QSC KW181 stacking (placement) - NEED ADVICE!

[Matt Gordon]

So I DJ at this bar/club every weekend and it has concrete floors. I have 2 KW181s and 2 Yamaha S115V's (powered off QSC amp). I am wondering where the best placement of said subs would be.

Things I have tried:

1. Subs on left and right side with poles for the speakers. Sounded alright, but not too much bass kick except right in the front. Also, I can't get my hands on the adjustable pole mounts anyways.

2. Subs placed side by side right in the middle underneath/in front of my table. Sounds great, especially where I am, but still not a big kick on the dance floor and also sounds lower than the speaker (i.e. not a hard punch).


So what I am thinking of trying, and need your advice on, is stacking two of the subs to the right side of my table with a pole on top for the speaker. And the other speaker on a stand on the other side. My thoughts are that since one sub is higher, it might give that chest punch i was hoping for.

Please help me out! I'm open to other options as well. Thanks!

 

[Tim Weaver]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

So I DJ at this bar/club every weekend and it has concrete floors. I have 2 KW181s and 2 Yamaha S115V's (powered off QSC amp). I am wondering where the best placement of said subs would be.

Things I have tried:

1. Subs on left and right side with poles for the speakers. Sounded alright, but not too much bass kick except right in the front. Also, I can't get my hands on the adjustable pole mounts anyways.

2. Subs placed side by side right in the middle underneath/in front of my table. Sounds great, especially where I am, but still not a big kick on the dance floor and also sounds lower than the speaker (i.e. not a hard punch).


So what I am thinking of trying, and need your advice on, is stacking two of the subs to the right side of my table with a pole on top for the speaker. And the other speaker on a stand on the other side. My thoughts are that since one sub is higher, it might give that chest punch i was hoping for.

Please help me out! I'm open to other options as well. Thanks!

There is really no fix for this except for moar bass. Stacking the subs higher won't "hit you in the chest" any more than on the floor. In fact it will probably be worse because of floor reflections cancelling out in the upper bass region, right where you need it for a good kick.

The most likely issue you have is poor alignment between your tops and subs. You need a dsp and the ability to set it up properly. Proper phase alignment at the crossover point will make your subs sound better. Promise.

 

[Matt Gordon]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

There is really no fix for this except for moar bass. Stacking the subs higher won't "hit you in the chest" any more than on the floor. In fact it will probably be worse because of floor reflections cancelling out in the upper bass region, right where you need it for a good kick.

The most likely issue you have is poor alignment between your tops and subs. You need a dsp and the ability to set it up properly. Proper phase alignment at the crossover point will make your subs sound better. Promise.

I think it might be the crossover since I am sending a full signal to both subs and speakers, since the KW181s don't have a built in crossover or high pass output.

So then from the options, should I just put them coupled side by side, or under each speaker with a pole? I am hoping once I implement the crossover itll fix everything and give it that kick I was hoping for. Low crossover at 100Hz correct?

 

[Tim Weaver]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

I think it might be the crossover since I am sending a full signal to both subs and speakers, since the KW181s don't have a built in crossover or high pass output.

So then from the options, should I just put them coupled side by side, or under each speaker with a pole? I am hoping once I implement the crossover itll fix everything and give it that kick I was hoping for. Low crossover at 100Hz correct?

Putting the 2 subs together will maximize the amount of noise they can make. If they are right next to each other, they will acoustically couple (effectively become 1 radiating surface) and will be around 3dB louder than when they are spread apart. It doesn't matter if they are on one side or the other, or right in the middle.

The crossover will help. Right now your tops are trying to reproduce those low frequencies along with the subs. 2 different types of speakers playing the same thing will cause all kinds of problems. There may be cancellations happening that would cause a suckout at the frequencies you"re most interested in.

At the very least, you will be able to drive the tops a little harder with the crossover in place since they won't have to play the low notes. It will sound cleaner too.

Don't mistake a cleaner sound for "less loud". Distorted, nasty speakers sound louder too our ears. Even when they're not that loud....

