OK. I admit it. I haven't put the time into tweaking my system as I would like, and haven't even set up the BFD that I bought something like six months ago! So I've tried to keep mum about my bass issues, as I believe in helping those that have first tried to help themselves… and that hasn't been me!

But I've done a day of listening/playing to try to figure out some of the bass issues I have in my 13' square room, and I think I've raised more issues than solved! I did not meter, calibrate, or set up the BFD today… (hopefully, tomorrow!). My goal was to try to determine exactly why, with an EP350, I can't get that "hit you in the chest" feeling from LFE. I know the 350 is no 500, but I am in a small room and I would think the 350 would be enough sub. Maybe not.

Before my Axioms, I was using a smaller JBL sub in the corner of my room behind the sectional:


With the smaller sub only, I got more bass than I do from my 350. I know that there is a big difference between the output of a sub in the corner and one that's away from a corner. So trying both in the same corner, I've found that the 350 doesn't put out any better than the JBL (which is a 10", 100-watt unit rated to 35Hz…. No mention of how flat that is).

Knowing that my square room is giving me "peak and null" headaches, I thought that two subs (placed as above in diagram) would even things out a bit, and it did. A bit…. But still no "hit you in the chest" feeling. For what it's worth, I was expecting more of a difference because the "favorite seat" (on the right side of the sectional directly in-line with the DLP) seems to be the mother of all nulls. If I sit towards either corner of the room (in the "angle" of the sectional or in the recliner) bass is more substantial. So I was really expecting that adding the second sub to offset the null from the 350 would help quite a bit… eeeehhhh, Not So Much.

So tomorrow I hope to run some plots and set up the BFD. But since I don't seem to get that "hit you in the chest" feeling ANYwhere in the room, even in the "peak" locations, I'm thinking that the BFD won't help me with this because I'm probably just not going deep enough for the bass I can feel. My room rattles a bit, if that makes a difference!!??!!

A secondary problem is how much noise I'm hearing from the 350, and I'm curious if others have noticed the same. From my first or second day, I was aware of some noise at a particular point on the SACD of DSOTM. Since then, I've kept the sub turned down a bit to avoid this noise. I had always thought that it was the driver, but putting my head on the ground in front of the 350 during the Darma "tap" scene (Bang-bang-bang, not BOOM-BOOM-BOOM, by the way) it seems as though what I've been hearing is port noise. I wonder if this is why the 500 uses that B/A oval port?

So, the questions:
1-Who wants to take a stab at whether or not a BFD will actually enable me to produce better "hit you in the chest" bass by taming peaks that will therefore allow me to turn up the sub a bit more…or, is a 500 justified even in this small a room? Anyone else using a 500 in a room this small? Overkill?

2-Anyone else getting "easily hearable" port noise from their 350? Maybe not so much on a really loud, LFE-laden soundtrack, but during music with pronounced bass?

Sign me,
Bass-Anemic in NH

Hmmmmm....wonder if maybe the JBL was producing more of a boomy bass which only "sounded" like "more" bass than the cleaner sound of the 350??

Also wonder if the noise(bang, bang, bang)you are hearing is the driver bottoming out?(my old 10" Peerless driver powered by a 150W amp, although rated at 200W, would, when plotted, indicate running out of travel at about 85W, albeit in a sealed cabinet)!!

I haven't the foggiest though, cause I've never had a "Killer Sub"(with a port,even)to be able to add much relavent input

Mark, in regard to your freakin' questions about your freakin' subs in your freakin' room, my guess on 1. is that yes, the BFD would allow an overall increase in bass after the peaks are lowered.

On placement of two subs to help with room modes, note that the paper by Dr. Toole and his colleagues at Harman(which you should certainly study if you haven't done so)basically suggests that placement in the middle of opposite walls(either front and back or on each side)is helpful(if practical), rather than the positioning which you have. Opposite corners also showed some benefit.

It really doesn't sound like the driver bottoming out, and I can change the tonality by placing a finger or two inside the port holes (Shaddup all of youse, BigJohn ain't even here!) to change the airflow.

John, you're a freakin' riot. Really.

I think the BFD will make a big difference. Right now you probably have a huge freakin' peak around 44 Hz, and probably smaller ones at 88 and 132 (being 2x and 3x). If you took down the peaks (esp. 44 and 88 Hz) you should be able to turn up the level almost the same # of dB, at which point you should start to get more bass you can "feel".

