Calculate enclosure for 15 inch sonotube...again

[chasw98]

My first post here. I have a BFD, an EP2500 amplifier, and a 10 yr. old Klipsch 10 inch 150 watt sub. The Klipsch doesn't cut it any more. I want to buy a 15 inch driver (RL-P15, Tempest 15D4, AV15, Titanic MK III, Oaudio TC2, or AA 15). I want to put it into a sonotube type enclosure. Where is the best place to start to calculate internal volume, and port diameter and length. I have never done this before. I know who Thiele and Small are but I do not know what their numbers mean at all. I've played with WinISD PRO but don't really know what to do with it. I have read that you tune the enclosure, but I know that the mix of driver, enclosure, and port (in a vented design) all involve tradeoffs. I am not wealthy enough to make 2 or 3 subs in order to get it to sound good. I watch mostly movies and would like the sub to go very low (20 Hz) very cleanly (oxymoron?). The room is 2688 cubic feet (15' 10" X 24'8" X 8') There is an adjoining kitchen (12' X 11' X 8') with a 4 foot entryway and a hallway (15' X 3' X 8'). Size and placement is not a factor. Are all these drivers close enough in their parameters that 1 enclosure would work well for any of them? Can anyone say just build a 24" diameter sonotube 60" tall with an 8" port 22" long and I will be fine? I don't know. I am waiting for Ascendant to have their new 15 inch driver available before making my choice. I have spoken with Chad a couple of times now but have no specifications on the forthcoming driver. All the rest of the drivers I have accumulated T/S parameters on. Any ideas? Where do I start? Thanks.

Chuck

PS I have a woodshop and a machine shop at my disposal so building and fabricating is not a problem.

[KeithM]

download winISD or unibox. You can get enclosure size, response, port tube size, and a bunch of other stuff to help you build it.

[ThomasW]

Start by bookmarking this link

http://www.quux.net/roo/diy/sonosub/tubecalc.html

Having the T/S parameter is nice but only 2 of the drivers you listed are currently available.....

20Hz is not problem for any of the drivers you've mentioned. If you want to simply copy a design, copy this. https://web.archive.org/web/20060830...PetesTube.html And put in the RL-p 15".

This was done by Marcus J. in this thread.

https://www.htguide.com/forum/showthread.php?t=15870

Now these are tuned to ~18Hz. They're not monster tubes like the one made by Steve Callas, but they have very good output.

If you go the route Steve did you'll have a much bigger tube that potentially has lower distortion. This approach is called EBS or extended bass shelf design. You can read up on that concept here.

http://www.diysubwoofers.org/prt/ported5.htm

or 1/2 way down this page

http://www.danmarx.org/audioinnovation/theories.html

Next you can spend time learning WinISD or some other box program or simply calculate the box using this

http://www.carstereo.com/help/Articles.cfm?id=17

And the port using this...

http://www.carstereo.com/help/Articles.cfm?id=31

Modeling programs like WinISD or Unibox tell you lots of cool stuff about output, excursion, etc. But knowing all that stuff really isn't necessary ......

[chasw98]

20Hz is not problem for any of the drivers you've mentioned. If you want to simply copy a design, copy this. http://home.comcast.net/~audio-worx/...PetesTube.html And put in the RL-p 15".

I have read where WOTW has down to 3Hz LFE in it and most subs will not play it at reference level. I am trying to be reasonable on a budget.

If you go the route Steve did you'll have a much bigger tube that potentially has lower distortion. This approach is called EBS or extended bass shelf design. You can read up on that concept here.

http://www.diysubwoofers.org/prt/ported5.htm

or 1/2 way down this page
http://www.danmarx.org/audioinnovation/theories.html

I have been talking with Steve and he has graciously offered to help me with plans. He told me to wait until Ascendant Audio has their new 15 inch drivers available, which I am patiently doing. I wish there was a dummies guide to T/S parameters that I could read up on. I know there are a lot of parameters and some weigh in more heavily than others depending upon the project. I will definitely start going through the links you have left for me. And if I ever get a driver (double edged sword waiting for new ones to come out after CES) before I build I will probably post a design before chopping up some sonotube. I have read quite a few of your posts here and respect your knowledge and time in helping people like me out. Thank you Thomas.