 

[Silas Pradetto]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

1. You need a crossover.
2. You need to align the crossover.
3. Cluster the subs to avoid power alley (comb filtering).
4. Avoid reflections that cause cancellation off the back or side walls (subs should be more than 8 feet from walls or less than 2 feet from the wall)
5. You need more subs.

PS. I've run a show with 4 KW181, properly deployed, aligned, crossed over, etc. They still sucked.

 

[Caleb Dueck]

PS. I've run a show with 4 KW181, properly deployed, aligned, crossed over, etc. They still sucked.

Aw, they aren't horrible. You do need a large quantity, in deep mode, and not expect the impulse and phase response to be perfect. Not my first choice, or even top 10.

Silas has some great advice, just giving some friendly grief over cheap subs.

 

[Matt Gordon]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

So my table is about 2 feet from the wall so the subs are about 4 feet from the wall and 6 feet from the other wall. Should I try stacking them on the side of my table so that they are about 6 feet from either wall? Or keep them together (coupled) under my table. I also can't buy any more subs so these two will have to do. They slap and I love them, and are more than large enough for the gigs I do.

 

[Matt Gordon]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

Also, what do you mean by "align the crossover"? I would set the low crossover at 100Hz.

 

[Jay Barracato]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

Also, what do you mean by "align the crossover"? I would set the low crossover at 100Hz.

Aligning the crossover refers to making sure the time of arrival of wavelengths in the crossover region from the the tops and the subs are similar (the goal is the same which is really not possible if the subs are not located with the tops. In reality, you have up to about 30 ms of difference before it really starts to make a difference).

In my opinion, your subs are well suited to your tops. If your tops are running full range, I would expect that to be the place you can make the most difference by setting up a good crossover. If that doesn't do it, it may be simply you are expecting too much from the entire system.

Just remember, one set of speakers (subs or tops) is going to set your max volume by running out of gas. Turning up the other set isn't doing you any good. Part of creating a system is to match the speakers so you can turn them up or down as a unit and they stay balanced.

 

[Silas Pradetto]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

So my table is about 2 feet from the wall so the subs are about 4 feet from the wall and 6 feet from the other wall. Should I try stacking them on the side of my table so that they are about 6 feet from either wall? Or keep them together (coupled) under my table. I also can't buy any more subs so these two will have to do. They slap and I love them, and are more than large enough for the gigs I do.

You didn't listen. More than 8 feet from all walls, or less than 2 feet from the walls. This is exactly why there's no bass out front.

 

[Matt Gordon]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

Well here's some pictures of the place I dj at. Or at least where the DJ sets up. Notice that there's a side wall to the left of the DJ (when looking at him) and the right wall is flush but there is too much shit over there (ATM and tables). SO should I set up my subs right up against that left wall that juts out? Or under my table?

 

[Matt Gordon]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

You didn't listen. More than 8 feet from all walls, or less than 2 feet from the walls. This is exactly why there's no bass out front.

Some help would be nice. See the pictures I posted above. Thanks

 

[Jay Barracato]

Some help would be nice. See the pictures I posted above. Thanks

In a room where the dimensions of the room are the same size as the sub wavelengths, there are always going to be cancellations. As close together as the tops are, the timing issue becomes less as well.

I would just put a block of two subs in front of your table with the two speakers on stands in line with them and call it good.

If two subs aren't slamming the space you showed either you have unrealistic expectations for the whole system or something else in your signal chain is seriously messed up. Placement in the room is minor details. Check that the polarity of one of the subs is not inverted.

 

[Matt Gordon]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

In a room where the dimensions of the room are the same size as the sub wavelengths, there are always going to be cancellations. As close together as the tops are, the timing issue becomes less as well.

I would just put a block of two subs in front of your table with the two speakers on stands in line with them and call it good.

If two subs aren't slamming the space you showed either you have unrealistic expectations for the whole system or something else in your signal chain is seriously messed up. Placement in the room is minor details. Check that the polarity of one of the subs is not inverted.

