Placement of Single Subwoofer Affecting Sound of Main Speakers

Hey, and yes, but I didn't know it could happen with a direct radiating subwoofer. :)

The effect you may be having is that the sub is acting like a tuned bass trap, OR you are finding it's reflecting a lot from the speakers.  The latter can be tested with a blanket.  If the blanket covering the sub fixes your problem it's purely an acoustic reflection issue.

If it sounds about the same it's probably because the sub is sucking an octave out of the room.

Thanks for all responses. I find the below from Mapman particularly useful.

Ideally you want one sub front and center. Front and slightly off center is next best. Avoid the corners. Rear center is another decent option especially if you sit closer to the sub than the front mains. You can get away with a lot with sub placement though when needed especially if sub is set to not do much above 60-80 hz or so.

The corner placement with a single sub mirrors my experience. The current placement at the rear of speaker slightly away from the corner yields much better result. However, the effect or impact of a working sub is minimal since I have to set the crossover quite low at around 50 Hz. I tried setting it up to 60-80Hz and the sub is doing more harm than good with the bass sticking out like a sore thumb. Turning down the volume helps but there’s very little to no difference with the sub switched on or off.

I will likely try the 3rd option by pushing the sub further out to the centre of the room / speakers but it cannot be directly at the centre. When I tried this placement about a week ago, I recall the sound to be good but again the impact of the sub was minimal. Pushing the crossover and volume up too much and the bass sticks out too much. I will attempt this placement again once I receive the Nobsound springs.

I understand 2 subs(or more) are better but it is out of question. It is either 1 or nothing at all.

Should ask what sub are you using and what speakers? Also consider using white noise and a sound meter ( app on smartphone) to get an idea of what is going on in regards to sub filling in lowest octave at your listening location smoothly. Some speaker sub combos may not be matched well to accomplish that.

The effect you may be having is that the sub is acting like a tuned bass trap, OR you are finding it’s reflecting a lot from the speakers.

Yes, either one must be true. Somehow any furniture in the room will affect the sound, especially things placed very close to the speakers. I tried placing a 2nd set of speakers just beside the main speakers in an attempt to run 2 pairs of speakers in the system. I hoped it would work but the sound was ruined. In the end only a pair of speaker can remain in the room.

Should ask what sub are you using and what speakers? Also consider using white noise and a sound meter ( app on smartphone) to get an idea of what is going on in regards to sub filling in lowest octave at your listening location smoothly.

The sub is a PMC TLE1 (dual 6.5" woofer, transmission line) and the speakers are Marten Duke 2. Will try the more advanced set up method you brought up sometime. At the meantime, using the ears will do it for me. I have a Radioshack SPL meter though.