SubWoofer Help ASAP...

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

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

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