well i had the money saved up to purchase drivers, but had to buy a new car. so i am currently saving again, but there is a chance i will be starting a new job and won't have access to some really good machines; CNC, panel saws..ETC...(i am currently an engineer for a wood working company). i wanted to start building before i leave this job. this build will be for live band applications only. most of the shows are indoors, but we do have a few outdoors. i currently have 2 amps i can dedicate to sub work both are QSC RMX2450s. thought about running 3 SS15s per side at 2 ohms (1200 watts per channel), which means using only one amp, or bridge and run 2 CB-18Es per amp. the SS15s will be loaded with Kappa Pro-15LF (or a driver similar in price) drivers and the CB-18Es will be loaded with either B&C 18TBX100, 18Sound 18LW2400, or cheaper drivers like Selenium 18SWS1100 or P Audio C18-650EL (would have to change amp set up).
i have modded the SS15s to use 18mm plywood (because that is what i have) and changed the outside design similar to kevinmcdonough post here THAM 15 - Touring Version! (and matching top) - Speakerplans.com Forums - Page 1
later on i'd like to build some tops that match the same dimensions as my bottoms. thought it would be an interesting challenge plus all the boxes would look identical. my SS15 design measures 22.5" H x 37.5" W x 26.69" D. the CB18s measure 22.75" H x 41.42" W x 27.36 D.
both set ups should work great, but i'm just torn between both designs. any thoughts?
i have modded the SS15s to use 18mm plywood (because that is what i have) and changed the outside design similar to kevinmcdonough post here THAM 15 - Touring Version! (and matching top) - Speakerplans.com Forums - Page 1
later on i'd like to build some tops that match the same dimensions as my bottoms. thought it would be an interesting challenge plus all the boxes would look identical. my SS15 design measures 22.5" H x 37.5" W x 26.69" D. the CB18s measure 22.75" H x 41.42" W x 27.36 D.
both set ups should work great, but i'm just torn between both designs. any thoughts?
Based on Stipe’s HornResp from #108 Post – thread: Speaker design project for Pyromusicals, both drivers will work. If Stipe’s model of the Cyclops Extended CBX18 is correct the average sensitivity within its bandpass is 101,9dB 1W/1m has an even higher efficiency as Jbell’s SS15 (average of 100.3dB 1W/1m with 3015lf). Use capable low cut filters at 38Hz!
from my understanding the width is increased to 1152mm. not sure where the added dimensions occur for the internals.
quote from staiper off the speakerplans forum;
"In fact there are drawings for few slightly modified variants every made on specific demand.
1. Standard CB-18
2. Extended front CBe-18 (streetsounds version, 700mm deep)
3. Full extended CBX-18 (extended pathlength, front and mouth area) - made on demand for extra few hertz LF extension
+ there is also standard CB-18Light version plans for 15mm plywood (extralight version ... as much as it can
)
Ofcourse it is possible to make to modify design to suit some new goals but all comes with some compromise .. If you want additional LF extension in compact size ..SPL suffers, If you want booth , max SPL and LF extension too cabinet size goes up rapidly.. etc
It is not big problem to make one "monster mega, giga, cyclops" but than size and weight will go much out of margins of regular "usability" and muscle and spines will hate em (however may be good for showing and shootouts)
I have thought about Cyclops idea to be good bass solution with "ideal" bandwidth for most jobs (flat ~40- ~130Hz), pretty easy manageable size and truckpack friendly. Any further increasing size (more than CBX-18 version) will go out of this goals.
"
quote from staiper off the speakerplans forum;
"In fact there are drawings for few slightly modified variants every made on specific demand.
1. Standard CB-18
2. Extended front CBe-18 (streetsounds version, 700mm deep)
3. Full extended CBX-18 (extended pathlength, front and mouth area) - made on demand for extra few hertz LF extension
+ there is also standard CB-18Light version plans for 15mm plywood (extralight version ... as much as it can
) Ofcourse it is possible to make to modify design to suit some new goals but all comes with some compromise .. If you want additional LF extension in compact size ..SPL suffers, If you want booth , max SPL and LF extension too cabinet size goes up rapidly.. etc
It is not big problem to make one "monster mega, giga, cyclops" but than size and weight will go much out of margins of regular "usability" and muscle and spines will hate em (however may be good for showing and shootouts)
I have thought about Cyclops idea to be good bass solution with "ideal" bandwidth for most jobs (flat ~40- ~130Hz), pretty easy manageable size and truckpack friendly. Any further increasing size (more than CBX-18 version) will go out of this goals.
