Myths about subwoofers

[spooony]

I'm still new learning this stuff but got about half the guy explained there. I have a question how do you know when walking into a store what a subs peak to peak is?

 

[bikdav]

Response

It really sucks that this link was taken down.

You may have hit it when something was wrong at their end. That happens at times. I opened it in a "new tab" and got right in. This article is good.

 

[bikdav]

This article is fantastic. There are lots of things said here that I have questioned. In the sealed verses ported section, there are lots of things that I just cannot here - pro or con. So far, my ears lean toward ported. Thank you for sharing this.

 

[haraldo]

The Science of Subwoofing

Checkout his, quite good reading from my point of view:
Even though it's quite old.......

http://www.stereophile.com/features/189subs/index.html

 

[haraldo]

Audioholics on Facebook to receive advanced notice of reviews http://daxibeidelang.teasm.cn/Index.aspx

Perhaps you should check links before posting them.... it's broken....

 

[lavath]

I have a 4th order bandpass box for my home theater I just built. I actually sucks for when I play music but for movies, i tune its output from the pinacille pin amp 800 and perfectly makes the tension music for the score, its great for movies but too sloppy for pure music

sorry but I need 5 posts to show my home theater build page I made

 

[l0gikal1]

Nice find, interesting information presented.

 

[saywhat]

The biggest myth is subwoofers are omnidirectional and you can put them anywhere.
I laugh when I hear this as I know better.

 

[gtpsuper24]

The biggest myth is subwoofers are omnidirectional and you can put them anywhere.
I laugh when I hear this as I know better.

The freq subwoofers produce is omnidirectional no myth about that. But that doesn't mean you can place them anywhere, room interaction comes into play and you need to set them up properly to combat room modes.

 

[TLS Guy]

The biggest myth is subwoofers are omnidirectional and you can put them anywhere.
I laugh when I hear this as I know better.

At frequencies that subs should operate they are full space radiators. That means omnidirectional.

However if you place a sub against a wall, it can not be full space, it has to be a half space radiator.

The other issue is that some speakers require a high crossover point, and that will get subs radiating frequencies that are easily locatable.

I don't use subs, as I have true full range speakers, but I have certainly heard setups that I can easily locate the sub source for reasons that are not clear. I have suspected placing the sub adjacent to the wall is the culprit in most cases. The problem then becomes, most people don't like the look of subs away from the walls.

I think that if a sub has to be placed close to a wall, it should be in the front sound field close to the mains, and two used. Even then in one sub situations, I do know were the sub is, and it pulls the bass section of the orchestra to that side. I'm certain the reason is that people forget, a sub right against a wall is a half space radiator.

 

[Nestor]

At frequencies that subs should operate they are full space radiators. That means omnidirectional.

However if you place a sub against a wall, it can not be full space, it has to be a half space radiator.

The other issue is that some speakers require a high crossover point, and that will get subs radiating frequencies that are easily locatable.

I don't use subs, as I have true full range speakers, but I have certainly heard setups that I can easily locate the sub source for reasons that are not clear. I have suspected placing the sub adjacent to the wall is the culprit in most cases. The problem then becomes, most people don't like the look of subs away from the walls.

I think that if a sub has to be placed close to a wall, it should be in the front sound field close to the mains, and two used. Even then in one sub situations, I do know were the sub is, and it pulls the bass section of the orchestra to that side. I'm certain the reason is that people forget, a sub right against a wall is a half space radiator.

What makes a half space radiator locatable?

 

[lsiberian]

In my experience sub localization is the result of placebo and/or high crossover points. My sub is corner loaded and doesn't real have localization issues.

 

[saywhat]

if its omnidirectional then why can you take a person in a room turn on the radio and if they are blindfolded point in the direction the subwoofer is.
Bass sound and feel is HIGHLY DIRECTIONAL.
if it was truly omnidirectional i wouldnt be able to tell from where it came.

 

[Steve81]

if it was truly omnidirectional i wouldnt be able to tell from where it came.

FYI, there is a difference between saying bass is omnidirectional (i.e. it radiates in all directions from the source), and saying that it can be localized (i.e. you can tell where it's coming from). Depending on setup, it's possible to localize a subwoofer, though a 24db/octave crossover at or below 80Hz usually ameliorates such issues.

 

[saywhat]

FYI, there is a difference between saying bass is omnidirectional (i.e. it radiates in all directions from the source), and saying that it can be localized (i.e. you can tell where it's coming from). Depending on setup, it's possible to localize a subwoofer, though a 24db/octave crossover at or below 80Hz usually ameliorates such issues.

gotcha that makes more sense.

 

[j_garcia]

I don't think the idea is that it is truly omni-directional. The deal is, the waves from lower frequencies are longer than the average room. In that situation, you are essentially ALWAYS hearing a reflection, causing the situation where the bass seems to be present everywhere. Based on the room dimensions and where you are in the room, you will experience room modes as a result of the waves always being partial at the point at which they begin to bounce.

 

[lsiberian]

if its omnidirectional then why can you take a person in a room turn on the radio and if they are blindfolded point in the direction the subwoofer is.
Bass sound and feel is HIGHLY DIRECTIONAL.
if it was truly omnidirectional i wouldnt be able to tell from where it came.

It really does depend on the subwoofer, crossover, room and placement. Very few people have experienced a top of the line subwoofer system or setup. The deeper the LFE this less directional it is.

 

[Irvrobinson]

FYI, there is a difference between saying bass is omnidirectional (i.e. it radiates in all directions from the source), and saying that it can be localized (i.e. you can tell where it's coming from). Depending on setup, it's possible to localize a subwoofer, though a 24db/octave crossover at or below 80Hz usually ameliorates such issues.

In my experience this is correct. I also find that if the mains are run full-range and they have good bass response down to 40Hz or so it is very difficult to localize the sub.

 

[Steve81]

I don't think the idea is that it is truly omni-directional. The deal is, the waves from lower frequencies are longer than the average room.

FWIW:
Baffle Step Compensation

The so called "baffle step" is an increase in output from a loudspeaker as the size of the baffle becomes significant in terms of the wavelength of sound for a range of frequencies. At low frequencies, where the baffle (the panel the loudspeaker is mounted on) is small compared to the wavelength, the speaker is assumed to be operating with a spherical radiation pattern. While this may be the case should the speaker be situated up a tree in the middle of a field, it hardly qualifies as true when the same loudspeaker is installed in your listening room. There may of course be something about you that I don't know (for example that your speakers really are up in trees), but for the majority this will not be the case.


As frequency increases, the size of the baffle becomes significant, and the spherical radiation pattern no longer applies. This is also partly to do with the loudspeaker drivers themselves - as frequency increases, typical cone drivers become more and more directional anyway - this occurs as the dimensions of the cone become significant with respect to wavelength.

 

[ImcLoud]

I have to agree you can point out where 80hz is coming from but when you get really low, its tough to find the subwoofer... Although I heard a DIY sub that the ports whistled for some reason, that one was easy to locate... I just added the second vtf2 to my room and it makes it even harder to localize the bass, with the single you could kind of tell where it was coming from, but now with them in opposite corners, its a lot smoother...