Axiom Home Page Forums General Discussion Home Theater Another Freakin' Sub Post....

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