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[Loren Jones]

Hi all,

I am aware that there are lots of discussions on this and I have read through many of them.  I've also read the recent "avoiding Power Alley" article on PSW.

I just wanted to ask for people's thoughts on my particular application.  I am going to be trying out a pair of groundstacked subs in our church as an alternative to our current flown subs (see pic).  In the pic each of the three hangs has a dual 15" sub in it.  I am planning to try turning those off and running a pair of groundstacked 21" subs instead.  Output for the levels we run at won't be a problem.  The question is best coverage.  For reference, I think the distance from the left side speaker cluster to the right is about 80 feet.

Position choices for the pair of subs would 1)  One on either side of the center stage stairs, that puts the subs about 12-14 feet apart.  2) Both together on either side of the stairs, which would put them about 6 or 7 feet off of the center of the room.  3) One sub under each of the left and right speaker hangs, which would put them about 75 or 80 feet apart.

I am guessing that #2 would be better than #1, but I don't know about option #3.  Of course I will try out a couple options and see what sounds best, but words from the wise are always helpful and appreciated.

Thanks,
Loren Jones

[Bob Leonard]

Loren,
I would want to avoid possible long delays that may tend to make the subs sound as if they were not a part of the same system. I realize that your DSP can cure that problem, however, humans feel the music or material also and that may lead to a strange listening experience. Looking at the photo, nice installation by the way, I would experiment as you suggested but start by placing the subs one each where the top of the stair railing meets the stage. Not at that level, but centered between the L/R and center speaker clusters.

[Ivan Beaver]

Hi all,

I am aware that there are lots of discussions on this and I have read through many of them.  I've also read the recent "avoiding Power Alley" article on PSW.

I just wanted to ask for people's thoughts on my particular application.  I am going to be trying out a pair of groundstacked subs in our church as an alternative to our current flown subs (see pic).  In the pic each of the three hangs has a dual 15" sub in it.  I am planning to try turning those off and running a pair of groundstacked 21" subs instead.  Output for the levels we run at won't be a problem.  The question is best coverage. 

If you are talking aobut "coverage" meaning as equal as possible across the listening area-the groundstacking is going to make it a lot worse.

The people near the subs are going to be a lot louder than the other seats (say at the back of the room).

There is no way to avoid that-inverse square law.

Part of your current problem is the 3 positions of the subs.  I would consider putting them all together in the middle-flown as close to the celing as possible.

[Loren Jones]

Loren,
I would want to avoid possible long delays that may tend to make the subs sound as if they were not a part of the same system. I realize that your DSP can cure that problem, however, humans feel the music or material also and that may lead to a strange listening experience. Looking at the photo, nice installation by the way, I would experiment as you suggested but start by placing the subs one each where the top of the stair railing meets the stage. Not at that level, but centered between the L/R and center speaker clusters.

Thanks Bob,

I will give that a try as well.  That I guess would make sense as far as doing the most possible to give the most equal distance between all parts of the audience and one of the subs.  Is that the perspective you were looking at it from?

Loren

[Loren Jones]

If you are talking aobut "coverage" meaning as equal as possible across the listening area-the groundstacking is going to make it a lot worse.

The people near the subs are going to be a lot louder than the other seats (say at the back of the room).

There is no way to avoid that-inverse square law.

Part of your current problem is the 3 positions of the subs.  I would consider putting them all together in the middle-flown as close to the celing as possible.

That is what I am afraid of Ivan.  Many members of our congregation comment that they are missing a sort of visceral impact or bass power from the current system which they felt was present with our previous all groundstacked system we had prior to building this facility.  So it is the old "ground coupling" idea that I am wondering about partly.  Also it is a suspended ceiling (probably 4 ft above the tiles) so we the current subs aren't that close to a hard boundary above them.  Finally the current double 15" cabs really roll off pretty strongly below 45 or 50 hz whereas the subs to try on the ground have solid extension to 30 or 35 hz with I think even a little more gentle rolloff below that.

I am really just planning to try this for a week or two just as a curiosity more than anything.  If we were going to do anything permanent I am sure that your suggestion for the subs all to be flown together just above the center cluster would be best.  I'd think a pair of TH118's above that center cluster would be more than enough for us

Thanks for your input,
Loren Jones

[Loren Jones]

Looking at the photo, nice installation by the way, I would experiment as you suggested but start by placing the subs one each where the top of the stair railing meets the stage.

Bob thanks for the compliment on the install.  It is good quality gear and installed properly and is bulletproof for our needs.  I do think it would be better overall frankly to have just a simple L-R hang just at the outer edge of the stage above the location you mention.  The L-C-R system just doesn't work well in a room that is overall wider than it is deep so we end up panning most things almost evenly to all three clusters which just ends up in excessive comb filtering.  Usually I actually try to keep vocals mostly in the center hang along with snare, kick.  Then I put the melody instruments panned somewhat preferentially to L and R together.  I rarely pan anything toward just L or R.  The other side of the room just loses it too much.

Thanks again,
Loren

[Tim Talbot]

For best coverage and the smoothest sound place both together in the middle (center of room)

[Bob Leonard]

Loren,
I think if you add what Ivan and I have said together you'll see that there really isn't a best spot for the subs until you do some experimenting with them. Take the time (and some long cables) to take measurements even if all you have is a meter. Run some program material with just the subs powered or top cabinets turned off via the DSP. Use a piece of paper and make some old school plots. Or. if you have Smaart use that. In either case there can be no best placement until you look (listen) for it. That is especially true if your goal is evenly distributed low frequencies.

[Ivan Beaver]

That is what I am afraid of Ivan.  Many members of our congregation comment that they are missing a sort of visceral impact or bass power from the current system which they felt was present with our previous all groundstacked system we had prior to building this facility.  So it is the old "ground coupling" idea that I am wondering about partly.  Also it is a suspended ceiling (probably 4 ft above the tiles) so we the current subs aren't that close to a hard boundary above them.  Finally the current double 15" cabs really roll off pretty strongly below 45 or 50 hz whereas the subs to try on the ground have solid extension to 30 or 35 hz with I think even a little more gentle rolloff below that.

I am really just planning to try this for a week or two just as a curiosity more than anything.  If we were going to do anything permanent I am sure that your suggestion for the subs all to be flown together just above the center cluster would be best.  I'd think a pair of TH118's above that center cluster would be more than enough for us

Thanks for your input,
Loren Jones

That is one of the tradeoffs that is made.  Even coverage or "impact".  You can get a lot of impact from flown subs (if done properly), but it is still not the same as ground stacked.

Just make sure the older people don't sit up front near the subs.

[Loren Jones]

That is one of the tradeoffs that is made.  Even coverage or "impact".  You can get a lot of impact from flown subs (if done properly), but it is still not the same as ground stacked.

Just make sure the older people don't sit up front near the subs.

Or the pastors

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