8 in driver.

I may try to fold this so its not as tall but is wider(longer).


edit-ok, after modelling it with 100 watts and a 1262W driver its way more efficeint(we are talking about 5db more efficient overall but its 17db more efficient at 20hz). The only problem is that its way over xmax after 20hz. Now to figure out how to refold it.
post #8 of 42
Thread Starter 
Thanks!! Well I had been working on checking output before taking some measurements. I was playing an old Boston Acoustics bass cd I had laying around to push the sub to it's limit in my living room. I found that I was able to hit 124db at one meter on my rat shack meter on the C weighted fast setting.
It was sounding very good until I got a knock on my door from a local cop informing me that one of my neighbors had been complaining about the noise. I have an ahole attorney that lives in my cul de sac that despises me and my friends. I'm good with that. Luckily my local cops are cool as they tend to visit me regularly in the summer due to Rock Band parties at night in my driveway with my projector. So I think the measurements will need to wait until tomorrow before I can push it again.

I'll let you guys know how it goes tomorrow.
post #9 of 42
Has anyone folded the design specific to this driver? The height for this particular build is not going to work for me. I have a spare Infinity Kappa Perfect 12.1 VQ and want something driver-specific.
post #10 of 42
Thread Starter 
Quote:
Originally Posted by fouZero View Post

Has anyone folded the design specific to this driver? The height for this particular build is not going to work for me. I have a spare Infinity Kappa Perfect 12.1 VQ and want something driver-specific.

What height is the max for you? I could refold it but it will make for a wider box which I did not want.
Btw I'm still using this sub but have not finished the cabinet. I can't beat to lose the bass on my living room long enough to complete it.
post #11 of 42
Quote:
Originally Posted by tsloms View Post

What height is the max for you? I could refold it but it will make for a wider box which I did not want.
Btw I'm still using this sub but have not finished the cabinet. I can't beat to lose the bass on my living room long enough to complete it.

Half as high and twice as wide would be fantastic. There is no hard max on the height, it is more of an aesthetic concern where I will be placing it.
post #12 of 42
nice work on the construction tsloms.

did you model a ported enclosure with the same driver?

just curious how much horn sensitivity you are getting with your "horn".
post #13 of 42
How did I miss this before?

Nice build. Looks like you fell into the pre-finish diy trap...taking the project inside to "test it".

Very cool.
post #14 of 42
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

nice work on the construction tsloms.

did you model a ported enclosure with the same driver?

just curious how much horn sensitivity you are getting with your "horn".

I modeled this driver in a 5 cubic foot enclosure tuned to 18hz as a comparison. At 19hz the horn has a 6db advantage and at 60hz has an 11db advantage. The smallest difference between the horn and ported enclosure is about a 4db advantage to the horn at 30hz. But keep in mind that in addition to this increased output and of course the decreased distortion since it is a folded horn with a sealed box that the driver excursion is kept in check. I'm using a Bash 300w amp and have never been able to audibly distort the driver even at full throttle.

Thanks for the compliments guys. I really should know better than to bring the unfinished sub into my house. I did the same thing with my small 8" tapped horn a couple of years ago as well. I never did finish that thing. It's good being single!!!
post #15 of 42
I've also looked at a tuned vented enclosure for this driver: http://forums.audioholics.com/forums...idq-plans.html but the excursion control possible in a tapped horn and the ability to tune down <20hz really appeals to me. I've played around with hornresp, but I run into a wall whenever I try and fold the design.
post #16 of 42
Thread Starter 
So for a little update for this build. I have finally decommissioned this sub. It was just too large and obtrusive in the room. I built a new sub using a pair of sealed Alpine SWR-1243D subs powered by an EP2500. Surprisingly I think that the horn with its little 300w amp puts out slightly more than the pair of sealed Alpines can but the Alpines are in a smallish 3 cubic foot enclosure for the pair. They also play much lower. I suppose I should do a build thread for the new sub.

