Generally speaking, spikes under a subwoofer are unnecessary, unless the enclosure is tall and/or unstable.
Rubber feet work better, and help reduce mechanical buzzing and resonances.
Room reflections and standing waves are usually the cause of flabby or "slow" bass.
"tight" bass is almost always the result of smooth, accurate in-room response, and has nothing whatsoever to do with the feet under the subwoofer.
This can be very difficult to achieve in some rooms.
For example, a perfectly cubical room made entirely of concrete would be the worse scenario, and would suffer from significant bass overhang at certain frequencies, due to overlapping standing wave patterns.
If your room dimensions are all different and not even multiples of each other, the standing wave distribution will be much better and the bass "tighter" and quicker.
Obtain an SPL meter and tripod from Radioshack, and a CD with 1/3 octave bass tones from Stereophile.
Measure from the listening position at ear height.
Depending on the size, shape and construction of your room, you may find that there is at least one really big peak/valley below 100hz(+/-6db is pretty typical, and some rooms are much worse).
Try to get it smooth; +/-3db or better should result in tight, realistic bass, depending on where the peak/valleys occur.
It may be necessary to move the listening position.
Rubber feet work better, and help reduce mechanical buzzing and resonances.
Room reflections and standing waves are usually the cause of flabby or "slow" bass.
"tight" bass is almost always the result of smooth, accurate in-room response, and has nothing whatsoever to do with the feet under the subwoofer.
This can be very difficult to achieve in some rooms.
For example, a perfectly cubical room made entirely of concrete would be the worse scenario, and would suffer from significant bass overhang at certain frequencies, due to overlapping standing wave patterns.
If your room dimensions are all different and not even multiples of each other, the standing wave distribution will be much better and the bass "tighter" and quicker.
Obtain an SPL meter and tripod from Radioshack, and a CD with 1/3 octave bass tones from Stereophile.
Measure from the listening position at ear height.
Depending on the size, shape and construction of your room, you may find that there is at least one really big peak/valley below 100hz(+/-6db is pretty typical, and some rooms are much worse).
Try to get it smooth; +/-3db or better should result in tight, realistic bass, depending on where the peak/valleys occur.
It may be necessary to move the listening position.