OO1 Posted January 10, 2015 Share Posted January 10, 2015 Happy 2015 to all the forum members -my question is something I have been thinking of for a while - basically installing an Eminence -EV-JBL 18 inch woofer in a Cornwall -cornscala cabinet - the idea here would be to improve the low end sound - - I am wondering if that trial has already been done with sucess by another forum member - the issue here is the fact that cutting the motherboard is irreversible once done - Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted January 10, 2015 Share Posted January 10, 2015 are you familiar with cabinet tuning concepts? 1 Quote Link to comment Share on other sites More sharing options...
OO1 Posted January 10, 2015 Author Share Posted January 10, 2015 By that , do you mean adding ports or venting or passive radiators etc - Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 10, 2015 Share Posted January 10, 2015 (edited) You will more than likely need a larger bass reflex cabinet for a 18" woofer. To answer your question in the other thread...I have swapped out stock Cornwall K33s for Fostex L475 lab series woofers. The L475 calls for larger cabinet than the Cornwall, and has a bit higher Fs. (free-air roll-off) The K33 is more specified for the Cornwall cab, and gets deeper, etc... The L475 had a warmer midbass, but the K33 has good midbass as well, and I want depth. Edited January 10, 2015 by mike stehr Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted January 10, 2015 Share Posted January 10, 2015 By that , do you mean adding ports or venting or passive radiators etc - I mean you can't take a cabinet tuned for some very specific driver parameters and expect to throw in a different, larger driver and immediately get deeper bass. You'd be better off taking those funds and buying a subwoofer to supplement the Cornscalas. 1 Quote Link to comment Share on other sites More sharing options...
OO1 Posted January 10, 2015 Author Share Posted January 10, 2015 point well taken , my goal was to build a cornscala with CP-1 front dimensions with the depth of a Cornwall 1 -I have a pair of CP-1 that are using an EV18 inch woofer with no issues for several years - the motorboard was cut for the 18 inch fit -these are not driven hard and are way better at delivering bass than a 15 inch CP-1 K44E - the time alignment of the woofer -mid and tweeter is fantastic to say the least - with no mods to the crossover as well - -bass is tight - mids are very detailed and the tweeters with Crites titanium diaphragms are very smooth - you can feel the punch in your chest and all the sound is there with great presence - -a hybrid of the CP-1 and Cornwall 1 is what I want to build and should be even better balanced - it would result in a slightly bigger bass reflex enclosure and could handle more power as well - TX Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 10, 2015 Share Posted January 10, 2015 By that , do you mean adding ports or venting or passive radiators etc - I mean you can't take a cabinet tuned for some very specific driver parameters and expect to throw in a different, larger driver and immediately get deeper bass. You'd be better off taking those funds and buying a subwoofer to supplement the Cornscalas. You HAVE been paying attention! 3 Quote Link to comment Share on other sites More sharing options...
moray james Posted January 11, 2015 Share Posted January 11, 2015 (edited) here is my off the top of my head thoughts. A pair of fifteen inch woofers will push the equivalent of 1.5 eighteen inch woofers. As you increase the size of the woofer that you want to use in a multy way design then you will have to lower the crossover point between the woofer and the mid and that means increasing the size of the mid horn as a K601 is not going yo play very much lower than it already is doing. You know that a fifteen inch works well in a CW with the mid horn used (K600/K601) so why not instead opt for dual woofers of the same size that you know work? If you corner load you will obtain better bass loading along with additional output and somewhat deeper bass and the dual diver will provide 3db more output right off the top Vs a single woofer plus what output you gain in the corner. Sounds like your best option to me short of a complicated re design from the ground up. Stepping back for a moment I cannot think of a single two or three way based upon a single eighteen inch woofer (though I am sure you could find some) so that in itself speaks volumes. Hope this is of interest. Best regards Moray James. Edited January 12, 2015 by moray james Quote Link to comment Share on other sites More sharing options...