I never did finish this horn sub. Would anyone have a use for the horn sub and be able to pick it up in WI for super cheap? I'm not sure if I can find anyone to buy it locally.
post #17 of 42
How cheap?
Where in WI?
Have you tested or measured it?
post #18 of 42
Thread Starter 
I live just east of the fox valley in Brillion. I did take measurements on it a while ago. I'll have to see if I still have them on my computer. They match the model pretty well though. I'd let the whole thing go for $100.
Let me know what you think.
post #19 of 42
Thread Starter 
Nobody? Do I really need to burn up this nice horn? It would be a shame!!
post #20 of 42
Quote:
Originally Posted by tsloms View Post

Nobody? Do I really need to burn up this nice horn? It would be a shame!!

I was thinking about it but the drive is a little far. Also, I was really hoping to see some graphs.
post #21 of 42
Thread Starter 
If you'd like I could take some measurements at the mouth. I currently have it sitting in my garage. Where do you live? Maybe I could meet you half way or something?
post #22 of 42
YGPM. Looking for the detailed .PDF of the dimensions...
post #23 of 42
Quote:
Originally Posted by tsloms View Post

I really should know better than to bring the unfinished sub into my house. I did the same thing with my small 8" tapped horn a couple of years ago as well. I never did finish that thing.

I know what you mean! I'll finish them for a car, but not for the house. Nice build!
post #24 of 42
Thread Starter 
I have been pming a fellow avs member who was asking about this horn build. In checking the specs on the Infinity Referenece 1260w driver that is available for about $60 on Amazon I found that this driver will work very well in this horn build.

The black line is the 1260w and the grey is the Perfect 12VQ. Even the 1260w can handle as much as 500w with an 18hz high pass filter.



post #25 of 42
Sorry for the very late reply on this thread but this setup might be just what I need. I have a friend I'm helping with HT system. I built a pair of Klipsch Cornwall clones for his LR and need some low sub extension.

He has an 18' x 17" x 9' room with two 2' x 6' x 80" closets in two front corners. I'd like to use the Infinity 1260 in the tapped horn but need the dimensions changed (shorter but wider deeper okay). I would live with 74" tall and 20" wide and 20" deep. I would appreciate any assistance since I'm not familiar with the horn response software. Thanks.
post #26 of 42
Thread Starter 
Quote:
Originally Posted by longdrive03 View Post

Sorry for the very late reply on this thread but this setup might be just what I need. I have a friend I'm helping with HT system. I built a pair of Klipsch Cornwall clones for his LR and need some low sub extension.

He has an 18' x 17" x 9' room with two 2' x 6' x 80" closets in two front corners. I'd like to use the Infinity 1260 in the tapped horn but need the dimensions changed (shorter but wider deeper okay). I would live with 74" tall and 20" wide and 20" deep. I would appreciate any assistance since I'm not familiar with the horn response software. Thanks.
Give me just a bit of time and I'll model this horn enlarged slightly. It will give some additional output at the expense of the larger size.
post #27 of 42
Slightly off topic (same shape/concept), does anyone know if there are any DIY plans/similar builds to a DTS20?
post #28 of 42
Thanks tsloms. I appreciate the effort. My buddy is itchin to get this installed. I could do one in each closet but that might be overkill (really, is there such a thing in a sub!????). Thanks again.
post #29 of 42
My buddy is measuring the interior height of the closets. I may be able to do 80 to 82" depending on my friends measurements which I should have later tonight. he has a large recessed area over the closets which may work as well.
post #30 of 42
Okay, me again. My buddy has 90" clearance in the closet so we're good to go with the 84" x 16" x 16" size. However, please send me the clearer pdf file on the dimensions/cuts/spacing of divider dimensions since I can't read the dimension on the posting I'll plan on using the Infinity 1260W in this version and will post/report back after complete with photos. Thanks again.
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