Noob attempting DIY Sono Sub

[JayhawkMD]

Hey everyone,

First of all I'd like to say this forum is awesome and I was very impressed with all the projects I have seen, and initially I was just trolling but you guys have inspired me to try a project of my own. Anyways, I have done a fair amount of research (other forums like AVS, and audioholiks, some personal web pages too, this is definately the deep end of the knowledge pool) but I still have some unanswered questions. Ill just start by throwing out some info about myself and what I am going for....

First of all I am a third year medical student so the ceiling on my budget is pretty low and I have a limited amount of free time. I am doing my family practice and geriatrics rotations in the next 12 weeks so I will have plenty of time, but once September/October hits my life is over when I start surgery. Also I have a very little experience with speakers and such, I am pretty good with my hands and woodworking, I was able to finish my basement from framing all the way to finishing (I contracted out mudding and taping of drywall). And I learn quick.

What I have: Anyways, we purchased a hi-def set just in time for the world cup and I am about to pull the trigger on a 5 speaker set from Axiom (the M22s with the higher end center and medium end surround speakers). Right now I have a Denon 2805 reciever. The room is 20 X 15 in my basement with finished walls. Size is not an issue. From my research I imagine i'll be pushing this thing with a Behringer 1500.

What I want: So I watch alot of sports, but unfortunately I dont have very many movies (that will probably change), and I love to listen to music from electronic, to rock and indie, to classical (basically everything besides rap). So I want a sub with clean, accurate bass. The boom-boom is not a must, but it would be nice since, I will end up watching more movies. So quality > quantity. My budget is capped at 600.

So my questions: Will I be able to finish this project within 10 weeks? I've done plenty of research and I have heard of the different drivers that are popular but I really don't know what would suit my needs? How tall do I need to make this beast? I've looked at SteveCallas's designs and both of ThomasW's designs and I like them very much, but I dont know the disadvantages/advantages? I kind of understand the technical jargon. I know what an ohm, impedence etc is but I dont really how to pragmatically apply the information into 'oh that sounds good or oh that sounds like crap'.


Thanks for your time and good luck on everyones projects....


Jaymarc Iloreta

[SteveCallas]

Here are some basics.

Regarding size: The larger the sub, the more internal volume it will have. The more internal volume, the less resistance there will be for the cone to move back and forth. The less resistance for the cone to move back and forth, the more efficient the subwoofer will be, especially at lower frequencies. Reproduction of low frequencies requires moving a lot of air, which means more cone travel.

Regarding driver: Also in regards to air moving capability, the larger the cone, the more surface area it will have. The more surface area, the less distance it needs to move to displace a given amount of air. Without getting too deep into other factors that will affect performance, generally, a larger driver will be better for subwoofer use than a smaller one. The easiest answer is to just go with the SS RLp15 because it is a proven performer and there really isn't anything better available right now

Regarding configuration: I'll stay real general on this one, but can link you to a more detailed explanation if you like. Sealed will perform better if you want to use a small to medium sized enclosure and ported will perform better if you want to use a large to giant sized enclosure. Sealed will typically require a more powerful amplifier and stuffing - ported will require a bit more design work. Here's where it gets interesting :B On a per driver basis, using a capable driver, I have yet to see an implementation that will extract more overall performance than a large, low tuned ported design.

Regarding enclosure: You basically can choose from a box, tube, dipole, or infinite baffle. For $600, I doubt a dipole will cut it, and with finished walls I don't know if an infinite baffle is an option (search for infinite baffle). Between a box and a tube, the box requires more labor and is a bit more difficult to construct, yet the materials should cost less. A box will need some bracing, a tube won't. A tube will typically be down-firing, while a box allows for mounting on any side.

Hope that helps. Oh, and 10 weeks is PLENTY of time.

[ThomasW]

You can find out what the technical terms mean by looking them up with Google. Doing that saves me from having to type a textbook. And my carpel tunnel symptoms aren't exacerbated when it comes time to answer your important questions.... :wink:

Boom is a function of a poorly designed sub (we don't let those happen on this forum) or much more often room placement.

Buy a SoundSplinter RL-15" ($269) and a Behringer EP1500 amp ($249). If there's any money left after building the enclosure buy a Behringer DSP1124P for EQ.

If someone knows what they're doing a tube sub can be built in a weekend.

Comparing and contrasting various subs via a forum is a bit like trying to explain why one food tastes better than another.

All the projects on this forum have very good sound quality. Pick one that seems to fit your needs/wants and copy it.

Henry's tube sub thread probably has every question one could think of ask and answered.

https://www.htguide.com/forum/showthread.php?t=18713

[JayhawkMD]

thanks for the prompt reply. you guys are awesome.

[chasw98]

You can see pictures of how I built mine here https://web.archive.org/web/20070221..._subwoofer.htm . I haven't written much about how to construct it but there are lots of pictures showing the various stages. You can construct it and have it running in a weekend if you have all the parts and tools at hand. Finishing it to make it look pretty can take longer. Listen to ThomasW and Steve and you won't go wrong.

Chuck