Why do subwoofers need to be so big and heavy?

[Defcon]

I hate this trend. Yes I know bass reproduction is cabinet volume, resonant frequency etc - the laws of physics canna be altered, laddy !!

But, but - there are alternatives. Use a sonosub cylinder design, or use a material other than MDF (or HDF, stupid Monoprice) like ply/balsa to save weight. What about other possible designs like horn loaded - can they save in size by increasing internal effective volume?

Everyone just takes a massive box, does some basic calc in WinISD, adds a driver + amp + port, and thats it. If you look at the higher end oem's like Paradigm, you see other options like multiple dual oppossing woofer designs (same is seen in Seaton Submersive, PSA as well) but its not common.

I honestly don't think this is the ultimate in sub design.

 

[William Lemmerhirt]

Lol! Well if it’s sooooo easy, where’s your design?

 

[shadyJ]

As you implied, subwoofers don't need to be heavy, but then there will be a compromise somewhere in Hoffman's Iron Law. The alternative designs that you mentioned do not avoid those physics, they just put them in a different shape or configuration. In order to get around the present limitations, you would need an entirely different kind of transducer. A cone driven by an electrodynamic motor is going to stuck with the present limitations. I think that someday a new audio transducer will overturn conventional loudspeaker drivers, although I have no idea what form it will take. I do think that future transducer may be able to reproduce deep powerful bass without a gigantic enclosure. I also think it will be vastly more efficient. Traditional cone loudspeakers are about 1% efficient; 99% of the energy sent to regular loudspeakers ends up wasted as heat byproduct.

 

[Drunkpenguin]

I get what op is saying. Lightning isnt heavy and its louder than anything. Maybe future generations will enjoy subs made of electricity. This may sound silly, but i imagine there is a better design that hasnt been discovered yet.

 

[TLS Guy]

I get what op is saying. Lightning isnt heavy and its louder than anything. Maybe future generations will enjoy subs made of electricity. This may sound silly, but i imagine there is a better design that hasnt been discovered yet.

How long would you like that sub to be? There already have been "electric" tweeters starting with the Ionofane.

These have no moving parts and use the brush discharge principle associated with lightening. However voltages are very high and they poison their owners with ozone. FR is well in the HF range.

Lightening has enormous voltage in the millions of volts, and sparks enormous distances across the sky cloud to cloud and cloud to Earth, so that it has a long enough path to generate the very long wavelengths of frequencies that generate deep rolling thunder.

So you are up against the long wavelengths of low frequencies. People say subs are all about moving air, yes but even more about creating pressure change to move that air. A vibrating cone is very inefficient as it created little pressure. What is required is an acoustic transformer that makes the vibrating element vibrate in a very high pressure environment and transform that into large displacements of air. Of this the horn is the most efficient and pipes second. However they are very large, significantly larger then the resonant ported box.

The only way to get the size down is to put the driver in a small closed box and overdrive it like mad. Actually a very nasty solution indeed, but the only one so far practical to get the size down.

 

[snakeeyes]

I like the look of current designs. The 12in subs aren’t too big. The 18in are maybe what is crazy.

I do see some subs are now coming in white instead of black. SVS has had the white SB1000 and Rythmik has a white F12SE now.

 

[lovinthehd]

While it might be nice if technology changes speakers/subs size I'm not holding my breath. As to using plywood, JTR does. DIYers often do as well.

 

[j_garcia]

My sonotube sub was 5ft tall. You aren't really giving up volume, just repackaging it.

 

[pewternhrata]

Would a light sub 'walk' across the floor?

 

[Irvrobinson]

Lightening has enormous voltage in the millions of volts, and sparks enormous distances across the sky cloud to cloud and cloud to Earth, so that it has a long enough path to generate the very long wavelengths of frequencies that generate deep rolling thunder.

Not only that, but lightning is produced by cumulonimbus clouds, which take up a lot of space and weigh a lot too. I fly a lot, and having flown around more than a few of these clouds, I can pretty confidently say that they're bigger than any subwoofer. Even those 24" things that occasionally make me think I need a pair of them.

On a more serious note, the evidence says you can choose materials that significantly lighten a subwoofer. For example, compare the Funk Audio 18.0 and the Velodyne DD18 Plus. 18.0's cabinet is made from Birch plywood and the driver uses a neodymium magnet. The DD18 Plus cabinet is made from MDF, and uses a steel magnet. The 18.0 has a shipping weight of 115lbs and the DD18 Plus ships out at 142lbs. Performance-wise the two subs are very similar, as measured by Josh Ricci.

 

[shadyJ]

On a more serious note, the evidence says you can choose materials that significantly lighten a subwoofer. For example, compare the Funk Audio 18.0 and the Velodyne DD18 Plus. 18.0's cabinet is made from Birch plywood and the driver uses a neodymium magnet. The DD18 Plus cabinet is made from MDF, and uses a steel magnet. The 18.0 has a shipping weight of 115lbs and the DD18 Plus ships out at 142lbs. Performance-wise the two subs are very similar, as measured by Josh Ricci.

