Anyone know anything about subwoofers?

[swee'pea99]

Just bought one, it looks like this:

My plan was to stick it under a bench unit at the side of the kitchen, with a hole on the front panel to let the sound out from the hole. Imagine my surprise to find a cone on the underside pointing down!

My revised plan is to have a hole on the front, and also a gap of maybe 100mm between the floor and the bottom of the front panel (to allow the sound from the underside cone to get out). Does this make sense? Forgive my ignorance, but this is all new to me. I grew up with a wireless you had to wind up.

 

[Chrisz]

Should work fine. Subs generate low frequenc sound that tends to travel well through/around objects (that's why you hear the "boom, boom, boom" of boy racers but no tune).

It may make the sound "softer" but shold still be perfectly audible - what's the flooring like? A hard floor (ie no carpet) directly under the sub will help the sound more than a shag-pile carpet.

 

[GrumpyGregry]

Just bought one, it looks like this:
View attachment 5505

My plan was to stick it under a bench unit at the side of the kitchen, with a hole on the front panel to let the sound out from the hole. Imagine my surprise to find a cone on the underside pointing down!

My revised plan is to have a hole on the front, and also a gap of maybe 100mm between the floor and the bottom of the front panel (to allow the sound from the underside cone to get out). Does this make sense? Forgive my ignorance, but this is all new to me. I grew up with a wireless you had to wind up.

Coupling effect with it pointing at the floor. If the floor surface muffles it try propping the leading edge up a bit. Bass frequencies at high volumes are generally perceived as non-directional compared with higher frequencies. Something to do with evolution no doubt. Earthquakes vs sabre toothed tigers or some such.

When playing electric bass I use a speaker cabinet with a downward firing woofer btw.

 

[swee'pea99]

Thanks Greg. I don't think I've explained myself very well. The thing is, I was planning to hide the thing away in a boxed-in bench, cutting a 6" hole in the front panel, covered with a metal grille, to let the sound out. Now it looks like doing that is going to leave a lot of (downwardly-projected) sound 'unable to get out' of the box and into the room. So my revised plan is to have the front panel of the boxed-in bench stopping perhaps 6" above flor level, leaving a sort of letterbox slit for the downward sound to get out into the room. Does that make sense? (Is it comprehensible?)

 

[GrumpyGregry]

You were going to enclose an enclosed sub-woofer in another enclosure....? At high sound pressure levels (loud) this could have destructive effects on the speaker cone. But if it is never going to be driven hard you should be ok. Especially as it isn't going to be pulling a lot of amps down that power cable Is it some sort of PC home entertainment speaker system type thing?

Anyway the slit at the bottom of the off the front panel sounds like the way to go.

 

[Dan B]

Bass frequencies at high volumes are generally perceived as non-directional compared with higher frequencies. Something to do with evolution no doubt.

Physics, I think, mostly. Phase differences between one ear and the other are less pronounced when the wavelength is very long; also, low-frequency sound tends to pass straight through the skull whereas high frequencies are blocked.

 

[GrumpyGregry]

Physics, I think, mostly. Phase differences between one ear and the other are less pronounced when the wavelength is very long; also, low-frequency sound tends to pass straight through the skull whereas high frequencies are blocked.

True but we have evolved the way we have because detecting/processing low frequencies offered no competitive advantage....

 

[Nigel-YZ1]

Subwoofers are intended to move air, rather than be overly audible.
The primary idea is to stop the case moving/vibrating, which is why many come with spikes for feet, which hold the cone a couple of inches off the floor. In fact one of the ideas is to sit them on a paving slab (not very pretty in the lounge!). If it vibrates the floor, then it's wasting it's energy - and treating your neighbours to the fallout. The hole in the side is a flow port to allow air behind the cone, so it can move easier.

I agree about not putting it in a box. Think of it as something that needs to 'breathe'.

 

[swee'pea99]

You were going to enclose an enclosed sub-woofer in another enclosure....? At high sound pressure levels (loud) this could have destructive effects on the speaker cone. But if it is never going to be driven hard you should be ok. Especially as it isn't going to be pulling a lot of amps down that power cable Is it some sort of PC home entertainment speaker system type thing?

Anyway the slit at the bottom of the off the front panel sounds like the way to go.

Apart from the PC bit, that's spot on. It's basically an add-on to a home hi-fi. I'm having tiny little monitor speakers in the four corners of a big room (to pacify 'er indores, who balked at even fairly small bookshelf speakers as 'far too big'), so I thought I'd add this to give it a bit of bottom end grunt. It won't be working hard. I'm edging ever closer to a 'letterbox slit'. But would I be right in thinking that if the hole in the side is a flow port, there's no need to cut a hole in the front panel for it (because it doesn't actually emit any sound)?

 

[GrumpyGregry]

Apart from the PC bit, that's spot on. It's basically an add-on to a home hi-fi. I'm having tiny little monitor speakers in the four corners of a big room (to pacify 'er indores, who balked at even fairly small bookshelf speakers as 'far too big'), so I thought I'd add this to give it a bit of bottom end grunt. It won't be working hard. I'm edging ever closer to a 'letterbox slit'. But would I be right in thinking that if the hole in the side is a flow port, there's no need to cut a hole in the front panel for it (because it doesn't actually emit any sound)?

It's a 'ported enclosure' the physics and performance of which start fights amongst bass players. So long as you have free movement of air around and in and out of the enclosure then job is a good 'un. But don't be surprised if it makes either the front panel or your bench or other things in the room rattle in harmonic sympathy. Now if it was me I'd be fitting it inside the chair I sit in to listen to music so I can feel the bass. If you want a laugh google "Euphonic Audio Rumble Seat" and picture the scene. A woofer in an enclosure that you sit on when playing. It worked surprisingly well as a practise tool.

 

[swee'pea99]

A bit of rattling in harmonic sympathy sounds like the sort of thing to me! Thanks all.

 

[ColinJ]

Upholster it to turn it into a seat!

 

[GrumpyGregry]

Ages ago I played a summer gig outdoors. I used a 1 x 15" cabinet and sat on it. I was wearing shorts. When I started playing the sensation of the air moving the hairs on my legs was well weird.

 

[ColinJ]

Ages ago I played a summer gig outdoors. I used a 1 x 15" cabinet and sat on it. I was wearing shorts. When I started playing the sensation of the air moving the hairs on my legs was well weird.

What - you don't shave your legs!
(Actually, I don't shave mine either, but as I'm getting older they seem to be getting naturally less hairy for some reason.)

 

[Milo]

Non ported is the way to go I think having had speakers both with and without. Just an opinion though.