Dear DIY Audio,
I am thinking about building my first subwoofer this year, and I don't know where to start.
I was wondering what the are most important factors to pay attention to. So far I believe I have to consider:
1. It will be in an apartment bedroom (not too loud, not too big, wall to wall carpet)
2. Should I design it to be placed in the corner like a REL subwoofer to take advantage of the long axis of the room?
What other parameters or considerations should I worry about? What shouldn't I worry about?
I am nervous and excited to start! I'm a couple years out of engineering school (EE) but I haven't touched this space before, so any help would be appreciated!
Thank you so much!
I am thinking about building my first subwoofer this year, and I don't know where to start.
I was wondering what the are most important factors to pay attention to. So far I believe I have to consider:
1. It will be in an apartment bedroom (not too loud, not too big, wall to wall carpet)
2. Should I design it to be placed in the corner like a REL subwoofer to take advantage of the long axis of the room?
What other parameters or considerations should I worry about? What shouldn't I worry about?
I am nervous and excited to start! I'm a couple years out of engineering school (EE) but I haven't touched this space before, so any help would be appreciated!
Thank you so much!
Thank you! I was originally thinking of trying to design my own to understand the parameters better but that may not be a wise place to start, and this may be a better option... Why try to reinvent the wheel? Thank you again!
I bet I will! If I may ask another question: What is the benefit of a downward-facing driver?
Thank you
Thank you
The only benefit is a visual one. It doesn't practically matter which way the driver is oriented and that is why you can place them within reason, anywhere in a room. One doesn't notice where the lower frequencies are coming from, just that they are there.
Regards Johnno
Regards Johnno
So I have figured out what I want my subwoofer to do:
I want it to play only music moderately loud but very clear and for placement in the corner of a bedroom. How do I go about quantifying these design requirements? I should probably narrow in on a desired spl? What other parameters?
Is there any way to use the fact that it's going to go flush in a corner to my advantage?
I want it to play only music moderately loud but very clear and for placement in the corner of a bedroom. How do I go about quantifying these design requirements? I should probably narrow in on a desired spl? What other parameters?
Is there any way to use the fact that it's going to go flush in a corner to my advantage?
In my case 90% of the time I want my subwoofer to simply disappear as an identifiable source, leaving all the imaging to my main speakers. I have preferred keeping the crossover frequency around 60Hz. I've also always found it useful to have a variable phase control rather than a simple 0 or 180 control switch. Also useful is some kind of equalizer control to deal with possible standing waves. I'm often running the volume a bit lower than some people like but have the option to crank it up a bit when the mood hits. Keeping all box resonances damped is vital. I have used butyl or plastic modeling clay on driver frames, constraint mode dampening on cabinet walls, and lead and other materials for vibration. Have fun with the journey. 🙂
Once you have your speakers here is a test I have used. I use solo piano recordings to start. I listen for the addition of body to the music. A grand piano has a massive body that conveys its presence in a live performance. This is the first place I go in dialing in levels. Too much and it will just make things wooly rather than real. Too little and the presence of the instrument disappears. Next I go to plucked Double Bass. Adjusting phase controls will help you dial in the point where the point source of fingers plucking the strings is distinct and clear. Once you mark those settings you can feel free to play around to your hearts content because now you always have a reference setting to come back to. 🙂
Maybe consider building 2 or 3 tiny 8" sub enclosures to give you smooth bass through the room. Could probably hide a couple under the bed ?
Rob
Rob
That's great advice for testing Octavia! Which values are you referring to? The crossover and the phase? So I guess I should make those adjustable, then.
Rob that's a good idea, I didn't really think about how I'll probably get some nodes if I only use one sub jammed in a corner. Is there a program to figure out the optimal placement/quantity of subs for even coverage?
Rob that's a good idea, I didn't really think about how I'll probably get some nodes if I only use one sub jammed in a corner. Is there a program to figure out the optimal placement/quantity of subs for even coverage?
😱
That was a fascinating paper! I wonder what would happen if they stacked subs vertically...
