Topic: Need help tuning bookshelf speaker placement

[datbrad]

Just moved a pair of small JBL bookshelf speakers up onto high shelves at the end of a long rectangular rec room. They are laying on their sides with the tweeters towards the inside of the pair, spaced 3" from the ceiling, 12" from the side walls, with the speakers about 2" off the back wall.

When these used to sit on top of a console at chest level in the same spot in the room, they sounded great. Now they sound strange, and I can't seem to dial them in.

I know I am having issues with the corner placement (the corner between the ceiling and the wall) which is why I kept them about a foot from the side walls. There is definately some sort of mid-bass mud that is always there, and when I play an audience tape with a lot of bass, it sounds boomy. Not deep bass boomy, but mid-bass boomy, if that makes any sense.

I tried giving them a slight downward angle, and that did seem to help, so I think I am going to try to angle them down even more tonight and see what that does.

My question here is basically; because I am forced to have the speakers laying on their side so close to the ceiling, does this mean my only option is to get a powered sub and hope the high pass crossover will deny the bookshelf speakers enough bass to stop the boomy sound?

[Jimna]

does this mean my only option is to get a powered sub and hope the high pass crossover will deny the bookshelf speakers enough bass to stop the boomy sound?

maybe, but i doubt it.  are you running the same electronics in front of them?  if so and they sounded good before  but bad now i would say its the room acoustics plus the position.  if it is the room i dont think EQ will fix it(ie sub plus crossover), EQ usually doesnt work for room correction.  try placing them in a config that sounded good previously and see if that fixed the problem, even if its temporary.   that will give you a good idea of where the problem is, sometimes knowing what works help to fix what doesnt.

whats the room size?   

[datbrad]

does this mean my only option is to get a powered sub and hope the high pass crossover will deny the bookshelf speakers enough bass to stop the boomy sound?

maybe, but i doubt it.  are you running the same electronics in front of them?  if so and they sounded good before  but bad now i would say its the room acoustics plus the position.  if it is the room i dont think EQ will fix it(ie sub plus crossover), EQ usually doesnt work for room correction.  try placing them in a config that sounded good previously and see if that fixed the problem, even if its temporary.   that will give you a good idea of where the problem is, sometimes knowing what works help to fix what doesnt.

whats the room size?

Same electronics as before the change in speaker placement. The room used to be a car port that was enclosed by the prior home owner. So, I guess it's about 25' x 12' or so. Paneled walls, finished ceiling with faux hardwood flooring. We have a 9' pool table taking up most of the center of the room. We used to have a TV cabinet at one end and I just had the speakers sitting on top, spaced roughly between 2' and 3', and about a foot from the back wall.

Now, they are up high on the shelves, spaced 5' apart, laying on their sides, and only a couple inches from the back wall, and about a foot from the corners. When you stand all the way in the back of the room, they sound better than they do when you are standing 6' away. I am also thinking that the sub woofer option might not be it, so I don't know if I should angle them down more, or move them closer together. Something to remove the mud in the center of the image.

[Jackpine]

Changing the angle can affect imaging and how well you hear the tweeter. You need to move them to fix the bass. In a corner near the ceiling or floor will give you the most bass reinforcement of any location.

[Chilly Brioschi]

small speakers are finicky on their distance from the wall

You also have them too close together and this may be causing standing wave cancellation

Be especially certain that you didn't throw them out of phase when reconnecting the wires with one pair reversed.

BTW, there are a few good sites on the web about speaker placement.
vonschwiekert had guides, and there were links on Audio Advisors (commercial) site.

Good luck!

[datbrad]

Thanks

[mosquito]

Without being able to hear it I'd guess you're getting strong reflections off the walls and ceiling that makes it muddy.  How to fix it?  Find a track that sounds particularly bad and set it to repeat and then rotate them downward, rotate them inward and move them closer until it sounds OK.

[datbrad]

Without being able to hear it I'd guess you're getting strong reflections off the walls and ceiling that makes it muddy.  How to fix it?  Find a track that sounds particularly bad and set it to repeat and then rotate them downward, rotate them inward and move them closer until it sounds OK.

That is exactly my thought. I listened to an Avetts studio CD last night and it sounded pretty good. Then, I put in my WSP audience recording from Portsmouth in October, and the bass mud is just horrible. I could barely stand it. And it's not really typical deep bass mud, it's closer to midrange boom, if that makes any sense. On my main system in the house, the bass on the recording sounds very deep and thick as it was at the show, but not boomy or muddy at all. Weird.

I am now thinking that they need to be farther from the corners than just a foot as they are now, since they are so close to the wall and ceiling. This will bring them closer together to within 3 feet, but I think that will be ok because of the narrowness of the room. One of the side walls is painted brick, so that can't be good for sound.

One question, when lying two way speakers on their side, is it better to have them where the tweeters are on inside towards each other, or is it better to have the main drivers on the inside of the pair against the wall?