SDA 1.2TL Placement Issues

nacam

Hi all;

I have been messing around with the placement of my 1.2's for the last few months now and can't seem to get the bass response right for my listening position. My room is an unfinished basement (unfortunately) and L shaped. My 1.2's are placed on the wall that is part of the bottom of the "L" pointing into the narrower part of my basement. The right speaker is on the wall but there is no side wall next to it.

See atttached image.....

I have always kept the Left hand speaker 3 feet from the side wall so not to interfear with the SDA effect which no matter what I do with the space between them, the SDA effect and overall imaging I am very happy with. It seems however no matter what I do I cannot get any decent bass response anywhere forward of where the couch is. If I am standing just to the rear of the couch the bass is MASSIVE. I have played with the positioning of them and have never been able to get decent bass in the wider area. The space between the speakers is currenly about 4.5 feet and the couch is about 6.5 feet away. I have tried to vary both distances without any positive results. I have checked all my wiring and everything is in phase and all the internal wiring is perfect. The only mod I have done to these is the RD0-198 upgrade.

Any suggestions on placement in this room? Should I just move the couch back into the "massive bass" zone or keep playing with the placement of these monsters? I would like to keep the couch in the forward area there for the listening room because if there's too much space I risk the wife turning that space into a play area for the kids.......

ANy suggestions would be appreciated!

george daniel

Hmmm, you should try them wider apart,if possible,, and you are a tad on the close side,, move a little further away.Good luck,,keep us posted.

F1nut

I can't get your attachment to open.

Anyway, place the speakers on the long wall, at least 6 feet apart and start at 6 inches from the back wall. An unfinished basement means a lot of hard surfaces, which is not good for music reproduction. Area carpet(s) and wall treatments will go a long way in helping with that.

treitz3

After looking at the attachment, try placing them both on the wall to the right of where they are now.

F1nut

Ok, I got it to open. Like Tom suggests, try the wall to the right. How long is that wall?

ben62670

I tell people to put them so far apart it looks stupid. Then move them closer till you get the sweet spot. To run big SDA's properly you need a long wall that really should be 16 feet or wider. The big boys also sound best when you sit further back. The speakers and your listening position should be a near true triangle as possible. In a few weeks I am going to post a write up about why a lot of arrays fail in the near field position.
Ben

nacam

Thanks to all for the suggestions, I moved them further apart and things are improving. I will have to start moving other things to get them further apart. Unfortunately my basement isn't exactly a "dedicated" room for these and they were the only place the wife would permit them to go (a part of the agreement when I purchased them!). It seems the further apart they are the better and the further back I move the couch the better as well. Next is to upgrade my crossovers and get a more appropriate amp for these but that's a bit off. Moving them around is a bit more cost effective right now.

Cheers!

OldmanSRS

My setup is like yours and it's not optimum for sure. I think you are listening in a null region (where the bass sine wave crosses zero) caused by one or more standing waves for the lower bass frequencies. I placed my speakers 5" from the wall, about 10' apart (measured edge-edge) and moved the couch closer to the rear wall, about 19' from the speakers. The bass is better but not as massive as if I sit all the way back.

If you have a bass tone generator source, you can scroll through the frequencies seated in your listening position and actually hear the amplitude change as the null moves back and forth at various frequencies. You can move move around the room and hear where the standing wave peaks and nulls. That may help you place your couch in best position to emphasise the bass frequencies you are missing. There will be trade offs at other frequencies but it's always a compromise.

nacam

Actually what you describe is what I am hearing now. Some frequencies are louder than others but overall it is better. I do have a tone generator, an Omni mic (which has a flat enough frequency response in the bass region) and a spectrum analyzer. Maybe it's time to take the more scientific approach to this.

F1nut

Unfortunately my basement isn't exactly a "dedicated" room for these and they were the only place the wife would permit them to go (a part of the agreement when I purchased them!).

Moving them to the wall on the right would still keep them in the same general area and would go a long way to resolving your room issues. Man up, tell the wife the agreement has changed a bit.

RichCanDo

This does not pertain to your bass issue, but the best thing I have found for positioning the SDA's was a CD test disk containing a "Clicker Test". I lost the CD but think it was on a Stereophile test CD. The clicker used is like a childs toy. A metal cup with a flat strip of metal attached to it. Push on the metal strap and it clicks. The clicking sound was recorded to sound like it was traveling around the room in a circle. Left to right around the room, behind you, then right to left, behind you, and then a circle across the floor, up the wall, overhead and behind you. (If I remember correctly.) Moving a speaker 1/4" or less I could hear the difference. Takes some time to setup speakers, but best test I have found to find their proper location. Test was for any stereo speakers, not just SDA's.

JohnLocke88

since when does the woman control the unfinished basement :rolleyes:

treitz3

Is there any way to convince your wife that in the current location, you are not happy with the sound? That would drive me nuts.

Or is it not a possibility at all?