You're gonna love this.... Greek Column Sonosub!

[chasw98]

A friend of mine was over the house this weekend, heard my system, and commissioned me to build a sub for her. But, she has a "Greek" theme in her living room where the sub will be going and wants it to look an ancient column like you see at the Acropolis. She would like it to go floor to ceiling, but I told her that the port needs room to breathe. She said OK, "How much room?". I haven't ever thought of this before but how much room does a port need to breathe? Off the top of my head, I guessed that I could build it 8 feet overall and leave 1 foot, 3 inches of room at the top (ceiling is 9'3" tall). Any ideas?

Chuck

[Carl V]

generally you want the 'breathing room" to be about equal to the diameter of the port. That being said, no reason why your port has to be at the end of the Column. Consider making the Doric, Corinthian or whatever capitals & pedestal part of the port's breathing room area. There are many sources for archtectural Columns. Hollow and otherwise. The pedestals all have recesses near the floor ostensibly for moisture control but which would serve for breathing. I've done surround speakers in Columns before, as well as the LCRs. Hire someone to do the faux marble finish and they look killer.

Oh & you should also be aware that a tall skinny sonosub will exhibit some pipe resonaces. A little math, geometry & acoustics will tell you at what length & diameter a standing pipe resonace will occur.
There is a reason why SVS only made 41" tall subs....
why some of us made EBS subs with 18" or greater
diameter sonotubes.

[chasw98]

Right now I am looking at 16 inch diameter by 90 inches tall with a 16 Hz tune which would give me a 24 inch X 6 inch port. I will be using a Soundsplinter RL-p15.

[---k---]

Wait,

I'm confused.

A chic wanting a subwoofer??? :huh:

Of course, that brings up the next question, chics hanging out with Chuck? :huh: :huh:


:B

[chasw98]

Wait,

I'm confused.

A chic wanting a subwoofer??? :huh:

Of course, that brings up the next question, chics hanging out with Chuck? :huh: :huh:


:B

Ummmm, she is a model who just got back from Cannes where she spent 6 weeks on a 150 foot yacht. Next you'll want a picture.

[SteveCallas]

A 15" driver with a 16" diameter tube? How's that going to work? Also note Carl's point, for a given diameter, you only want to go so tall. Seems both SVS and I used a 2.5/1 length to diameter ratio.

[Amphiprion]

You're putting a standing wave resonance right in the passband of the sub with H=90", assuming an 80Hz crossover...

[chasw98]

A 15" driver with a 16" diameter tube? How's that going to work? Also note Carl's point, for a given diameter, you only want to go so tall. Seems both SVS and I used a 2.5/1 length to diameter ratio.

A 15 inch driver will sit in the base of the column which will be approx. 20 inches square narrowing down to 18 inches square as it hugs the sonotube. There will be (or she wants) molding around the square sections of the column at the top and bottom. This is all very preliminary and I am not even sure it can be done with so small a diameter. As you know, I can build, but I am short at design. Which is why I am here. Let me get back to the drawing board and come up with plan b.

[ThomasW]

Ummmm, she is a model who just got back from Cannes where she spent 6 weeks on a 150 foot yacht.

Oh right and you expect us to believe you know someone like that.... :B

Next you'll want a picture.

Yep and no technical assistance until you produce one.... :lol:

[Bent]

In fact, if you don't put up a "technical diagram" within 24 hours, I'm gonna post a picture of me B-B-Qing in a speedo in the rain.

[chasw98]

OK, here she is in her underwear.



This is a family oriented forum, right? No off color postings, correct?

[chasw98]

Tell me if this feasible. Using the 2.5/1 ratio for height to diameter, a 20 inch tube would allow for 50 inches tall. If I took a 20 inch tube and mounted a "plug" at the desired height in a, say 80 inch tall tube, the internal volume could be adjusted to what I needed for the driver to perform. The port which would be approx 27 inches long could be mounted on top of the plug and rising to the 80 inch height of the tube. The port would, in effect, be mounted external to the enclosure that the driver would be mounted in. Will this work?



The total height could close to 90 inches, yet the internal volume the driver "sees" would be appropriate for the specs. What do you think?

Chuck

[Carl V]

That ought to work....cleverly camoflauged Stove Pipe. :T

[ThomasW]

That's fine if she's willing to live with a piece of 20" diameter tube.

Are you planning on using a 3rd 'cap' at the top?