I'm guessing you will also start to hear more difference between the 350 and your JBL sub with the BFD. I don't think the room is letting you hear much below 35-40 Hz without making the higher freqs too loud -- the BFD will help.

Do check around for vibrating house parts though; when I was running the PSB 6i (comparable to the EP350) all of the "sub noise" and "port noise" I heard turned out to be "heating duct noise" up in the ceiling.

Good luck. If all else fails you could try sitting on the sub

Mark, I will come and hit you in the chest if that would help.

I'd come up there and give you a hand Tom, but it's way too freakin' cold in New Hampshire during this time of the year for my butt. Typically South Carolina is about as far as I can make it until spring...and that's really pushing it.

Wanna wait 'til summer?

Jeeez, Outlook never listed today as "Pick on Mark" day! Stupid Calendar!

Anyway, John.... (he says while giving the hairy eyeball to Tom and Rick... and that's serious with my eyes!) I guess much of my concern is that the plots are pretty different even from one seat on the couch to the next. And they are something just a bit short of "dramatically" different if you sit in the corners of the room in the elbow of the sectional or in the recliner. I have six plots here that were metered for three seat positions with the sub both in it's current position and also with the sub in the corner to the right of the DLP. Actually, they're really not fitting the "44Hz, 88Hz, and 132Hz" math too well.

For reference:


I'm not saying I won't try the BFD tonight, but how can an EQ help if there's so much variance in measurements from seat to seat? That's a bit rhetorical, John… I know it can't and yet I'll never know what results I can achieve till I try.

Regarding the "port noise" though, I'm confident it's as described. I looped the "Darla scene" while putting my face on the floor directly in front of the sub and it's definitely the ports.

I appreciate your help on this one, John (he says while sneering at Tom and Rick). It's been a year since my HT "redo", and this is the only area of dissatisfaction. I just can't nail down whether the room is completely at fault or if the 350 isn't enough sub… or both. I guess I just can't believe that the 350 isn't capable of performing magnificently in a smallish room. Heck, I was originally considering the EP175 because I thought the 350 would be too much!

I have so many deadlines this time of year, and I really shouldn't be doing this right now. Yet, I always believed that when you work harder, you should play harder. So, despite my schedule of late, I'm tired of seeing the BFD just sit there and flash while not feeling those massive explosions!

Just a quick thought: Is it generally a good idea to put a sub in the center of a room? Last night (while getting very tired) I imagined two down-firing subs with a fashioned top to make a coffee table!

>>Jeeez, Outlook never listed today as "Pick on Mark" day! Stupid Calendar!

There is a "display all holidays" option which you probably need to enable.

>>I have six plots here that were metered for three seat positions with the sub both in it's current position and also with the sub in the corner to the right of the DLP. Actually, they're really not fitting the "44Hz, 88Hz, and 132Hz" math too well.

Understood. I'll go find a high-speed line and re-read the MOAP.

I still think you could sneak in some pretty effective and aesthetically pleasing bass-traps which AFAIK would also make a big difference.

>>I looped the "Darla scene" while putting my face on the floor directly in front of the sub and it's definitely the ports.

Pity. I was doing much the same last night after setting my sub to 16 Hz tune and for some reason wasn't as impressed with Darla after the change. I'm not sure Darla is a great scene for sub tuning -- does anyone have a waterfall plot ?

>>Just a quick thought: Is it generally a good idea to put a sub in the center of a room?

I'm not sure, but I think the answer is "no". For reasons I don't fully understand there doesn't seem to be as much bass when you are "half a room" away from the sub, and a coffee table in the middle of the room would put you "half a room away" when leaning back against the wall.

End tables are good, though...

Your need to have rags handy with the coffee all over the table.
boom boom boom splish splash crank bang

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Understood. I'll go find a high-speed line and re-read the MOAP. I still think you could sneak in some pretty effective and aesthetically pleasing bass-traps which AFAIK would also make a big difference.

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Actually, I didn't go into the bass issues too much in that post…. It was about the only thing I left out, though!

I should have mentioned that I did experiment with something else yesterday: Three big "leaf" bags of rags and blankets in the corner of the room behind the sectional. I read somewhere awhile ago that it was an effective, though non-attractive way to determine if bass traps might work. I wouldn't really expect that it would work as well, but thought it was worth trying. As mentioned, I didn't do any metering yesterday, but I heard no difference. If anyone is curious, I'll meter it both ways and post results. I'm a fan (in theory) of room treatment, but when the bass traps are running ~$300 each and you're not even sure they'll work……

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I'm not sure Darla is a great scene for sub tuning

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I'm not sure either in the big scheme of things… but it sure got my sub "chuffing" so I could listen for the noise…!

