• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Bass build up in diagonal opposite corner of subwoofer

soyabeaner

Member
Joined
Jan 26, 2019
Messages
31
Likes
20
My listening position is near the front wall where my subwoofer is in the front left corner close to my left speaker. In my small bedroom (around 11.75 x 9.5 ft) the back right corner is where the sub-bass is overwhelming (which I'd rather have at my listening spot). Other than bass traps or acoustic panels, would adding a second subwoofer in that back corner fix or mitigate this? I also plan to test by placing my existing subwoofer in the back corner to listen for curiosity sake.
 
In my experience and not as a expert but the dual subs are generally placed near the front speakers is what I found successful. But matters change and things are different sometimes. Let's see what the speaker experts have to say.
 
If a second subwoofer helps, while I would enjoy adding it to the front right to satisfy my OCD, it wouldn't work because that's where my door is. BTW, my back right corner where the excessive bass occurs is also where my open closet is, so likely another contributing factor.
 
If a second subwoofer helps, while I would enjoy adding it to the front right to satisfy my OCD, it wouldn't work because that's where my door is. BTW, my back right corner where the excessive bass occurs is also where my open closet is, so likely another contributing factor.
Have you used PEQ and a calibrated USB mike with software to analyze the room? For ~USD $90 you can get going that way.
 
Yes. UMIK-1 + REW + Equalizer APO was what started this.

Thanks to measuring my listening spot, I was able to EQ it, but ultimately ended up with my target curve of +12dB to 20hz by cranking up the subwoofer and then EQing down the peaks (for another reason in my attempt to combat the dips and notices between 100-300Hz due to Speaker Boundary Interference Response of my speakers being near the front wall and no room treatment). I know it's a crazy amount :facepalm: since I'm a basshead, but without it it doesn't sound satisfying. At first my target curve was a straight line down to 20hz (due to nearfield listening), but the bass sounded unnatural and less bassy before EQ. Of course the repercussion of +12dB meant the back opposite corner ends up with an ungodly amount of bass whenever I'm at my closet.

Then recently I cut my target cut in half to be 6+dB down to 20hz, and as expected, bass is still anemic at my listening spot, but at least the back corner is no longer out of control like when I had the +12dB curve. The back corner sound quite satisfying with the correct amount of subbass, so if only there was a way to switch that sound/sensation with my listening position and then it would be nearly perfect.
 
Last edited:
my subwoofer is in the front left corner close to my left speaker. In my small bedroom (around 11.75 x 9.5 ft) the back right corner is where the sub-bass is overwhelming
Is your sub pointed at the back right? If so, try a different angle, maybe sideways at the right wall?

I second a mike and some measurements, then eq/PEQ for the bass issues.

sub-bass is overwhelming (which I'd rather have at my listening spot)

Perfect reason to use the sub crawl. Put your sub in your seat, find the spot(s) on the floor where the bass is strongest, put your sub there. No measurements need, just a long RCA.

Good luck!
 
Is your sub pointed at the back right? If so, try a different angle, maybe sideways at the right wall?

I second a mike and some measurements, then eq/PEQ for the bass issues.
My sub is JBL LSR310s, so it's down firing. Changing the angle/direction won't matter and sideway position isn't practical due to how small my room is and how big my bed is, and it blocks my pathway. See my post above about my measurements.

Perfect reason to use the sub crawl. Put your sub in your seat, find the spot(s) on the floor where the bass is strongest, put your sub there. No measurements need, just a long RCA.

Good luck!
Thanks. Do you think sub crawl would eliminate the need for a second sub? Given how scarce my space is relative to the practical positions I have, I'm not sure this would work for me. I basically have my left front and right back corners for subwoofers.
 
Thanks. Do you think sub crawl would eliminate the need for a second sub? Given how scarce my space is relative to the practical positions I have, I'm not sure this would work for me. I basically have my left front and right back corners for subwoofers.
No idea, but it is free to try. And if you do find a spot, you can evaluate whether moving things around could work.

A second sub is generally a good idea, but you have a tight room, but if you only have two locations, better hope they work with both!

Do you expect to have a larger space in the near future? If so, maybe a second sub now is a better idea, given future uses/spaces.

How do you feel about hanging subs from the ceiling?
 
I've no plans to move. This has been my bedroom for eons and I've never even thought hanging subs is possible. I won't do any renovations to my walls, floors or ceilings. Despite my tight room, the back corner does have enough space for the sub. I've planned my setup after careful deliberation a long time ago and won't change it again. My experiment to switch the sub from front to back corner has definitely got my curiosity, so I'll do that when I have time and with no other family members around during the loud measurements.
 
My listening position is near the front wall where my subwoofer is in the front left corner close to my left speaker. In my small bedroom (around 11.75 x 9.5 ft) the back right corner is where the sub-bass is overwhelming (which I'd rather have at my listening spot). Other than bass traps or acoustic panels, would adding a second subwoofer in that back corner fix or mitigate this? I also plan to test by placing my existing subwoofer in the back corner to listen for curiosity sake.

