Hi diy audio form,
Im imagining to build a subwoofer couch- a couch that can observe normal couch functions, but also be a capable deep reaching subwoofer when i need to throw big party in my house or to suprise people.
background:
So, my idea is that I don't want the woofers visible, both to protect them from damage and I don't like the look of metal mesh / grates over the drivers. just a personal issue sorry. I already have an 18 inch eminence impero i want to use for this, and then I want to get a 21" as ive never used one before. The idea I have is to have the couch split into two separate subs internally, intimately crossed together. I'm thinking the 21" to cover 18hz to 40 or so, and then the 18" section to cover 40 to 90 or higher. Since the subs are enclosed in the couch, and these are such narrow bands that I only need, want to take advantage of the situation and do them 4th order or 6th order bandpass to make it earthshaking. I'm thinking the space under the arm rests could be big vertial ports on each side, the left side for the 21" and the right side for the 18". What if this could also create some interesting phantom stereo bass action with the different frequencies coming from each port. Again, don't care about perfection. Want interesting.
SO, just putting this here to get people thoughts on this, 4th order or 6th order, or other configs for the two woofers in the couch. Anything you want to say. Love speaker building
Im imagining to build a subwoofer couch- a couch that can observe normal couch functions, but also be a capable deep reaching subwoofer when i need to throw big party in my house or to suprise people.
background:
- Ive built sealed and ported boxes before, 18 and 15 inch woofers for permanent pa system, designed coverage for specific rooms. but i want to go wilder-
- i have access to a cnc machine, and lots of cheap good MDF. subwoofer design dream, i know-
- I dont have a problem with a complex internal structure of the couch / bracing. I can build box.
- I dont give a thought about size or weight. this thing could be 600lbs.
- I'm not religious, I dont give thought about adhere to audio dogma. I want this design to be unorthodox, I don't care if it's not perfect. I want it to be loud, still good sounding, and be an interesting talking point for guests as well as able to run the dance floor.
So, my idea is that I don't want the woofers visible, both to protect them from damage and I don't like the look of metal mesh / grates over the drivers. just a personal issue sorry. I already have an 18 inch eminence impero i want to use for this, and then I want to get a 21" as ive never used one before. The idea I have is to have the couch split into two separate subs internally, intimately crossed together. I'm thinking the 21" to cover 18hz to 40 or so, and then the 18" section to cover 40 to 90 or higher. Since the subs are enclosed in the couch, and these are such narrow bands that I only need, want to take advantage of the situation and do them 4th order or 6th order bandpass to make it earthshaking. I'm thinking the space under the arm rests could be big vertial ports on each side, the left side for the 21" and the right side for the 18". What if this could also create some interesting phantom stereo bass action with the different frequencies coming from each port. Again, don't care about perfection. Want interesting.
SO, just putting this here to get people thoughts on this, 4th order or 6th order, or other configs for the two woofers in the couch. Anything you want to say. Love speaker building
While interesting in theory, I think you'll lose some output capability going this way instead of just using two woofers to cover the full subwoofer range.
If you're likely to get out of hand with the volume knob in a party scenario, bandpass may not be the best approach. They can mask distortion, making it harder to judge when things are straining.
yes, i agree with that- but if I do want to see whats going to happen with the two different ranges coming out of the ports that would be 8' apart from eachother, do you think something interesting would happen (some sort of different feeling in the room with phantom stereo bass) or is it not worth it? again would be used in a small/medium sized residential space, and with the power of the woofers im fine with sacrificing some output capability
Compared to a matched pair of drivers covering the same range, using only one in the 18 to 40Hz range will be a -6dB drop in output, sounding less than half as loud.
That said, Eminence Impero 18" has only 8mm Xmax, a 21" Eminence NSW6021-6 has 21mm Xmax, (over 3 times the displacement) so would be capable of ~10dB more output at 20Hz.
To get the full peak potential from the NSW6021-6 would require 5 to 10,000 watts, ~140-200volts depending on design.
Two Impero 18" would be ~-5dB compared to one NSW6021-6 at 20Hz, around half as loud.
Then again, most "dance floor" bass is in the 40-160Hz range, using it alone 40-90Hz will reduce the "guts" by a big margin. In room, around the couch using a band-pass or even a ported design, the 18" should still have well over 120dB output above 40Hz, enough to shake most guts..
A 40Hz wavelength is ~28.25' long, 8' is just over 1/4 wavelength, so not much interesting as far as stereo bass, though there will be a different "feel" sitting closer to either port.
As a practical matter, horizontal cones will eventually sag downward, reducing output and increasing distortion. To avoid the inevitable sag, you may want to design the chambers to allow vertical driver placement in the seat back or arm areas.
You might look at Josh Ricci's M.A.U.L. design for inspiration:
https://data-bass.com/#/systems/5aa4a25261feb10004121e18?_k=5u61zx
The M.A.U.L. uses a shared chamber for the four matched drivers, your idea using two different drivers would each require separate chambers and tunings. The bass reflex chamber shape makes no difference to the output.
The "horn" exits and ports could be down firing to avoid any visible exits.
Aty
so do you mean that it would be a better use of drivers to just have one 21" run the whole thing, and that trying to incorporate the 18 is unneeded? I would agree, and I could use the 18" for something in the future
Yea- i will probably go that mounting the driver vertically under the seats inside the couch down firing- with the inside configuration a 6th order still have the ports on either side under the arm rests outputting the different ranges of frequencies?
Since a 21" could cover the 18 to 90Hz range, and splitting two drivers into two ranges covering the same range gives no real output advantage but increases complexity, I agree you could use the 18" for something in the future.
I'm not visualizing what you have in mind in post #16 or what the question is.
Post a sketch of the configuration you are considering and specifics will be easier to address.
I'm not visualizing what you have in mind in post #16 or what the question is.
Post a sketch of the configuration you are considering and specifics will be easier to address.
heres a quick sketch of what the 6th order bandpass with the ports under the arm rests could look like- havent started designing the chambers this is just the structure idea. Here the seat is flat but I would want the whole seat on the couch to be angled backward in the final design. Is there a big phase cancellation question here?
