Driver question non BFM

[JazzyRick]

I work at a small music venue where they are having a problem with blown subs. They are installed under the stage, so building new ones or replacing them with better stuff isn't an option really without rebuilding the entire stage.

My question is is there some software or suggestions for replacement drivers I could put in these enclosures that just have better sensitivity and/or more power capacity?

They are a relatively simple 2x12 vented design by EAW(VRS12), but the sensitivity without processing is abysmal in the 40-100hz range.

[Bill Fitzmaurice]

You'd have to reverse engineer the cabs with a modeling program like WinISD Pro, and to know if a driver will work better than stock you'd need to know the specs on the stock driver.
But don't hold out much hope for turning this sow's ear into a silk purse. Looking at the unprocessed SPL chart here, I wouldn't even call it a subwoofer:
http://www.fullcompass.com/common/files ... S12_SS.pdf

[JazzyRick]

They are literally just a box with a rectangular vent in the top(side) depending on orientation. Do I just need the dimensions of the box and vent size?

I'm just trying to help them out as it seems they blow a driver about every couple of months, and the OEM EAW drivers they are putting in there are nearly $200 a pop I think.

[Michael Ewald Hansen]

They are literally just a box with a rectangular vent in the top(side) depending on orientation. Do I just need the dimensions of the box and vent size?

I'm just trying to help them out as it seems they blow a driver about every couple of months, and the OEM EAW drivers they are putting in there are nearly $200 a pop I think.

Yes and the specs of the driver. Does it say on the driver which it is? If not, I don't know if EAW will give the specs to you, but you can always ask..

[JazzyRick]

Do I need the specs on teh original driver other that the mounting holes to determine if I can put something better in there? These things are pretty crappy, so I'd bet I could put almost anything in there and they'd be better...

I think even the listed sensitivity is about 92, but that's with processing. Unprocessed they are down around 80dB at 40hz and don't even make 90 by 100hz in the enclosure.

[JazzyRick]

All that's on the driver is a part number and some other numbers on the magnet....then a small sticker with order number and serial number on the basket.

P/N 0010140
LC12/3007-B

are the numbers on the magnet...

[JazzyRick]

Yes I know Bill that they are crap...LOL, but it's what they have and short of building a new stage it's what they have to deal with as well unfortunately...

[Michael Ewald Hansen]

Do I need the specs on teh original driver other that the mounting holes to determine if I can put something better in there? These things are pretty crappy, so I'd bet I could put almost anything in there and they'd be better...

I think even the listed sensitivity is about 92, but that's with processing. Unprocessed they are down around 80dB at 40hz and don't even make 90 by 100hz in the enclosure.

The cab is built around a specific driver - you can't just put a random driver in there and expect it to work..

[JazzyRick]

Here is what they look like. I can't imagine it'd be hard to determine what kind of driver specs would be acceptable for a box with a vent. They aren't horn loaded or band pass or anything at all. Here's a pic.

[JazzyRick]

I understand they are designed around a specific driver, but I don't have the driver specs and it's just a box...it's not some special super baffled design. I would think I could get the volume of the box and the vent size and at least get in the ballpark. I'm not new to speaker building, I have build 6 BFM designs myself, but as I said I'm just trying to help these guys not wast a couple hundred bucks every 2 months...

[Bill Fitzmaurice]

You need to provide the precise internal dimensions.

[JazzyRick]

When I go there I'll pop out the drivers and make sure there's nothing weird going on inside the box and measure it.

Best guess is about 10000 cu inches

Vent hole size about 28 sq inches, but I can measure it from the inside to be exact...

[Bill Fitzmaurice]

I did a model based on the size specs and impedance chart. They must be using inexpensive drivers to get the result they are, but since it has only a 500w rating for a pair of twelves they're obviously nothing special. I wouldn't be surprised if they're Delta 12 LFs, as those model fairly close to the response on the EAW chart. I modeled the Impero 12 and it's a lot better. Xmax is 6mm, not huge, but Pe is 1100w, and that's probably the main concern here. You'd need to replace the pair in a cab, but sooner or later that would happen anyway. I have a pair on hand that I only used to test, send me a PM and I'll give you a price.

[JazzyRick]

Ha! They've replaced them all a number of times. I bet at least 8 to 10 drivers over the last year and a half. If we could find something even close that won't just blow up at the drop of a hat they'd be happy. I can't obviously control what goes on when I'm not there, but I keep a very close eye on the amps and have redone the gain structure, so it's a bit more difficult to kill them with the amps, but it seems to me they are just poorly manufactured drivers. They always just come loose at the edge. No cooking them or ripped cones, just where the cone attaches to the basket rips or comes apart from the basket and starts flapping like dying bird...

I do understand I'd have to replace all 4 of the drivers(2 each in 2 cabinets) BTW. I'm not just looking to drop in one and expect it to work in any way shape or form.

[DJPhatman]

FTR, nice to see you posting again.