Axz Hout Posted January 12, 2015 Share Posted January 12, 2015 s Quote Link to comment Share on other sites More sharing options...
OO1 Posted January 12, 2015 Author Share Posted January 12, 2015 I cannot think of a single two or three way based upon a single eighteen inch woofer EV had the Patrician iV using the EV 18WK in a corner Horn. http://electrovoice.com/downloadfile.php?f=Patrician%20IV%20DIY%20Manual.pdf Quote Link to comment Share on other sites More sharing options...
OO1 Posted January 12, 2015 Author Share Posted January 12, 2015 (edited) Hi Morey - Electrovoice had the S-1803 EDS with an 18 inch woofer , the cabinet is wider and deeper than a Cornwall but just as high -200 watts rating - S-1803 EDS.pdf Edited January 12, 2015 by Randyh Quote Link to comment Share on other sites More sharing options...
OO1 Posted January 12, 2015 Author Share Posted January 12, 2015 (edited) I cannot think of a single two or three way based upon a single eighteen inch woofer EV had the Patrician iV using the EV 18WK in a corner Horn. http://electrovoice.com/downloadfile.php?f=Patrician%20IV%20DIY%20Manual.pdf The Patrician iV was essentially a licensed 18 inch KLIPSCH khorn , and pretty rare to boot - the 18 inch woofer added bass accuracy in larger rooms - in this case , larger is better while remaining efficient - Edited January 12, 2015 by Randyh Quote Link to comment Share on other sites More sharing options...
OO1 Posted January 12, 2015 Author Share Posted January 12, 2015 so why not instead opt for dual woofers of the same size that works. Best regards Moray James. hy Morey - I think PWK had the same idea when he designed the Jubilee - Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 12, 2015 Share Posted January 12, 2015 I think PWK had the same idea when he designed the Jubilee Except he dropped the single 15 for two 12 inchers. 1 Quote Link to comment Share on other sites More sharing options...
moray james Posted January 12, 2015 Share Posted January 12, 2015 (edited) I cannot think of a single two or three way based upon a single eighteen inch woofer EV had the Patrician iV using the EV 18WK in a corner Horn. http://electrovoice.com/downloadfile.php?f=Patrician%20IV%20DIY%20Manual.pdf I did make an edit saying that examples could probably be found if looked for. The point is that using an 18 inch driver in a multy way it is a very difficult and compromised design and one which has not enjoyed great popularity for a variety of reasons. The reason that the Jubilee came into existence was because PWK could not make the Khorn play high enough to be used as a two way. If you were to horn load the woofer and go three way the mid horn needs to become larger due to the requirement to play lower to meet up with the woofer horn. If a bass horn is not used and the woofer is used as a direct radiator then dispersion issues arise at the crossover point and to deal with these the woofer to mid crossover point must again be lowered and so demands are again placed upon the mid. So yes it has been done but it has not proved to be a very popular nor successful set of compromises either horn loaded or as a direct radiator. If the OP is willing to experiment then a build or two would be most interesting and I am sure a worth while experience. Best regards Moray James. PS: the Jubilee's ability to play higher is not a result of PWK having used dual twelve inch woofers but rather as a direct result of the less complex (reflective) horn folding of the Jubilee horn. Driver response is not a limiting factor in larger drivers, even a twenty one inch woofer can play many octaves higher than necessary. Edited January 12, 2015 by moray james Quote Link to comment Share on other sites More sharing options...
Stevenarrow Posted January 12, 2015 Share Posted January 12, 2015 I really couldn't imagine needing more bass from a modern CornScala: Unless you are installing them into a movie theatre... Quote Link to comment Share on other sites More sharing options...
OO1 Posted January 15, 2015 Author Share Posted January 15, 2015 I really couldn't imagine needing more bass from a modern CornScala: Unless you are installing them into a movie theatre... one hell of a small movie theatre for single 15 inch speakers - twin 15 inch cabinets would sound more appropriate - Quote Link to comment Share on other sites More sharing options...
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