Chuck

[SteveCallas]

I wish there was a dummies guide to T/S parameters that I could read up on

Something like this? Scroll down a bit.

http://www.diysubwoofers.org/define.htm

[Joe L.]

Another bookmark you might want to make is this link for a sonosub calculator

It makes it easy to figure out the length of sonotube needed when taking into consideration all the factors that determine the internal volume.

Use it to find out how long you need to cut the sonotube once you have determined the targeted internal volume and know the length and diameter of the port you will be using.

As Thomas has said, 24" sonotube is huge. Here you can see me standing next to my 18" diameter tube. It has already been cut to size, and it is big!

I used the link above for the sonosub calculator to determine the overall length of 18" diameter tube I needed when building my 260L sonosub.

As far as War-of-the-Worlds goes... reproducing 3 Hz at reference levels is an admirable goal, but you better be prepared to use something more than a single 15" driver. I'm not sure if the large IB sub Thomas has can accomplish that trick. Most folks would be very very happy getting reference levels at 16 to 18 Hz.

Joe L.

[chasw98]

Steve:
I have been to that site numerous times and never saw that. Now to thoroughly read and understand.

Joe:
Reference level at 3Hz would be nice but, I agree, an impossibility with a single 15. Ref Level at 20 would be fine for me for now (I don't even know if that is possible). I believe I will end up with something like you are standing next to Joe. Are there any more pictures? What driver did you use?

Steve:
Thomasw talked about an ESB type of enclosure. Is that what the sonosub is based on?

[Joe L.]

Joe:
I believe I will end up with something like you are standing next to Joe. Are there any more pictures? What driver did you use?

chasw98
I used a 15" Adire Tempest driver when I built my 260L sonosub.

You can see many other pictures as I built my sonosub in
this DIY Loudspeaker thread on AVS (A warning... my sub was only one of many projects described in the DIY Loudspeaker thread on AVS, pictures of its construction are interspersed with other commentary and other folks projects in the following pages in that same thread. Allow a few hours if you want to read the entire thread... it has grown over the years. )

Jeff Hovis built a similar size/tuned 260L sub using a Dayton DVC driver. (It is a near-clone of the Adire Tempest) The links he supplied early in the AVS thread are no longer valid, but you can see his build pages for his sonosub at http://europa70.tripod.com/diy_sonosub001.htm

Towards the end of the AVS thread are pictures of my current pair of 18" Ascendent Audio Avalanche based subwoofers (the 260L 15" Tempest sonosub is now idle at the rear of my theater ) Pretty sure I can't get to reference levels at 3 Hz with the new subs either, but I can get a lot closer than with my sonosub and War-of-the-Worlds sounds (and feels) awesome. :B :B

Joe L.

[ThomasW]

3Hz is a pipedream unless you buy one of the $13K Thigpen Rotary sub.

Without EQ my big IB is about -3dB 10Hz and -21dB at 5Hz.

[SteveCallas]

Steve:
Thomasw talked about an ESB type of enclosure. Is that what the sonosub is based on?

To be honest, I didn't even know that what I settled on was a specific type of design :B

A couple things I like though, and as Thomas said, this is all based on what the programs are showing me, is that aside from the fast increase in excursion below the tuning point, which leads to overexcursion point somewhere just under 13hz at full 600 watts (which with room gain I will probably never see), the biggest amount of excursion is 23mm around 21hz at full 600 watts. So first off, the sub is virtually bulletproof - the amp will give up before the sub does.

Second, and perhaps more important, the driver has an xmax of 27mm, and with XBL^2, I've read something to the effect that if you can keep cone movement within 70% of xmax, distortion will be pretty close to nonexistant. 70% is about 19mm, at at full 600 watts power, that's from about 29hz and up. Realistically, I'll probably never come close to full 600 watts power as I value my hearing, and because of that 70% won't be reached until much lower, but for the context of what I'm getting at, I'll say 29hz. Group delay from 30hz and up is less than 8ms and port velocity is less than 4 m/s at full 600 watts power. The tuning point is about 14.8hz, so a full octave above is about 30hz. So what am I getting at with all this babbling? From 30hz and up, the sub should behave pretty similarly to a sealed design. Distortion should be almost nonexistant and sound quality should be superb, which I will vouch for

Below 30hz is when the benefits of the ported design come into play, and I start getting "free" output from the port. Distortion is still theoretically very low, as xmax can't get higher than 23mm, the 8" diameter port with a top flare keeps port noise to a minimum, and group delay - relative to say an SVS subwoofer - is still low. Ed Mullen has stated that group delay below 20hz is a non factor anyway. So it's kind of like I am getting the best of both worlds, sealed above 30hz and ported below it. When I get my HK receiver, I can set a 20hz high pass filter for music listening and make the sub even more efficient, while still allowing it free reign with movies. Then I still have the second sub to assemble :T

Now as I'm still learning, some of that logic may be off a bit, and if it is, I'd be interested in learning more about it. But from all that I have read, that seems about right.

[ThomasW]

I'm just going to paste in the EBS info from Dan Marx's website. There are trade-offs with this design, those are noted in the text

EBS - 4th Order Large Vented Enclosure with Low Tuning

EBS- Extended Bass Shelf. This is only one of the various different types of vented alignments which are possible and follows many of the same characteristics of vented enclosures. The idea is to intentionally design the enclosure to be 125-175% larger than the optimal calculated volume and then tune the enclosure much lower than optimal as well. The result is a significant amount of extended low frequency response. When the response curve is simulated, a visible "shelf" can be seen in the curve just above the tuning frequency before it sharply rolls off. The LEAP manual explains EBS theory like this: "The name [EBS] was derived simply from the visible appearance of the response curve. The bass response is extended to a lower frequency than would be possible from the QB3 alignment, but at a lower level or shelf relative to the mid band level. Although the EBS alignment is not a nice neat flat alignment such as the QB3, it is very often a much better choice than the QB3. The EBS alignment has some interesting features. Consider a loudspeaker with a Qts of 0.30, the QB3 alignment would have about 2dB more output at a frequency of twice the Fs, while the EBS alignment would have over 2db more output at Fs. In most cases the EBS alignments will have far more subjective [low] bass than the QB3 alignments. Also, if you were to equalize the responses flat to Fs, 10db more boost would be required for the QB3 versus the EBS. This can dramatically consume large amounts of headroom in the power amplifier, and may also far exceed the linear excursion limits of the speaker. The EBS alignment will maintain much lower cone excursion at frequencies near Fb than is possible with the QB3 alignment. This can be very important for high power systems."

Advantages

Extended low frequency response down into the teens. Subsonic earth shattering bass response. Increased efficiency at the lower frequencies (below 25 Hz) but decreased efficiency at higher frequencies (above 30 Hz). This is a rough figure since many different combinations can be designed to yield specific results. In general, low frequency is extended and efficiency increased at the expense of reduced efficiency at higher frequencies.

Disadvantages

Cut-off rate can be as high 36 dB/octave below fB. Transient response is degraded as a result of this. However it may be argued that because the tuning frequency is so low, that is it far enough out of normal operating range that it may be considered a negligible downside. The enclosure size is huge. Anywhere from 5-15 cubic feet depending on the size of the driver being used. Power handling capability of driver is reduced anywhere from 25-50%. Driver may reach Xmax sooner above fB even if it never reaches Xmax right at or below fB. Lack of real presence. Lack of kick or punch. The overall impact of the bass is much softer. Signals between 40 and 60 Hz are significantly reduced. Harder to "sell" because most people are more receiving to a pronounced upper bass response rather than an incredibly low and deep bass response . It takes 8 times as much power (as well as moving air) to make 20 Hz sound as loud as 40 Hz.
Best Applications

Where the truly deepest of all heavenly deep bass is desired. For drivers with a large Xmax and the ability to consume large amounts of power. For drivers whose T/S parameters dictate an optimal enclosure size that's smaller than what the designer wants to build. Large Home Theaters and varying kinds of music with heavy bass tracks would take the best advantage of this enclosure alignment

[exipnos]

Without EQ my big IB is about -3dB 10Hz and -21dB at 5Hz.

please forgive the completely newbie question but what does it mean when you say the above?

Is it that you set the amplifier to a certain level to give you the desired output. Then it plays flat with the same db output during most of the frequency range but when it goes down to 10hz the output is 3db lower?

What is it when people talk about reference level?

Thanks for clarifying.

Exipnos

[ThomasW]

No this isn't related to so-called 'reference levels'. Those are arbitrary settings created by the people in the mutli-channel world (Dolby, THX) to confuse people .....

The numbers mean if there were a frequency response plot of the output from my 12 driver IB subwoofer, the output it would roll-off (decrease) -3dB at 10Hz and be -21dB down at 5Hz.

[chasw98]

Thomas, Steve:
I had to take my son back to college over the weekend. There seems to be a lack of 15 inch or 18 inch drivers to be purchased at this point in time. I am still hoping that Chad at Ascendant will have his 15 ready to sell soon. I have looked at the Soundsplinter RL-p15. Even been talking to Mike there. He has suggested a 5.8 cu ft enclosure with 3 each 4 inch port tubes with 30 - 35 inches cross section (12.5 sq in * 3). Tuned at 18 Hz this would be a 51.14 inch port length. Taking into account enclosure volume of 5.8 cu ft, driver volume of .21 cu ft, and port volume of .355 cu ft all this translates into an 18 inch diameter sonotube approx 48 inches tall (don't have exact meas w/me at work). Now it will be very hard to stuff a 51 inch long port into a 48 inch tall enclosure. Is it OK to put 2 90 degree bends on a port tube and end up with a "J" shaped tube? Then I could fit the ports into the enclosure. Thanks again.

Chuck

[ThomasW]

I'm not a fan of anything other than straight ports. Besause bends in a port change the physical characteristics of the air spring.

Now there are certainly people that use 'bent' ports As a matter of fact Dan Wiggins posted a design years ago that featured a piece of corrugated plastic drain pipe coiled on the bottom on the box.

So to each their own ....

I think we'll see new drivers popping up all over the place shortly. If one's impatient then buy the RL-p 15's

[chasw98]

I'm not a fan of anything other than straight ports. Besause bends in a port change the physical characteristics of the air spring.

>>I thought that flow and velocity might have something to do with it. You have now confirmed it.

Now there are certainly people that use 'bent' ports As a matter of fact Dan Wiggins posted a design years ago that featured a piece of corrugated plastic drain pipe coiled on the bottom on the box.

So to each their own ....

>>Ron Stimpson (sp?) made one about 5 or 6 years ago also.

I think we'll see new drivers popping up all over the place shortly. If one's impatient then buy the RL-p 15's

Tap foot, tap foot, tap foot. Me? I'm not impatient. I am just tired of listening to that poor old Klipsch wheeze. Thanks, Thomas.

[SteveCallas]

with 3 each 4 inch port tubes with 30 - 35 inches cross section (12.5 sq in * 3). Tuned at 18 Hz this would be a 51.14 inch port length.

He probably suggested this because 4" ports are readily available. Why not just go with a single wider port?

[chasw98]

He probably suggested this because 4" ports are readily available. Why not just go with a single wider port?

Steve:
Here is the email I received today from Mike at splintersound.
"Hey Chuck,

No problem on the questions, and just to hit on a few of 'em for ya:

> Such as port cross section. You say 30 - 35 sq inches.
> Does that come from experience or number crunching of driver
> parameters?

Experience. There are varying methods for crunching numbers, but numbers don't tell all! ;-)

> I really want to pronounce those low frequencies.
> Is that where the 5.8 cu ft come from?
> Would this then be an ESB enclosure?
> Is that cu ft number experience or calculated?

Indeed, the 5.8 cu ft net volume spec is an EBS (Extended Bass Shelf) style enclosure. I arrived upon the number through computer simulation since I myself have not built an enclosure that large - however, I have read of other projects aiming for the low lows and using a 15" driver very similar to our RL-p, and they used a large enclosure with great success. So you could say that this recommendation is both calculated as well as based on anecdotal evidence.

> I could just extend the ports up into the open air outside of the
> enclosure. True?

Yes, you can definitely do this - a fine idea in fact!

> I could put an internal end plate of MDF in the sonotube to limit the
> volume

Yep, you could do that too. Considerably more practical than my loony idea of tapering the inside heh, sometimes I just make things more complicated than they need to be

> what is the effect of using 90 degree bends on the port pipes

With a round port, there shouldn't be much adverse effect. With flat edged
(slot) ports, you would want to curve the angle so that the wind rushing through doesn't hit a hard edge, which can in turn create a whistling effect.

Sounds like you're getting a good handle on the situation - if you need anything else just ask and I'll do my best to help ya out.

Take care,
~mike"

Some of his answers allude to other questions I have asked in previous emails. Mike seems to have a handle on the speakers he sells and mixes raw numbers and modeling with real world experience. I am also finding that asking questions and getting answers from a diverse group of knowledgable people helps me to learn and understand some of the basics of low frequency enclosure design. Steve, Thomsasw, and Mike have given me some good advice, some good links (many of them the same) and I definitely feel more knowledgable than a week or two ago. I really want to take some vacation time from work, spend a few hundred on materials, buy some diverse drivers, and build and measure some subs to see what numbers, forum talking, common sense, and some intuition will produce. Maybe some day.

Also 3 4 inch ports have a cross section of 12.56 sq in * 3 and 6 inch ports have a cross section of 28.27 sq in which don't come close to 30-35 sq in cross section proposed by Mike. That is why Mike said he chose 3 4 inch ports. I also wonder what the effect would be of building a larger enclosure. I tend to see it written in between the lines that larger size will get you lower FR with trade offs! I don't know.

Then again I may be obsessing. I have placed an order for a set of Ascend 340's to replace my aging KEF's that should arrive by the end of the month. After reading the HSU-SVS crowd talk about their store bought subs, I definitely feel I can build a comparable unit if am careful in design and execution.

[Dennis H]

Then again I may be obsessing.

Yes you are.

I have placed an order for a set of Ascend 340's

Why, when there are DIY designs on this forum that are so much better?

[chasw98]

Why, when there are DIY designs on this forum that are so much better?

I feel more comfortable building a sub as my first DIY speaker project.

[SteveCallas]

Yeah, 3 4" ports will have more area. An 8" would have 50, but that would probably be too long.

[chasw98]

Yeah, 3 4" ports will have more area. An 8" would have 50, but that would probably be too long.

According to my calculations 3 4" ports would have 37.6992 sq in. and a single 8 would have 50.2656. More port length would be needed with an 8, I believe. Correct me if I am wrong.

[SteveCallas]

Yeah, the 8" would have to be longer.

[chasw98]

Just an update. I am waiting patiently for a broader spectrum of products to become available after CES. Ascendant in particular. Waiting like this has given me pause for thought. I have started reading and trying to educate myself about IB. It looks relatively easy to build a manifold into a ceiling with an attic above it. There don't appear to be too many technical parameters to be worried about. The only drawback I can see to IB is that a person should use more drivers than for a sealed or vented enclosure. But rather than putting time and money into a pretty enclosure, it goes into hardware. I believe that a person should use some sort of high pass filter for the safety of the drivers. Is this true? Would 2 15 inch drivers in an IB perform better than a single 15 in an enclosure? I am sure the answer is yes and no depending upon the volume of the room and some other facts and figures. I don't know for sure. Anyway, as products become available to purchase I shall ask for help and knowledge. You have all been wonderful with your time and patience in getting me this far. Thank you all:

[SteveCallas]

Though I haven't built one, I'd probably say the main thing to consider with an IB is the location in the room the drivers will be mounted and what the result is at the seating position. If you are stuck with a horrible spot, then it will be hard to get good results. If you have a pretty good spot, I'd say go for it.

[chasw98]

I've been up in the attic running wires to the projector and I have a clear area from the end of the room where the screen sits on the wall all the way to behind the couch. Essentially if I drew a center line down the ceiling longways, I could put it anywhere along that line or to the left of it as you face the screen. (There is an AC duct running the length on the right hand side). Towards the left hand side of the ceiling it gets cramped by the peak of the roof, but thats the extreme left hand side. How does one go about determining where to place an IB in a ceiling? It's very hard to hold a sub up to the ceiling and then walk around the room listening and measuring. Or.... (light goes on!) do you put the sub in the listening position and put the mike at the ceiling?

[ThomasW]

This is a whole other thread......

Or.... (light goes on!) do you put the sub in the listening position and put the mike at the ceiling?

Yep

Might want to wander through the various FAQ sections at the "IB Cult" website

[chasw98]

Thats what got me thinking about IB, wandering through the cult site. Also, Thomas, GO BRONCOS!!! I lived in Aspen for 20 years and suffered with them for so many years. They are still the only team I enjoy! Hope they win.

[ThomasW]

Also, Thomas, GO BRONCOS!!! I lived in Aspen for 20 years and suffered with them for so many years. They are still the only team I enjoy! Hope they win.

I was quite amazed that they won .... :T

[chasw98]

Thomas:
THEY WON!!!! But the Steelers won today and that is where my wife was born. So we have a divided house (not really).
Back to the thread. I am curious as to why "car stereo" subwoofers are not used more often. I have seen some rather lavish , expensive drivers available. Most of them, when you look at the specs, don't appear to be able to do what I, we want out of a home sub. But some of them seem to have respectable specs. Here is a driver from soundstream that seems to be a reputable company with decent specs.


T4-10 T4-12 T4-15
RMS POWER (WATTS) : 800 900 1000
VOICE COIL DIAMETERS (INCHES) : 3.0 3.0 4.0
MAGNET WEIGHT (Oz.) : 160 200 250
FREQ. RESPONSE (Hz) : 28 - 1.8k 25 - 1.7k 20 - 1k
Fs (Hz) : 40 36.5 34
Qes: 0.397 0.414 0.449
Qms: 1.975 3.584 3.722
Qts: 0.330 0.371 0.401
Vas (Ft3) : 0.35/9.79 liters 1.03/29.27 liters 2.08/58.77 liters
Xmax (INCHES) 0.63 0.63 0.551
SPL (dB) : 87 89 91
HOLE SIZE (INCHES) : 9.5 11.25 14.25
WOOFER DEPTH (INCHES) : 5.75 6.1 8.25
RECOMMENDED ENCLOSURE (Ft3) : Ported 1.7 Ported 2.2 Ported 4.25
RECOMMENDED ENCLOSURE TYPE : Vented Vented Vented
AEROPORT DEMENSIONS (INCHES):
4 x11.25(1) 4 x 7.5(1) 3 x 3 (2)

What are your thoughts? Have you ever found any "car stereo" drivers that you would use. I am not even sure what makes a car stereo driver different from any other driver. It is still just a motor that pushes air in response to a signal.

[Dennis H]

There's nothing wrong with car drivers quality-wise but many of them, like those you list, have a high Fs. It's not a problem with the cabin gain of a car but it's not so good in the home.

[chasw98]

Kind of like a 6 inch speaker designed for a boom box and a 6 inch driver designed for a sound system for home. Or the proverbial pro sound driver versus home driver.

[ThomasW]

JL Audio makes some drivers that work well from home use. And somewhere in the archives we did a ported box for Bing F, using an Infinity Perfect 12. He eventually blew it up and we replaced it with a BP1203.

[chasw98]

I have seen JL Audio. They have a facility right here in Miramar, Florida. They offer no internet sales and there is a dealer nearby where I live. I have thought about them. But I am still holding out for Chad and Ascendant. If that does not come through, I will probably go with a RL-p15 or two of them. hehe

[chasw98]

I have a question about Aeroport flared ports. The ad says 1 6 inch Aeroport flows 18% more air than 2 4 inch ports. If a 4 inch port with a 1/2 inch roundover exiting the enclosure is equal to 12.5664 sq in, what is an Aeroport equal to? How would you define the Aeroport in calculations because it appears to be different than a plain 6 inch piece of PVC which works out to 28.2744 sq inches?

[chasw98]

Thomas:
Do you recommend a 1/4 inch up spiral router bit and a Jasper 200 for cutting the circles?

[ThomasW]

Do you recommend a 1/4 inch up spiral router bit and a Jasper 200 for cutting the circles?

Yep, in addition I use a 3/4" flat bottom bit if you're going to flush mount the driver.

Here's a link to a tutorial for flush mounting drivers.

https://web.archive.org/web/20070223073850/http://home.comcast.net/~audio-worx/page5FlushCutTutorial.html

BTW, are we building an IB or a ported design?

[Dotay]

Do you recommend a 1/4 inch up spiral router bit and a Jasper 200 for cutting the circles?

Check out post 26 in my thread about building my sonotube sub.

https://www.htguide.com/forum/showthread.php?t=13681

Depending on how big you need to make the cuts for the sonosub the 200 model will probably not be big enough. You can either create your own jig or jasper does make a model 300 jig that will cut bigger holes. It would be nice to have both of these jigs but if you're only going to be making the sonotube the 300 will probably be the only one you'll need. That being said my homemade jig worked just as good as the fancy jasper jig once i measured and made the necessary holes in it.

[chasw98]

Thomas:
It will be a ported sonotube design with a 15 inch driver. If Ascendant does not come through shortly, I will go with RL-p15 D2. Right now a 16 inch diameter sonotube will give me the length to accomodate 3 4 inch ports inside. I am currently making my own circle jig out of 1/4" Brushed Aluminum plate in the machine shop at work. It will be fitted to my Porter Cable 690 series router. I have a 3/4" flat bit and a 1/2" roundover bit, but I will acquire the 1/4" up spiral bit as suggested.

[chasw98]

Check out post 26 in my thread about building my sonotube sub.

https://www.htguide.com/forum/showthread.php?t=13681

Depending on how big you need to make the cuts for the sonosub the 200 model will probably not be big enough. You can either create your own jig or jasper does make a model 300 jig that will cut bigger holes. It would be nice to have both of these jigs but if you're only going to be making the sonotube the 300 will probably be the only one you'll need. That being said my homemade jig worked just as good as the fancy jasper jig once i measured and made the necessary holes in it.

Dotay:
I just couldn't justify the cost of the Jasper for this project. If I were to do any more projects, I would probably invest in it, but not right now.

[Dotay]

Dotay:
I just couldn't justify the cost of the Jasper for this project. If I were to do any more projects, I would probably invest in it, but not right now.

Yeah, the Jasper certainly is nice but a homemade jig will work just as well. I just wanted you to be aware that even with the 200 model jig it might not work for your intended purpose. Good luck with your project. :T

[chasw98]

I talked with Ascendant today and it does not look like their "Home" drivers will be available any time soon (at least a month). I went to Soundsplinter and tried to price a RL-p15 D2 and they are out of stock. I have thought about it and have 3 Dayton drivers to choose from in varying price ranges. I am leaning toward #1 (the cheapest) purely out of putting least money into a throwaway driver to gain experience with. I have to buy 12 feet of Sonotube anyway so I am thinking of spending little money on a Dayton driver, build a sonotube, live with it for a while and when there is more choice of better drivers build another. Plus I will have some experience under my belt when I build a better one in the future. The original can go to one of my sons for his system. Here are the 3 choices below. Can you tell me what internal volume of sonotube to use for a given driver? What ports should be installed for a 20 Hz tune (diameter and length) if possible? #1 or #2 as they are relatively inexpensive. Will I need a subsonic filter? If so, where can I get a circuit to build? Thanks in advance. ;x(

