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Discussion Starter #1
I have two extra 15" JBL bass drivers that I’m thinking about sticking into a sonotube.

The design looks relativity straight forward and simple, just requires tools and patience in building it.

I have no idea where to obtain the tubing itself within the UK? I’ve fished around other forum sites and even a few in US have pick it for $35.00 (around £15.00) so I guess it’s cheap, I mean its hollow tube.

The Google link here where, oh, where is there a UK supplier?
http://www.google.co.uk/search?hl=en&q=where+to+buy+sonotube+uk&btnG=Search&meta=&aq=f&oq=

Also I was thinking of tubing that is used on roadwork’s as I have seen some yellow tubing that my dad says is used for gas. Blue water, and black he thinks fresh water.

Ether way this could be used, and often there are off-cuts lying around after the job has been done. I, might look at one works this week if, its still be worked on and providing they say it’s okay to take an off-cut as its only scarp.

I would like to do 12 footer twin tubes mounted close to ceiling corners to throw the lows out, would this not work (yes or no, or (maybe) as that is an option).:D

Also I see there is calculator on the site that can determine size for required sub bass diy projects, very interested.

Options gentlemen?

 

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Discussion Starter #4
Here is the pdf specifications can you work out the calculation by stretching it beyond in the lower frequency register?
http://www.jblpro.com/pages/pub/components/2226.pdf

Gotcha I, know what you mean, now. Pour the concrete into the tube then remove and bingo a concrete pillar.

Cheers I’ll ask around should be too hard now. I asked my, dad and it went over his head? When I ask him again, he’ll most likely say, (I know what that is now).
 

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Discussion Starter #5
I have looked up and down Google lol unless anyone knows of UK based company that supplies these hollow tubes, because I haven’t the first clue I have tried at least 5 different keywords and it keeps coming up with sub bass threads and so on.
 

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G,day Andy, I had the same difficulty trying to locate sonotube via the web. I used the Yellow Pages and let my "fingers do the walking". Look up concrete forming companies or similar in your area, and you will probably find what you need. Hope this helps, Mike.
 

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G,day Andy, I had the same difficulty trying to locate sonotube via the web. I used the Yellow Pages and let my "fingers do the walking". Look up concrete forming companies or similar in your area, and you will probably find what you need. Hope this helps, Mike.
Good day to mate as well. Yes I have new yellow pages here in front of me and I’ll flip though the pages to find a supplier, in the local area.

Cheers Mike:T
 

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Discussion Starter #9
Well I see (concrete ready mix) I’ll call one of the firms up in the morning and quiz them, on where to find the supplier of the tubing.

My dad mentioned oh, I know what you mean now. He said those things are custom made. Is that true?

My dad doesn’t give hoot about the project and he was in bed when I called him LOL. Its only 8:30pm!
 

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Discussion Starter #10
The 2226H/J driver has an accordion surround. I'm not sure if it would be acceptable in a downfiring position. With a Fs of 40 hz and 7.6 mm Xmax I assume this wouldn't be for home theater, correct?
I don’t intend to use it for downward or upward! One it will take up walking space around the room as I’ve seen many of those projects.

I’m going to use the horizontal length of the room. I think 10 foot would be wise 12 is just a bit too long. So I’ll have to find a way of mounting it 100% to the corners of the ceiling attached to the sidewalls, follow?

So the thing you mentioned about the edge surround shouldn’t present a real issue. Only unforeseeable issue is will it work on the sidewalls. Only way tell is to build it?

So any ideas/data on the rough frequency response for that length, cheers.
 

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The 2226H/J driver has an accordion surround. I'm not sure if it would be acceptable in a downfiring position. With a Fs of 40 hz and 7.6 mm Xmax I assume this wouldn't be for home theater, correct?
Certainly not for home theater. I'd build it sealed too. 7.6 mm is very low xmax and FS of 40hz is very high. You'd get a 2% sag unless there is some kind of effect the accordion adds. This is acceptable. Still this is not a good home theater sub.
 

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Discussion Starter #13 (Edited)
What are your goals with this? A sealed or ported music sub?
Well give me some options then I’ll listen to what you have to say on the pros and cons of ported over sealed. I don’t mind as long as one can achieve better over the other.


It will be mostly used for film soundtracks and a little music now and then.

I’m tested the frequency response REW free air, since I have no box for them as of yet. I guess you’d like to see my, upside down REW charts and yes I’m using the vertical thingy to set the chart up.

