Subwoofer advice

I run sound at a local skating rink that has a 10,000 square foot oval skating floor that is coated concrete. Has walls on three sides with one long side open to the rest of the building.

We currently have four Yorkville 18" subs (two at one end of the rink two at the other end of the rink) which never sounded good.

We replaced three of the 14 QSC 8" two way powered speakers (only three of them actually still worked) with three of the Mackie 212 powered speaker.

Decided to look up subs and found the Rockville RBG18FA as I'm looking for the ability to reproduce bass under 40Hz and the Frequency Response spec is +/-3dB 25Hz - 120Hz which should fit the bill quite nicely.

Would that be a good sub for the application and if so how many are needed and where should they be placed?

If that is not a good sub, what sub would be recommended for about $1,000 or under?

The system gets turned up a good bit once a week for four hours continuous by a local DJ who plays there.
Rockville specs aren't worth the paper they are written on, do't go there. What Yorkville subs do you have?. My suggestion is add some processing to tame the boominess(upper bass buildup) which will make it sound like there is more low bass. Unfortunately I think any attempt to get sub 40hz bass in there is a fools errand, it will just excite the structure even more than it is now which just adds more mud, and besids that getting complimentary SPL levels would be very expensive.
We have four of the Yorkville LS1208.

They are arranged in pairs of two one pair on the back wall (long side of skate floor) at one end of the rink and one pair on the other end of the rink on the same wall.


I've got them sounding the best they possibly can using EQ, but they still don't sound good.

Before I applied the EQ to them they reproduced one frequency real well and that was 59Hz.

What sub would be recommended?
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Joined 2011
Seems more like the acoustics and speaker placement are the problems.
A sub won't help that at all, and will just waste money best put elsewhere.

Post a drawing of the rink, with dimensions, and the speaker locations.
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Placement definitely is an issue, but I need better subs first so I can place them better.

Also one of the four is disconnected as it has a rattle in it at louder volume levels and it's not the driver given the rattle has been there several years.

The idea when I get better subs is to also get a speaker processor which will eliminate the separate EQ and crossover.

That will give me much more control over the tuning
The way we're doing it we will only replace two speakers on the back long wall. There's 5 posts evenly spaced along each long side of the rink and we currently have three Mackie 212 speakers along one wall spaced one post apart and we'll put two along the other long side of the rink spaced one post apart.

It will be like this. __ is an empty post. O is a speaker on a post.

__ O __ O __

O __ O __ O

That way no speaker is directly across from another speaker.

Basically I'm just getting ideas for the subs so I can get a price together and present it to the one who deals with the tech stuff.
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We have four of the Yorkville LS1208.

They are arranged in pairs of two one pair on the back wall (long side of skate floor) at one end of the rink and one pair on the other end of the rink on the same wall.
So the two clusters are 75-100ft apart? That will produce some pretty serious lobing at varous places around the rink, you would get smoother coverage with all of them clustered together.
I've got them sounding the best they possibly can using EQ, but they still don't sound good.
What kind of EQ.. graphic? DSP is what you need. The thing is these boxes do 40-100hz really well. How well? It would take a pair of double 18's with 4x the amplifier power to equal each 1208 box in SPL. And these things contain high end B&C or RCF drivers these are not junk speakers so you really need to look at all your options before throwing in the towel and buying something else. Low bass response inside a building is ALL about positioning... especially for the lowest frequencies. I suspect some of your problem is that the subs aren't co-located with the tops as well, the very best solution would be to fly the whole works(subs and tops in a single cluster over the center of the rink, that would produce much better coherence between the subs and tops and a much more even low bass coverage.
The problem is without any sort of EQ they seemed to peak around 59Hz.

Also in my opinion even the bass they do produce with a 31 band EQ doesn't sound all that good.

Plus I've heard better sounding subs at other rinks. They might only get down to 40Hz but they sounded better in my opinion than these.

Originally I had been looking at some OAP W bins two years ago for the bass under 40Hz but that would have required 8 stacked to make a true 40Hz horn and that would have been 15' high.

Also high efficiency isn't what I'm after as I can take lower efficiency better sounding subs and just use more of them which if grouped together may be more beneficial than using fewer higher output subs.

Given the space I need to fill I most likely will need a long throw subwoofer design.

Honestly the subs to me sound like the subs car audio people use when they only want max SPL.