[chasw98]

That's fine if she's willing to live with a piece of 20" diameter tube.

Are you planning on using a 3rd 'cap' at the top?

She specifically asked for a floor to ceiling column anywhere from 16 to 20 inches in diameter. I knew it could not go to the ceiling (9 foot tall) because the port had to breathe and she said OK. For a "cap" on top, I will be making some sort of Greek column looking, crown molding thing. Haven't worked that part out. Got some ideas though. The bottom cap will also resemble a greek column thing also. Something like a Doric style here: http://www.crown-molding.com/index.a...S&Category=267
I just wanted to get the design down first and worry abiout the looks second, but the esthetics are important to her.

[chasw98]

That's fine if she's willing to live with a piece of 20" diameter tube.

Are you planning on using a 3rd 'cap' at the top?

PS, you got your picture, now your helping, huh???? Thanks. :T

:rofl: :rofl:

[seattle_ice]

Is the column viewable 360 degrees in the room? Or could you take it to the ceiling and have an open slot on one side that would not be (mostly) visible?

[chasw98]

Is the column viewable 360 degrees in the room? Or could you take it to the ceiling and have an open slot on one side that would not be (mostly) visible?

The column will be up against a wall so only 3 sides are visible.

[Dennis H]

I think the logic for not having long tubes is to avoid standing waves. But stuffing works well for that too. If you filled the area around the port with fiberglass, you'd have a 1-2 feet of stuffing and that should be plenty to kill any standing waves. As long as you don't have any stuffing between the port and the driver, it should work fine. It should model as a slight decrease in Qa but it shouldn't affect Qp.

Bottom line, if it were me, I'd go ahead and build it tall and skinny.

[ThomasW]

Bottom line, if it were me, I'd go ahead and build it tall and skinny.

:agree: Am I helping now?.... :B

https://web.archive.org/web/20070513035245/http://www.fiberglasscolumns.com/suggested_combinations_round.html

[chasw98]

:agree: Am I helping now?.... :B

https://web.archive.org/web/20070513...ons_round.html

Yes, oh yes, you are! Thanks.

When Dennis says go tall and skinny, how skinny. Could I get away with a 16 inch diameter tube? I will have enough area to mount the driver in at the base because of the build up of the column base. 9 cubic feet of volume with allowances for driver and port will end up being approximately 80 inches, which would be very satisfactory.

[SteveCallas]

Chuck, just a thought.....what if you used something like that Corinthian column top with fancy curled legs holding up a top plate with some final decorative molding on it? The space between the top plate and port would be open except for the legs - you could get several inches of breathing room and the legs could be pretty thick without impeding air flow, so it would still look somewhat solid.

[ThomasW]

You don't really need 15" for the port, 6" would be plenty depending on the 'capital' you use.

For the base use something with feet that gives plenty of opening between them.

If you're careful and use BB ply instead of MDF for the endcaps, you could probably get away with 16" tube, otherwise go with 18" (I'm assuming you have access to these sizes. The bigger tube suppliers carry sizes every 2")

To do this I'd cut the endcap (no driver hole) install it, cutting the driver hole last. That way you'll have the support from the tube available to help prevent breaking/splitting the narrow section of wood.

With 16" tube and the RL-p opening ~14" you'd only have 1" to play with, so I'd make the cap thicker than usual.

The base could of course be designed as a structural element to reinforce the endcap if you go with the narrower tube.

[Dennis H]

Often those columns have a square base and cap above/below the decorative end elements. You could run the whole structure from floor to ceiling as at should be for a real column. The square top/bottom thingies could be wood with big holes on all 4 sides and cover the sides with grill cloth to match the color of the column.

[ThomasW]

You could run the whole structure from floor to ceiling as at should be for a real column.

Hows he going to tip it to an upright postion in her room?

If he goes a bit shorter, he can slide the capital in place after getting the tube upright. So an 1" or 2" shorter than the wall height might be a good compromise.

Or he could create a way to raise the tube against the ceiling, then shim the base with the legs or something.....

Anyway just thinking out loud, dangerous, I know...:wink:

[chasw98]

Steve:
Chuck, just a thought.....what if you used something like that Corinthian column top with fancy curled legs holding up a top plate with some final decorative molding on it? The space between the top plate and port would be open except for the legs - you could get several inches of breathing room and the legs could be pretty thick without impeding air flow, so it would still look somewhat solid.