Thanks for your reply Scameron78. I have my doubts about the HornResp Response of the CBX-18. To get such grafic response you will end with a cab way bigger as the real one.
Meanwhile I did my best to reverse engineer the CBe-18 to get a more realistic response from it. I still end up with a bigger volume (374litre in HornResp and the actually build one is less than 374Litre) than it is in reality.
Anyway, I hope this response helps in finding the answer to your question.
Meanwhile I did my best to reverse engineer the CBe-18 to get a more realistic response from it. I still end up with a bigger volume (374litre in HornResp and the actually build one is less than 374Litre) than it is in reality.
Anyway, I hope this response helps in finding the answer to your question.
The problem in most models I have seen so far is that the volume in the cone is included in the front chamber. If you do so you have to make up the volume of the cone + the rest of the driver in the S4 area. Otherwise you will end with an extreme volume in your model that doesn't translate to the real thing.
The problem with HornResp is that it doesn't support more point within the path so for some values like S3 I used a more average value which is slightly lower. But actually it would be a great if Martin or Oliver could model it more accurate with a roll-out path.
Any comment is welcome.
The problem with HornResp is that it doesn't support more point within the path so for some values like S3 I used a more average value which is slightly lower. But actually it would be a great if Martin or Oliver could model it more accurate with a roll-out path.
Any comment is welcome.
I don't want to make you doubt, but a slightly bigger THAM (1/2 size of the CBe) loaded with 18Sound 18LW2400 can beat one CBe-18 in dual settings by 1,5dB in sensitivity (1W/1m) and about 4dB in max... and I still love the compactness/weight/performance of such system in quad-stack settings..... Never mind, just an idea to make your head go crazy
I don't want to make you doubt, but a slightly bigger THAM (1/2 size of the CBe) loaded with 18Sound 18LW2400 can beat one CBe-18 in dual settings by 1,5dB in sensitivity (1W/1m) and about 4dB in max... and I still love the compactness/weight/performance of such system in quad-stack settings..... Never mind, just an idea to make your head go crazy
any links to a cabinet? i am open to something smaller. right now i have the packing for the CBe figured out in the truck we use to haul the equipment. something smaller would make it easier.
what do you mean by dual settings; 2 THAM to one CBe-18?
That last sketch was helpful since it is bigger than the one I had. I corrected the lengths and also corrected the volume of the front chamber that was way of. The results so far; the CBe-18 has a 1/4WL of 37Hz and a 1/3WL of 49Hz. It would be nice to see some real measurements including some impedance plots...
there is some measuring on this page. not sure if this helps.
Djyves Projects CB(X)-18's, TH-SPUD, Duran tops... - Speakerplans.com Forums - Page 7
Djyves Projects CB(X)-18's, TH-SPUD, Duran tops... - Speakerplans.com Forums - Page 7
It does deliver an interesting view if you compare it with JBell's measurement of the SS15. A few things should be considered; JBell measured outside and the CB-18 is measured inside (not against a wall), no idea about differences in equipment although both use a low cut filter.. The CB-18 uses an 120Hz high cut filter. Of course the overlap is no more than an indication.
Edit: the dip at 48Hz of the CB-18 is probably caused by room acoustics.
Edit: the dip at 48Hz of the CB-18 is probably caused by room acoustics.
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I did get a question about the last grapgh. You can't use it to compare decibels since both measurements used a different dB scale! While the CB18 is measured in steps of 20 dB (main horizontal lines) the SS15 is measured in 12dB. You can only use it as an identification for the similarity in resonance points of the tapped horns/pipes as the horizontal frequency line is linear between the two. So the only conclusion from this graph is that the Cyclops CB-18 has similar resonance points and therefore is designed with similar 1/4WL, similar path length. I made a new one with both dB setting in the same colour as the cab they represent to prevent wrong assumptions.
Green represents the CB18
Red represents the SS15
Green represents the CB18
Red represents the SS15
I am seriously considering building the CBE-18. I don't quite have the money for a Driver to do it justice, but I may do the wood work and pop in some Turbosound 18s I have here at the house, as the Bass reflex boxes they are in are just disappointing. No T/S specs on the drivers at all. Only specs I can get at all are for the driver in the TXD series BR box it came in, so I am not expecting miracles, but maybe I will luck out. It will be a crap shoot as to whether they work well in this box, but when I can afford some decent drivers, I will take these back out, unless of course they work, in which case I will just make two more CBE-18s. I really like the design, and as far as I can tell, no angle cuts over 45 degrees so no vertical jigging, which appeals greatly. Last time I had to do those, the cuts were really ugly.
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