Low level bass only when standing

[GSamF]

I am running my B&W 804's as fronts and they just sing now that I purchased the Rotel 1068 processor and 1095 amp. However, I was a bit surprised on my low end not opening up as much as in the showroom. What is crazy is when I stand up from my main listening position (~11 feet back and centered with speakers about 10 feet apart--this can't be changed) I get the bass I want and heard at the showroom. It is just plain fuller. It happens with both bypass 2 channel and my 5.1 discs without the sub on.

This did not occur when I was running my Denon receiver previously. I am assuming since I was underpowering the 804's previously that is why it didn't happen before.

Any thoughts?

Is this just an accoustic thing that can't be helped or do you fine people have any ideas on how to bring the bass sound down to my seating area?

I have yet to try putting them on blocks but pulling them back and forth from the back wall has minimum impact... when I stand it sounds great-especially if I take one step forward. However, if I walk in between the two speakers, it sounds "boomy" and "muddy".

Thanks for your help in advance,
Sam

[ThomasW]

Note that comparisons between one's own listening room and a showroom aren't valid. That's like comparing apples vs oranges.

All your descriptions indicate a room or placement issue. To test things out; measurements should be taken at the 'listening' position, vs the 'standing' position where you state the bass is better. Doing that is the only way to know what's happening.

And no it's not unusual for there to be fairly significant changes in bass output moving just a few inches one way or another.

[David Meek]

Sam, Thomas is right on with his comments. What you are seeing - excuse me, hearing - are instances where the soundwaves coming from the speakers are bouncing off the walls, ceiling, floors, furniture, etc. These waves interact at many points causing cancellation or re-inforcement of various frequencies. These points are unique for every individual room as there are no two rooms the same. Things as simple as a picture on a side wall can make a noticable difference in what you hear at your seating position. This applies with respect to all three axis - width, depth and height.

It sounds like (no pun intended) you have a cancellation point at your listening position, a re-inforcement point between your speakers and a "sweet" spot where you are standing. This most likely a speaker placement issue and it it going to take a bit of work to overcome. First off, if the 10' width is an absolute, it's possibly going to limit what you can do to help the situation. Start by moving the speakers straight out away from the wall and towards your seating position in say 4" increments. Don't change the toe-in at this time. Do this 6 times (24" total movement) and see what happens to your bass, mid-bass, mid-range and treble presentation. Find the best point and then repeat the process only move the speakers in a sideways direction in 2" or 3" increments (if you are allowed) both towards the side walls and then towards each other. Once you've found the optimal sound, try adjusting the toe-in again in small increments - be careful not to move the drivers out of their positions except for the angle of rotation. When you've found the best location/angle for your speakers start looking at the room itself.

First order reflection points are easy to identify. Have your wife, significant other, friend, Fed Ex guy or whomever take a mirror and hold it on the side wall, moving it along until you (sitting in your prime listening position) can see the speaker drivers in the mirror. Make a small, inconspicuous mark at that location. Repeat for the other side wall. Now, hang an acoustic absorption panel one those two points. Okay, it can be a heavy bath towel, or artsy wall hanging or whatever. Just use something that will act to absorb the sound waves striking that point. Now go back to your seat and listen for any changes /improvments. Place some other absorptive panels on the wall behind the mains. Listen again. Okay, don't laugh at this, but try the mirror process on the floor and ceiling as sound radiates vertically as well as horizontally. Put a throw rug down on the floor and see what you hear. Now, try placing some diffusing-type panels on the wall behind your seating position, this will break up the reflections rather than absorbing them, giving you a broad "field" of sound behind rather than a point-sorce. At some point in this process you'll start hearing (hopefully) what amounts to a substantial change in the sonics at your listening position. Some of those being better bass clarity, better clarity overall, wider/deeper soundstaging, better placement of instruments in the soundstage, etc.

It's not a quick process generally, although some people do get lucky, and you can take it as far as you want to go financially with absorptive/reflective panels, diffusors, bass traps, and on and on. . . .

One other thing to consider: You can purchase computer modeling programs such as CARA (Computer Aided Room Acoustics) which allow you to draw you room, specify the materials, create the furniture, create the speaker (many are pre-created for you), place it all just like your room and then produce the varous sound models you'll get by moving things around.

I hope this helps. Keep us posted on how things are going, okay?

[GSamF]

thanks for the responses.

I did some tinkering and I am proud to say I have found a happy medium between acoustics and livability. The bass has increased by about 25% in the seating position, and the boomyness has decreased about 80% after standing and taking a step forward. It just took some creative re-arranging and a lot of trial and error.

thanks again for the advice,
Sam

[George Bellefontaine]

Sam, what exactly did you do to aleviate this problem ?

[GSamF]

I basically moved one out of the corner by pulling it pretty forward, and I matched the other speaker to the same distance. I also toed it in until the drivers were aimed about 3 feet behind the listening position.

I believe pulling the speaker forward away from the corner made the real change, but my soundstage is still from the back of the tv and to up to my face. I am real happy with my Rotel 1095/1068 and B&W 804's.

Sam

[George Bellefontaine]

Glad it worked for you.