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End tables are good, though...

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Well, our plan is to ditch the sectional and recliner and replace them with a separate couch and loveseat so the couch can be centered "on the screen". If so, I would look for furniture that has built-in recliners and maybe ditch the coffee table as well. This will "open up" the room and allow for twin 350s!

It looks like the way you would have the subs placed in the pic would create some cancelations problems.Is there a way to put one sub next to the right M60 and the other as an end table directly across from the first sub.This would be the cloeset optimal placement according to the Harman white papers as you room would allow.

If I were going to buy a second sub, I would take a hard look at the 500 instead of a second 350.

Mark looking at your last diagram the middle of the room sure looks bare without the coffee table, you may want to consider an ottoman as opposed to the coffee table. They come in various sizes and I would imagine you can find one that will be smaller than the existing coffee table but will still tend to your needs, i.e. ... feet!

Whenever I was considering 2 subs I was told by both the Axiom and Hsu folks that catty corner placement would probably be ideal while keeping in mind to correctly set the phase for each sub. Like Wid says, maybe one in the corner by your right hand 60 and the other in the corner where you have the existing JBL sub placed in the first two diagrams.

An ottoman's a great idea, you could sell that to the s.o. as a vibrating foot massager. It just happens to cost a grand and for some strange reason you need to watch Star Wars Ep III to make it work.

You could put on one of those CDs of whale calls and really be soothed... a 100 foot whale can generate lots of nice LFE for the foot massage

>>Actually, they're really not fitting the "44Hz, 88Hz, and 132Hz" math too well.

I went back to the MOAP and looked at the graphs. What I saw was :

- a huge honkin' peak at 44

- a hole around 100 which swallowed the 88 hz peak, presumably caused by cancellation between sub and M60s around crossover freq, which you could might be able to address with the Phase switch on the sub

- small bump around 133 but too small to matter

If you still have that big hole around 100 hz, try flipping the phase switch -- it should help. Then you'll have an 88hz bump to fix, but it's easier to BFD down a bump than it is to fill in a hole.

Hey John:
Thanks again for your input! The plot on the MOAP was an old plot from a different sub position. Give me a little while and I'll post a new plot for the current sub position by the radiator.

Mark, on your question about a sub exactly in the middle of the room, the benefit is that there's the point where both the modes for length and width are at a minimum(to also get to the minimum for the height mode, the sub should be raised half way to the ceiling). The disadvantage is that the lack of reinforcement from the room would lower the sub output. The Harman paper which I mentioned and Rick linked studies a lot of possible locations. Middle of opposite side walls, for example, is at the minimum for the length mode and although at the maximum for the width mode, they're of opposite phase and tend to cancel. Diagonally opposite corners are at the maximum spots for both length and width modes, but being of opposite phase tend to cancel those modes.

Interesting. That big hole at 38 hz has to come from somewhere. We're looking for about 7.5 feet... I'm guessing (a) ceiling height is 7-8 feet, and (b) the sectional is about 7 feet on a side so the EP350 is 7-8 feet from the left hand wall in your drawing ?

If you put the sub in the corner that will certainly reduce the 38 hz hole... I'm on dial-up now so I can't go back and check the MOAP for details, any chance you could post back the height of your room ?

Hey Mark--You got me worried here buddy--I have a room 18 X 18.5 and I was going to buy Epic60--2-M60ts, 4-QS8s,VP150 and a 350 subwoofer (my wife hates bass) but what if I have the same problem --not enough bass? How common is this? Due to the room I have to put the 60"LCD in the corner with the M60ts on either side. Axiom people said I could put the 350 subwoofer anywhere. Are other people having the same problem with the 350's?? Your thoughts? Should I get the 500?

Hey John!
The sub is 10' from the corner behind the sectional to the center of the dustcap.... three feet to the wall where the eqpt. closet is. The ceiling height is 8' 4".

Hi Chivas!
I'm no expert here...John (Bridgeman), JohnK...oh hell, everyone here knows more than I do.

What I have learned is that square rooms are problematic.... and small square rooms compound the issues. I don't think your room will fall under the small category. Hopefully others will chime in.