I’ll post in shot jiff.
 

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Discussion Starter #14
I took this quickie frequency response sweeps in free air as I have no box for them.
I can see the drop on the lower end of each angle I placed the mic.

To me it looks like the sweep is off the curve line is that normal. as long as I can see sweep curve it looks okay it has no nulls or such.

I wonder if the box or sonotube will improve on the lower end. I stared the sweep off at 10Hz to end at 130Hz its passing though the AVR so it has its own crossover filter maybe around near 80Hz as it seems to be going a bit queer with that odd bend nearing 70Hz, it doesn’t worry me really.

Okay a picture of what I’m doing in the living room at present time. As you can see I’ve placed the middle of the speaker on top of two speakers to clear the vent holes from the floor.

While doing the sweep I noticed that I could feel on of the frequency bands. I used sine wave and (went step by step up the scale from 20Hz to plot which tone) around 38Hz I can feel the tone in the chair vibrating nicely but the amount of power I’m seeing going to the amps seems unnecessary its only a few bars on the display of the Alesis RA300 and I prefer (less is more) its because its in free space I guess. No popping no distortion!

Within 42Hz its vibrated the night storage heater in the living room which is 9 feet away!
I give the heater a little thump with the hand, its only the output vent on the heater that is vibrating.

Nearing 50Hz the tone settles down and the pressure is no where near to pressurizing my ears, no box.

I can feel a mild low at 70Hz.

The rest of the tones seem smooth going upwards.
 

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Discussion Starter #16
I'll assume you have the H model which is 8 ohm. Ported would require a hi pass filter at 35 hz, sealed would require a hi pass filter at 30 hz. Ported would give good output down to 30 hz for soundtracks and music.

View attachment 17748
Is that the best it will do and would it not also be possible that 20Hz will be manageable at lower SPL db. I’m not looking to break world SPL db records, I prefer smooth tone that doesn’t colour the spectrum.

Cheers

Besides from making a few calls around (local) to find a UK suppler. Does needle in haystack meaning anything? Even they where baffled one called it (shuttering) which is miles off from the name its been called on the sub bass projects.

Would this be under any other name worldwide?
 

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Discussion Starter #18
I found a UK supplier its Rapidobat
http://www.forsite.co.uk/rapidobat.html

I got this info, on similar thread from member, on the Lansing Heritage Forums, as I like to get multiple views on this subject from both sides.

The cost for x2 10 feet tubes is £130.00 if I buy now, its charismas I’ll have to wait! Waiting will only bump the price up a few bob, due to VAT rise in January to £135.00 not too bad its only £5.00.
 

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Discussion Starter #19 (Edited)
20 hz can be done at the expense of overall output. Shown with 80 watts input and a hi pass filter at 18 hz. Two 4" ports 13.5" long would handle the porting.

View attachment 17797
I know what you mean by that as I have noticed this issue with my large JBL sub and looking at most other members threads on this site at the numbers in the (SPL db VS frequency)

I’d sooner use less power which I have done recently.

Only thing is the DCX2496 doesn’t go lower than 20Hz for selecting a 18Hz HP filter it’s near enough, LOL.

What about (chuffing port noise) issues have any members reported this issue with this type of sub bass project?

The length is now an issue! The room is mostly taken up at the front with speakers! The TV and JBL sub stick out the furthest.

In 15 foot room this now leaves me with only 13 feet and it wouldn’t like nice with two 13 footers placed ether side. LOL

10, foot I’m willing to go with. The diameter of the tube does it not have to be the same as the bass bin diameter?

So the inner tube that goes down the centre of the tube for turning has to be 4inchs!

Arrr, right I see where you’re going with the ports. The part that attaches to the end of the tube the base part, has to have cuttings for (four holes for the four port tuning ports).

I just doodled a little drawing.

Cheers for the help on this greatly appreciated.:T
 

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10, foot I’m willing to go with. The diameter of the tube does it not have to be the same as the bass bin diameter?
I'm assuming you will have one driver per tube. The drivers are 15", they would fit in a 18" diameter tube. 270 liters would be a 50" length of 18" diameter tube. Here's is a program that will calculate the lengths you need.

http://www.subwoofer-builder.com/sonosub.htm

The porting can be two 4" diameter ports or one 6" diameter port, which ever is easier for you.
 
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