Axiom Home Page Forums General Discussion Home Theater Advice for better bass response

So i recently moved into a new house and setup a new theater in my family room. My new setup lacks bass impact and I'd like some help on what to do next.

I redid the TV wall because there was no good way to fit in a bigger TV. The old TV space fit a 50" TV and limited me to bookshelf speakers. This is the old setup.



The new setup features an 80" TV with a cutout for a 95" TV in the future. I sit about 15 feet away so I am now at the recommended distance of 2X screen size.

I also dropped in in-cabinet m80s and a VP160. Power is from an Onkyo 875 with 130W per channel THX certified. In wall M3s are in the ceiling behind the couch and since the ceiling is vaulted they are pointed at the listening position. The back is open the the kitchen and there are two 7 foot open spaces leading to the rest of the house. So, this is a VERY big room with a vaulted ceiling. Maybe 1000 sqfeet plus a 15 foot ceiling over the family room. The kitchen has a 10ft ceiling. Here's the after picture and I apologize for the poor quality:



Since this space is open to the rest of the house I just wanted decent sound. I didn't need 2 EP800s in this room shaking things off the walls. Especially with little babies in the house. But, I get almost no bass impact at all now and I'm not sure if it a problem with the m80s or my room is just too big for them. I figured I would not get earth shaking bass, but I did figure on some impact. Enough to hear the bass without the need for a sub. I didn't need to feel it in my chest.

My old setup in my old house was in a smaller room but still open to the kitchen had m60s and I rarely needed the SVS PB12 NSD subwoofer turned on. That system is now in my 1200sqft basement and I still don't need the sub. The basement is the same size as the family room but without the vaulted ceiling and I still get adequate impact from those m60s alone. Should I be getting more impact from the m80s? Do you think maybe I have a driver that isn't working right? Or are the drivers' polarity reversed in the speaker canceling each other out? Or do I just need to suck it up and install a sub that I stupidly didn't pre-wire for?

edit: I should note that all front speakers are set to full range. I should also note that I've tried my bass heavy movies and found that I got mostly distortion in the low end. The explosion in the first part of Hurt Locker sounded pretty bad with a little bit of bass but a lot of flapping noise. The drivers were moving a lot and I could feel air out of the port but very little actual impact. This was at about -10 db on the volume dial which is about where I would normally listen to movie if I didn't have 2 11 month old kids.

You have a beautiful home.

I'd get a test disc and run some sweeps (there are probably a number of places you can download and then burn a CD with test tones). Or find some material that has pretty consistent bass content. Change your position in the room throughout and try to listen for differences. It seems likely to me that your listening position is in some kind of null created by the specific dimensions of your room. i.e. is there a difference in bass response at other positions in the room?

And definitely check to see if all the drivers are firing.

It's kind of hard to see from the picture, but try moving any "stuff" away from the M80's and see if that makes a difference.

I'm not sure what kind of material you are listening to. The M80's should provide quite a bit of impact down to about 40Hz, even in a big room.

For listening sessions I moved the pack and plays (which are mostly mesh anyways) and the chair in the corner has since moved over a bit out of the way of the driver.

How do I know if the drivers are firing? They are moving but there are two in each speaker so if one was dead then I couldn't tell since the one moves the other right? Or do they not move much in a vented enclosure?

I don't get much bass anywhere in the room. There isn't' a sweet spot. It's pretty light anywhere you go.

I'll look for some test tones. I used to have some mp3 test tones but didn't move them when i got a new computer.

I am pretty sure all the drivers are supposed to be active.

If you've got some material that includes content under ~100Hz on at a decent volume, then you should be able to see/feel that each driver is moving.

I definitely would try different listening modes on your receiver, too. And make it as simple as possible ("pure direct" mode or similar). Turn Audyssey off. Even though you are sure you have them set to full range, try to take as many variables out of the equation as possible.

While it is miles better than my old Denon, I still find my Onkyo 805 to be "complicated". And I don't think I'm a technophobe or technotard. There's just a lot of stuff going on there that could be part of your discontent.

Is it all sources? That is, no difference between CD's, TV, etc?

I sympathize with you.

I think Tom is on the money with his posts, but I'll just add one quick thing: If you're hearing distortion and "flapping" in the bass, turn the volume down before you blow your speakers!

I would think this is a room issue as well but you would think that you would hear some good bass somewhere in the room huh? If a driver is faulty, you wouldn't think that this would be the case with all woofers. Do your m80's have multiple binding posts on the back?

