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<blockquote data-quote="PV Audio" data-source="post: 6266088" data-attributes="member: 554493"><p>//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif You're an ME? You should be teaching me, the EE, about this stuff man. What's going on? //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif</p><p>Anyway, that was a misspeak, you're right. Yes, I meant the larger the box, the lower the SYSTEM'S resonant frequency. Obviously the larger the box, the lower the box's resonant frequency, but that isn't exactly important nor startling information. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif</p><p></p><p>On your Q discussion, I need to know what you mean when you say compliance: compliance of what? I know very little ME stuff beyond what I know about speakers, and even that is limited, but there are many different compliance values for loudspeakers: Vas, Cms, etc...</p><p></p><p>Seeing as you're talking about .707, what does a sqrt(2) value of stiffness mean in ME? I haven't the faintest idea, however I do know quite well that 1/sqrt(2) is a very important factor in almost all engineering fields, and since compliance is just 1/stiffness, I'm wondering what that signifies //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif</p><p></p><p>Again, what damping are you talking about? Ported boxes naturally damp the cone at the tuning frequency, so I'm not too sure what damping you're talking about: cone, box, or some otherwise electrical damping that I might have missed in the conversation (sigma).</p><p></p><p>Yes, people have tried and failed since it's impossible to obviously reach theoretical numbers in practical applications. The problem is that it isn't feasible to take into account every single factor that can affect how a speaker responds, so instead, people merely tailor their sound to their tastes but use theory to make the initial design.</p><p></p><p>Your guess is mostly correct as well. Outside of the sub's passband, you're right, there is little cone movement, however, as you decrease in frequency, the cone movement gets greater until a certain point. At tuning frequency, the cone's movement is actually less than at other frequencies. But you are correct that under tuning frequency, the air in the enclosure can no longer control cone movement effectively and thus your sub can bottom out (which is why it's pretty stupid to test subs just sitting on your carpet if they are not designed to play free-air.</p><p></p><p>A FANTASTIC treatise on box design is Bullock on Boxes, it's a small book all about ported box design and theory. i just started reading it and am like 5 pages in, and already have learned more from those 5 pages than I have in literally years here listening to second hand accounts and tricks of the trade.</p></blockquote><p></p>
[QUOTE="PV Audio, post: 6266088, member: 554493"] [IMG]//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif[/IMG] You're an ME? You should be teaching me, the EE, about this stuff man. What's going on? [IMG]//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif[/IMG] Anyway, that was a misspeak, you're right. Yes, I meant the larger the box, the lower the SYSTEM'S resonant frequency. Obviously the larger the box, the lower the box's resonant frequency, but that isn't exactly important nor startling information. [IMG]//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif[/IMG] On your Q discussion, I need to know what you mean when you say compliance: compliance of what? I know very little ME stuff beyond what I know about speakers, and even that is limited, but there are many different compliance values for loudspeakers: Vas, Cms, etc... Seeing as you're talking about .707, what does a sqrt(2) value of stiffness mean in ME? I haven't the faintest idea, however I do know quite well that 1/sqrt(2) is a very important factor in almost all engineering fields, and since compliance is just 1/stiffness, I'm wondering what that signifies [IMG]//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif[/IMG] Again, what damping are you talking about? Ported boxes naturally damp the cone at the tuning frequency, so I'm not too sure what damping you're talking about: cone, box, or some otherwise electrical damping that I might have missed in the conversation (sigma). Yes, people have tried and failed since it's impossible to obviously reach theoretical numbers in practical applications. The problem is that it isn't feasible to take into account every single factor that can affect how a speaker responds, so instead, people merely tailor their sound to their tastes but use theory to make the initial design. Your guess is mostly correct as well. Outside of the sub's passband, you're right, there is little cone movement, however, as you decrease in frequency, the cone movement gets greater until a certain point. At tuning frequency, the cone's movement is actually less than at other frequencies. But you are correct that under tuning frequency, the air in the enclosure can no longer control cone movement effectively and thus your sub can bottom out (which is why it's pretty stupid to test subs just sitting on your carpet if they are not designed to play free-air. A FANTASTIC treatise on box design is Bullock on Boxes, it's a small book all about ported box design and theory. i just started reading it and am like 5 pages in, and already have learned more from those 5 pages than I have in literally years here listening to second hand accounts and tricks of the trade. [/QUOTE]
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