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

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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?

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.

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

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 :)

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

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?

Hi, Stump909

Yeah, your center speaker issues are a bit puzzling. Especially you Trinnov auto-EQ program turning it off automatically! That is VERY strange, and would seem to indicate that it did not detect the speaker at all during the auto-calibration!

Having the Sierra-1 Center in the horizontal orientation should not be any problem at all. Arguments can be made that its dispersion from side-to-side could be even a tiny bit better if it were vertical, but that's honestly splitting hairs, and not the source of your current problem.

Having it decoupled using the Auralex MoPads is great! Not enough people decouple their speakers, in my opinion. But that's really just about stopping any rattles in your TV stand, and getting rid of any resonance that might come from the stand vibrating in sympathy with the speaker.

You mentioned that the Center speaker is at ear level and also aimed slightly upwards? If the Center speaker really is at ear level, then you shouldn't need to angle it upwards at all. Most people either have their Center speaker below or above ear level, so that is why we often recommend angling the Center speaker either upwards or downwards, respectively. But if your Center speaker is actually at ear level already, then you can have it aimed straight ahead. Otherwise, you're pointing its sound at the ceiling a bit. If you have the regular Auralex MoPads, they should have come with a very thin, removable wedge of foam that lets you make the MoPads flat, rather than angled. And if you have the MoPad HD, you can just turn them upside down to make them flat.

I'm not exactly sure how you have the Center speaker positioned on your TV stand. Make sure that the front edge of the Center speaker is proud of the front edge of the TV stand - that is, have the front edge of the Center speaker sticking out a little bit over the front edge of the TV stand so that none of the sound is getting reflected off of any surface of the TV stand. And the "solid" Q-Plugs are what you should use.

After all of that, and if you have moved your seat or your Front Left & Right speakers, you really need to run your auto-setup Trinnov program again. I suspect there might have been some errors when you ran it previously.

When you run any auto-setup program, there are a few things to do that not everybody knows about:

1) Before you start, make sure that your master volume is being shown in "Relative" or "THX" terms - which means that the volume numbers are negative numbers when you are changing the volume.

In case you are not familiar, there is a standard called "Reference Volume", which is the THX and commercial movie theater standard. On any AV Receiver, when the volume readout says "0 (zero) dB", that is meant to represent Reference Volume. And value quieter than Reference Volume is then shown in negative numbers to let you know how many dB below Reference Volume you are listening at. Reference Volume is very loud! 85dB average, with 105dB peaks in the speakers and 115dB peaks in the subwoofers! So, very few people actually listen at full 0 (zero) dB Reference Volume at home. Most people listen at least 10-20dB quieter, and many people prefer up to 30 or more dB quieter. So having the front panel of your AV Receiver show "-20dB" for your volume level is very normal.

Anywho, make sure, before you begin, that your AV Receiver is showing relative volume (negative numbers), and then turn up the volume dial (nothing is playing at this point...just silence) to 0 (zero) dB.

Technically, you are not supposed to have to turn the master volume to 0 dB before you start any auto-setup program. Technically, the auto-setup program is supposed to set the level of the test tones automatically. But I have had too many first hand experiences where what is technically supposed to happen doesn't! Doing a full factory reset of all the settings also works. But if you don't want to lose all of the settings you might have made to things like input names and which plugs are assigned to which input and whatnot, then it's easiest (and simple) to always just set your master volume to 0 dB before you run your auto-setup program.

2) With the master volume set to 0 dB, go ahead and plug in your auto-setup microphone to being your auto-setup program.

Now, here's the second trick: make sure your first position that you measure is your favorite seat, put the microphone at seated ear level (using a tripod or microphone stand), but make sure the microphone is 12-18 inches away from the back of your seat! I've seen a lot of people just set the microphone on top of the back cushion, or, even worse, right on the seat cushion. That's going to give you really bad results. Again, it's about reflected sound waves. The microphone needs to have at least a good 12 inches of free airspace all around it.

3) If your auto-setup program allows you to measure more than one seating position, start with your favorite seat, and then only ever use the width of a three seat couch for your other measurement positions. For example, if your favorite seat is the middle seat of the couch, your second and third measurement positions can be the seat on the left, and the seat on the right - again, microphone at seated ear height and 12-18 inches away from the back cushion. But do not put the microphone anywhere outside of that radius. For example, many people have a couch plus a single chair that is over to the side. It can be tempting (and seems to make perfect sense) to also measure over at that side chair. But do not do it! Stick to the width of a three seat couch. Again, auto-calibration programs can make a nice improvement, but they are not magic, and they are not a panacea. They all work best within a relatively small area. The width of a three seat couch is about perfect.