My living area is large, but not on the same scale as yours (which I would classify as huge). For reference, In my living room (17.5 x 21 with 12 foot ceilings), I find the m80's to put out plenty of bass. My room is also open to a kitchen with 9 foot ceilings. That being said, even with my room I find the ep500 necessary, and in all honesty feel like I need a second sub for movies to smooth out the bass response and add a little "oomph".

I wonder if the shear size of your room lends to having a dedicated 2 or 3 channel amplifier to obtain the punch you are looking for?

I will add that you have a beautiful looking room as well

Here is a link to some test tones:

http://www.realtraps.com/test-cd.htm

However, Last time I talked to Axiom I think they recommended not using constant tones of a single frequency on your speakers. That being said, several of us have done this.

I think you need a sub in that room.

AB, you've mentioned polarity, but have you actually double-checked that your speaker wiring has been done correctly? Possibly the easiest way to check is to reverse the wiring connection at the 875 terminals to one of the M80s to see if the bass gets stronger.

Hi Autoboy,

Everyone here has offered some good advice, however, even in your very large space, if the M80s are not out of phase, and your listening area is not in a big fat null because of room cancellation (which would almost eliminate audible bass), then you should still hear some good solid decent bass from the M80s.

I think there may be a wiring issue or you may have clipped the Onkyo on bass-heavy material and damaged the woofers. Leave the system off and gently press in each woofer back and forth to see if there is any scraping sound. If there is, the woofer is gone and will need replacement.

Overall, in a room that size, you could benefit from a separate power amp for the front channels and at least one powerful subwoofer, an EP500 to start. I've always found the THX guarantee dubious in terms of power output levels on rated receivers.

Check the wiring of the M80s first to ensure they're in phase, and then each M80 woofer (with the system turned off) for damage.

Good luck. Beautiful room, by the way.

Regards,
Alan

With the bass I sometimes get, I'd be a little leery of those glass vases on the shelf. (Sorry, not much help.)

I'm hoping to get enough bass out of the towers to not need a sub. That is pretty much the whole reason I went to all the effort to build out this cabinet. I wanted a bigger TV, and BIG speakers. Axiom's BIG in cabinet speakers and huge center channels are awesome. This is mostly just for TV viewing. I just need to hear the bass for TV to be enjoyable.

The receiver is setup properly. I have had this receiver for awhile and I know how to operate it well. I've tried direct mode, stereo, manual setup, and then automatic setup. Nothing fixed my problem.

I think this is a polarity issue. The contractor installed the speaker wiring and probably didn't pay much attention to polarity. I hadn't considered this as the problem but now that you guys mention it that is probably the issue. I will have time to test it tonight I think.

As for a blown woofer. I don't run this system that loud. The most it has even been turned up is -10 which is loud but not oh my gosh loud. -10 is a comfortable movie watching volume while most TV is watched between -25 and -15 depending on the time of night. The flapping was more like wooshing from the speaker cones. I may have overstated that a bit. When I push on one of the 6.5" drivers I am able to get some scraping noises but only if I push it off center. This woofer will scrape easier than the other 3 but I don't think it is blown. Not that I would really know what a blown speaker is like. I assume as soon as you push it in a little bit it scrapes. This one scrapes only if I push it off center and pretty hard. The only thing I can think of about it is that maybe the babies got the speaker cover off and pushed that woofer a bit, though it looks fine. The new magnetic covers look great, but are less effective against little hands. They can pull the grills off pretty easily, but have generally left them alone.

Ok, so the polarity is correct, but I sit in a pretty big bass hole. The bass 5 feet forward sounds much better. The worst offender was actually from the center channel and when I had that turned to full range it canceled out the bass from the mains. I turned it to cross over at 120 hz and it fixed the issue on test tones. I think this will be ok since the bass goes to the mains and not a sub that can be localized in the corner. I got about 5 extra db from doing this. Kinda a bummer I got the VP160 but hey, whatever. It looks cool in there. I'll keep working on it tomorrow. My wife is furious about the buzzing from the family room. I have not been able to test it with actual material since I've been kicked out of the room. Thanks everyone for your help.

Ok, so I still have a bit of a bass hole. Are there ways to fix this with settings in the receiver? Distance settings or reversing polarity on one of the speakers? Or can I put up bass traps? There aren't really any good places to put up traps and I can't move the speakers. I could move the couch a bit closer to the TV but only by a foot or so.

Are you sure that the center is in phase with the Left and Right?

Nulls are a function of the distances between the transducers, the boundaries (walls) and the listening position. I don't think there is anything you can do in the receiver.