I would not really need to put a top plate on the tube, just mount the decorative column top thing that would allow the port to be open to the air.

Thomas:
You don't really need 15" for the port, 6" would be plenty depending on the 'capital' you use.

Yes, I am planning towards a 6 inch port.

Thomas:
For the base use something with feet that gives plenty of opening between them.

If you're careful and use BB ply instead of MDF for the endcaps, you could probably get away with 16" tube, otherwise go with 18" (I'm assuming you have access to these sizes. The bigger tube suppliers carry sizes every 2")

To do this I'd cut the endcap (no driver hole) install it, cutting the driver hole last. That way you'll have the support from the tube available to help prevent breaking/splitting the narrow section of wood.

With 16" tube and the RL-p opening ~14" you'd only have 1" to play with, so I'd make the cap thicker than usual.

The base could of course be designed as a structural element to reinforce the endcap if you go with the narrower tube.

I have access to all sizes of tubes locally. I understand what you are saying when going with smaller diameter tubes and chewing up the wood. I think 18 would be the smallest I would want to go, but I am still mulling it over in my mind. I need to find someplace that would sell these types of architectural bases and caps so that I could see them in person and find out how they are made physically, openings, ability to modify, etc. Otherwise I would design and build my own base and cap. Yes, I plan on using the base as a structural element to hold this upright and provide a solid platform.

Dennis:
Often those columns have a square base and cap above/below the decorative end elements. You could run the whole structure from floor to ceiling as at should be for a real column. The square top/bottom thingies could be wood with big holes on all 4 sides and cover the sides with grill cloth to match the color of the column

This would be ideal. I just don't know where to go and find this stuff so that I could hold it in my hand and see and talk to the people that make them so that I would know I was buying something right for the job the first time. So far, I have not investigated local suppliers that offer architectural columns. That is on my list. I wanted to get my design parameters in order first (height, diameter, port length, port diameter, etc.) so that I would have a starting point from which to approach hanging or building in this column stuff to it. Lots of great ideas and some legwork needed on my part to pull it all together.

[ThomasW]

I think 18 would be the smallest I would want to go, but I am still mulling it over in my mind. I need to find someplace that would sell these types of architectural bases and caps so that I could see them in person and find out how they are made physically, openings, ability to modify, etc. Otherwise I would design and build my own base and cap. Yes, I plan on using the base as a structural element to hold this upright and provide a solid platform.

All the bases/caps are cast, either plastic, plaster, structural foam, or alu.

The 16" could be done and might look best. Here's the idea.

Make the endcap/insert flush with the end of the tube. Then fab a larger outside 'collar', sized to the OD of the tube. The driver end of the tube should sit inside this collar a couple inches. When glued and screwed in place this will be 18", 20", or whatever in diameter, this will give you a virtual endcap that size. With this construction in place there's plenty of support to make a ~14" hole in 16" tube.

[chasw98]

All the bases/caps are cast, either plastic, plaster, structural foam, or alu.

The 16" could be done and might look best. Here's the idea.

Make the endcap/insert flush with the end of the tube. Then fab a larger outside 'collar', sized to the OD of the tube. The driver end of the tube should sit inside this collar a couple inches. When glued and screwed in place this will be 18", 20", or whatever in diameter, this will give you a virtual endcap that size. With this construction in place there's plenty of support to make a ~14" hole in 16" tube.

OK, this sounds good. This is workable and I think will be best for the "look" I am trying to achieve. I can also build this without much of a problem and it will look column-like. She can choose a capital from a catalog that will fit 16 inch diameter.

Now, WinISD tell me that for a 7.75 cu feet and a 16 hz tune, a 35 inch port is needed. This will put the total height very near to 9 (68" for tube and driver, 6" for base plate and feet, 35" for port = 9.08') feet tall which is her ceiling height (actually 9' 3"). This is based on the port being mounted outside of the tube as I refered to back in an earlier post. The 2.5 / 1 ratio is definitely being exceeded. How will it sound, how would you deal with this? Obviously, the exact numbers can be juggled a little bit so that it will fit in the room, etc.

Dennis says to use stuffing " If you filled the area around the port with fiberglass, you'd have a 1-2 feet of stuffing and that should be plenty to kill any standing waves. As long as you don't have any stuffing between the port and the driver, it should work fine.".

[ThomasW]

She can choose a capital from a catalog that will fit 16 inch diameter.

