Arman Posted July 12, 2005 Share Posted July 12, 2005 Hi all, I can't remember where I read that raising a subwoofer several inches off the ground is actually more beneficial... If you were to raise it, what would you do - place it on a stand or something? Any truth to this? 1 Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 13, 2005 Share Posted July 13, 2005 Raising it off the floor is actually a bad thing because it reduces boundary gain. AKA, being in a corner increases your bass response by a lot. The farther you move away from the corner, the closer to half space you get, which means you'll start to see a drop in the frequency response. The only time this would be beneficial is if your subwoofer had way too much output in the lower frequencies (which I don't think could ever be the case). Just curious, what subwoofer do you have and how close to the wall do you have it? I read your other 1/2" wall thing and I got the impression that you had the sub rather close. With an active rear driver you'll want to be a good 4"-6" bare minimum from the wall. Quote Link to comment Share on other sites More sharing options...
Arman Posted July 13, 2005 Author Share Posted July 13, 2005 DrWho, mi amigo...thanks for the quick reply. I have a RSW 15, I leave a 5 inch space on both sides of the subwoofer (from the walls). Should I move it out further? You are the man! 1 Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 13, 2005 Share Posted July 13, 2005 ---------------- On 7/13/2005 12:54:28 AM Arman wrote: Should I move it out further? ---------------- Try it and see what it sounds like. You might be surprised by how moving the sub around can drastically change the sound. Quote Link to comment Share on other sites More sharing options...
Colin Posted July 13, 2005 Share Posted July 13, 2005 Raising it off the floor is actually a bad thing because it reduces boundary gain. DR! your information is so right, but your statements are so wrong. Placing a subwoofer up on a very solid stand was one of the tweaks the late Dr. Harvey "Gizmo" Rosenberg recommended in his long-winded audiophile columns. Hoisting the thunder and explosion maker for your action movies onto a stand does create a monolithic black tower worthy of big ole horns, but visually, it overpowers all but the largest of loudspeakers. Enjoy the Music.com's spousal/wife acceptance factor (WAF) is low. This thing will not go over well with "she who must be obeyed." http://www.enjoythemusic.com/magazine/equipment/1004/ascsubtrap.htm Read over the part about mid and upper bass being locatable. The fact of the matter is that while corner placement improves the deepest notes, many subwoofers should be placed according to their mid-bass response. Raising a sub off the floor reduces boundary gain, but that does not automatically mean it a a bad thing. Quote Link to comment Share on other sites More sharing options...
picky Posted July 13, 2005 Share Posted July 13, 2005 I have my RSW-15 raised 4" Max on a semi-wedge-shaped stand that I constructed to allow speaker placement near a basement floor drain. The stand does not seem to affect the sound quality but it allows the sub to sit level over a very uneven portion of the concrete floor that slopes steeply towards the drain. The stand also provides some margin of safety for the speaker should a small amount of water ever come up through the drain. That has yet to happen, but I've got my fingers crossed. As a precaution, I have also installed check valves in the floor drains and the basement shower drain in the bathroom. That's one of the risks of having a basement theater. There is plenty of good, deep, tight bass in our theater, so I do not consider my sub stand to be a detriment to good performance. I was careful to calculate the compound angles of the floor to make certain the stand held the sub level. This was a rather tedious exercise in trial-and-error because the floor is at such odd angles. But, I got it! I was also careful to fit the stand with soft rubber feet to prevent it from sliding on the floor or buzzing when the large sub goes into action. Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 13, 2005 Share Posted July 13, 2005 Here's a short tidbit concerning how our ears hear: DIRECTION PERCEPTION The brain is able to detect the relative direction of a sound using the following mechanisms; Interaural delay Depends entirely upon time delays between similar excitement levels in each ear. The distance between each ear can be taken to be about 150mm. This means that there exists a vertical plane, running through the centre of the head, within which sound reach each ear simultaneously. The Effects of the Pinnae These are designed to collect frontal sound and reflect it down the aural canal. Sound entering from above and behind must have been diffracted by the pinea and, as a result, slight spectral changes to the sound will have occurred (more on diffraction later). Subtle Head Movements These assist in determining the height of a sound source in the medial plane (as described above). -http://www.kemt.fei.tuke.sk/Predmety/KEMT320_EA/_web/Online_Course_on_Acoustics/index_acoustics.html First of all, changing the height of the sub only changes in the vertical plane so we can ignore interauaral delay. And when we listen, we don't usually move our heads around that much either so let's ignore that for now. So now we're left with the pinnae which is very small relative to the wavelengths of low frequencies, which basically renders it useless as a tool for detecting direction. I only mention this to point out that the ear isn't built for detecting direction of low frequency sounds... I decided to post this pic as I used it to calculate the change in angle between a normal sub and one sitting on this platform. I figured most of us listen about 15 feet back and our heads are about 3 feet off the floor. I then measured the angle from the center point of each driver. All that to say, I highly doubt that there is $400 worth of difference by raising the sub...and raising the sub isn't necesarily better either. His descriptive adjectives "tighten, define, detail and image the mid-bass better" sounds to me like he's just hearing less bass...which many mistakingly refer to as these adjectives. Personally, I don't want any midbass coming from my sub...80Hz is well into the low range of things. Quote Link to comment Share on other sites More sharing options...
mbajner Posted July 13, 2005 Share Posted July 13, 2005 go to this link http://www.audioholics.com/techtips/setup/index.php a lot of info on setting things up, especailly subwoofers which really are harder to get just right as others have mentioned, do not be afraid to try different positions for the sub you might find that "the corner" placement is not always the best place I know for my M&K sub, corner placement is the worst mine is place on the left side wall about 1/3 from the front wall and about 6" off the side wall you should also try the Stereophile web site for info too Quote Link to comment Share on other sites More sharing options...
Speedball Posted July 13, 2005 Share Posted July 13, 2005 I put my cylinder sub on spikes and on top of a 2 dollar square slab of concrete (painted flat black) to stop the violent house shaking. May be different for you. Quote Link to comment Share on other sites More sharing options...
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