Hi,

Bass traps won't help. You have too little bass, not too much. There are no settings on the receiver that will fix this. You have to move the seating area--and sometimes a foot or so will make a huge difference. An old friend and former colleague, Dr. Floyd Toole, scientist and acoustician, once measured and graphed the bass response differences in the three different seats on a single couch, and the audible bass would vary as much as 10 to 15 dB or more. Such differences make the difference between hearing virtually no bass and hearing too much. (He called the room "the forgotten component" and it's so true.)

Play a recording with lots of good deep bass and walk around the room slowly noting the areas where the bass seems good but not overpowering --- that's the spot where you should move the couch. Don't feel victimized. Virtually every room has lots of areas of cancellation and reinforcement caused by standing waves and the particular dimensions of the room interacting with the speaker/sub locations and the seating area.

Good luck in finding the right location for the couch.

Alan

Moving the couch is the only way to combat this? Bummer. I used test tones and it was very clear where the bass was and wasn't and my whole couch was in a null. 5 feet up was a peak but I don't really want to move up 5 feet. I'll give it a try with one or two feet and see what happens.

The center channel was in phase with the mains.

I may just add a sub to the corner with the leather chair.

You mention possibly "reversing polarity on one of the speakers", but isn't that what you did when checking polarity?

Although this appears to be room, rather than speaker, related, bringing the M60s up and temporarily connecting them in front of the M80s to check for bass might be interesting.

I didn't reverse the polarity. They were all set right. I thought maybe since I have problems with waves canceling each other out, that I could reverse the polarity of one of the speakers to move the bass hole somewhere else. It's just something I thought of from my understanding of waves. I have no idea if it is a proper way of fixing a bass hole.

Moving the m60s sounds like a good experiment. I'm not sure I'll be able to do it. I rarely get time to myself in the family room since we have 2 kids who just turned 1 and that's their play area. At night bass experiments won't go over well. Thanks for everyone's tips. I'm glad it is not something wrong with the m80s. I had a nagging feeling something was broken and that is gone now. The bass is strong enough for me just 5 feet forward so I'll try to get that working for me somehow.

By the way, autoboy, your tests of the bass drivers were fine; you'd only hear a scraping sound if the driver was killed when you pushed the driver in and out with equal pressure around the cone (the scraping sound results from a warped voice coil that's been fused or melted by the DC current from clipping and its travel is no longer linear).

The annoying thing about a bass null is that you can't use EQ to boost it or fix it -- to supply bass in the hole where there is none. If you had a bass peak, you could use EQ to reduce the peak in that listening seat. If everything else checks out--and it seems like it does--then moving the couch is the only solution.

Can you not move the couch back farther to an area where there's good bass?

Alan

Auto, if you have a sub downstairs that isn't needed, why not move it upstairs?

I'm guessing in a huge room like that, it won't be overkill by any means, but might give you some lower end that you're not getting in that null....especially if you do the sub crawl to find the best location to fill the null.

If it works, then you can decide if you want the sub there, want a sub that might look more aesthetically pleasing in that nice room, or if you're willing to not use a sub at all.

But I would say that as long as you have a sub downstairs that's not needed there, why not try it upstairs?

If you didn't try swapping wires at the receiver, I'm still confused about how you tested for phase coherence (polarity consistency) among the front three speakers. Did you use a test disk or is there a Audyssey routine within the receiver or something?

And, yeah, just try a sub in there (in various positions) and see how that might work. That seems like less trouble than moving the M60's, and I think it probably gets you closer to your ultimate solution.

Have you tried adjusting the phase alignment or diverting some of the power from the main deflector to compensate?

I've had the same issue with my M80s; I've corrected it to a point where I don't think there is much else I can do. The system's low end sounds better but still not ideal (for me that is). From my listening position, if sit on the couch, it sounds like I'm into that bass null; if I stand up, I can hear a big difference in the low end. Weird.
In any case, what I had to do to improve the bass response was to move the speakers: distance from the wall, distance between the speakers and the toe-in. I played with this countless hours, but in the end it was worth it as I've some improvement for sure.
Now that you've read all this... you'll probably find it useless as I don't think it applies to your case?
In an effort to at least give you something useful, I would try a different set of interconnects (and I would've suggested speaker cables as well if not in-wall/cabinet speakers) and try a power amp.
One last thing: if you have your receiver plugged into a power bar/conditioner/surge protector, try switching it directly into a wall outlet; the reason I'm suggesting this is that I've heard with my own ears, where a power conditioner was taking the edge off an amp at louder volumes.