Questions about DIY Sonotube subs.

[slayer]

At work last night, UPS, a couple SonoTubes rolled through. This is the first time I've seen one up close. I thought they were thicker. They sound really thin with the knock test.
My questions are these.
Of the DIY subwoofer designs on this site, are the SonoSubs the best performing?
If so, what design stands out as the best.
Is there anything done to the tube itself to strengthen it from flexing?
Thanks for the help. I am considering doing one to replace another sub in my system to free up a bit of floor space. It sits behind my couch in a corner and the Sono setup would tuck into the corner better.

[SteveCallas]

Of the DIY subwoofer designs on this site, are the SonoSubs the best performing?

The enclosure shape doesn't affect performance - x volume is x volume whether cylinder or box.

Is there anything done to the tube itself to strengthen it from flexing?

What diameter tube did you get, and what is the wall thickness? It shouldn't flex much at all to begin with, and when you put the end caps in place, it won't flex period.

What is your budget? There are capable 15" drivers currently available in most price ranges.

[slayer]

I did not get any tube. I had just seen some being shipped at my work place. UPS.
Not sure of the size, guessing around 18" diameter. Do they come in different thicknesses? I'm concerned with the cost. I'm looking for the best proven design to look at building. Enclosure, driver... I will use a Velodyne SMS-1 as an EQ for it and the amp is still in the air as far as what one I will use.
Is there a design on these forums that most consider as the best? I want it to play very low for HT.

[SteveCallas]

Yes, Sonotube of a given diameter does come in different wall thicknesses.

A "best" design will probably vary from person to person. Do you have any idea of what listening levels you are aiming for? And any idea of how low you want to extend?

[slayer]

Well, it depends on what is reachable with these designs. My mains play full range and begin to dip around 45hz. To get the best response in my room, using the Velodyne SMS-1, I have my subs playing from 65hz down. I can reach 110db pretty easy from 30hz up. From 30hz down it starts to drop very fast. I am still close to 100db at 20hz but it drops fast from there. I want to be able to extend below 10hz at over 100db levels.
Is this too much to ask or not enough? I have read people saying they get a flat response down to around 5hz. What are realistic #s?

[Dennis H]

Is there anything done to the tube itself to strengthen it from flexing?

Ah, that's the beauty of a cylinder. It can't "flex" without expanding the whole cylinder. A flat panel is supported on the ends and it doesn't take much pressure to bend it a little in the middle. But a cylinder can't bend, only stretch. That's why air, propane, etc. tanks are cylindrical, not square. Suffice it to say, sonotube is hella stout. Think how much pressure there is on a sonotube when it's doing its intended job. A form for a tall column will be holding several tons of concrete without bursting. The fraction-of-a-psi pressure a sub exerts is nothing compared to that.

[SteveCallas]

Well, it depends on what is reachable with these designs

Anything is possible with enough space and enough money.

I want to be able to extend below 10hz at over 100db levels

Fair enough, but consider this - for you to get anything perceivable at 10hz using real material and not sine waves, your response is going to have to at least be flat to 10hz or have a house curve that boosts the extreme low end. So with that said, making 100db at 10hz a goal is going to be kind of pointless if your sub can do 115db levels above 20hz. And since you already have the capability to do 110db from 30hz on up easily, you wouldn't want to build a lesser sub, so your "real" goal would be 110db+ flat to 10hz, if I am interpretting you correctly.

It can be done no doubt, but what is your budget and do you have size constraints?

[ThomasW]

. I want to be able to extend below 10hz at over 100db levels.
Is this too much to ask or not enough? I have read people saying they get a flat response down to around 5hz. What are realistic #s?

No problem, just pay the $12K price of admission and here's the sub for you....Bruce Thigpen's rotary sub....... :T

[slayer]

110db+ flat to 10hz would be great. That would be plenty low and with enough headroom for movies. I believe my usual listening level for movies is in the 78db - 85db range. The sub is usually calibrated a bit higher.
Not sure what my house curve is. Is there a formula to figure it out?
Budget would be around $600 not including finish. So materials and driver. I might consider a JL W13 if it would be good for the design.

[SteveCallas]

You're not going to get that for $600. For that amount just go with a RLp15 D2 in ~265 liters with a 6" diameter port that is between 28-33" long, many have used that design or something similar to it with good results. Give it 600-1000 watts.

[ThomasW]

110db+ flat to 10hz would be great. That would be plenty low and with enough headroom for movies.

And ice would be nice for people living in the Sahara....:wink:.......You can get there but it's a pipe dream unless you drastically increase the budget.

[slayer]

I figure the sub would be around $500 and materials another $100. I already have plenty of MDF for a project so I assume all I need is the Sonotube and port material.
What am I missing?
BTW, an amp is not included in this budget.

[ThomasW]

What am I missing?

The extra $1000-$2000 more you'd need for drivers, plus the cost of 2 or 3 or 4 Crown K2 amps. If you really want to reach 110dB @10Hz

[SteveCallas]

Lol - I like this thread :B

To ground your performance expectations a bit considering your budget, look at the subs created by w8liftr, nick77, HMenke, chasw, ssabripo, etc.

[slayer]

Were can I find theirs?

[ThomasW]

Were can I find theirs?

Cut and paste those user names (individually) into a search of the DIY Mission Impossible forum. You'll find that this forum has an excellent search engine.....

[SteveCallas]

Beat me to it - all of those members are in this forum.

[slayer]

I guess a flat resonse to 10hz at about 95db would be a better goal. Or not. I just want to get the lower octaves I'm missing with my current setup. It's not the insane db I'm concerned about, the the ability to play the low stuff at a good level so I can truly enjoy some of the great movies out there. What are some great drivers out there for say $400 - $600?
I mentioned JL because I can get them at dealer cost. I can also get some custom Alumapro drivers that are made for California Audio Technology(CAT).

[ThomasW]

How about forgetting 10Hz performance since is it's indistinguishable from 15Hz?

If you want to use JL drivers then we need to see some specs. They aren't something I know much about. I know some people have used them for home audio.

What are some great drivers out there for say $400 - $600?

Simply looking at the treads from the people listed above, will tell you what drivers we recommend.

[SteveCallas]

slayer, I'm 99% certain you could put good headroom in the 20-80hz range to better use than 95db capability to 10hz. Like I said before, you're only going to be able to perceive anything from ultra low frequencies with actual material if your frequency response is flat or rising to that frequency, and you don't want to limit yourself to 95db in higher frequencies.

In your budget range, you can get still get low, clean, and loud, definitely a lot better than your old sub (you have a 10db drop from 30-20hz), but don't obsess over 10hz. If you are willing to spend $600 on just the drivers, take a look at Steve nn's dual RLp15 box with a 10" port or w8liftr's dual RLp15 sonosubs - either one will give you a bass experience in another league from what you seem to be capable of doing now.

[---k---]

Were can I find theirs?

Also make sure you check the Mission Acomplished forum and the DIY Subwoofer Showcase thread.

(OT, I'm starting to miss some of the stickies. I usually just visit this forum only. )

[slayer]

I posted a pic of the other sub I built in the sub showcase thread above.

[slayer]

BTW, thanks for the help guys. I will keep picking your brains until I come to a design that sounds good. This is a great forum for DIY.