And don't forget one huge benefit of DIY speakers: it is easy to step up to active bi-amplification with an external electronic crossover and amps. At this level you can select amplifiers that complement the frequencies to be amplified among other things. Performance in this realm goes way beyond what you can get with even the most costly "store bought" HT gear.

wmeckle, those are impressive cabinets!

Do you have any impression on the Thor kit that is offered by Madisound? I will be building my own cabinets.
Sorry to change the subject but I wanted to ask.

Hi row1x:
I read the write up on the Thors in AudioXpress, and they appeared to be a lot like my Aria5s, so no changes are likely.
I haven't heard any speakers under $3,500 per pair that I'd trade for my Aria5s.

I have to say this is really inspiring to see such beautiful cabinetwork. I have been on the market for a sub woofer to be used 50/50 music/HT but I have been a little intimidated as to what kit I should choose. I know that I am handy enough to put some kit together although it would have to be pre-cut since I don’t have access to a good saw (just a drill, sander, pipe clamps and hand tools). As far as subwoofer design goes, what factors go into making a “good” product?

What makes a sub more “musical” versus good for HT (I assume if it is good “musically” and has enough output/range it will be good for HT too.)

Pro/cons of a sealed vs. vented box.

What impacts does the shape of the enclosure have on the sound (cube vs. rectangular) or is it just about the volume and the drive choice?

What are the pro/cons of having a passive radiator? Also what does the mass have to do with a PR?

Is it better to brace internally or to just beef up the cabinet itself i.e. thicker wood?

What do you do about an amp and controls if you choose not to use one of those plate amps?

So far I have been most interested in Acoustic Visions and Stryke Audio. In particular SA’s kit for the little brother of wmeckle’s brute force monster looks like fun. The other side of the coin is that I just say the heck with it and get an SVS or wait for the Outlaws’ LFM. I would imagine that some of these questions are ones that other fence riders like myself might have when it come to DIY subs. What are you thoughts, guys?




[This message has been edited by Joshorr (edited June 27, 2003).]

Thanks a lot Bill for you input. I also talked to Kyle at Aucoustic Vision (very helpful) and we put together a package that should more of less rival a SVS PC+ for about $200 less (and that with the unassembled enclosure; it would be an ever better deal if I could make my own). I now see how good the value can be,

Joshorr,
I believe you've made a good choice by ordering from Acoustic-visions. You will get a better value by doing it yourself. I've ordered mine from them and I've been happy with that decision. I see that you did it as I was writing my reply but I'll post it anyway FYI.

What makes a sub more “musical” versus good for HT (I assume if it is good “musically” and has enough output/range it will be good for HT too.)

- According to the experts, music sound rarely goes below 30 HZ whereas in movies there are sound effects that reach 20HZ or even below (inaudible but you can feel it) such as during an explosion scene. Generally, pricy subs ($500 and up) will do fine for both music and HT in an average size home. Cheaper ones may do ok for HT but can be boomy or sound muddy for music. It has to do with the quality of the driver (material, magnet, craftsmanship & …etc.) and or amplifier. Other cheaper ones may be ok for music but doesn’t have enough punch for that floor shaking rumble – the driver just can’t produce enough air movement or not enough power from the amp. Keep in mind, these are just generalized descriptions. There’s a lot of depth in acoustical engineering.

It all comes down to compatibility. If you have high-end electronics, you want to select a sub (and speakers) that can optimize the performance. Any less would be waste of money on electronics and any more would be waste on the sub.

Pro/cons of a sealed vs. vented box.

-Check out http://www.diysubwoofers.org/
For 50/50 music and HT, I’d personally use a large sealed enclosure, something like 5 cu ft or more with high power amp like Adire Audio’s A750 in combination with a driver like Tumult, Tempest or Shiva. That ought to give you a sweet bass in music and a chest pounding, wall picture tilting shake for movies.

What impacts does the shape of the enclosure have on the sound (cube vs. rectangular)

- Not much unless the shape starts to get real lengthy and compromises the strength of the enclosure. Although, I heard something about the “pipe effect” in a long shaped enclosure… I’m not worried because my sub is fairly close to a cube in proportion.

or is it just about the volume and the drive choice?

Internal volume and driver choice play a big role. Unless you have a good understanding of the enclosure calculations, I’d recommend using the ones that are already done such as the kits.

What are the pro/cons of having a passive radiator? Also what does the mass have to do with a PR? See above website or go to www.adireaudio.com and look up passive radiator design. Acoustic-visions has it too.

Is it better to brace internally or to just beef up the cabinet itself i.e. thicker wood?

Depends on the wood you are using. The most popular material to DIY projects are ¾” thick MDF (medium density fiberboard) which can be found at local Home Depot or stores alike. You can beef up the box itself and skip the bracing but it may end up weighing so much that you’ll need to put wheels on it or need a hand truck each time you try to reposition it. I’d would opt for internal bracing.


[This message has been edited by Spiker (edited June 27, 2003).]

[This message has been edited by Spiker (edited June 27, 2003).]

Spider,
First, thank you so much for you great responce. DIYsubs.com is fantastic. It answered a lot of my questions. Now I have to play with that spreadsheet model to see how all the relationship work. But I do have a question for you. Your responce to my 50/50 music/HT usage was to use a sealed box. Now from most of the responce curves I have seem a sealed rolls off very gradually starting around 40-50 hz while a vented is realtively more flat down to its tuning point and then drops off fast (I think I said that right). What sonic qualities do you feel make up for the roll of a sealed (is that why you said a large enclosure to counter this)? Does room gain fit into this roll off better than a flat responce?

The way these kits can come everybody should make their own subs.

Sealed subs are said to have the least amount of sound distortion compare to ported or PR. Nevertheless, if not designed properly, it can still have considerable distortion (quote from Kyle at Acoustic-visions). Generally speaking, because of it’s smoother transition towards lower frequency, its better for music. Keep in mind, there are exceptions among ported and PR subs. Also, with sealed sub, no need to worry about the port noise.

The larger enclosure was for HT purpose. By having a larger internal volume, it allows the roll off to occur at a lower point thus getting more rumble. Then again, there are exceptions such as REL and M&K. But do you really want to spend over $1,000 when you don’t have to? This is where DIY gets it’s role.


In car audio design, I’ve been told that the difference is significant. The size of room, shape of room, placement of sub, furniture and room surface treatment all contribute to the performance of sub (and speakers). This is an area where most consumers including myself, will have a hard time fully comprehending. You may count on room gain but the amount you actually end up getting may be less than you desire. In other words, its unpredictable unless set in a room specifically designed for music or HT. Hope this answers your question. Try writing to someone like soundhound and see what he can add.


I’ve been trying to convince other outlaws on benefits of DIY subs and speakers but the response seem to be less than stellar. Perhaps you can write once you have your DIY sub and let those skeptical outlaws see the light.

Good luck.


Spiker