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Discussion Starter #1 (Edited)
I am getting ready to finish up the first of two, so I figured it's about time I started a proper build thread and post some photos...

These are going in two corners of my living room, which is connected to a huge space of about 11,000cf. Each one is built with a 24" diameter sonotube @ 11'-1" high, with 4.5" legs on the bottom and 10-3/8" round ports @ 38" long, giving them each a total height of 11'-5.5" and the ports 12" of breathing room above them.

They net out at just over 30cf each, and a designed tune of 12.5Hz, with my expectation that they will come in around 11-11.5Hz at the end of the day.

Each will be fitted with an SI HT18v2, wired in series (4ohm) and powered by an iNuke 6000DSP.

There are 3 pillows stuffed around the port, and 1 pillow stapled and glued to an inner ring at the midpoint of the tube. These should effectively kill any resonances.

Two photos are attached, showing the first tower getting ready for paint. I peeled the outer plastic coating of the sonotube which exposes bare cardboard, so I am going to coat the entire tube with a coat of wood glue to stiffen and seal it, then two coats of paint to match the living room walls.

I'll take some build photos as I build the second one so I can post them here.

Edit: Finished Photo

 

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Epik build!!!!!!!!!!!!!!!!
 

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Discussion Starter #4
You probably have the lightest weight 30cf sub on the forums.
And it's still really freaking heavy. Getting it into the house and into place will be a challenge.
 

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Awesome build!! It was my understanding that subs build like this don’t have resonance issues because of the shape? Is this not true? Either way.......should be awesome in the room.
 

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Discussion Starter #8
That's a big tube build! Any concern about them tipping over with that height?
Definitely some concern. I will likely put a small eye bolt in the top cap and the wall and wire it just to be safe.

Awesome build!! It was my understanding that subs build like this don’t have resonance issues because of the shape? Is this not true? Either way.......should be awesome in the room.
There are definitely resonances with a bare empty tube, but the pillows seem to totally kill them.
 

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I'd put three more legs on there. The tripod you have now will be very likely to tip over.

Awesome build anyhow.
 

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I'd put three more legs on there. The tripod you have now will be very likely to tip over.

Awesome build anyhow.
3 legs have inherently more stability than 4 or any other number. If your floor were perfectly level, then perhaps 4, but I would take 3 legs any other time.
 

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I never filled mine and I had no resonances.
The sonotube subwoofers I built many years ago had a terrible end to end resonance that rang like a bell.



Shown another way, treated vs. untreated:

 

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How did you measure that? Mic in the port?
It's been quite some time ~10 years, and I didn't write a full description with the measurements I took. I think that measurement was 1 meter from the driver, but not certain. I do know when I fired the first one up, it sounded terrible.

Pulling the driver, just speaking into the enclosure you could trigger resonance. A few polyfill pillows took care of it 100%.

I left one treated, one un-treated and pulled out the measurement gear to see how bad it was. The waterfall plot is quite ugly, showing the resonance rings out well past 300 msec with little to no attenuation.
 

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Never heard any, if I can’t hear it I don’t care. They were 6 feet tall and 26 inch round OD. The ports were 7.5 and 8.5. I can’t remember how long though, 38-40 comes to mind. They always were just clean bass with no noises even with my ear to the port. If they were there it was not audible.
 

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Yes I started measuring once I went sealed. The spl meter with c-weight was as accurate as my calibrated behringer mic from CSL for the bass frequencies. Notnyt measured and tested it for me.
 

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Never heard any, if I can’t hear it I don’t care. They were 6 feet tall and 26 inch round OD. The ports were 7.5 and 8.5. I can’t remember how long though, 38-40 comes to mind. They always were just clean bass with no noises even with my ear to the port. If they were there it was not audible.
Just because you didn't hear it, doesn't mean it wasn't present.
 
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