Cool. I've heard tho that the KW181 has a built in crossover from some people but others say it does not. Can anyone confirm?

Also, how does the new JBL718XLF stack up to the qsc?

 

[Bill Hornibrook]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

You've already got plenty of sub for a space this size.

Small spaces can be tricky and this room is complicated by the fact that you're located in front of a facade. My first choice would be in front of your table as well, but it sounds like you tried that. If it didn't work I can believe it, because sometimes in really small live rooms like this there will be nulls right in front of the subs.

But somewhere in there they are going to just boom - assuming you're set up correctly. If I were doing this, my next choice would be to split them and place one against each wall on either side of you. You might have to slide them forwards and backwards to find the sweet spot. I'm not a fan of corner loading usually, but this room is so small that you could try that as well - in the corner stage-ish left. You could also try them together behind you against that facade, but make sure the tops are against the facade too and not out in front of them.

 

[Bob Harvey]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

The KW181 has a low pass filter that it uses internally and QSC states the frequency response to be 38 - 124 Hz. The KW 181 does not have a crossover or high pass filter for routing mid/high audio to the tops.

I have 4 of the KW 181 subs and 2 of the KW 153 tops. I stack two of the subs and put a 153 on top of each stack.

The 153s are set to "External Sub" and the system nicely fills any indoor or outdoor venue where we may play.

 

[Matt Gordon]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

The KW181 has a low pass filter that it uses internally and QSC states the frequency response to be 38 - 124 Hz. The KW 181 does not have a crossover or high pass filter for routing mid/high audio to the tops.

I have 4 of the KW 181 subs and 2 of the KW 153 tops. I stack two of the subs and put a 153 on top of each stack.

The 153s are set to "External Sub" and the system nicely fills any indoor or outdoor venue where we may play.

Yeah I have Yamaha S115V's and since they don't have anything like an "External Sub" mode, I just purchased a crossover so I can have the subs handle anything below 100Hz (kinda like a High Pass output thing).

The façade is actually a glass wall type of thing so there's no use in cornering the subs there. I would consider putting them behind me, but I would get bombarded with bass. I might give stacking them a try tomorrow to see if that works better. My crossover is coming tomorrow so I'll see if that makes a difference. But I feel like with the shape of the room, putting them stacked to the right of my table might allow for a greater hit. since they are away from walls and shit. Let me know your thoughts everyone.

 

[Rob Spence]

Yeah I have Yamaha S115V's and since they don't have anything like an "External Sub" mode, I just purchased a crossover so I can have the subs handle anything below 100Hz (kinda like a High Pass output thing).

The façade is actually a glass wall type of thing so there's no use in cornering the subs there. I would consider putting them behind me, but I would get bombarded with bass. I might give stacking them a try tomorrow to see if that works better. My crossover is coming tomorrow so I'll see if that makes a difference. But I feel like with the shape of the room, putting them stacked to the right of my table might allow for a greater hit. since they are away from walls and shit. Let me know your thoughts everyone.

What crossover did you get?

I use KW181s with K12s. I have stacked 2 on one side and got thumping bass.
One time i didn't get what I was expecting and got out a flashlight and it turned out that the polarity switch on one got flipped in transit. Check it.



Sent from my iPad HD

 

[Jay Barracato]

Yes... check the polarity.

It is the most likely thing to cause what you have described.

Then set up the crossover.

Only after both of those things are correct, then worry about placement.

 

[Matt Gordon]

Re: QSC KW181 stacking (placement) - NEED ADVICE!

Yes... check the polarity.

It is the most likely thing to cause what you have described.

Then set up the crossover.

Only after both of those things are correct, then worry about placement.

Polarity is fine. But why would I switch it to Reverse polarity? Whats the advantage of that? Will the subs fire in reverse (per-say)?

Should I align the front of speakers with the front grill of subs? RIght now the speakers are on stands about 6" behind subs because thats really the only way i can set it up. I got the dbx 223XS Crossover.

I think once I get the crossover, im gonna try it out both ways and see which gets more bump. Any other advice you guys can give me?