It's not that the 350 is a bad sub, I'm particularly looking for that "hit you in the chest" feeling and combining that desire with a problematic room. That being said, my gut feeling is to go with a 500 instead of a 350 for three reasons:

-- More and more, movies are making real use of that LFE (sub) track. I think a good sub is more important now than it was 5-10 years ago.

-- You can always turn down the 500 when your wife is watching... you can't turn a 350 up beyond it's capabilities.

-- She might end up appreciating the bass.

I don't mean to be too forward with that last one. I know some people that have hearing issues that have a problem with bass and that or any other reason could be legitimate. But... not knowing the situation and playing Devil's Advocate... Is it possible that she's saying she doesn't like bass because of the ear-splitting thumping she hears from the cars next to her at stop lights? I'm not trying to be facetious... but some people that say they don't like something have only been exposed to poor samples of it. If the bass is tight and well-controlled and just adds some "weight" to the presentation, and doesn't just go BOOM BOOM BOOM, THUMP, THUMP, THUMP she might actually enjoy it???

I would say if you can swing the extra $$ for the 500, go for it. You're assemblinfg a top-notch system there and more and more, proper LFE playback is a big part of that satisfaction.

shivas, also what you can do is order the EP350 sub and listen to it for yourself. if your not happy with it you can upgrade it. thats what i did. just wasnt enough bass for me. the EP500 is almost to much bass for me!! haha. i love it.

>>The sub is 10' from the corner behind the sectional to the center of the dustcap.... three feet to the wall where the eqpt. closet is. The ceiling height is 8' 4".

Hmmm. That doesn't work out at all

The graph didn't mention crossover frequency... there's no chance you were crossing the mains over at 40 Hz, were you ? Doesn't seem likely -- that's the kind of thing HK owners do, and I don't think you have an HK...

The bigger thing nagging at me is that there are some big up/down spikey things going on in the response curve but it's not really all THAT bad. The problem may be nothing more than the combination of a decent midrange sub and a small room which doesn't give much reinforcement below 40 Hz, that being a combination which doesn't give you much output in the "wow did you feel that ?" frequency range. Perversely enough the 350 in a larger room would probably be quite a bit more satisfying because of the room reinforcement at lower frequencies.

I'm having a tough time believing that the BFD is really going to make a big difference except by using it to boost the 20-35 Hz region, where a larger room would give you some reinforcement. It may be time for someone who lives near Mark and has one of those "flat below 20 hz" subs to pay a visit and see if an EP500, SVS or VTF-3 fixes the problem.

I would like to understand that suckout at 38 Hz though, just in case that is also affecting your lower frequencies. I do think the sub in the corner gave you a better starting point for BFD-ing than the sub by the radiator and from your earlier graphs it definitely eliminated the 38 Hz hole.

It probably is worth trying the "sub in the center of the room" placement, maybe even on the coffee table. JohnK (I think) said that you won't get much effective room gain that way but your room is only giving you gain in the "boom" frequencies, not the "holy $#%" frequencies anyways.

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The graph didn't mention crossover frequency...

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Unfortunately, I didn't have the crossover frequency listed on the original chart from April. I did note that on the top of the chart…but that's not much help! It's very likely 80Hz since that's the setting that I've used for the vast majority of listening since buying the Denon.

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a combination which doesn't give you much output in the "wow did you feel that ?" frequency range. Perversely enough the 350 in a larger room would probably be quite a bit more satisfying because of the room reinforcement at lower frequencies.

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Well, maybe that just makes this whole situation moot.

I've had two goals here: To try to smooth out the frequency response and to get bass that I can feel. I have been assuming that any sub I use in the same position (and without the BFD) is likely to give me the same spikes/null as if have now with my 350 as they seem to be primarily room-related. Yet, if I replaced my 350 with a 500 I could reach the depths to produce bass that I can feel. If what you're saying is true, my room might "fight" the 500s abilities to play lower anyway?

I have to check my PMs… you might have told me something along these lines several days ago!?? I guess I thought that getting the best sub position possible, using a BFD to knock down some of the spikes and using a sub that goes stronger and deeper will offer reasonable gains in my room. Maybe not? Geeez, now I'm depressed…..

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It may be time for someone who lives near Mark and has one of those "flat below 20 hz" subs to pay a visit and see if an EP500, SVS or VTF-3 fixes the problem.

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Geez, again. No one lives near me. Well, among Axiomites anyway. Where in the World? Yup. Lonely out here.

So let me cut to the chase here: looking at the room layout and the freq. plot above (I won't re-post in deference to our dial-up friends), is there anyone here that thinks a 500 will or won't help with my goals above? (with the BFD I already on, of course…)

Taking bets……

So, a remodel is out of the question, then?