Now, WinISD tell me that for a 7.75 cu feet and a 16 hz tune, a 35 inch port is needed. This will put the total height very near to 9 (68" for tube and driver, 6" for base plate and feet, 35" for port = 9.08') feet tall which is her ceiling height (actually 9' 3"). This is based on the port being mounted outside of the tube as I refered to back in an earlier post. The 2.5 / 1 ratio is definitely being exceeded. How will it sound, how would you deal with this?

Dennis says to use stuffing " If you filled the area around the port with fiberglass, you'd have a 1-2 feet of stuffing and that should be plenty to kill any standing waves. As long as you don't have any stuffing between the port and the driver, it should work fine.".

Finding a 16" cap maybe problematic that's a pretty big. Most of the readily available ones are much smaller since they're designed for the front of a house not an office building.

Know anyone with a large diameter wood turning lathe?

With her tall ceilings, the 16" should look good as far as 'scale' is concerned.

What's WinISD? ......:wink:

This place is interesting to shop for ideas. They're to architectural products what McMasterCarr is to hardware. And their free catalog makes for a great reading when attending to matters of state.... :B

http://208.245.181.35/cgi-bin/worderc?confc=B2C

Randon thought....you might look at structural foam ceiling medallions to be used as a part of the cap. These are sold in the big box stores in the diameter you'd need. And they're easy to cut with standard woodworking tools.

[SteveCallas]

Chuck, the 2.5/1 ratio I mentioned isn't any particular limit, just an observation that I made about SVS's and my tube subs.

For clarification on the parameters, are you going to be using a dual 2ohm version powered by an EP 2500?

[chasw98]

Finding a 16" cap maybe problematic that's a pretty big. Most of the readily available ones are much smaller since they're designed for the front of a house not an office building.

Know anyone with a large diameter wood turning lathe?

With her tall ceilings, the 16" should look good as far as 'scale' is concerned.

What's WinISD? ......:wink:

This place is interesting to shop for ideas. They're to architectural products what McMasterCarr is to hardware. And their free catalog makes for a great reading when attending to matters of state.... :B

http://208.245.181.35/cgi-bin/worderc?confc=B2C

Randon thought....you might look at structural foam ceiling medallions to be used as a part of the cap. These are sold in the big box stores in the diameter you'd need. And they're easy to cut with standard woodworking tools.

16" caps here http://www.crown-molding.com/index.a...ROD&ProdID=611 but expensive.

WinISD is a modeling program, primarily for subwoofers, that will help you figure what it will be before you do it! :P

Just went there and ordered a catalog. Cool place. They must have something I need!

I'm not too worried about the capital at the moment because I don't know how fancy she wants it to be. Simple Tuscan, I can build, Corinthian she can have made or buy. I have to be reasonable, ya' know.

And here are some simple 16" units I have found. http://www.crown-molding.com/index.a...ROD&ProdID=611

[chasw98]

Chuck, the 2.5/1 ratio I mentioned isn't any particular limit, just an observation that I made about SVS's and my tube subs.

For clarification on the parameters, are you going to be using a dual 2ohm version powered by an EP 2500?

Yep, I'm gonna use the tried and true classic of the moment. RL-p15 D2, EP2500, BFD. Can you check my modeling for 7.75 cu feet in a 16 inch tube and 35 inch port length, 6 inch diameter for a 16 Hz tune? Thanks.

[SteveCallas]

33-35" should do it, I'm showing right about 34" even. Though not a big difference, anyway you can bump that thing up to about 8.125 effective cubic feet and then use a 35" long 6" port, or am I asking for too much? :lol:

[chasw98]

33-35" should do it, I'm showing right about 34" even. Though not a big difference, anyway you can bump that thing up to about 8.125 effective cubic feet and then use a 35" long 6" port, or am I asking for too much? :lol:

More, more. Hurt me, hurt me! ;x(

[jonathanb3478]

More, more. Hurt me, hurt me! ;x(

I've read that poor self esteem causes this issue.

Quick!!! How do we improve his self esteem?!?!

[SteveCallas]

Quick!!! How do we improve his self esteem?!?!

Well it looks like he did a great job on his Dayton TMWW's :T And I'd pat him on the back and give him a "Great job" if he decides to bring them to Jon's place so I can compare them to my speakers :B

[Dennis H]

Esteem? Heck, who was begging whom for pictures of the client? Chas rocks!