Pressure build-up in corners is normal behaviour for bass. If you think of a sine wave, the point where the wave crosses zero has maximum velocity and minimum pressure. Where it hits the crest it has maximum pressure and zero velocity. Now if you think of a wall, it is not possible for air molecules to move. So the velocity has to be at zero, and pressure will be at maximum.

On top of this, there are two zones for bass - the pressure zone and the modal zone. The pressure zone is where a 1/2 wavelength is too long to fit inside a room, so it pressurizes it instead. For your 11.75ft room dimension, this corresponds to a freq of about 50Hz. The modal zone is between the pressure zone and the Schroder frequency, where bass behaves the way we expect to, it forms room modes. Where the modes are, and what freqs they occur at, depends on the room.

So I doubt if adding a second sub will help build-up of pressure in the corners. It will help smoothen out bass modes in the middle of the room, and more than likely a small room like yours does not need much smoothing because most of the room bass is in the pressure zone. Your Schroder frequency is likely to be quite high. As a guess, perhaps about 130-140Hz (I need the actual room volume and the T30 to calculate it). The only remedy I can think of is either don't listen there or turn your subwoofers down.
 
Previously I had my subwoofer at the front-right corner, and true enough there was bass buildup at the diagonally opposite corner. With some music tracks it got pretty bad and caused the cupboard at that corner to rattle.

I recently repositioned the subwoofer to the middle of the front wall. Seems to work better. No more cupboard rattle. REW measurement at the MLP showed a little less bass region amplitude variation (slightly more even bass i guess)
 
Last edited:
Might try placing the sub other than in a corner, if you can. Second sub may help smooth out response, tho sounds like placement options are limited?
 
Thanks for the suggestions. My earliest measurements had the sub at the front centre wall and the bass response at the listening position wasn't that much different from the corner, although back then I never paid attention to the back corner by the open closet. I may have to revisit that position, although it would require me to pull my desk back, leaving even less space between my chair and bed. However, as an easy test I can at least place the sub close to the front centre wall (under my desk) to check if it will reduce the back corner bass.
 
My sub is JBL LSR310s, so it's down firing. Changing the angle/direction won't matter and sideway position isn't practical
Those have a port, can you change the port direction?

You have room based problems, and there are a lot of limitations on what you can change. But I have a few additional suggestions that might help.

You clearly have a room node at the closet. But you also have some audio information shooting out of the closet, I assume up the side wall. Setting up the closet in different ways can kill more sound or less. That might come in handy, but how much sound is "some" I have no idea.

So I do think trying the sub near the closet is a good idea. But keep a clear line of sight to your listening position, make sure the bed is not between you and the sub.

Your bed is big, no matter what that means in numbers it means it covers up a lot of floor surface area for the room. That will eat a lot of sound near the floor. And since your sub is downfiring, there will be a lot.

You could try a corner placement where the sub is, speakers 3-4 feet apart.

You could try to shift your listening position back and maybe to the side a bit to try to pick up a good bass spot, even a few inches might help, a foot should be audible is my guess.

If you were doing just a listening room, there would be a lot more you could do. If you were looking to cut bass, ditto. But to get the big stuff down low, you will have to do whatever you can with location, but both with placement and seating position in mind. The bass will be different in each spot, there's no stopping that, so you have to work with what your room wants to do.

And if it makes you feel any better, even with far more options than you have, I make a choice on WHICH base node to live with, because there will always be at least one. I have lots of corners. :)
 
My bed setup is also strange because it's on top of a 16-inch high bedframe foundation to allow storage of various object/items underneath. It's a messy and busy room, but there's still enough space under the bed to allow bass waves to travel from corner to corner.
 
Bass reproduction gets harder the smaller the room because room modes occur at higher and higher frequencies. At the same time, equalizing them is only possible at ever narrower listening positions, the higher the frequency.
My own experience thas been that even in a large room a smooth response over a wide listening area is only possible with multiple subs and dsp room eq such as Multi Sub Optimizer. Personally I would not bother with subs in a room this small. If you really must, two is the minimum (with MSO), but three or four will be better. They don't have to be large or expensive. Perhaps the slim Monoprice subs that you can put under a bed are an option.
 
Last edited:
I use 2 SVS 3000 Micro's - basically 11 inch cubes. They do a good job and are very adjustable from your phone and have a 3 band equalizer that gives you a chance to correct some things.

One question - were you happy before measuring? If so, you could try not to "worry" and enjoy your "basshead" needs.
 
I was pretty content before measuring, but I already heard some narrow bass frequency spikes while playing test tones and sweep runs. Sure enough, measurements correlate to my listening experience to be ~140hz. So measurements have helped to tame it, along with various treble frequencies from my speakers.
 
Back
Top Bottom