That said these have been in use 10 years and I think they were bought used.
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A peak at 59hz is not characteristic of this type of box however they have a rising response peaking at about 120hz, so that problem is a product of thier position in the room. I have seen the same thing with a reflex box, measured in my shop there was a nasty peak at around 60hz but outside away from structures the box itself measured very flat.
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Could it be the rising response I'm hearing and maybe lowering the 60Hz EQ slider helped that in some way? I'm sure the building and sub placement have a lot to do with it as well.

Now would these work better if all four were at one end of the rink side by side?

That said I still have to find what's rattling in the fourth box.

Also as the subs go louder I hear some of what one might hear from the port of a ported sub. Perhaps that's just a function of the design.

One rink has four JBL 4520 cabinets used as subs. They definitely don't go below 40Hz, but it's some of the cleanest bass I've ever heard from a sub.

What other subs out there are good?
Here's what I'm thinking.

Cheaper is obviously out.

Expensive is most likely going to be a no go, however I honestly believe that expensive doesn't necessarily have to be the only way to go.

What is the general consensus about the JBL 4520?

A local skating rink that has been there since the early 80's has one in each corner and while they don't do much under 40Hz, the bass they do produce is some of the cleanest most natural sounding bass I've ever heard from anything pro audio that hasn't cost multiple thousands of dollars. Also the bass seemed to be heard all over the floor no problem.
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Ok after more thinking here's what I'm gonna do.

I'll look at the sub that has a rattle. I'm pretty sure it's not the driver as it's been doing that for several years when played loud only. I figure maybe it's a loose panel or loose hardware.

Once it is fixed and no longer rattles I'll try all four subs on one end of the rink and see how they sound then I'll try one sub in each corner and see how it sounds.

If need be maybe I can get more of these subs, however I'd need more QSC RMX2450A amps. I love that amp as it's maximum output bridged is also the maximum RMS two of the Yorkville subs in parallel can handle and with the built in limiter on the amp turned on I can run the subs at max output without damaging them. Plus the QSC amps are very robust having been ran hard like that most every Saturday night since about 2017 without a single amp failure. Just have to open them up occasionally and blow the dust out.

Now if there's an amp that works better for these subs I'd definitely want to try that.
Also one of the four is disconnected as it has a rattle in it at louder volume levels and it's not the driver given the rattle has been there several years.
The rattling could be from a loose speaker or grill, ripped cone, cabinet parts or drywall- any of which can go on for years.

If the disconnected LS1208 "basspipe" cabinet does not have it's input shorted it will function as a resonator, sucking level down and peaking at some frequencies- could be 59Hz.

As an example, the shorted Keystone tapped horn cabinet (blue trace) increases level by 1dB over a single driven cabinet(green), while the unshorted "drone" cabinet next to it creates +/-2dB peaks and dips.

EQ for that pair will be wrong for other pair, like you said: "the bass they do produce with a 31 band EQ doesn't sound all that good".

Plugging the cabinet in and turning the amp down would short the input, improving response, but finding and fixing the cause of the rattle should be done before judging the LS1208 as the problem.
Sine wave frequency sweeps, a microphone on a tall boom stand and headphones make it more easy to find the source of rattles without climbing around..

The LS1208 should sound better than JBL 4520 scoops (-8dB at 40Hz..) if positioned the same in the same room- like Conanski wrote: "Low bass response inside a building is ALL about positioning."

I figure it must be hardware rattling as the rattle has been there several years.

Running the subs at near max power certainly would have caused any torn cone or other driver issues to virtually destroy the driver by now. Also a driver issue would be heard at lower volumes and the rattle is only heard at high volumes.

That said should I try all four standing vertical side by side at one end of the rink and see how good the bass is then and if it can be heard at the other end of the rink without much drop in output?

That said if four together sound great should I get four more and put them on the other end of the rink?

Unfortunately connecting the rattling cab to the amp and turning it down isn't possible as two cabs are run in parallel on one amp running bridged.
Could just be loose driver fastener/s on the box that makes noise, maybe somebody pulled/replaced the driver at some point and they didn't torque the fasteners properly, or it could be an internal panel that has worked loose.

Yes try placing all the boxes together at one end, it will produce very different results than what you get now.
Boundaries affect sound but for sub bass the boundaries have to be quite large as the wavelengths at these frequencies are also quite large.. the wavelength at 40hz is 8.5m for example. The general rule of thumb with subs is that they should be placed as close to structural boundaries as possible to minimize cancellation notches resulting from reflected waves off those boundaries, or you put them well away from everything. Experimentation is key so try as many different setup configs as is practical, sometimes it takes a bit of work to get the best possible results.