[chasw98]

Well it looks like he did a great job on his Dayton TMWW's :T And I'd pat him on the back and give him a "Great job" if he decides to bring them to Jon's place so I can compare them to my speakers :B

I want to bring them to Jon's place. We just have to organize! With some lead time.....

Esteem? Heck, who was begging whom for pictures of the client? Chas rocks!

Like Ryan said: "A chick wanting a subwoofer!" No WAF involved here.

[ThomasW]

Esteem? Heck, who was begging whom for pictures of the client? Chas rocks!

The request for photographic proof was to make sure Chuck wasn't trying to pull as fast one on us as an excuse to build a 'girlie' sub....

[jonathanb3478]

He does seem to have snapped out of it. Maybe all it took was SteveC's virtual pat on the back and "Great job".

[chasw98]

OK, I have a plan! Here is a crude drawing (not to scale) of the base of the column.



As Thomas suggested, there will be inner circles to bolster the strength. The circular ring will be 18" in diameter while the square portions will be 22" in diameter. The legs will be 4 1/2" tall.

The top of the tube will be just one layer inside the tube and one layer outside the tube flush with the 16" diameter. That way, whatever goes on top, whether I build it or she buys it, can be set in place and attached to a 16" diameter. Here is an example of what is available.



This capital came from Pacific Columns located here https://web.archive.org/web/20230401...als_empire.php .

I have worked out 6" of exposed base at the bottom and a tube 7 1/2' tall will leave approx. 15" clearance to adorn the top. Will it fly?

[Greybeard191]

a couple of thoughts...

1) Have the decorative greek flange at the top sit on the outside of the sonotube and be able to slip up and down. That way you can get the thing standing upright easily... you'd need varying amounts of 'slippage" depending on the diameter of the tube/decorative flange. A handful of screws covered afterwards with plugs should hold everything in place.
2) slot the back of the flange where it can't be seen as exhaust for the port. You could bend the port to meet with the slot, but bent ports probably are an acoustic compromise. On the other hand, a slot in the back of the decorative flange is probably going to act as some kind of extension to the port anyways, unless the exhaust area is reasonably large in comparison to the port area. You'll want to keep the port exhaust well away from the flange (centered), and make the slot as large of aesthetically possible.

GB

[ThomasW]

I have worked out 6" of exposed base at the bottom and a tube 7 1/2' tall will leave approx. 15" clearance to adorn the top. Will it fly?

Yep I think so... :T

Now you just need to take one of those classes in faux-finishing so everything will look like real marble. Then get a get spot on the Martha Stewart show. Not long after that you'll have started a revolution in interior decorating with high performance subwoofers..... :B

[chasw98]

Graybeard:
1) Have the decorative greek flange at the top sit on the outside of the sonotube and be able to slip up and down. That way you can get the thing standing upright easily... you'd need varying amounts of 'slippage" depending on the diameter of the tube/decorative flange. A handful of screws covered afterwards with plugs should hold everything in place.

My thoughts exactly.

2) slot the back of the flange where it can't be seen as exhaust for the port. You could bend the port to meet with the slot, but bent ports probably are an acoustic compromise. On the other hand, a slot in the back of the decorative flange is probably going to act as some kind of extension to the port anyways, unless the exhaust area is reasonably large in comparison to the port area. You'll want to keep the port exhaust well away from the flange (centered), and make the slot as large of aesthetically possible.

I am not going to complicate it. I have told her that the port needs room to breathe and that's that. But if she buys that decorative capital there is a bit of airspace around it for port fumes to escape!

Thomas:
Now you just need to take one of those classes in faux-finishing so everything will look like real marble. Then get a get spot on the Martha Stewart show. Not long after that you'll have started a revolution in interior decorating with high performance subwoofers.....

I respect your intelligence immensely but lately I am starting to wonder. First, you want a picture to make sure I am not building a "gurlie" sub, now you want me on "gurlie" TV. ops: I can't wait for your next idea.... ballet, anyone? I plane on painting it gray and handing it off to her. She had the other columns in her place painted by someone, so they can do it. That's not the fun part anyway.

[ThomasW]

I respect your intelligence immensely but lately I am starting to wonder. First, you want a picture to make sure I am not building a "gurlie" sub, now you want me on "gurlie" TV. ops: I can't wait for your next idea.... ballet, anyone?

Nope just thinking you could revolutionize the SAF/WAF issue with the concept (it is a very clever idea.... :T ). So just trying to help you get your 15 min of fame....:wink: