Patman's Sunosub II Construction Resource Page

The SunoSub II Construction page.

Sunosub I Sunosub II Sunosub III

This is a DIY (Do-It-Yourself) project. I hope to give you insight in the overall construction process of the Sunosub II that I built all by myself over the course of months from September 1, 2000 to March 29, 2001. The reason for the length of time was due to my changing the porting design after I had completed the subwoofer. Actual construction time shouldn't take over a couple of weeks if you know what you are doing. There are some places where I screwed up in doing this project, but I'll show a few shots of where I went wrong.

Design


I'm using the Tempest 15" driver from Adire Audio. Just to recap the design specs for this effort:

My original porting design had three 4" wide ports 36" long for an enclosure tune of 16hz. I built this, and discovered that the ports were just too long and too close to each other on the bottom endcap. This created some noises, rattling, resonances at high SPLs. You'll see photos of when I cut off the original bottom endcap later on. So I ditched this design and had to retrofit a new bottom endcap with a single 6" wide port. I should have heeded the KISS (Keep It Simple, Stupid) principle.

The 22.5" length for the 6" wide port comes from modelling for the port length for a targetted tuning frequency of 16.5Hz for the enclosure by using a handy little program called WinISD (ISD = Interactive Speaker Design). You can download the program at Linear Team.

The reason I chose 16.5Hz as the tuning frequency is to provide as much driver protection with such a low tune without the need of a subsonic filter. This is because the driver is "unprotected" at frequencies underneath the tuned frequency of the box/enclosure, so by going with 16.5Hz, it's protected for most low end frequencies while sacrificing a little bit of output near the 20-25Hz range.

Why use a round cylinder of Sonotube? Sonotube is just one brand of cylinders made up of fiberboard for pouring concrete for the formation of round concrete poles and structures. It's very strong stuff. Here's a link for the Sonotube FAQ if you want to know why to use sonotube over conventional wood-making.

Tools

I was able to use the power tools from my previous Sunosub efforts, as well as non-power tools:

Tool costs: roughly $245 - but I had all of these tools from my previous construction efforts, so dividing among 3 sunosubs, my tool costs were about $90/subwoofer project (including tax).

Materials

As a bare minimum you'll need the following in raw materials:
Material costs - roughly $285 (these prices listed are estimates from my sieve-like memory)

Personal Protection

As a bare minimum you'll need the following in personal protection - wear them while using power tools:

Hint: For faster navigation, when you click on your first picture link, don't close that 2nd window, but resize this window and position it so you can see both windows concurrently. I've designed it so that you can leave that 2nd (photo) window open, and you can click to your heart's content in this first window, and the images will only show up in that 2nd other window. This should also speed up your visit here. If you want separate windows, then right click of the photo links and select the "open in new window" option.

Day 1: September 1, 2000

I took a leisurely pace on this project. Again, it'll feature some different construction challenges from the other Sunosubs. The top will have a rounded off look to it. I'll be using a silver silk cover on the sonotube. The bottom outer endcap will provide a ledge for the sonotube to rest upon.

I go shopping and come home with most of the raw materials from Home Depot:


That's it for the raw materials for now (you'll see the circle jig later on). Let's make some endcaps, shall we?

Endcap cut/preparations:

Day 2: September 2, 2000


Good afternoon, I went shopping for ideas for the outer covering for Sunosub II, but came back empty handed for now, but that's okay, I have almost a month to wait for the Tempest driver.

I decided to make the holes and cuts for the endcaps today. It's threatening to rain, and I'll be damned if I cut MDF inside my garage (I learned that lesson the hard way on Sonosub I), so I wait to around 4:30 p.m. to start cutting the endcaps. I start with the top endcap because it's very basic (no inside holes)

I will have about 1.15" layer of MDF on the inside of the top endcap and 1" (3/4" MDF plus 1/4" plywood) on the inside for bottom endcap.

This means I'll be cutting each layer for the bottom endcap individually because they will have different widths to them. The outer bottom endcap will be around 25" wide (just flush enough to provide a ledge for the sonotube material) and both inner endcap will be roughly 23.75" wide.