4) If your auto-setup allows for more than 3 measurement positions, keep the microphone within that same three-seat-couch width, but move the microphone forward or backward (most often forward) for the additional measurements. What you are trying to do is to provide your auto-setup program a sort of virtual 3D sonic image of your seating area. Thing of sitting in your favorite seat, and then having sort of a "bubble" around you. Anywhere within that "bubble" the sound should be good. Outside of that "bubble", maybe not so much ;) You want your auto-calibration program to get a good sonic image of that "bubble" area. So start with the mic at your favorite seat. Move it to the two seats directly next to your favorite seat. Then move the mic 12 inches or so forward so that the auto-setup program gets a good sense of your "bubble" area.

5) After it has completed, double check all of the settings that your auto-setup program made. Pay particular attention to the cross-over settings. I've never seen an auto-setup program get the cross-over settings correct!

If you do not have a subwoofer, then just set all of your speakers to "large" or "full range" or whatever name is used to indicate no cross-over. You would not do this for genuinely small speakers that really cannot handle any bass. But your Sierra-1 speakers are fine. You can set them all to "large/full range" if you do not have a subwoofer.

If you do have a subwoofer, then the Sierra-1 ought to be set to 60Hz for the cross-over. 70 or 80Hz are also fine. But I typically see auto-setup programs set the cross-over lower, like 50 or 40Hz. That's too low, and doesn't provide a good blend between the speakers and the subwoofers. So if you're using a subwoofer, manually set the cross-over for all of your speakers to somewhere in the 60-80Hz range.

6) That should do it for now! Errors from using auto-setup programs are very common. And any time you make a change to your room (move the furniture, move the speakers, etc.) you really should run the auto-setup program again. Also, while the auto-setup program is doing its thing, make sure that you are physically out of the way yourself (stand as far off to the side as you can), and keep everything quiet! Remember that the auto-setup program is still "listening" and measuring in between the test tones! Lots of people forget, and they start to make noise during the silent parts in between when the test tones are playing. Don't do that :) The auto-setup program also listens to the "silence" in order to measure ambient room noise and reverberations. So keep everything quiet until the auto-setup program is fully complete, or until it gives you the ok to move the microphone to the next measurement position.

Hopefully, this will be of some help. :)

Hey Jonathan,

I can't thank you enough. The amount of detail you're willing to provide to a total stranger is commendable. Many of the issues you described matched my setup perfectly. Actually, besides the toe-in, you were dead on 100%.

My rearrangement plan is as follows:

1. Move couch from 3" to 12" away from the back wall (2-3ft is pushing it).

2. Move the L/R closer together, maintaining 0 toe-in. When you say 6ft min, I assume the middle of the woofer is the start and end point? With the speakers 6 ft. apart (inside edge) I was getting about 40 degrees of separation. Moving the couch closer should expand that past 45, I hope. That amount of separation also gave me 12" from the back wall and about 16" from the side. I assume even with the 12", I should keep them sealed (a-plugs), correct?

3. While I said all my speakers are ear level, the center is a few inches lower. I'll maintain the 4 degree slope and hang the drivers over the edge. That should give me about 14" from the wall (still use the A-plugs?). Also maybe I should just level it out so the port doesn't aim slightly towards the glass stand?

4. When I remeasure, what's the best surface to place my mini-tripod on? Currently I've been placing it on stacked (and leveled) pillows with ~12" min. on all 4 sides. I figured pillows would be better than say books, but I'm pretty clueless.

5. Sadly my mic only measures one position, but it is technically 4 mic's in 1 haha.

6. I want a subwoofer badly (SVS SB-1000), but I'm not sure how apartment friendly that would be. I'll have to see how intrusive my current setup, when functioning, will be :p.

7. If those changes don't get me the results I need, I'll buy two 6" bass traps for the back. It's amazing how much fiberglass can run for. If I were to limit myself to, let's say, $150-200 dollars for panels. Would you say the rear bass-traps are the most crucial? I figure since I can move the speakers almost in the acceptable range, limiting rear reflections would be the most crucial. What would be your #2 option (assuming I have spare money afterwards)?

8. Finally, could just the room acoustics make my center sound so dull and isolated? Honestly, it sounds like a broken tin can when I run 5.1 without room correction...

Thanks again for all your help! You've been a tremendous resource.

You're welcome! I really hope that some of these adjustments help.

1) Getting any additional distance from the wall behind you is good for your seat. If you were at only 3 inches before, that would definitely cause problems. Even the move to 12 inches should help.

2) I'm not sure the trigonometry works out, exactly. If your seat is about 12 inches from the back wall, and your speakers are about 12 inches from the front wall, we can toss in another 12 inches or so to account for the depth of your speakers and your ears being a bit forward of the seat back, but that would still make the distance from your ears to the speakers roughly 11 feet or so, yes? With the room length being 14 feet? At that distance, a 45 degree spread between the speakers would have them roughly 9 feet apart.

