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<blockquote data-quote="squeak9798" data-source="post: 2937687" data-attributes="member: 555320"><p>You keep saying that....but so far all I've ever seen you mention is impedance....</p><p></p><p>Let's go back to some of your first comment;</p><p></p><p></p><p>YOU DO NOT KNOW THIS.</p><p></p><p>Where is your reference to efficiency? All I see is assumptions based <em>solely</em> on impedance.</p><p></p><p>You are <em>assuming</em> that <em>another</em> 4ohm driver will have a higher sensitivity....THIS WILL NOT INHERENTLY BE TRUE.</p><p></p><p>You can't say "well I meant if all else was equal" because that driver is not available in 4ohms, so you WILL NOT have the opportunity to compare the two different drivers "with all things equal".</p><p></p><p>You CAN NOT make an assumption of efficiency or output level of driver A vs driver B based solely on impedance, as you are obviously attempting to do.</p><p></p><p>Carrying on;</p><p></p><p></p><p>You are again making the HUGE assumption that "all else will be equal". This will happen....hmmm......<em>hardly ever</em>. <em>Especially</em> when comparing two completely different drivers.</p><p></p><p></p><p>Hoffman's Law dictates that in order to increase efficiency while reducing low frequency extension, the driver would require a <em>substantially</em> larger enclosure.....not practical in most applications. Most times a higher efficiency driver will <em>lack</em> in low end compared to a driver with lower efficiency.</p><p></p><p></p><p>Great!</p><p></p><p>But you need to provide more thorough information and stop making so many assumptions, especially when they are based solely off of impedance.</p><p></p><p></p><p></p><p>Lets.</p><p></p><p>Using the T/S parameters listed on PE's product page;</p><p></p><p>4ohm:</p><p></p><p>SPL = 112+10*LOG(9.64*10^(-10)*40^3*22.9/.48) = 86.69db</p><p></p><p>8ohm:</p><p></p><p>SPL = 112+10*LOG(9.64*10^(-10)*38^3*24.9/.47) = 86.48db</p><p></p><p>Only .2db difference, and that's actually in favor of the 4ohm driver.</p><p></p><p>If you use the T/S parameters listed on the "Exported CLIO" page;</p><p></p><p>4ohm:</p><p></p><p>SPL = 112+10*LOG(9.64*10^(-10)*38.32^3*22.59/.49) = 85.98db</p><p></p><p>8ohm:</p><p></p><p>SPL = 112+10*LOG(9.64*10^(-10)*40.26^3*24.35/.49) = 86.95db</p><p></p><p>Only 1db difference in favor of the 8ohm driver.</p><p></p><p>And if you use the T/S Params Zaph measured for the 8ohm driver;</p><p></p><p>SPL = 112+10*LOG(9.64*10^(-10)*40^3*20.06/.5153) = 85.8db</p><p></p><p></p><p>Looking at the above, I fail to see any sign that the 8ohm driver is actually 3db more sensitive than the 4ohm version. At best, so far, it has a sensitivity that's 1db greater......and that's only if we use the parameters that best suit the point you are trying to make.</p><p></p><p>Just a few more examples, lets check out madisound a little bit here too....</p><p></p><p>Vifa MG18WK09 using manufacturer stated parameters.</p><p></p><p>4ohm;</p><p></p><p>SPL = 112+10*LOG(9.64*10^(-10)*36^3*41/.32) = 89.61db</p><p></p><p>8ohm;</p><p></p><p>SPL = 112+10*LOG(9.64*10^(-10)*34^3*45/.41) = 88.19db</p><p></p><p>Scanspeak 7" Revs using manufacturer stated parameters.</p><p></p><p>4ohm;</p><p></p><p>SPL = 112+10*LOG(9.64*10^(-10)*33^3*42/.38) = 87.83db</p><p></p><p>8ohm;</p><p></p><p>SPL = 112+10*LOG(9.64*10^(-10)*28^3*59/.44) = 86.53db</p><p></p><p>Vifa PL18W using manufacturer stated parameters.</p><p></p><p>4ohm;</p><p></p><p>SPL = 112+10*LOG(9.64*10^(-10)*37^3*25/.33) = 87.68db</p><p></p><p>8ohm;</p><p></p><p>SPL = 112+10*LOG(9.64*10^(-10)*38^3*25/.4) = 87.19db</p><p></p><p>First three I could find that were offered in both 4ohm and 8ohm, chosen at complete random.</p><p></p><p></p><p>Practice what you preach ?</p><p></p><p></p><p></p><p><em>Very</em> large assumptions, especially when comparing two completely different drivers and even apparently when comparing the same model driver in both coil configurations looking at the figures I calculated above. So many assumptions that the statement alone doesn't really hold true at all in reality. You <strong>must</strong> compare the two drivers in question and NOT be making assumptions based off of theory, impedance and/or generalizations.</p><p></p><p>The units above would need some pretty large (and I would say unacceptably large) variances in stated vs actual T/S parameters to come even close to having 3db higher sensitivity.</p></blockquote><p></p>
[QUOTE="squeak9798, post: 2937687, member: 555320"] You keep saying that....but so far all I've ever seen you mention is impedance.... Let's go back to some of your first comment; YOU DO NOT KNOW THIS. Where is your reference to efficiency? All I see is assumptions based [I]solely[/I] on impedance. You are [I]assuming[/I] that [I]another[/I] 4ohm driver will have a higher sensitivity....THIS WILL NOT INHERENTLY BE TRUE. You can't say "well I meant if all else was equal" because that driver is not available in 4ohms, so you WILL NOT have the opportunity to compare the two different drivers "with all things equal". You CAN NOT make an assumption of efficiency or output level of driver A vs driver B based solely on impedance, as you are obviously attempting to do. Carrying on; You are again making the HUGE assumption that "all else will be equal". This will happen....hmmm......[I]hardly ever[/I]. [I]Especially[/I] when comparing two completely different drivers. Hoffman's Law dictates that in order to increase efficiency while reducing low frequency extension, the driver would require a [I]substantially[/I] larger enclosure.....not practical in most applications. Most times a higher efficiency driver will [I]lack[/I] in low end compared to a driver with lower efficiency. Great! But you need to provide more thorough information and stop making so many assumptions, especially when they are based solely off of impedance. Lets. Using the T/S parameters listed on PE's product page; 4ohm: SPL = 112+10*LOG(9.64*10^(-10)*40^3*22.9/.48) = 86.69db 8ohm: SPL = 112+10*LOG(9.64*10^(-10)*38^3*24.9/.47) = 86.48db Only .2db difference, and that's actually in favor of the 4ohm driver. If you use the T/S parameters listed on the "Exported CLIO" page; 4ohm: SPL = 112+10*LOG(9.64*10^(-10)*38.32^3*22.59/.49) = 85.98db 8ohm: SPL = 112+10*LOG(9.64*10^(-10)*40.26^3*24.35/.49) = 86.95db Only 1db difference in favor of the 8ohm driver. And if you use the T/S Params Zaph measured for the 8ohm driver; SPL = 112+10*LOG(9.64*10^(-10)*40^3*20.06/.5153) = 85.8db Looking at the above, I fail to see any sign that the 8ohm driver is actually 3db more sensitive than the 4ohm version. At best, so far, it has a sensitivity that's 1db greater......and that's only if we use the parameters that best suit the point you are trying to make. Just a few more examples, lets check out madisound a little bit here too.... Vifa MG18WK09 using manufacturer stated parameters. 4ohm; SPL = 112+10*LOG(9.64*10^(-10)*36^3*41/.32) = 89.61db 8ohm; SPL = 112+10*LOG(9.64*10^(-10)*34^3*45/.41) = 88.19db Scanspeak 7" Revs using manufacturer stated parameters. 4ohm; SPL = 112+10*LOG(9.64*10^(-10)*33^3*42/.38) = 87.83db 8ohm; SPL = 112+10*LOG(9.64*10^(-10)*28^3*59/.44) = 86.53db Vifa PL18W using manufacturer stated parameters. 4ohm; SPL = 112+10*LOG(9.64*10^(-10)*37^3*25/.33) = 87.68db 8ohm; SPL = 112+10*LOG(9.64*10^(-10)*38^3*25/.4) = 87.19db First three I could find that were offered in both 4ohm and 8ohm, chosen at complete random. Practice what you preach ? [I]Very[/I] large assumptions, especially when comparing two completely different drivers and even apparently when comparing the same model driver in both coil configurations looking at the figures I calculated above. So many assumptions that the statement alone doesn't really hold true at all in reality. You [B]must[/B] compare the two drivers in question and NOT be making assumptions based off of theory, impedance and/or generalizations. The units above would need some pretty large (and I would say unacceptably large) variances in stated vs actual T/S parameters to come even close to having 3db higher sensitivity. [/QUOTE]
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