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[Ray Buksa]

  Post topic might be a bit off base but I'll fill in the blanks.

 I have some daul 18 boxes which I'm looking to improve upon. Mostly the power handling of them and the drivers.

 What I'm backing into right now are some big excursion issues when any real power is applied to these boxes. Heres the specs on these boxes as of right now.

 19.9 cubic feet
 ports have been

 4- 6" x 3/4
 3- 6" x 3/4
 3- 6" x 2"
 4- 6" x 6"
 4- 4" x 3/4

 The best workable ports look to be in the six inch area with the best being the 3- 6" x 2" ports.

 Boxes are loaded at this time with 2- EXV 180Bs

 I'd like to tune these to 30 to 38Hz maybe a bit higher with 2000 or so watts.

I was hoping someone might be able to model these things with some good software and come up with some tunings. I'd like to work with the six inch ports if possible.
 

[Paul O'Brien]

What drivers do you want to use.
Is the volume stated the box internal?

I can tell you right now even without running a simulation the EVX's are not even close to suitable.. they simply don't have enough excursion capability to take anywhere close to 2000w at that tuning range.. probably not even half that much power.

[Ray Buksa]

 Box volume is at this time 19.9 cubic feet internal. Volume can be modifed.

I'm looking for options that are workable with the Evx drivers.

I am however not set on any tunings.

Power will be closer to 1800 watts.

[Paul O'Brien]

OK.. well here's the bad news. Those drivers reach xmax at their rated rms of 600w in a 4.6cu ft box tuned to 52hz, bigger enclosures and lower tuning just decreases power handling from there. In a 5.5 cube box tuned to 40hz power handling is down to 400w.

[Ray Buksa]

 
Its my understanding that cone excursion is at it lowest at box tuning.

Also keep this in mind. I do plan on using filters in an attempt to tame excursion above and below box tuning as needed. This should help tenfold no?

Just about every manufacture today seems to do this.

Boxes are to be loaded with two drivers each.

[Jared Scott]

If you limit excursion at certain frequencies, you're also going to limit output, effectively giving you a speaker with an extremely peaky and nasty response.  You would do well to find a different set of drivers to make your goal plausible

[Paul O'Brien]

Ray Buksa wrote on Fri, 31 July 2009 11:37

Its my understanding that cone excursion is at it lowest at box tuning..

Yes, but it's also highest slightly above tuning right in the meat of the subwoofer range.

Ray Buksa wrote on Fri, 31 July 2009 11:37

Also keep this in mind. I do plan on using filters in an attempt to tame excursion above and below box tuning as needed. This should help tenfold no?

Tenfold.. no. I modeled some filters with the examples I gave above and it allowed about 100w more input power.

Bottom line is these are terrible sub drivers by modern standards, and the boxes are almost twice the size they need to be. A pair of B&C 18TBX100's will take 2000w in a 13cu ft box tuned to 36hz with no EQ besides a low cut filter.. for example

[Nathan Short]

+1

[Elliot Thompson]

Ray Buksa wrote on Wed, 29 July 2009 20:28

Post topic might be a bit off base but I'll fill in the blanks.  I have some daul 18 boxes which I'm looking to improve upon. Mostly the power handling of them and the drivers.  What I'm backing into right now are some big excursion issues when any real power is applied to these boxes. Heres the specs on these boxes as of right now.  19.9 cubic feet  ports have been  4- 6" x 3/4  3- 6" x 3/4  3- 6" x 2"  4- 6" x 6"  4- 4" x 3/4  The best workable ports look to be in the six inch area with the best being the 3- 6" x 2" ports.  Boxes are loaded at this time with 2- EXV 180Bs  I'd like to tune these to 30 to 38Hz maybe a bit higher with 2000 or so watts. I was hoping someone might be able to model these things with some good software and come up with some tunings. I'd like to work with the six inch ports if possible.

You can download the software Here

Those drivers will have no problems taking 1000 watts each (2000 watts total, two drivers in one Double Eighteen) long-term. My EVX 180B’s have 7 years of use getting 1000 watts each sitting on Crown MA 5000s. They offer a lot of cone movement, which is the nature of the EVX 180B.

The drivers can also perform in small cabinets as well. I would suggest you go to Electrovoice and, download the TS Parameters, punch them in WinISD Pro and, tune the box accordingly.

Best Regards,

[Antone Atmarama Bajor]

Ray Buksa wrote on Fri, 31 July 2009 08:37

Its my understanding that cone excursion is at it lowest at box tuning.

    So you want to produce one note??  At port tuning?