But that would very likely push them into the corners, once again :p The 45-60 degree spread is just a guideline, not a hard rule. If you put them any closer together than 6 feet (and yes, "on center" is fine - it's just an estimate ;) ) you'll typically start to lose stereo separation. So you pretty much never want them closer together than 6 feet or so. But yeah, if I've got that room length correct, a 45 degree spread would have the speakers somewhere close to 9 feet apart. It's much more important to get them out of the corners, though. So yeah, having a nice 12-18 inches (or more, if your room were much wider) from the side walls is good. Don't drive yourself nuts worrying about the exact distances :) But yeah, keep them at least 6 feet apart, try to keep them at least 12 inches from the side walls, and anything else within that range is fine.

3) If the Center speaker is below ear level, then it's perfectly fine to have it angled upwards a little bit. You just want that Center speaker to be aiming right at your face.

4) If you don't have a regular height tripod or mic stand, putting a small tripod on top of pillows is fine. I would recommend that you put a blanket or towel over the stack of pillows though, just to decrease the irregular surfaces that a stack of pillows might create. Make it into sort of a plush, absorptive square column with the blanket or towel over the pillows ;)

And, as I said, have the mic at seated ear height, and a good 12 inches or more of free air space all around the mic :)

5) No worries. Just put the mic in your favorite seating spot.

6) A subwoofer would totally transform the sound of your system. When folks are putting together a speaker system in pieces at a time, I always recommend getting the Front Left & Right speakers first (you pretty much have to ;) ), but I recommend getting a subwoofer second. And if you care about more than one seating position, I recommend getting a 2nd subwoofer right after that! If you only really care about one seat though, then a single subwoofer is adequate. Fourth would be Surround speakers, and fifth would be the Center. And if you want to go beyond 5.1, I recommend getting Front Wides, then Surround Backs, then Front Heights come last.

For me, it's all about buying the speakers that make the most improvement and difference with each step :) Good Front Left & Right speakers SHOULD be able to produce a good "phantom" Center image, which is why I put the actual Center speaker so far down on my list. I've run many speaker systems with no Center speaker at all - just relying on the "phantom" image. Done properly, it can sound excellent! But if you have any seats that are quite far off center, then a Center speaker becomes much more important.

Anyways, a subwoofer would have a tremendous impact on your overall sound. When it comes to using speakers in an apartment, it's very important to realize that there are really two types of sound: there is airborne sound, but there is also structure-borne sound. Sound is nothing more than vibrations travelling through a medium. That medium can be the air, or it can be the wood, sheetrock, steel, and concrete of a building.

The thing about waves (of any kind) is that they do not like to change between mediums. If you have two different mediums meeting (say, water and air, or air and a sheetrock wall), most of the energy of any wave will get reflected back the way it came. Just think of putting your head underwater. If someone is speaking to you from above the water, you can barely hear them! But if someone makes a noise under the water, you can hear it very, very easily. More easily, in fact, than if that same person made the same sound from the same distance while you both were standing above the water! And that is because water is more dense than air, and sound travels more easily and more quickly through a denser medium.

When you understand all of that, what you realize is that the air borne sound waves are not really the biggest problem in an apartment. You definitely want to make the room as close to air tight as you can. Anywhere that the air CAN move, it WILL move. And any openings - such as electrical boxes, pipes, and especially HVAC ducts - create what are called "flanking paths" for air borne sound to easily travel between rooms or apartments. Do your best to seal up any openings so that the air cannot easily get around the walls, ceiling or floor.

But the real problem for apartment dwellers is structure-borne sound! Ever put your ear to a railroad track and been able to hear the train coming from miles and miles away, even though you cannot hear the train at all when you stand up? That's an example of structure-borne vibration. Again, the metal is much denser than air, and the waves travel very easily and quickly through the metal. Same thing in your home. The wood, sheetrock, metal and concrete all transmit vibrations very easily.

So, what happens in most cases with a subwoofer is that you have it sitting on the floor. When a subwoofer makes sound, it also physically vibrates. And with it sitting directly on the floor, those vibrations very easily get into the floor itself. Well, the floor is connected to the walls, and the walls are connected to the ceiling. So, before you know it, the entire building is vibrating away, in sympathy with the subwoofer! Same thing happens with Tower speakers, too.

Bass sound waves are very long and powerful. And many of them also happen to line up with the natural resonant frequencies of the materials that make up your apartment building! This is the reason why you can so often easily hear bass thumping away, coming from another apartment - even one that is way on the other side of the building! And yet, you cannot hear the higher frequencies. That's all due to the bass sound waves travelling via the structure of your building, not the air borne sound waves.

