ELECTROVOICE T-18 DESIGN

HI im making the T-18......

http://www.fullcompass.com/Products/pages/SKU--19707/

Just a qestion on the inside, do i need to put some wadding inside ?? the cabs are being made out of 3/4" m.d.f.

Also any1 selling any cheap PD 1850's or 186 drivers for these cabs,???

cheers Guys/girls

Hi,

I would go for the PD 184, as it has a simular Qts and BL to the original EV driver. You will benifit from the increased xmax, better efficiency, bigger voice coil, and 200watts extra output.

You can find the specs of the original driver here....

http://www.ofgb.org/reference/Music/ElectroVoice/dl18mt-eds. pdf

Jamie

CHAMPION wrote: or might just wack in a Kilomax 18" !!!! Beef things up a little

Why would you want to stick a toy in like the Kilomax? Go with the PD driver.

The ARLS is an acronym for Advanced Reflex Loaded System and supposedly the port loads the driver over a larger spectrum that a normal BR. The design is specifically designed for the low budget Kappa 15LF as an alternative to a bass-reflex box and is the result of much experimentation by aw-audio. There are also some different versions of this cabinet floating around, most notably the ARLS Mod by tthorsten which has a higher cutoff but also efficiency and better mechanical reliability when high-passed supposedly.

How did this thread end up on the Kappa 15LF though?

A couple of German developers have reported good success with the Oberton 18XB700 in similar enclosures and Oberton itself has a box of similar construction, but these things might very well be quite sensitive to driver variation due to the hybrid nature (aka one cannot just start up WinISD and thus it would probably be a safe bet to take drivers with very similar T/S)

Rog also once mentioned that he has software suitable for the design (my suspicion lies with a custom MathCad or similar circuit equivalence model because he didn't mention AkAbak in that context) of such hybrid enclosures (and VOID have a box that looks related to the ARLS)

Martin

Heya

It would mean that the acoustic system starting at the back of the "flared port" to the outside world would present an impedance to the rear chamber + driver system over a greather bandwidth than a port of non-varying cross section as I see it. Whether this is actually true for the ARLS is still up for discussion, but the measurements certainly show something different from that of a ported box is going on.

Martin

heya Champion - I've  no expertise in PA work - probably seal the inside of the MDF boxes and use a couple of fiberglass pads

heya Martin - ARLS may work very well - nice size cabinet too

re:AkAbak - once asked gent if original Karlson coud be modeled .. no real reply - acted as if not heard of design.....

Karlson show very little gain bleow a point compared to reflex - but cone seems ot move less for gvein Z-minum tuing point - (assuming vent is efficient as in 1951 design) - 95l/50Hz reflex cone flopped pretty bad at 20vrms/36Hz with large vent velcocity  - K15 had cleaner fundamental, maybe 1/4 the movement and very little vent velocity - both had JBL M151 - but K's add bulk vs vented box so my not be practical for PA work.

sometime FWIW like to start thread on picking folds and cutoff within a given bulk vs tradeoffs and music genre (I;'m not hip on dub/gaab - only know rap as fan of genre)- a  Punisher - if 1st section were removed then would be 15" with somewhat shorter path and i have no 12".  some folks might make a pipehorn which shelves below a point.

freddy