I sure do learn a lot from your tribulations, Mark.

I'll drive my PB12 out there if you pay my mileage and expenses. IRS rate. Shouldn't be more than about four grand. I'll throw the "whack in the chest" for free.

Have you actually called Axiom on this?

How about an infinite baffle sub? Would putting a IB manifold in the basement be feasible or would doing so change the wavelength problems?

Tactile transducers?

You just keep that hairy eyeball to yourself.

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Have you actually called Axiom on this?

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Not meaning to sound too obtrusive but I often find myself asking this very question upon reading some of the inquiring post and replies on this site.

I dont know what kind of receiver you have but if it is like my HK AV 300 at -30 the .1 of the 5.1 signal is pretty weak. I would go ahead and turn it up to plus 6 or 7 or 10. and see if it sounded louder. I like to listen at -25 with the sub level at plus 4 or 5. I am not familiar with Axion subs but crank the gain up to about 50% and see what happens.

Hey Tom!
Yes, actually I called Axiom yesterday and talked to Brent. He recommended the 500 for the infamous "hit you in the chest feeling" and that I check the bolts in the subs' driver regarding what I was hearing as port noise. He felt that if tightening the bolts on the driver didn't help, I should call back and speak to someone in the service department... It didn't work, BTW.

I really have wondered about Bass Shakers and such. Maybe in the end, it'll be my only option. Of course then, "in the end" is the only way I'll experience bass.

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talked to Brent

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No way I disagree about the 500!

Looking at the specs of the 350 it should give you some of that " in the chest " feeling you're looking for.Are you certain that the sub is working correctly.My VTF 2 is rated down to 25hz and can thump the chest pretty good.I am a bit suprised you are not getting this with your 350.

Anechoic Resp. +/- 3dB 28 - 150
Room Resp. + 3dB/- 9dB 18 - 150
Max SPL Anechoic 107 dB
Max SPL In Room 118 dB

Hi Rick:
No, I'm not actually sure that the sub is working correctly as I was told I definitely should not be hearing the noise that I'm hearing (it's not subtle) but my gut feeling is that the big problem is still the room.

The room might be a bit problematic but if the sub is not working correctly all the graph plotting in the world isn't going to do much good.It sounds like your 350 is not in properly working order imo.

Mark, I figured you had consulted the experts. I did not mean to offend. Just trying to help by sending you towards someone who has the science to actually analyze the situation.

Perhaps you could test your subwoofer in another room, or even outside on a Finnish basketball court or something. Just to see if you can confirm your suspicions about either the sub or the room. I am always impressed by the analysis provided by you, JohnK and Bridgman about the room nodes, and I can be convinced that your small, square room is the culprit.

I still like either knocking out a wall or trying that IB thing. Or maybe constructing a special Home Theatre Shirt with some bass-shakers on the chest area. Perhaps one of those portable defibrillators plugged into the LFE port?

How much is return shipping on a EP500?

Tom:
Absolutely no offense taken whatsoever!

Actually, the idea of taking the sub into another room is a good one! I have four stereo setups in the house right now; three are in small, squarish rooms as well but not long ago I set up some old Design Acoustics satellites and Cambridge Soundworks passive subs with a receiver, CD player and XM Roady in my studio which is approximately 14' X 30'. It's very "open" and has bare walls and hardwood floors. It will be very interesting to see how differently the sub responds in a vastly different room!

Good Idea! (Not to mention if I buy a 500, that's where the 350 could likely end up anyway!!)

Well, there you go! After listening to some sub-relevant reference tunes, take the sub to the studio! And if you can get meaningfully better bass response in the studio (especially with so much more air in the room), we'll know that your existing viewing area is the Bermuda Triangle of Bass. And that you have to rearrange your whole house.

Finishing off the attic might be my only shot at getting a decent room.

Of course, I've bugged Bridgeman so much with this topic up to this point, I don't dare ask him for tips on getting good audio under a high roof peak!

The new house should be ready for occupancy and the financing finished in about two weeks, so in two weeks I expect to be submitting the "dial up-friendly Second Cousin Of All Posts" on the subject of room acoustics under a high roof peak. The new HT area is a 23x25 loft, under a 12/12 roof finished in drywall, so I expect to get about the same acoustics Mark would get if his room were also 13 feet high in addition to being 13 feet wide and 13 feet deep ;(