The (partial) solution is to decouple your subwoofer, just like you decoupled your Center speaker to stop any vibrations in your TV stand! This is remarkably effective. By removing the direct contact between the subwoofer and the floor, you greatly decrease the structure-borne sound transmission, and your neighbors hear your bass thumping away MUCH less. Now, this does not prevent ALL bass from reaching your neighbors. Even though most of the air borne sound waves reflect back when they hit a wall, ceiling, or floor, some of their energy does make its way into the walls, and it then BECOMES structure-borne sound. If you are prepared to take on some construction, you can greatly increase the soundproofing of your room by adding mass, adding more changes in mediums, decoupling, and damping the walls, ceiling and floor of your room. This can be as simple as hanging a second layer of drywall over the existing walls. Or it can be as complex as building entirely new, second walls within your room! (a true "room within a room"). One amazingly effective thing you can do if you are going to hang a second layer of drywall over the existing walls, though, is to use a damping material in between those two layers of drywall. There are the GreenGlue and QuietGlue products. Both of these are thick, sticky substances that never harden, and they act as an amazingly effective "shock absorber" for the structure-borne sound waves when "sandwiched" in between two layers of sheetrock or plywood.

But, the main takeaway here - particularly if construction of any kind is a no-go - is to decouple your subwoofer! Auralex makes the SubDude, GRAMMA, and Great GRAMMA isolation risers (they're all the same thing, just different sizes). They start at around $50. I don't mind the price, myself. But it IS a bit high for what the platforms are, which is just some MDF wrapped in carpet with some foam on the bottom :p You can easily and cheaply make your own isolation platform. But the Auralex risers work really well if you don't want to spend any time making your own :)

7 & 8) If none of the changes you're making help, then I'm afraid there's a bigger problem than a couple of acoustic panels would fix. I'm all for acoustic panels and bass traps, don't get me wrong. But your Center speaker definitely should not be sounding "like a broken tin can". Especially not a speaker as good as the Sierra-1 Center! If it sounds that bad, that's a much bigger problem than just room acoustics. I really have to think that something went really, really wrong with the original setup. There's just no way that a speaker as good as the Sierra-1 should ever sound that way. Kind of makes me wonder if there's a defect in either the speaker or the AV Receiver, to be honest.

One thing you might try is simply using only one speaker at a time. Connect them one at a time to just the left speaker output. And try all of them one at a time in the very same position. I just want to be 100% positive that what you're hearing is all due to positioning and setup, and not some defect in a speaker itself, or from one of the outputs of the AV Receiver. So a bit of troubleshooting here might go a long way.

Acoustic panels and bass traps can make a surprisingly large difference. More than most people would think. But not enough to take a "broken tin can" to "great!". What acoustic panels do is simply remove reflections. So you get "tighter", "cleaner" sound with a lot less reverb, echoes, and "smearing". But it doesn't suddenly make bass appear where there wasn't any before, nor does it make bass disappear. It just "cleans up" what is there.

Personally, when your seat is very close to the back wall, I think that panels directly behind you make the most difference. If you have more space for your seat, then panels on the side walls and ceiling at the first reflection points (basically half way between your seat and the speakers) make the most difference.

What can really help you out in a big way, though, is to make use of GiK Acoustics' free room analysis: http://gikacoustics.com/acoustic-advice/

The folks over at GiK are wonderful to deal with, much like the folks here at Ascend! :) And acoustic treatments is all they do over at GiK. You can actually learn a ton just by browsing their website! But the room analysis is FREE! So why not, right?

That's all for now. But I'm eager to hear how things sound after you've made all the changes. I know for a fact that you've got excellent speakers. They really ought to sound very good, indeed. So hopefully it was just a placement and setup error. But if not, do the troubleshooting - one speaker only at a time, and every speaker (one at a time) in the same spot. Once that's sorted, adding a subwoofer on a decoupling riser will be a huge improvement! And adding acoustic treatments will clean everything up and really optimize the sound in your room.

Thanks again for you help, but sadly I wasn't able to resolve my issue. There are probably a couple of more tweaks I can perform, but it's not looking too hopeful.

I should have been more specific when I said "broken tin can". A much better analysis would be, it sounds very localized no matter where you sit. It no longer has the stereo-like envelopment I'm used it. I'm wondering if it's a (lack of) side wall issue. Perhaps I'm used to the reflections filling out the sound...but to me it sounds incredibly dull. I feel a simple solution would be giving some of the work to the L/Rs but keeping the center as the main driving force...still Trinnov doesn't really negotiate haha.`