New Member + Calculating Box Volume

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   Hello there! I'm Colin, and just signed up to the forum.

I've just recently come across this forum that seems to be packed full of awesome info and helpful guides on building speakers, can't wait to get stuck in and learn new stuff from you guys.

Im not a pro on any level but I love working with wood and a hobbyist when it comes to audio. so I thought of giving it ago at designing my own little cab.

My first Hurdle is, calculating the volume of a box. I plan to build a small simple 6 sided symmetrical cab to seat a B&C 8CXN51 (500w) coaxial driver I have laying around. Because this is my first time designing a box i've been trying to learn how to calculate box volume for the size of the driver so I can get my final cutting dimensions, I can't seem to find how to calculate a 6 sided cab with different size sides on the net as there all just simple 4 sided cubes on each link I click on.

if anyone has any links to something better than what i've found it would be appreciated! Unless someone already has the knowledge to pass on. Or even an online tool for the job (which i've search and failed )

Any help on this would be greatly appreciated!

Thanks, Colin.

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ColinP Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 13 April 2021 Status: Offline Points: 28	Post Options Post Reply Quote ColinP Report Post Thanks(0) Quote Reply Topic: New Member + Calculating Box Volume Posted: 13 April 2021 at 5:13pm
	Hello there! I'm Colin, and just signed up to the forum. I've just recently come across this forum that seems to be packed full of awesome info and helpful guides on building speakers, can't wait to get stuck in and learn new stuff from you guys. Im not a pro on any level but I love working with wood and a hobbyist when it comes to audio. so I thought of giving it ago at designing my own little cab. My first Hurdle is, calculating the volume of a box. I plan to build a small simple 6 sided symmetrical cab to seat a B&C 8CXN51 (500w) coaxial driver I have laying around. Because this is my first time designing a box i've been trying to learn how to calculate box volume for the size of the driver so I can get my final cutting dimensions, I can't seem to find how to calculate a 6 sided cab with different size sides on the net as there all just simple 4 sided cubes on each link I click on. if anyone has any links to something better than what i've found it would be appreciated! Unless someone already has the knowledge to pass on. Or even an online tool for the job (which i've search and failed ) Any help on this would be greatly appreciated! Thanks, Colin.

DMorison Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 14 March 2007 Location: Aberdeen Status: Offline Points: 1649	Post Options Post Reply Quote DMorison Report Post Thanks(0) Quote Reply Posted: 13 April 2021 at 8:53pm
	Hi, and welcome! If you mean 6 sides plus top and bottom, then you need to calculate the area of the hexagon created by those 6 sides, then multiply that by the height. If it's a regular hexagon, this should work: If it's an irregular hexagon, you might need to split it up into parts, eg this could be one rectangle plus 2 triangles: The area of this would be AxB for the central rectangle plus 0.5xBxC for each of the side triangles, which simplifies to BxC for both of them combined. Remember also, if you're working from a suggested design either from a datasheet or modelling program, the volume it gives you is always the NET volume, after accounting for any inclusions within the space. What that means is that the volume of the backside of the driver(s) themselves, handles, braces, HF horns, ports etc etc all need calculated up and added to the number from the design before you then calculate your panel sizes. HTH, David. Edited by DMorison - 13 April 2021 at 8:54pm

DMorison Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 14 March 2007 Location: Aberdeen Status: Offline Points: 1649	Post Options Post Reply Quote DMorison Report Post Thanks(0) Quote Reply Posted: 13 April 2021 at 8:56pm
	PS, if you want an online tool, you're outta luck - Donald Trump got banned from social media. But seriously, the search term you'd want is "volume of a hexagonal prism".

ColinP Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 13 April 2021 Status: Offline Points: 28	Post Options Post Reply Quote ColinP Report Post Thanks(0) Quote Reply Posted: 14 April 2021 at 6:31pm
	Hi David Thanks for that, thats gave me more of an idea now. Also found some more info to read online now I know what i'm looking for.. hopefully i've figured out how to post photos haha... below is a sketch I dragged off the internet of a 6 sided box, that is the design id like to build my self, just to give more of an idea in visual. I've just downloaded winisp also so im currently in the middle of learning that programme... sure ill have plenty more questions in the near future but I believe ill be able to find most answers from the post on this forum. Cheers Colin

DMorison Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 14 March 2007 Location: Aberdeen Status: Offline Points: 1649	Post Options Post Reply Quote DMorison Report Post Thanks(0) Quote Reply Posted: 15 April 2021 at 1:44pm
	Cool, so for that shape, I'd take the total area of the rectangle defined by the width and depth, then subtract each of the 2 triangles formed by the corners, easy enough. Cheers, D.

Beau23 Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 06 June 2021 Location: Bristol Status: Offline Points: 7	Post Options Post Reply Quote Beau23 Report Post Thanks(0) Quote Reply Posted: 06 June 2021 at 3:44pm
	yo I'm beau I'm 17 and I'm new on this website, to speaker building and the whole forum thing so far I've only got sketches and rough idea but would be really good to talk to some people who know what their doing 😂 I was thinking of 2 15" mini scoops (650mm600mm800mm)(with 500watt drivers) 2 horizontal mid woofers (still working out a design)(with 300 watt drivers) and a small tweeter (100 watt driver) if anyone can suggest any good designs, driver, places to get 18mm thick ply or can see any obvious mistakes in my plan drop me an email on beausemail23@gmail.com or reply to this (and ill try to work out how it works😂)

JonB67 Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 22 April 2016 Location: UK Status: Offline Points: 1376	Post Options Post Reply Quote JonB67 Report Post Thanks(0) Quote Reply Posted: 06 June 2021 at 5:59pm
	Hey beau, welcome to the forum. No need to post twice, people read all parts of the forum. Also considered bad form to drop your stuff into someone else's thread if its not really the same question. It can derail their thread and stop them getting the help they require.