DAYTON QT385-4 15" QUATRO SERIES SUBWOOFER 4 OHM $87.09
Specifications: *Power Handling: 300 watts RMS/600 watts max *VCdia:
2-1/2" *Le: 3.5 mH *Znom: 4 ohms *Re: 3.45 ohms *Frequency range: 20-125 Hz *Magnet weight: 67 oz. *Fs: 21 Hz *SPL: 91.8 dB 2.83V/1m *Vas: 6.60 cu. ft.
*Qms: 14.0 *Qes: .42 *Qts: .41 *Xmax: 10 mm *Dimensions: Overall Diameter:
15-1/8", Cutout Diameter: 13-7/8", Mounting Depth: 6-5/8".

DAYTON DVC385-88 15" DVC SERIES SUBWOOFER $118.20
Specifications: (Note: All specifications are with voice coils connected in parallel.) * Power handling: 350 watts RMS/per coil, 600 watts total * Voice coil diameter: 2" * Voice coil inductance: 1.81 mH * Nominal
impedance: 8 ohm per coil / 4 ohm total * DC resistance: 2.60 ohms * Frequency range: 20-450 Hz * Magnet weight: 112 oz. * Fs: 20.4 Hz * SPL: 90 dB 1W/1m, 93.4 dB @ 2.83V/1m * Vas: 9.92 cu. ft. * Qms: 12.28 * Qes: .39 *
Qts: .38 * Xmax: 15.1mm * Net weight: 20 lbs. * Dimensions: Overall
Diameter: 15-1/8", Cutout Diameter: 13-7/8", Mounting Depth: 7-3/8", Magnet
Diameter: 6-1/2".

DAYTON TIT400C-4 15" TITANIC MKIII SUBWOOFER 4 OHM $191.20
Specifications: *Power handling: 800 watts RMS/1,100 watts max *VCdia:
2-1/2" *Le: 3.84 mH *Impedance: 4 ohms *Re: 3.68 ohms *Frequency range:
19-500 Hz *Magnet weight: 136oz. *Fs: 19.93 Hz *SPL: 91.7 dB 2.83V/1m *Vas:
7.79 cu. ft. *Qms: 5.89 *Qes: .41 *Qts: .38 *Xmax: 20.5 mm *Dimensions:
Overall Diameter: 15-9/16", Cutout Diameter: 14-1/16", Mounting Depth:
8-3/8".

[ThomasW]

I suggest you buy the DVC15", it's a good middle of the road driver, virtually a clone of the Adire Tempest
Ported enclosures are basically tuned to themselves. That means you can drop in any normal driver and it will work fine.

Adire's designs for the Tempest will work for any of those drivers

http://web.archive.org/web/20030808212649/www.adireaudio.com/Files/VentedTempestApplications.PDF

[chasw98]

OK Thomas:
Using WinISD and the Adire Application note I have "modeled" a sonotube subwoofer using the Dayton DVC 15 inch driver. There will be a 3/4" thick Oak Plate at the outside of each end. Inside the tube will be 2 each 3/4" mdf panels. I will be using a 20" diameter sonotube 45.75" tall. The internal volume minus the volume of the port, driver, and end panels will be 7.557 cu ft. The port will be 1 each 4" diameter 16" long for a 15.4 Hz tune. Adire recommends stuffing with 64 oz of polyfill but I can add that as needed. The graph plotted by WinISD shows a +4 db peak at 15 Hz sloping down to 0 db at 19 Hz. I believe I can deal with that using my BFD. Does this look good to you? Is there anything you would change? There will be legs, dual GR jacks, and t nuts to hold the components in as well as best practices described by you for putting it together and sealing it. Thank you.

[ThomasW]

Sounds good .....:T

Be sure and pay the extra few bucks to get a flared port