good bass in small theaters & why I have none...  

SVS is pretty much the sub of choice around here.

www.svsubwoofers.com

*cough*

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get your self a sub, HSU Research link above and sponsored by this site makes a fantastic sub that has got some excellent reviews. You can step into one for about 800. If your an audiophile which I gather from your main speakers you may be more inclined to get Velodyne which frankly is some of the best sub product out there. I typically use when watching movies since I find it hard to get that low end punch from a main set of speakers.

whats your basement room made of, floors, walls etc... what the difference in size of these two rooms?

how big was the room that you originally had them in? Is there a lot of sound dampering material in the new room (ala heavier carpet or more stuff on the walls)?

have you picked up an spl meter to test the response in that room. If your getting plenty of bass upstairs and with a room easily three times the size in volume something is clearly wrong. You said they were in phase are you positive the wires are hooked up correctly? One more thing do you happen to have dedicated 20 amps runnning into your theatre room? I am just throwing ideas out here but maybe you are running into surge issues and your A/V Amp etc is soft clipping or retarding power to prevent problems? That might be a little far fetched. Oh BTW you can pick an SPL meter at your favorite radio shack for about 40.

A wooden floor really makes a huge difference in the transmission of bass.
I have my HT in a basement which has a carpet over a concrete floor. The bass has very little to vibrate except our chairs and bodies. The walls are concrete (covered in drywall) up to four feet from the floor (seven feet total height) so there is not much flex to help the bass. It is a rather trapezoidal room but serves the sound fairly well. I need more bass but one thing I do like about the space is the clarity and good transient response I get there. But I want more low digit Hz.

Do You have Your 5.1 amp in its right setup?
In my (Yamaha RX595) I must tell the amp what speakers I have. For ex if sub is activated then are all bass below some Hz cut of from the mains. If I want the mains have bass also I must change some variables in the amp setup. And I must also set what type of mains and surround that are connected, "small" or "large" speaker. If "small" are selected then are the bass mixed into the sub channel instead.

Bass frequencies are the most troublesome when dealing with a room. If you really want to get an understanding, go read some of the white papers here: Harmon White Paper Index

Great source of info. I suspect your lack of bass is directly related to the location of both your listening position and the speaker position.

RG

Speaker forum is a better place to ask.

I suspect it has something to do with standing wave (medium size rectangular room), but I am no expert.

Check out the home theater construction forum where bass issues are discussed to great lengths. The Harmon white paper mentioned is also very good. Basically, if all your settings and connections are ok, then your problem is with the room construction and/or speaker placement. Don't be surprised as I too noticed massive differences when moving my HT from upstairs to downstairs as well as in different rooms of downstairs. With some research and room mods you will get what you are looking for, and IMO the HT builder forum here at AVS is the best source you will find. There are some extremely knowledgeable professional HT design folks that frequent there and will likely already have addressed everything you need to know. Good luck, and don't give up.

I'll have to move this to the speaker forum. You could try the HT Builder forum as well.

Good luck!

I am about 48 hours away from setting up my basement which is built in the same manner as yours. I have a 16x15 room which is not good to begin with because it's virtually a cube, 9 foot ceilings, 6 inch thick 9 foot tall concrete walls and concrete floor. Everything is dry walled and carpeted and other than a tray ceiling and some minor pieces of furniture there is nothing else in there to break up the music. I may find myself building some wall columns if the sounds don't come out right.

Setup is extremely important in rooms with open back walls. The first thing you might consider is speaker placement. Find another person, have them sit in the most optimal viewing position and have them hold a piece of string to their nose. Extend that string out to the center channel and then hold it tight and walk left and right to your front main speakers. Where that string ends is where the speakers should sit. From there you are going to want angle them so they fire past your head in sitting position to back corner. You want thier signals to cross behind you not in front of you. That is typically how you begin a HT setup, there are more technical ways to do it along with software that can pretty much tell you where to put anything but for DIY'ers this should be sufficient. You will still want to get an SPL meter and probably the Avia HT setup DVD that has all the test tones you'll need to make sure you are getting the frequency reponse you need from each speaker. These are all very inexpensive ways to help, I think.

Good luck

Stupid question here to rule out......

Did you make sure on the receiver you are using that the Subwoofer out is turned off since you are not using a subwoofer, but mains for speakers and as a subwoofer?

I will be honest with you. I don't think the room has much to do with it. If you are missing the bass, something is wrong with your speakers/receiver setup.

Did you try changing your speakers to only the B channel and running them just in stereo mode? This should rule out any problems with your speakers and keep it to just the receiver.

Treatments and placement will enhance, but not replace missing bass. I have a small room in a Basement with extremely powerful bass coming from my mains. They have 12" woofers as opposed to your 10" woofers, but that should have little difference in missing that much bass.

Sporty,

To be honest, the room could have everything to do with it!

It is likely that the combination of speaker position and listening position are both exacerbating the room's modal nulls (bass frequency cancellations). A good way to test this theory is to listen to music that produced good bass upstairs and walk around the room to see if there are any positions (including up against the walls) where the bass approaches what you heard upstairs.

If you do find a location that approximates the upstairs bass, then you need to spend some time positioning speakers and listening couch for best bass.

How far out from the front and side walls were the front speakers positioned?

How far out from the rear wall was the listening couch positioned? How far from the front speakers?

Sounds like the reflections in your room have created a large bass null.

Its the room!!! Try some placement experimentation using an SPL meter, but due to the squareness of the room, it may not make a difference.

My room measurements are 10'6 inches wide and about 16' feet long in a basement with paneling thats wall-papered over with a door right next to the couch. I don't have any problems with bass. You can hear the bass through out the whole house with the mains only if you want. We are not there to hear it so it is hard to tell... Just how much bass are you missing? 5% or 50%? That makes a big difference in answering the question.

I took a closer look at your speakers and compared them with mine. My 12" woofers are front facing while your 10" ones are rear facing. I wonder in your situation you need to put your speakers like an inch or two against the wall (like subwoofers) as opposed to mine where they say about 2 feet away from the walls. That might make some improvement. Let us know if that is possible.....


Good Luck.

I can't offer any useful suggestions, but wanted to comment that rigid (i.e., concrete) walls and floors are notorious for caused boomy bass, not reducing it. The flexibility of walls and floors helps absorb some of the unwanted relections. It does sound to me like there's some technical problem with the hookup, but you sound like a knowledgeable person whose has checked all that out. I would be interested in the results if you set up the Vandersteens with the exact same electronics you had when they were upstairs.

For what it's worth, I had pretty good bass in my theater, but decided to add a pair of Vandersteen subs using the Vandersteen hookup strategy after reading a strong recommendation for them in The Audio Perfectionist. The results were impressive and I'm happy I spent the money. The low end doesn't attract your attention, but the instruments that are supposed to go low are very solid without distortion.

Good luck!

Crazy thing to rule out.....

Maybe one of your woofers aren't working? That would equal 50%. Have you tested them to make sure you are getting output out of both 10 inch woofers?

Did you try my idea of running them in stereo and bypassing the 5.1 out mode and see if that improved the bass in them? If so, did it help? That would focus the issue on the speakers themselves instead of the receiver.

Good Luck!