Internal Enclosure Volume - Have i got it right?? |
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Khyber
Registered User Joined: 28 October 2017 Location: Whitby Status: Offline Points: 89 |
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Posted: 30 November 2017 at 1:51pm |
Hi everybody! :) after alot of deciding, re-deciding then undeciding and a bit more deciding i have finally decided on building a full bass reflex rig. I did have some help along the way from my first post. so my current question is if i used this driver for e.g. http://www.ciare.com/Products/catid/9213/eid/9639/ndc15-4dc (i have input the specs etc.. into WinISD) These are my results along with a draft of the internal enclosure volume Does this look correct? the curve is looking pretty good i think... Sketchup is telling me that the volume of this box is 99976740.2 mm³ which i translate to 99.98l Anything i have missed??
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DMorison
Old Croc Joined: 14 March 2007 Location: Aberdeen Status: Offline Points: 1649 |
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Your curve looks OK, but make sure you check the excursion and vent airspeed graphs to be sure that you can actually use a decent amount of power over that whole frequency range.
Also, make sure you check out availability of those drivers - I recall reading that since they were taken over by 18 Sound a year or so ago that they were not as easy to get a hold of - maybe have an alternate driver from another brand modelled out as well just in case. For the box volume, WinISD is reporting only the empty space inside the box - it does not take account of the volume occupied by the backside of the driver, the ports, handles, bracing and anything else you end up including within the box. You may therefore need to add a few litres to your target for sketchup and you'd have to cut your timber panels so they fit around the outside of the shape you eventually come up with. Other than those couple of points, looks like a decent project, good luck, and keep us up to date how it goes
Edited by DMorison - 30 November 2017 at 2:39pm |
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Khyber
Registered User Joined: 28 October 2017 Location: Whitby Status: Offline Points: 89 |
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Thanks for the speedy reply, surprisingly that actually made sense haha. I haven't settled on a driver yet just wanted to see if i could actually figure out an enclosure from scratch (i would love to be able to say i designed my entire rig from the ground up ;) ) so thanks for the heads up. yeah the measurements take into account panel width on the ends making it 450mm wide in total. I did wonder whether you need to account for the back of the driver thanks for the clarification. I have excluded the ports from that volume calculation already but did forget about handles etc. At least i know i am on the right path :) I plan on building the cabs to hold 2 15" drivers. Initially i have chose to enclose them independently like the pic. Would it make sense to do that or together and work out the volume of the entire cab for 2 drivers as a whole?
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DMorison
Old Croc Joined: 14 March 2007 Location: Aberdeen Status: Offline Points: 1649 |
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Hi, sorry this one was a bit slower, got a bit busy with work. Technically, putting two chambers in the same box gives a very slight advantage in rigidity, and means there's less of a risk to the second driver if one fails mid-gig, but it's a small difference and many properly pro boxes use a shared chamber. So, just make sure it's properly braced - I see you're getting good feedback on that in your other thread. Or if you think you'll have the opportunity to use the rig for smaller events, you could do them as single driver cabs to maximise your flexibility.
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Khyber
Registered User Joined: 28 October 2017 Location: Whitby Status: Offline Points: 89 |
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Cheers man i have decided to have them sharing in the end end its well braced now :) check out my other thread
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