standing waves


i notice when i stand from my listening position, the bass is fuller, louder, better than when seated. I rearranged some furniture and it helped a bit. Ive got an area rug in front of speakers for first reflection..i just picked up from Accoustical solutions a pr of basstraps...not impressed with these...im pleased with my current speaker location/placement (after a long time of experimneting) not sure what my other choices are. I have a Rel Storm 3 sub..should i put this on a piece of granite? on a stand? thx
jaf2290
audiopath, thanks for whats got to be the most detailed, and informative answer ive yet to get..ive asked this ? many other times... I already have the stereophile test cd..i have heard (specifically from Rel's owners manual) Not to use the spikes, as Dgarretson stated. I may go the Aurelx route after i take you advice with the measurements...thank you all!
BTW, I just ran another 20amp dedicated line, so now i have 2..1 for power, and 1 for source...i should have system back together tomorrow for a listen..
Simple solution:
Get on your hands and knees and move all around the room. Where the bass sounds best, move the sub there (if you can). That is the simplistic way to find the optimal placement for your sub. This will make your seated position sound that much better.
Nice analysis. But generally sub manufacturers recommend corner placement for a single sub, which generally develops more deep bass at the possible cost of increased distortion. Spiking may turn the entire floor into a resonator, which may be desireable or undesireable depending on floor composition and personal taste. I prefer slight elevation on an Auralex foam plaform to minimize resonance of my sprung wood floor.
When you sit down, you're closer to the mid / tweeter axis of speaker dispersion. This shifts the tonal balance higher. When you stand up, you're further off axis, shifting the tonal balance down. The end result is a warmer presentation with less potential for treble brightness or harshness.

While one could interpret this as more solid or pronounced bottom end due to the shift in tonal balance, what it is really saying is that you want a softer, fuller sound when seated. There are many ways to go about achieving this, so you'll have to figure out what route you want to go. Hope this helps.... Sean
>
Hello Jaf2290,

I have four recommendations: 1. Move the sub. 2. Move the rack. 3. Get a Radio Shack SPL meter (here is the link)
http://www.radioshack.com/product/index.jsp?productId=2103667&cp=&origkw=spl+meter&kw=spl+meter&parentPage=search

and a Stereophile Test CD2 disk (here is a link)
http://ssl.blueearth.net/primedia/home.php

While it's convenient to have the rack between the speakers, for best integration with the sats, the sub needs to be smack dab in the middle.

The rack should be on the side wall (probably where the sub is...I couldn't see it in any of the photos) to keep it away from bass nodes. You'll need longer interconnects and an amp stand so that you can leave your amp up front close to the speakers.

Now you're ready to take out that sound pressure level meter and set it on a range that you are comfortable with (like 70db or 80db) and spin up the Stereophile test disk (Test CD2) Track 16 1/3octave warble tones). Set the volume to keep the readings in the middle of the range you set. Note the readings as the warble tones fall in frequency. You should see a rolloff below 50hz. Next set the crossover on the sub to just below the rolloff freq... say 45 hz. Now play the tones again to see where you need to set the volume on the sub to fill in the bottom at the same levels as you are getting from 80hz on up. What you are shooting for is a smooth transition between the sats and the sub with no bump at the crossover point. It is best to put the SPL meter on a tripod and level it at listening position height. Once you have set the sub, now you can concentrate on the bass traps. Usually they will work best in the corners. Play the tones again while watching the meter to see where the room modes are. Here is a link to a room mode calculator:

http://www.mcsquared.com/metricmodes.htm

Move the traps a few inches in or out of the corners to find the right spots. Keep in mind that the traps need to be tuned for your room's modes.
Oops, I almost forgot... recommendation #4. Spike the sub. Make sure that you have the sub setting on the carpet spikes that came with it. If you want to put something on granite, put the turntable on a slab.
Your system sure looks great...have fun setting it up.
Best regards,