SubWoofer Help ASAP...


Hello, can anyone recommend a solution. Just moved into a condo with carpet all over. I am currently running 2 M&K subs... MX-350 THX and MPS 5210 THX... Both are dual 12" drivers.

My problem is that the bass notes on both music and home theater sound very boomy and almost hollow in a sense. I had the same exact setup at my previous place and sounded amazing. Concrete floors on previous place. Oh yeah and new place, set up is in the second floor.

Question is what can I do to get that tight accurate bass that I had. Any help or suggestion welcomed. Thanks in advance guys.
jurm
Yes-keep moving the sub away from the corners, behind your speakers is usually a good place. However, a suspended wood floor (I assume its suspended wood rather than concrete since youre on the second floor) will probably never sound as good as a concrete floor but im sure you can find a place for the subs that is not boomy.

Good luck with your downstairs neighbors.
There are many ways to configure your subs. Not just positioning, although that is the most important, but also try placing them on theirs sides, up and down and pointing in all positions. It is really hard to place subs and without very sophisticated equipment (and even with, as stated by Harman Kardon in their white papers) it is a case of trial and error.
Check your crossover point maybe set to high. Move away from all boundaries if possible. Make sure all connections are right. Good Luck
I posted the following in another thread a couple days ago...
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IME, the two simplest and most effective methods for subwoofer setup that require no equipment other than a SPL meter are...

METHOD 1: Optimizing frequency response. Place the sub at the listening position, then walk around the room and listen for the location where the bass is the most *consistent* across low frequencies. You can do this by ear with music, or you can use a SPL meter and low frequency test tones. Once you find the location in the room that has the smoothest frequency response, place the sub in that location. Now the bass response at the listening position should be in pretty good shape.

METHOD 2: Optimizing transient response. IMO, good transient response requires time aligning the sub with the mains. A procedure that can help with time alignment...

1. Flip the polarity of either the sub or the mains (but not both).
2. Play a test tone at the crossover frequency.
3. Use an SPL meter to measure the output level.
4. Adjust the sub position (or digital delay, if you have that capability) until you MINIMIZE the SPL at the listening position.
5. When the sub is in place, flip the polarity back so that the sub and the mains are the same polarity.

In steps 1-4, you are essentially maximizing the *destructive* interference between the sub and the mains. In step 5, you are restoring the sub to the correct polarity, which now maximizes the *constructive* interfere between the sub and the mains. That will help with both frequency response and transient response.

IME, the first method is the best place to start. When the sub is roughly in position, use the second method to fine tune.
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Good luck.

Bryon
You might also want to read the thread I have started a few month ago:

Looking for the BASS

However, Bryon suggestions are very good and clear and pretty much cover the subject. I have but two minor comments, which I hope he does not mind and also agrees with them:

1) When applying "METHOD 1", it is helpful to play a jazz walking bass line (make a loop with the cd player if possible) and look for the position in the room where all notes of the double bass sound equally loud and tight. This is what Bryon means when he writes "listen for the location where the bass is the most *consistent* across low frequencies"

2) When applying "METHOD 2", at step 2) is the crossover frequency of the subwoofer, of course.

Finally, start with only one subwoofer. The second one you can place following the exact procedures outlined above.

Good luck and be patient!
Paul
08-16-12: Nvp
When applying "METHOD 1", it is helpful to play a jazz walking bass line (make a loop with the cd player if possible) and look for the position in the room where all notes of the double bass sound equally loud and tight.
Hi Paul - I think this is a very good suggestion. It's exactly how I make fine-tuning adjustments after general placement has been determined through measurements.

One of my favorite tracks for double bass is "Use Me" from Patricia Barber's album Companion, especially the solo in the first 30 seconds. If you can make the bass on that track sound deep, even, and fast (the most difficult), you're in very good shape.

Bryon
Thank you so much for your suggestions. Looks like I have some homework to do... Ok I'll keep you guys posted, I'm gonna get some work done to fix this this weekend. I appreciate all your insight and suggestions. Thanks a bunch... And yes Paul, I need to be patient. Ha ha
Great answers so far, so nothing to add. Bascially your new room has a bass node right on top of your listening position. So it's just a matter of tweaking to even out the in room response by the methods laid out above. It takes time, but pays off so be patient.
It takes some time till one starts to hear the frequencies that are reinforced
or weakened by the room. This is why it takes time to set up decently a
subwoofer.

A pair of decent headphone, however, can solve this problem in no time. By
listening the selected walking bass (or bass solo) alternatively via the
headphones and via the speakers one can easily identify the artifacts
induced by the room, viz. what one hears in the headphones is not affected
by the room and consequently the bass is always tight and fast (no bloat).

To find a decent position for the subwoofer I play track 3 on Norah Jones'
"Come away with me" album, i.e. "Cold cold heart". I
make a look with my cd player and play only the first measure of the bass
line starting the song. The passage lasts 3-4 seconds and has only 6 notes
which are easy to follow but are sufficiently different frequency-wise.

To find tune the position of the sub I use a bass solo. Any will do. The one
suggested by Bryon is certainly good.

Funny you mention NJ's "Cold Cold Heart," Paul. That's a track I've used many times during tests.

Probably my most frequently used test track is Cassandra Wilson's "Strange Fruit" from the album New Moon Daughter. It has great low level detail, explosive instrument attacks, and a variety of instruments, rhythms, and timbres. So it's useful for judging not only bass quality but also resolution, dynamics, soundstaging, PRaT, and harmonic accuracy. And it's wonderful music.

I often bring "Strange Fruit" to shows like RMAF and ask a vendor to play it when there isn't much traffic in a room. I can't tell you how many manufacturers have leaned over half way through the song and said, "What is this? It's great."

It's both a great way to show off a system, and a great way to reveal its shortcomings. If you haven't heard, give it a listen. :-)

Bryon
Hey Bryon,

Thanks for the suggestion. I am not very familiar with the music of Cassandra Wilson, which is yet another reason to buy the "New Moon Daughter" album.

Paul