ELECTROVOICE T-18 DESIGN
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Category: Plans
Forum Name: New Projects Forum
Forum Description: Forum for new speakerplans projects, in memory of Tony Wilkes, 1953 - 2014
URL: https://forum.speakerplans.com/forum_posts.asp?TID=686
Printed Date: 27 March 2026 at 8:37am
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Topic: ELECTROVOICE T-18 DESIGN
Posted By: CHAMPION
Subject: ELECTROVOICE T-18 DESIGN
Date Posted: 09 October 2004 at 9:20pm
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HI im making the T-18...... http://www.fullcompass.com/Products/pages/SKU--19707/ - 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 |
Replies:
Posted By: CHAMPION
Date Posted: 10 October 2004 at 8:01am
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Is there anything you should to inside to make the cab more acoustical....like where you have corner braces at 45degree, there are empty cavitys...can i filll them with wadding or foam etc ?? |
Posted By: whitehousejamie
Date Posted: 10 October 2004 at 8:28am
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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 - http://www.ofgb.org/reference/Music/ElectroVoice/dl18mt-eds. pdf Jamie |
Posted By: CHAMPION
Date Posted: 10 October 2004 at 1:06pm
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Naa i want more power more SPL, i will probly end up blowing them, if i use anything under 600w !! its the type of music i will be playing, mixture or might just wack in a Kilomax 18" !!!! Beef things up a little |
Posted By: Tony Wilkes
Date Posted: 10 October 2004 at 3:08pm
Why would you want to stick a toy in like the Kilomax? Go with the PD driver. |
CHAMPION wrote:Posted By: freddyi
Date Posted: 10 October 2004 at 5:11pm
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did you already build? MDF seems like poor choice for anything that
moves (or cna get damp) vs decent plywood - MDF rounds ok and can save
some money - but look at ARLS 1-15" Kappa LF scoop - has triangular brace tying top to back and or course bottom plate should tie to angled baffle re:stuffing - experiment but don't overdamp anything - I use almost nothing in Karlson types - might be similar story in reflex-scoop |
Posted By: Timber_MG
Date Posted: 10 October 2004 at 6:04pm
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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 |
Posted By: freddyi
Date Posted: 10 October 2004 at 6:27pm
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Hi Martin does ARLS broadband subjectively somewhat like a Karlson box? better yet - how is this "proved" in ARLS? - do they play without getting "stuck"? Karlson = tough cookie to measure - near-cone and near-aperture plots show shanges as mic is moved vertically - latter (maybe both) may be pressure distributioin changes Freddy (who else would ask this Karlson stuff -ha) |
Posted By: Timber_MG
Date Posted: 10 October 2004 at 8:34pm
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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 |
Posted By: CHAMPION
Date Posted: 10 October 2004 at 8:56pm
| ok is there any good paint or sray i can use to dampen the sound inside ?? Trimite or somehting ?? insted of wadding |
Posted By: freddyi
Date Posted: 10 October 2004 at 9:56pm
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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 |
Posted By: Timber_MG
Date Posted: 10 October 2004 at 10:16pm
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I would hope that one could model a Karlson in AkAbak somehow. But to
be honest I think this is a design of days gone by as shown by the lack
of interrest in it by most PA manufacturers. I recon the reduced excursion would be because you were operating the vented box significantly below the port tunig frequency. IIRC the Karlson has an odd opening to a front chamber in front of a driver placed in a sealed chamber right? Time to re-visit EG Becks site. How about you start that thread on the subject, listing what you intend to do with the system (or just a theoretical discussion), what drivers and means are available to you and what not as this is getting a wee bit OT ;-) ? Regards, Martin |
Posted By: nschana
Date Posted: 13 October 2004 at 4:17pm
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I have 4 * Void 18" 1000RMS drivers. I was thinking of building 1850 folded horns. However these may be very heave when coupled with these drivers plus added build complexity of the various internal miters required. Someone has suggested that T18 type of design would much lighter and easier to build than 1850 folded horn. I have also been told for the most part they behave like a folded horn. I have one problem I can’t find any design anywhere on the web for T18 type of cabinet. If anyone has experience of these types of cabinet design I would be grateful if you could send me detail or point me in the right direction. Thanks |
Posted By: Timber_MG
Date Posted: 13 October 2004 at 6:15pm
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Hi nschana To be very honest it would be a great pity to put that driver in anything other than a horn. A hybrid design such as the T18 will never achieve the same result as a proper folded horn and a lot of potential would be lost. The VOID driver is right up there with the PD1850 as far as horn drivers go, but has a fair bit more x-max. Another member of this forum has reported very good results with this driver in a WSX cab if you're looking for alternatives. Regards Martin |
Posted By: CHAMPION
Date Posted: 13 October 2004 at 9:43pm
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i can not afforf PD1850 as im making 10 boxs T18, if i sell a few then on the next batch i will invest in thoes drives, but as for now i can afford PD186.... The cabs are looking good, just in the process of routering edges, and cutting handle holes etc, for easy access also iv put castors on them for easy transport...they look better than the orignal E.V cabs !!! if i may say so myself !! |
Posted By: CHAMPION
Date Posted: 13 October 2004 at 9:46pm
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1 question guys, how would you know if they sound good or not, and how will you know if you really get that 30hz bass lin etc ??? i mean every speake box will give powerfull output, bass etc, but how do u know if that box should sound or to would it is suppossed to do !! ??? |
Posted By: tb_mike
Date Posted: 14 October 2004 at 4:07am
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how will you know if you really get that 30hz bass lin etc ??? Input a 30hz sinewave When inputting sinewaves ,dont do it for too long over the rms rating of the driver it will easily be destroyed! but how do u know if that box should sound or to would it is suppossed to do You measure the response in db,to see how low it goes,you listen to sinewaves to see how pure it is at different frequencies and SPL levels
Everyone has an idea of what a pure sound is-when you turn good subs down low,the sound is extra pure,when you turn them up theyl eventually distort a little. Listen to a low distortion sub and youl have a comparison. Cheers! |
Posted By: JD01
Date Posted: 16 October 2004 at 11:18pm
| Don't try 30Hz on this design. In fact, the original design won't work well below 50Hz. |
Posted By: tb_mike
Date Posted: 17 October 2004 at 9:11am
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JD01-Ofcourse its important to note where your subwoofer is loaded,and not to destroy it in testing.When i mentioned sinewave testing i meant at 1watt levels.
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