Advice on building Dual Sonotubes?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi all,
New to the forums and pretty much a complete noob when it comes to subwoofer specs, graphs, modelling, etc... I've been doing what reading I can, but I need a bit of help on where to get started.

So, a bit of background. I've been looking at replacing a 20+ year old Paradigm prd-10 I've been using as a bandaid in my hometheater setup for the last few years. I had been looking at the PE ultimax 18 kits for quite awhile, but they were either out of stock when I was ready to build or I didn't have the time/patience to build when they were available. a couple weeks ago, after much discussion on AVS forum, I had decided to go with a single SVS PC4000 (and eventually going dual with a second one or a PB3000/4000, either of which SVS told me would match perfectly with the PC4000). My budget for subs took a bit of a hit when I decided to upgrade my theater seating, so I'm looking hard at the dual ultimax 18's again(which I could put together for almost half the cost of a single PC4000). I would have already ordered the kits from PE, but I've got a pretty big room (long and narrow, but still 6500 Cubic feet) and primarily do movies with my setup, so I really want to go ported. I was settled on the PC4000 because the cylinder offered up a lot more placement options for me. Only thing biting me was the price.

Last night I got to thinking, "could I possibly build a clone of the PC4000, using one of the ultimax drivers?" That's when I came across sonotubes and started to realize it'd be even cheaper and easier for me to put together my own cylindrical sub than one of the PE kits. Now I'm just trying to decide which driver amp combo I want to go with and finalizing the specs.

Building and finishing the subs themselves isn't much of a problem, but I am fairly lost at designing, modeling, and tuning them (After they're built I plan to have a Behringer NX3000dsp or NX6000dsp driving them and supplemented with Dirac Live correction provided by my Nad t758 v3 receiver).

Right now I'm looking at trying to build a tube close to the same size as the PC4000. I can easily drive a few miles down the road and grab a couple of 16" ID x 4' tubes (which would match the PC4000 dimensions pretty close). If I do this, I would be looking at going with the 12" ultimax or the 15" ultimax.

Running the sonosub calculator, the 12" recommended optimal volume would match the volume of a 16"x4' tube pretty dang close with zero cutting of the tube needed. All I'd have to do was cut some mdf endcaps (out of boards I already have) add some finishing work and call it good. I figure I could put each subwoofer together for in the neighborhood of $250 max. Combine that with a NX3000dsp (or would the extra overhead of the NX6000dsp be better?) and I would be at less than half the cost of a single PC4000 with probably pretty equal performance.

Option 2 would be to fit a 15" ultimax in the above enclosure. It would be tight (but doable), but I don't think I'd be able to match the internal volume need that well. I'm not sure, but I think it would put me at the bare minimum needed for a ported enclosure. Thoughts?

Option 3 would be to special order an 18" ID x 12' tube and cut it in half. This would add about $10 per sub enclosure (maybe more due to my spare mdf not being wide enough, so new board needing to be purchased and some extra fiddling to get a nice level cut on the tubes) but would allow me to build a 6' tall sub that matched up well with the 15" ultimax.

Option 4 would be to go for a 22-24" ID tube and pair it with either the 15" or 18" ultimax and aim for a height of around 4'.

4' would be the ideal max height for me (allowing for the most placement options). Based on that, what would your recommendation be for me on the driver and ID to go for?

I've been looking for anyone who has done similar builds in the past, so that I'd had something to build from, but really haven't found much that's fit the bill... or at least provided feedback on their performance after having built them.

I'm very confident I can build them, but if someone could really just help me nail down the specs/dimensions, I'd really appreciate it.

I've attached a sonosub calculation of a 24" x 48" enclosure for an 18" ultimax alongside PE's data for optimal vented enclosure. It seems to match up pretty dang close from what I can gather. That being said I have no idea what tuning frequency I should be aiming for, nor do I know what I'm doing with the ports (Right now I have it set for 3 pvc ports. No clue what would be ideal for this). I also have no idea what it means (or if it's good/bad) by having the first port resonance at 549hz or driver to box top resonance at 146hz. Are those numbers good? bad? What, if any, changes should I be making?

attachment.php


Any help would be super appreciated. Thanks! :)
 

GM

Member
Joined 2003
Greets!

Link is invalid..........