Well, after some experimenting with the router on my previous Sunosub, I figured out how to cut circles with the router guide. The main thing is to draw out the circles in pencil, and find the center of the circles, and drill a 1/8" hole all the way through the endcaps for the router guide to pivot around. Use the plunge router, make several circular cuts - starting with 1/2" depth, and then 1" depth since we are just cutting through 3/4" of MDF thickness. Do the largest circle first, and start on the smaller circles inward on the endcap. Make sure you route in the recommended direction for your router. I have to go in a counter-clockwise direction for my particular router, otherwise, you'll risk injury and bad router cuts.


Note: I make the revised bottom endcap routing on February 3, 2001.
Now I start on the bottom endcap and the holes needed: driver hole, terminal cup hole, and the port hole (which will have to be done when I receive the flared port since I don't know how wide of a hole to cut into the endcap).

Day 3: September 3, 2000


Today I paint the legs:

Finishing up the bottom endcap - we'll be fast forwarding to March 19, 2001.

Day 4: September 4, 2000

Sonotube preparation and internal top endcap attachment:
Here's the application of the batting on the inside wall of the sonotube:
Here's the table legs and drilling of the holes for the caster wheels:

A detour


Here's a few photos of what I had to do with my former design to salvage the sonotube for this project:

Day 5: March 24, 2001

Okay, after I made that detour with my original design, I had many months of inactivity on Sunosub II. So I finally got all my parts in place, and was able to make some progress on the completion of this project (I had a hard time finding those straight table leg mounts and got super-lucky when Home Depot got some of them in - though they are clearing all of those products out forever). Another delay was getting the dual-input terminal cup (local supplier ran out of them, and I finally broke down and ordered one from Madisound). Now that I have all the stuff, I can cruise on in.


That's it for today. I'll be working on the top endcap's finish next.

Day 6: March 25, 2001


Well, it's getting close. I need to paint the top endcap and wrap the cover around it.


Day 7: March 26, 2001


Here's a graph of the near field response of Sunosub II:

Graph 1 : The nearfield measurement shows a F3 around 22Hz (using 105dB as the average SPL level), you can see where the Fb (tuned enclosure frequency) of 16.5Hz show up in the dip near 15Hz on the 1m measurements. I expected the low end F3 not to reach 20Hz, and I was right. If I tuned higher, I might have gotten it, but I would sacrifice driver protection, and I just would rather have driver protection (from bottoming out the driver) over a few dB's down really low.

I made the near field measurement by playing a 22Hz tone, placing the SPL meter right near the dustcap of the driver, and turning up the volume until it was near 95dB (totally arbitrary dB number, you can use any useful SPL, like 75dB if you wanted to, but I wanted some separation between the near field and the 1m measurement for the graph.

Day 8: April 8, 2001


Here's some of my comments in regards to how Sunosub II performs in my Home Theater setup:

My reaction: Music sounds full, rich, enveloping with the sub engaged. The sub was pretty tight in its transient response too.

I tested The Phantom Menace (TPM), and everywhere that I use to get pops/bottoming out (the Jedi ship getting blasted, Pod Race toward the end of the race, and some other spots) with Sunosub I (before I re-tuned it to 16Hz), I got no such pops or bottoming out with Sunosub II. It handled all those scenes with aplomb.

I tested the space dogfight fight at the beginning of the Lost In Space DVD, and it played through it without a hitch.

It also survived the dts version of The Haunting DVD (for my purposes) with peaks hitting 107dB from my seating position (and even then I needed to be listening at insane volumes, probably measuring a reference level of 80dB at the same position) from 10-11 feet away, I normally wouldn't even listen to DVDs at this level, but I was curious to push the sub a little harder than normal.

Sunosub II didn't even break a sweat playing the opening sequence from Toy Story II.

Hope this helps people get off their duffs and build their own sonosub, with the right tools, they are easy to make and you'll be surprised at the quality of bass you can get with a lot less money. Also, the pride of building stuff you use in your HT is another plus.

Well, there you have it, how to build a Tempest sonosub in 130 photos. Take a bow if you been here with me the entire way! Thanks for words of wisdom and encouragement along the way from the following folks at: Home Theater Forum, Home Theater Talk, and Home Theater Guide:

I hope you've enjoyed looking at how I created my 2nd SunoSub! It was a time-consuming process, but I learn something from each one of these subs I build. And as always, I make mental notes on how I'd do something different/better the next time I do one of these subwoofer in the future.

So how many have visited this subsonic webpage since 4-8-2001?

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