Help with room acoustics? (Sierra-1 L/C/R)

[Stump909]

floor.jpg

Attached is a picture of my apartment floor plan. My couch is backed into the straight living room wall and my speakers are placed on stands near the corners of the oddly shaped living room wall (8" of space behind them/ear-level). I have a TV stand in the middle of that wall, and my center sits on a pair of auralex isolation pads angled 4 degrees up (ear level as well). Clearly this setup is not working at the moment. When listening to the test tones of my speaker calibration (Trinnov/R-972), it's quite apparent the bass output is greater from the Left, compared the the Center and Right. As a result, my calibration chooses to play dialogue through a phantom center. It sounds great when sitting straight ahead, but move an inch left or right and speaker localization becomes horrendous. When I turn off the calibration and play 5.1 material without processing, the center sounds dull and isolated (still better than the phantom if I don't feel like sitting center)

So far I've tried swapping out both sets of Q-plugs, moving the center more forward (12" of space), but the dull bass of the C/L remains. I'm guessing it's room cancellation issue. Should I try pushing all the speakers against the wall with the A-plugs? Any possible suggestions?

[natetg57]

I think if anything, you want more space around the speakers. Can you flip your room around? I would try the couch on the odd shaped wall and the speakers on the long wall. That would give them more space on the sides.
Another option would be to use sound deadening panels. They can make your room act as if it is bigger.

[Blutarsky]

I agree with Nate. That odd shaped alcove is problematic.
B.

[FirstReflect]

From your description, there are a number of acoustic issues to consider:

1) First and foremost, consider the placement of your seats. Having the seat pushed right back against a wall is a big problem. It's very common. Lots of people push their seat against the wall for looks and floor space. But acoustically, it's the worst. You get very strong, easily noticeable reflections of sound waves coming off the wall directly behind you. And bass builds up along walls and in corners.

So, pull your seat as far away from the wall as you reasonably can. Even if that is only 1 or 2 feet, it will help. And if you cannot get a good amount of distance (3 feet or more), then you should definitely put some bass traps behind you. 6 inch thick bass trap panels from GiK Acoustics or Acoustimac would be very effective. 2 or 3 of those 6 inch panels would be best. 4 inch panels are decent if the 6 inch panels are just too big or expensive. Again 2 or 3 of those panels. And if dedicated bass trap panels are just a total no-go for some reason, then try to do anything you can to get something plush and absorptive behind your seat. Big pillows, a thick wall hanging, thick drapes. Just something to cut down on the sound wave reflections and trap some of the bass.

2) Next is speaker placement. I agree with the suggestions above. But if you cannot rearrange the way the room faces, try to get your speakers as far away from the side wall and the wall that is behind the speakers as you can. Again, if you cannot get a good size distance of at least 2 feet from the side wall and 1 foot from the wall behind the speakers, then you should definitely acoustically treat the wall with 2 inch or 4 inch acoustic panels, or use those pillow, thick wall hanging, thick drapes, etc. Again, you're trying to reduce the strong reflections, and trap some of the bass.

If you're within a foot or so of any wall, use the "solid" Q-plugs to essentially make the Sierra-1 into sealed speakers.

3) From your description, it sounds as though you might have your Front Left & Right speakers toed in a great deal. It sounds like you maybe put them in the corners and then aimed them pretty much straight at your face.

If you can, get them out of the corners. You don't want them closer together than about 6 feet at the absolute minimum. The ideal is to have anywhere from a 45 degree to a 60 degree spread in between them. But they are not supposed to go in the front corners.

And as for the toe in, start with them basically facing straight forward. Have a listen, and then gradually toe them in little by little, having a listen each time you make a change. The Sierra-1 have wide, even dispersion. They should not need to be toed in heavily. And if you do toe them in heavily (and basically have them aiming right at your face from the corners) you'll get what you described, where the "phantom" Center image collapses the moment you move your head. With them positioned closer to firing straight ahead (no toe in at all), they should create a fairly wide "sweet spot", even when the Center speaker is not playing.

4) Since bass seems to be a big problem for you, do you have a subwoofer?

The best spot in your room for producing nice, even, linear bass is rarely the exact same spot as your Front speakers! That is why I always recommend using a subwoofer (or better yet, 2 or 4 subwoofers), and setting your speakers to "small" in your AV Receiver, even if they are big Tower speakers! It is not about the loudness or even the deepness of the bass. It is about getting even, linear, accurate bass. And when it comes to bass, because the bass sound waves are so long and strong, we do not hear them directly. Not ever! What we hear are reflected bass sound waves that bounce around any room. Your room would need to be over 90 feet long in every dimensions before you would actually hear bass waves directly! So it's all about finding the best spot in your room where a subwoofer can send out its sound, and then the bass waves bounce around, interacting, cancelling, doubling up, and going through every form of interference with themselves, before you finally hear them at your seats!

5) If subwoofers are a no-go, and you must run your Sierra-1 speakers "full range", then it's simply going to be all the more important that you get your seat in a good spot, get your speakers in good positions, aim and setup your speakers optimally, and then treat the heck out of your room acoustically. With bass traps in the right places (mostly the vertical corners, the wall behind your seat, and any wall that is within 1-2 feet of your speakers), you should be able to get nice, even bass.

6) After taking care of the seat, speakers placement, speaker setup, room acoustics, and subwoofer placement - only after all of THAT is a room correction system, like Trinnov or Audyssey run in order to be the "cherry on top". Automated room correction and EQ programs can help bring a very good system to greatness, but they cannot make a bad setup good They're not a panacea! But after everything else has been optimized as best as possible, then an auto-EQ program can clean it up another few notches

[Stump909]

Thanks everyone. I'm going to definitely see what can be done with these suggestions.

[Stump909]

Hey Jonathan, I appreciate the help. If you don't mind, I was wondering if you had any advice regarding the center speaker. I feel the fact it's completely neglected after calibration (plus sounds isolated and dull in direct) means it's placement has some issues as well. I've moved it as far from the back wall as possible (12") and that didn't seem to help. I've also utilized the plugs without much improvement (I may have skipped the A after the replacement, so I'll retry that). Could the sideways TM design of the center be a problem in such a small space. Would it be worth trying to rotate the tweeter 90 degrees and standing it up right?