Hi a newbie here...
I'm looking to make a small sub for use under our bed for low volume listening. As you know bass sort of disappears at bedtime volumes, so I want to add a small sub for use with our vacuum tube amp and bookshelf speakers. (I have a full range output on the amp that doesn't go through the amp output transformer so thinking that will just feed a small class D to the sub).
Not to shake the earth, just warm up the sound at low volumes. I have a fully equipped wood shop including CNC, and 50 years of wood skills. Looking for a working plan and driver type someone might know of. My only restricting factor is that the box has to slip under the bed so 7 inches must be one of the three dimensions. Maybe a 10 inch driver, or two 4-6 inchers, sealed, ported, doesn't matter as long as I can resize the box volume to meet that 7 inch height. Nobody but nobody sells a subwoofer that fits under a bed, so I must make one, (sounds like a market opportunity).
Is there a plan or even just a driver and enclosure volume suggestion that should work for this?
I'm looking to make a small sub for use under our bed for low volume listening. As you know bass sort of disappears at bedtime volumes, so I want to add a small sub for use with our vacuum tube amp and bookshelf speakers. (I have a full range output on the amp that doesn't go through the amp output transformer so thinking that will just feed a small class D to the sub).
Not to shake the earth, just warm up the sound at low volumes. I have a fully equipped wood shop including CNC, and 50 years of wood skills. Looking for a working plan and driver type someone might know of. My only restricting factor is that the box has to slip under the bed so 7 inches must be one of the three dimensions. Maybe a 10 inch driver, or two 4-6 inchers, sealed, ported, doesn't matter as long as I can resize the box volume to meet that 7 inch height. Nobody but nobody sells a subwoofer that fits under a bed, so I must make one, (sounds like a market opportunity).
Is there a plan or even just a driver and enclosure volume suggestion that should work for this?
Put two units of 4" or 6" woofers, under the head board.
Bear in mind that the cushions will muffle the highs and lows.
Or put one on the wall above your pillow, in which case size will not be so big an issue, and the sound will be clearer.
The sound will have to travel from the floor, through the bed, cushions and covers before you can hear it, and will get distorted.
Bear in mind that the cushions will muffle the highs and lows.
Or put one on the wall above your pillow, in which case size will not be so big an issue, and the sound will be clearer.
The sound will have to travel from the floor, through the bed, cushions and covers before you can hear it, and will get distorted.
Some brand also make very shallow subwoofers like the SB SW26DBAC76-4. That could fit a 30L sealed and still go lower than 30Hz. You could make a very shallow box (driver is 8cm deep) and make it upfirering trough you mattress. That would be someting like (with 18mm plywood) 60cm width, 60cm deep and 15cm high. 7" is 17.78cm so you got some room left for xmax and let the speaker breath...
My first question is: do you want a complete under-bed sub or do you want the 'project'?
Everybody, the world, his wife, and the dog makes a sub-woofer that will fit under your bed. The 0.1 component of almost every commercially available 5.1 AV system is a sub that'll likely fit under your bed.
If you're looking for a custom project, I have completed one I'll happily share the details of.
Question: what is your true under-bed height restriction? I have a wooden framed bed. The clearance between the transom and the floor is about 8" but the clearance between the floor and slats (supporting the mattress) is closer to 9.5". This simply means I have to lift the bed slightly to slide a larger sub underneath.
For my project I used two diametrically opposed 6.5" drivers in a 200(h) x 200(d) x 550mm(w) ported cabinet. The reason for the opposition was the clearance challenge; I didn't want any kind of feet but I didn't want the sub waltzing across the carpet. Twin drivers also offered the benefit of not having reduce the signal to mono.
Construction was 12mm MDF. The port was 6" x 2" flared both ends.
Version 2.0 of the sub had a plate amp salvaged from a Yamaha SW-P130 - Auto-sensing is a Godsend if you don't want to keep crawling under the bed!
I can generate a cutting list if you need it.
Everybody, the world, his wife, and the dog makes a sub-woofer that will fit under your bed. The 0.1 component of almost every commercially available 5.1 AV system is a sub that'll likely fit under your bed.
If you're looking for a custom project, I have completed one I'll happily share the details of.
Question: what is your true under-bed height restriction? I have a wooden framed bed. The clearance between the transom and the floor is about 8" but the clearance between the floor and slats (supporting the mattress) is closer to 9.5". This simply means I have to lift the bed slightly to slide a larger sub underneath.
For my project I used two diametrically opposed 6.5" drivers in a 200(h) x 200(d) x 550mm(w) ported cabinet. The reason for the opposition was the clearance challenge; I didn't want any kind of feet but I didn't want the sub waltzing across the carpet. Twin drivers also offered the benefit of not having reduce the signal to mono.
Construction was 12mm MDF. The port was 6" x 2" flared both ends.
Version 2.0 of the sub had a plate amp salvaged from a Yamaha SW-P130 - Auto-sensing is a Godsend if you don't want to keep crawling under the bed!
I can generate a cutting list if you need it.
I have some free woofer designs for pairs of Silver Flute W14. The woofers are good, cheap, and under the bed you are gonna get below 40-45 Hz for the small ones.
http://www.planet10-hifi.com/downloads/SF-W14-woofers-120218.pdf
The shape might need to be morphed. abit to fit under the bed… how much clearance do you have?
dave
I find your leanings toward sealed cabinets for smaller enclosures particularly interesting as manufacturers tend to opt for ported.
A bespoke under-bed sub offers a unique set of challenges as primary output is effectively into a room with a height of 200mm. To compound this you are attempting to set up up for extreme listening positions. Originally, my sub was placed at the head of the bed. When listening to music in the bedroom the sound was pleasant, clean, and well-balanced. Sitting on the bed offered a somewhat more tactile experience. Lying in bed caused nightmares! SPL's are measured at 1m but when lying in bed only a 15cm mattress and 8cm of pillow separates your ears from the source. Every gun-shot and punch impacts you skull and movie sub-bass tracks vibrates your internal organs. I had to move my sub to the foot of the bed.
You know what, I wasn't googling for or considering department store cheapo systems and not getting any hits, there are a lot of those. I couldn't listen to the boomed upper-bass speakers of one of these all-plastic consumer systems for very long, but the subs that come with them actually would work. I don't need 30hz, basically I just want the loudness contour to not disappear the bass at low volume. The treble also diminishes at low bedtime volume but that is ok, its mostly overtones, the midrange stays put at low volume which is the nice feature of the human ear. I guess I can cannibalize the sub and use the speakers in the garage.
Thanks!
If you want the benefit of my experience the LG sh54ph is a great cabinet with a fair 300w driver. You should be able to pick them up, used, for $20 on any weekday. My favourite mod: use a 90" fitting from a rainwater down-pipe to extend the port length and lower the tuning frequency by around 10hz.
Attachments
Maybe not very well. Cheap systems have cheap subs; money and physics prevent them from going very low or moving much air. If you can do the woodwork MAKE IT, you'll be more satisfied.
Bass is a funny thing, you may be listening at an overall low volume but you literally cannot hear the lowest notes unless they are fairly loud. Due to the nonlinear nature of hearing* they may not *seem* very loud; also because of this small changes in the bass volume control can make huge changes in the apparent bass volume
--> Ya need a really handy sub level control!
I would want a frequency response out of the sub that is kind of tilted up towards the lowest frequencies, which in conjunction with the sub level control will function vaguely as an adjustable loudness control. If you port, under-tune the port to get a more gentle low end rolloff. And a less steep lowpass filter would be good for that as well: Harrison's crossovers when I measured seemed to be stacked 1st order filters, so this thing would let you play around and it's not too expensive Parametric Crossovers Or were you going to use a plate amp with built-in crossover? MUST be adjustable if so. Or what ARE you going to use for an amp?
Also consider that bass shakers might do what you want more simply. They are also sensitive to level, but dialed in well really add a dimension to, say, the THWACK when the Terminator smacks guys in the bar with a pool cue and then the rumble when he rides off on a motorcyle.
*Search "fletcher-munson"; this paper is the one where they found that if your sub can't generate fairly high sound pressure at low frequencies, it is useless AES E-Library >> Subwoofer Performance for Accurate Reproduction of Music
Ported is probably optimal in terms of output vs size. However, sealed boxes have a few advantages for home HiFi:
- There's no lower cutoff. All sealed boxes can produce 1Hz, but SPLs may vary.
- The relatively shallow rolloff tends to fit better with typical room gain. Very variable, though.
- The box can typically be small.
I use ported boxes for my PA systems because I want the extra output, but don't want huge (horn) cabinets.
Chris
So, what's wrong with a good'ol easy-to-make sealed box instead of a poorly implemented ported one?
Bass reflex is not the immediate answer for any and all needs.
Closed box: It's a good suggestion, and under a bed I would rather have a sealed box than a ported. Would not be able to sleep at night wondering what could've crawled into the port
Nothing new that most manufacturers cut a heap of corners and since "seems impressive" sells way more than "accurate", it's no wonder there's so much shiny trash on the store shelves.
Ported is easier to get low bass from a cheap driver in a cheap system of plastic, but the quality of the low bass often suffers from it. Sealed needs a good woofer to go low, but it's very often a better sounding low, and in a room under a bed, sealed would be by far better i think. Especially for small cabinets as small ported cabinets need a very long port to go low.
Most of what you are saying has no place in reality. I've never seen a plastic subwoofer. Small systems do not require 'longer' ports. To maintain the tuning frequency you simply reduce the diameter.
Finally, your concept of a 'cheap' small driver is severely flawed. There is no real after-market for small sub drivers. If an individual is stupid enough to buy one from Dayton they'll charge you fifty bucks. All the tooling and R&D for that driver is paid for by Sony / Samsung / Yamaha. When these companies order 50,000 units Dayton will charge them $3 per unit.
The world is full of idiots who insist on paying for brands. Back when I was an apprentice, a set of rear brake pads for a Ferrari 308 would set you back around $400. However, Ferrari are owned by Fiat and there's no way they would re-tool for such a rare component. Be smart enough to ask the dealer for Fiat 128 front brakes pads you'd receive the same product for $30.
Because you've no practical experience you have no idea what you're talking about. Is the bedroom carpeted? Should the damping provided by the carpet and the mattress enter the equation? What are the implications of a 200mm wavelength?
The guy wants the 40-80Hz range reinforced in his bedroom at low volumes - that was the question.
Answer that.
Me no experience, check again... I don't post all projects i do, but i did post a few (mostly on the fullrange section) and i did build many speakers, especially subwoofers. I'm not the "know it all" down here, but i surely got some experience.
Reducing the port diameter raises the air velocity, often to high (above 17m/s) so the port start having coughing noises on higher volumes.
And Dayton is a brand, not a factory, It's the brand that Parts Express use to sell OEM ordered speakers and other parts, partly designed in house, but partly by their OEM partners (worldwide) who make them for Parts Express/Dayton Audio just like they do for a lot of other brands.
So your arrogant post is full of nonsense... If you got something to say down here, make sure you have real arguments, and i'm ready to learn things (that's why i'm here), not to listen to arrogant people who talk ********.
Here you can find 4- and 8-ohm versions of the Anarchy subwoofer in 5.5” or 8” diameters. These were used in a tapped horn subwoofer build, one of which would fit nicely laid on it’s side under your bed. The tapped horn enclosure plans should still be floating around and should be trivial to construct for someone as experienced as yourself.
Last edited:
LittleMike's Anarchy Tapped Horn: LittleMike's Anarchy Tapped Horn | Home Theater Forum and Systems