Axiom Home Page Forums General Discussion Home Theater Major sub issues

First off, I'll post a link to a thread on AVS I created, which explains the problem in more detail and what I've done to try and alleviate it.

http://www.avsforum.com/avs-vb/showthread.php?t=1197293

The bass in my room is just totally dead. I am getting some ok levels around the back walls near and behind my sofa, but in the center of the room or towards the screen, there may as well not even be a sub in the room. I've tried everything short of starting to throw a bunch of money at the problem.

My next option I think is some acoustical panels, but I don't know if they'll do anything with lower frequencies. The only other thing I can think of is to order an EP350 to compare and see if perhaps the SVS is just not a good match for the room, but then I either have to deal with selling the SVS or return shipping the 350.

Anyway guys, any ideas are greatly appreciated.

All I can think of right now is do the sub crawl with your sub in the listening position. I have my system in the basement, concrete everywhere, so lack of bass was an issue for me as well. Now I'm running with EP500 AND another 10" sub up front. With both subs going and my main tower speakers to LARGE, and having done the sub crawl to determine the best bass sound in the room, I finaly have the amount of bass I want.

As for acoustic panels, they certainly will not increase your bass response, but they will help with echo / ringing etc.. if you have those issues.

Have you done any frequency sweeps to see if you are really lacking @ certain frequencies.

The problem is that the punch in your chest is not from your sub, it is usually from the mains and as you have M22's it won't happen. The chest thing is said to be around 60 -90hz and the sub is busy playing ALL low frequncies and smoothly. If you want to feel it in your chest you need to try to optimize the frequency response for around 60-80hz. I have seen this question many times, check out MikeC on AVS, he bought MANY subs looking for that chest thump only to find out he was searching in the wrong frequency range. You could possibly benefit from Hsu and their Mid Bass Module(MBM) System. . This was one reason I went to M80's, with them I get more impact than I did with M22's/sub.

What's the height of the room? You said it is 12' wide by 19' long.

With those two anyway, I can tell you that you'll have the biggest problems at 93 Hz because of the width, and 60 Hz from the length.

That's a very good point Jay.

I can tell you that when I stood (with an unnamed Commander) on the flight line at NAS JAX at a Blue Angels preview several years back, the low level, low speed demo by the F14 - I had no problem feeling that in my chest. My face, legs and arms as well. I didn't have to do the crawl either - although I am sure many have at the receiving end of that awesome sight.

Interesting. I had never heard of a Mid Bass Module. Does it get fed by the LFE channel and go first in the chain and have a built in crossover stripping the mid bass from the LFE channel before sending it to the sub or does the sub still get the full frequency load. Didn't seem clear to me from the article.

I don't know the exact working either, I just know it is out there and there are reports from those that have one that it has helped with that slam feeling. I know I had LOTS of slam with the M80s and A1400, oh how I want one...........

Just to add, I know many are looking for that slam like in a bar, if you look at the specs of those pro speakers many only play into the 30-40 hz range with a bit of a boost in the mid bass range (60-90hz) which gives them that slam(along with oooddlles of power) and believe it is a sub doing the job, but it is not. I also know there are some pro subs out there spec'd for this slam range as well.

The graphs of the PB12-NSD has a bit of a boost in the 50-60hz range, (I had one briefly but didn't like the thump it had) but your room could be killing that frequency and Chris has nicely pointed out it looks to be the case.

It seems the concrete could be an issue for me as well. I do have all walls insulated and a proper subfloor, but maybe that is not enough. Now I wish I didn't sell my smaller Velodyne, at least to test. I have done the sub crawl with the sub in my listening position twice, same result both times.



I don't know how, to be honest. I looked into this REW thing but I have no idea where to even begin. I know nothing at all about computers and sound cards. It certainly sounds like I am lacking in the 50 - 80 range though. I have my crossover on the W22's set at 80, which is where Audyssey set it. The very first time I ran Audyssey (sub in a different position) it set them at 60hz. Maybe I should lower it back to 60?



Thank you, I think this just has to be the problem, there really is no other explanation. I will look into this.



It's 8' ceilings, but with a bulkhead on one side which makes it about 7' which takes up about 14" of ceiling space.



Is there any way to correct this? I assume not. Is it possible a different sub would change anything? I guess this mid bass module would solve it, it's just a major pain to ship stuff back to the US if it doesn't help.

Again guys, thank you for the help.