Anyway, when pipes get to be near room height it really energizes the room, but if 4 ft is an overall better solution, then go with it and however big around it has to be to get the desired net volume [Vb].

Driver wise, the one with the most swept volume [Vd = Sd*Xmax] and lowest Fs that you can afford unless you choose to limit it to the THX 20 Hz tuning reference, driven with an amp that has sufficient power/crest factor to meet your SPL requirements at low distortion, which would normally be 115 dB/listening position [LP] or more if running the surrounds, CC in 'small' mode.

Since 'we' don't yet know what driver you wind up with nor how low you want to go at 'x' SPL, can't speculate on amp, vent requirements.

GM
 
Hey, sorry it took me awhile to get back to you. I've been doing some more research and learning this last week, including fiddling around with winisd. I'm still pretty clueles on what I'm looking at on most of the graphs, but I think I'm closing in on something that might work.

My room layout is a bit challenging in that it is fairly large (6300 cu ft), but only 12.5' wide... so also narrow. It's on a second floor so has the unfortunate aspect of having sloped ceilings on both sides. the side walls go up to right at 56" before angling towards the center of the room at about 50 degrees. Due to this I'm pretty limited on height. I'd say right at 56" for 24" tube and maybe as much as 60" for a 16".

I know my room would do better with 18's, but after really playing around with the configurations, I just wouldn't be able to fit them anywhere in my area.

The 12" in a 16" tube is what I am looking at and have been playing with this week and is what I'm seriously considering right now. I can also source 16" x 48" tubes locally. I could special order bigger tubes, but I'm looking at mid to late march as the earliest arrival and that puts me in a real bind as far as actually having the time to put them together due to it being one of my really busy times of year.

So... Right now I'm really looking hard at the Dayton UM12-22 12" Ultimax in a 16"x 48" tube. I was aiming for a tuning of 17 hz, but I needed a bit more height than a 48" tube could provide, so I raised it up to 20hz. Some people might be able to tell the difference, I've made peace with the fact that I'm probably not one of them, so I think it's a fair compromise to keep my tube where I want it. :) As far as SPL goes, I really have no idea what to shoot for. I'll include the winisd graphs I came up with below (not sure why the last one didn't show). I mainly watch movies with my setup and I like it loud, though I don't often have it that loud. I don't really need wall rattling, wake the neighbors bass. A nice tight response with a little kick to the chest on explosions, would keep me happy. I don't like it overly boomy, and I definitely want to avoid any port noise. I was going to get the NX6000d to drive them, but since I'm looking at building the 12's I'll probably go with the much better matched NX3000d.

Before I throw the graphs up I'll write out the key stats, just in case the images don't work again.
From Sonosub:
Effective volume: 4.76 cu ft
Tuning: 17hz
ID of Tube: 16"
ID of Port: 4" x2 (it's given me the best results in winisd, from what I can tell) Flared 3/4" on both ends
Height (endcap to endcap): 49.5"
Port Lengths: 33.27
Gross volume: 5.4 cu ft
Estimated weight: 75 lbs
Total height (with floorplate): 53.5"
sonotube: 48"
Effective port length: 32.52"
first port resonance: 208hz
boxtop resonance: 142hz

From Winisd
HPF: set at 18.8hz
System power: 599.5 W
Port Air Velocity: 21.87 m/s @18.95hz
Cone Excursion: 18.815mm @15.55hz (xmax = 19mm)
SPL: Shows max around 111.5dB @39hz. falls below 110dB @21hz

That's about all I've got for now. How does it look and is there any other graphs I should be looking at or trying to get data for? I'm not hard set to the 12" ultimax, so if there are any other drivers you can think of that would fit in the enclosure size I'm shooting for that hit a little harder and louder, I'm definitely willing to give them a look.

Images should be attached below... I hope. :D
 

Attachments

  • driver and sonosub datajpg.jpg
    driver and sonosub datajpg.jpg
    260.9 KB · Views: 35
  • box.jpg
    box.jpg
    124 KB · Views: 36
  • vents.jpg
    vents.jpg
    116.4 KB · Views: 30
  • filters.jpg
    filters.jpg
    104.6 KB · Views: 33
  • Signal.jpg
    Signal.jpg
    122.2 KB · Views: 31
  • advanced.jpg
    advanced.jpg
    125.2 KB · Views: 30
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.