Will elevating speaker height help countering vertical bass null?

[Mentalrudy]

Hi there,
Found out I have a huuuge vertical bass null in my room, in all practical seating positions. Is there sny chance of countering it by elevating speaker height, f.i. Wall mounting active monitors?
Grts!

 

[andreasmaaan]

Could you explain what you mean by "vertical bass null"?

If you mean a cancellation resulting from the floor reflection, then elevating the speaker will shift the frequency of the cancellation but not eliminate it.

Or maybe you're talking about something else?

 

[Mentalrudy]

Could you explain what you mean by "vertical bass null"?

If you mean a cancellation resulting from the floor reflection, then elevating the speaker will shift the frequency of the cancellation but not eliminate it.

Or maybe you're talking about something else?

Hi,
Yes, bass cancellation at seating height. It’s ok when standing upright, but when i sit down, bam! Practically no bass from 70-60 hz down.

 

[TankTop]

Do you have solid flooring or carpet?

 

[Mentalrudy]

Do you have solid flooring or carpet?

It’s a wooden floor. Not suspended but over concrete floor plate. Do have a large, thick carpet between speakers and listening position

 

[Eetu]

Could you share your room dimensions? And do you have an idea where in the freq range the nulls are exactly (maybe with the help of test tones or a mic)? 50hz?

If it's really the vertical (floor-ceiling) room mode null I'm under the impression your seating position would have to be around 1/4 room height (edit: to be in a null). But I'm guessing it's a combination of room modes & SBIR

Here's a couple of useful calculators for these different effects:
Room mode
Floor/ceiling bounce
SBIR

 

[pozz]

If it's a room mode, you can help the situation but not cure it with EQ and bass traps (real ones: Helmholtz or membrane-type).

If it's a standing wave, the above will be more effective, but shifting speaker and listening position will help the most.

Given the frequency range, I would assume it has something to do with the 8-foot ceiling common in NA, and is therefore a room mode.

 

[Mentalrudy]

If it's a room mode, you can help the situation but not cure it with EQ and bass traps (real ones: Helmholtz or membrane-type).

If it's a standing wave, the above will be more effective, but shifting speaker and listening position will help the most.

Given the frequency range, I would assume it has something to do with the 8-foot ceiling common in NA, and is therefore a room mode.

Yes, the ceiling height is exactly 8 feet.

 

[Mentalrudy]

Could you share your room dimensions? And do you have an idea where in the freq range the nulls are exactly (maybe with the help of test tones or a mic)? 50hz?

If it's really the vertical (floor-ceiling) room mode null I'm under the impression your seating position would have to be around 1/4 room height (edit: to be in a null). But I'm guessing it's a combination of room modes & SBIR

Here's a couple of useful calculators for these different effects:
Room mode
Floor/ceiling bounce
SBIR

Should look up the exact dimensions but it’s close to 8m20x6m70x2m40

 

[Duke]

bass cancellation at seating height. It’s ok when standing upright, but when i sit down, bam! Practically no bass from 70-60 hz down.

Significantly changing the height of the woofers may help. You might try the speakers upside-down to keep the tweeters at or near your desired height.

Adding an overlapping subwoofer near the ceiling (instead of on the floor) may help even more, as this will distribute your bass sources significantly in the vertical plane. Ideally the subwoofer would have a continuously-variable phase control, as that can help fine-tune the net result.