It was also neat to learn that there's a complex component to nodes, too. Thank you for suggesting that paper!
I'll be sharing my room with another person and 14 potted plants (I just wanted a habanero) so I think i'll have to settle for 2 subwoofers.
Is 8 inches a good size for double subs? Should they be different sizes?
Thank you
That was a fascinating paper! I wonder what would happen if they stacked subs vertically...
It was also neat to learn that there's a complex component to nodes, too. Thank you for suggesting that paper!
I'll be sharing my room with another person and 14 potted plants (I just wanted a habanero) so I think i'll have to settle for 2 subwoofers.
Is 8 inches a good size for double subs? Should they be different sizes?
Thank you
There are no rules for this. It's whatever suits your taste/expertise/budget.
Don't over complicate things especially on your first project. If I were you I'd settle on a single sub of moderate size that will fit the room physically. If you build a two or three sub project it's twice the cost and work but the result won't necessarily be two or three times better. If physical size in an issue, you might want to stick with an eight or ten inch sub. For instance I have an 8" 150W sub in my room that is about 14 feet x 20 feet which compliments two 4" full range speakers and it's plenty.
That's good advice. This is my first project so I'm trying to read as much as I can and glean knowledge from people who have done it before. Ideally for my first project I want it to sound good and be well made, and fully understand all the math and acoustics that go along with it.
I originally made this post to figure out what parameters and values the community thought were important to a great basic sub, but I bet I'll come up with my own opinions too along this journey 🙂
I'm all for people doing as they please, however with that said 🙂 when it comes to subwoofing there's no replacement for displacement. I MUCH prefer shorter throw bigger drivers to small long throw drivers. Never had a satisfying sub less that 12 inches. Doesn't mean I'm right but that's been my experience so far. You might want to take a look at MJ King's H Frame woofers. OK for near wall but not really for a corner. As said before the Rythmik DIY stuff is highly regarded too and they are really helpful on the phone.
What determines the throw? Diameter? Surface area of the driver?
I'm not sure what the best way to go about this is, but realistically I can only control so many things, right? I was thinking of grabbing a driver (specs) and then trying to optimize the cabinet and crossover.
Looking at the specs just briefly I think that I should try to focus on 35 Hz to your recommended 60 Hz because that's where the frequency response graph looks pretty smooth. Then again, I'm still learning and reading, and may be completely wrong! I also am not sure what effect the cabinet can have, as the desired output wavelengths are acoustically large compared to the expected size of the box.
As I said, I'm not sure if this is the best way to approach the task. Also this is a pretty inexpensive driver compared to the others offered, but may be a good first try for optimization.
I'm not sure what the best way to go about this is, but realistically I can only control so many things, right? I was thinking of grabbing a driver (specs) and then trying to optimize the cabinet and crossover.
Looking at the specs just briefly I think that I should try to focus on 35 Hz to your recommended 60 Hz because that's where the frequency response graph looks pretty smooth. Then again, I'm still learning and reading, and may be completely wrong! I also am not sure what effect the cabinet can have, as the desired output wavelengths are acoustically large compared to the expected size of the box.
As I said, I'm not sure if this is the best way to approach the task. Also this is a pretty inexpensive driver compared to the others offered, but may be a good first try for optimization.
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The throw is the excursion or the distance the speaker moves along the horizontal axis. As Octavia said, there's an argument for larger diameter driver with a shorter excursion but that also has a bearing on the overall volume of the enclosure. There are lots of great articles online devoted specifically to subs. Just be careful that you don't start by accident getting into car audio subs. That's another ball of wax. Isn't it fun?
Here's the thing, if you cut too many corners or make the wrong compromises you will be disappointed in the results. Hence my suggestion of a tried and true kit. The 60Hz I mentioned was the crossover point between your main speakers and the subwoofer. If you want to go the Parts Express route then I'd suggest sticking with on of their recommendations. They have some nice bundle packs for subwoofers that include baffles and boxes, etc.