[xyzkum]

Hello,

Please give me some advice on speaker and subwoofer placement.

For now the subwoofer has been placed under the table

Thanks,

[WGH]

General rule of thumb is place speakers and sub where it sounds the best. If the sub sounds good under the table leave it there. Speakers 6'-8' apart and 2' from the front wall.

I only have one spot in my living room where the sub fits, so that's where it went. Luckily it sounds good there.

Usually we ask for more info about room size, furnishings, perhaps a drawing with doors and windows, a few photos, speaker model and electronic description, woofer model and size, type of music you like (headbanger or classical), your age and do you have any tattoos. 

[nlitworld]

Tattoos are important for this issue. Lol.

If your sub has variable phase adjustment rather than just a 0°/180° switch, then it does make it a bit easier to implement in less optimal placements. The more out of phase you have to set it can smooth out room response but at a cost of sometimes sounding muddy and vague. Just food for thought.

[Letitroll98]

Go over to the Enclosures circle and check out the speaker placement links.
https://www.audiocircle.com/index.php?topic=87093.0

[Mike-48]

I position subs in a fairly complex way, but the method gives me the best (flattest) bass response, which is my goal. It depends on measuring equipment like REW + UMIK1 or the Dayton OmniMic2 system.

Think about the possible positions of the sub.

In each position, measure combined frequency response of the main speakers and sub, 15-300 Hz, while adjusting the sub's phase control (if it has one) or polarity switch for flattest response at that position. (The adjustments will be different in different positions.) Save a graph.

When you have done, some patterns will emerge. There is usually one very deep null in the audio range that can be filled with the sub in only one or a few positions. There you have it! Or if you are blessed with a room that does not generate a deep null, pick the spot that has the flattest response overall.

People have all kinds of theories about how to do this based on room dimensions, etc., without measuring the actual frequency response. The problem with such approaches is that wall materials and furnishings affect the results strongly. In addition, setting sub phase correctly has a large influence on overall flatness.