If you wanted to get super fancy, you could probably use carbon fiber as a enclosure material and lighten that load up even more. And the stronger the motor is, the less cabinet volume is needed, so if you has a really beefy neo motor like Funk's, you don't need a big cabinet.

 

[Defcon]

Actually you could use plastic as the material - there is pretty much no material property you can't do with plastics these days.

Or how about building a chassis with e.g. steels, just the edges, and use a much lighter/thinnner material for walls, and a strong cage for driver mounting? There is no need for 1.5in thick walls.

There are many options. No one has bothered to try because why would they, subs are a small market anyway and people think size/bulk == good.

 

[lovinthehd]

Would a light sub 'walk' across the floor?

I figure my subs weigh approx 85-90 lbs each, made from plywood, and before I put feet on them they scooted on the carpet....

Actually you could use plastic as the material - there is pretty much no material property you can't do with plastics these days.

Or how about building a chassis with e.g. steels, just the edges, and use a much lighter/thinnner material for walls, and a strong cage for driver mounting? There is no need for 1.5in thick walls.

There are many options. No one has bothered to try because why would they, subs are a small market anyway and people think size/bulk == good.

Lighter materials like carbon fiber, metal frames, etc along with the technology all cost significantly more than plywood let alone mdf. At one point the weight for shipping wouldn't matter due to the bulk (volume/weight ratios are used for determining chargeable weight for shipping purposes).

 

[William Lemmerhirt]

There are many options. No one has bothered to try because why would they, subs are a small market anyway and people think size/bulk == good.

Ummm...It’s more that size is a necessity. Have you ever encountered a subwoofer that is small and has exceptional playback capabilities? I doubt it. Unless it’s in a closet maybe... No matter what the materials are, you still have to deal with physics. Try this.
http://sites.psu.edu/speakerdesign/2013/01/24/hoffmans-iron-laws-of-speaker-building/
So it seems you feel like there is an industry conspiracy to keep things huge for no apparent reason. I can assure you this is not true. You also seem to have the answers, so could you possibly humor us with a design that is light and small and amazing? Just curious to see how you’d do that.

 

[pewternhrata]

I figure my subs weigh approx 85-90 lbs each, made from plywood, and before I put feet on them they scooted on the carpet....

Haha that's great. Especially on carpet, excellent job.
My dad had a cambridge HTIB for a room he rarely used, the tiny 8" sub would spin in a circle if it wasnt for the cable. (Tile floors)
Thankfully his theater room had a much better setup, the cambridge sounded pretty good, especially for the money but, that sub bouncing around was annoying

 

[lovinthehd]

Haha that's great. Especially on carpet, excellent job.
My dad had a cambridge HTIB for a room he rarely used, the tiny 8" sub would spin in a circle if it wasnt for the cable. (Tile floors)
Thankfully his theater room had a much better setup, the cambridge sounded pretty good, especially for the money but, that sub bouncing around was annoying

I'd heard about it happening and at first didn't think there was anything to it then after testing with a couple movies of significant bass content I noticed it had shifted position a couple inches (fairly much a straight line, tho IIRC). This was not on a shag or very thick carpet and without padding which may have played a role. Was planning to put feet on it in any case but thought I'd check it out first.

 

[pewternhrata]

I'd heard about it happening and at first didn't think there was anything to it then after testing with a couple movies of significant bass content I noticed it had shifted position a couple inches (fairly much a straight line, tho IIRC). This was not on a shag or very thick carpet and without padding which may have played a role. Was planning to put feet on it in any case but thought I'd check it out first.

Heres your wow factor. You have some friends over, you tell them "my subs are soo bad @ss I had to bolt them to the floor" the look on their faces would be priceless.

 

[lovinthehd]

Heres your wow factor. You have some friends over, you tell them "my subs are soo bad @ss I had to bolt them to the floor" the look on their faces would be priceless.

LOL not likely. Most of my friends give a rats-ass about audio gear let alone subs (which most think I'm a little overboard on ).

 

[pewternhrata]

LOL not likely. Most of my friends give a rats-ass about audio gear let alone subs (which most think I'm a little overboard on ).

Most of my friends dont care either. They are always intrigued by the quality, but they dont think it's the worth the money over a cheap soundbar, almost breaks my heart lol.

 

[snakeeyes]

Actually you could use plastic as the material - there is pretty much no material property you can't do with plastics these days.

Or how about building a chassis with e.g. steels, just the edges, and use a much lighter/thinnner material for walls, and a strong cage for driver mounting? There is no need for 1.5in thick walls.

There are many options. No one has bothered to try because why would they, subs are a small market anyway and people think size/bulk == good.

Plastic? Sonos subs are made with some plastic I think and are light weight. LOL.