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<blockquote data-quote="squeak9798" data-source="post: 1400636" data-attributes="member: 555320">They are useless because they don&#039;t include the effects of the enviornment or different enclosures.&nbsp; How they are rated varies manufacturer to manufacturer (another reason they are useless)....but many are probably rated in an anechoic chamber.If a manufacturer &quot;rates&quot; response down to 20hz, but I put the sub into a ported enclosure tuned to 50hz, I can promise you it won&#039;t play 20hz well....at all.Likewise, if they rate response only down to 30hz in an anechoic chamber, then I put the sub in a sealed enclosure in my car, it may have flat response down to 10hz due to the transfer function.Wrong.&nbsp; Low frequency extension (output) is dictated by factors such as Vd (how much air the sub can move) and Qtc (or box volume &amp;amp; tuning frequency, if a ported enclosure).High frequency extension dictated by Le; or voice coil inductance.&nbsp; A large sub will not necessarily have high Le, and therefore will not necessarily lack in high frequency capability.&nbsp; Don&#039;t believe me?&nbsp; Look at pro audio...they have 15&quot; and 18&quot; midwoofers.&nbsp; Just the same, you can have an 8&quot; with very poor high frequency response....why?&nbsp; Because of a high Le.If you are playing the sub balls to the wall....yeah, maybe.&nbsp; But that&#039;s solely for balance of the frequency spectrum..so that the bass isn&#039;t overwhelming the rest of the music spectrum.&nbsp; But then again, you could always just lower the output of the sub //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gifErm.....No.&nbsp; Large subs can play higher frequencies fine (Le allowing, ofcourse).&nbsp; Ask audiolife on here about his pair of 15&quot; IDW&#039;s...he lowpassed them at 90hz, and qualified for IASCA world finals with such //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif&nbsp; Again, high frequency extension is dictated by Le, not subwoofer diameter.</blockquote>

[QUOTE="squeak9798, post: 1400636, member: 555320"] They are useless because they don't include the effects of the enviornment or different enclosures. How they are rated varies manufacturer to manufacturer (another reason they are useless)....but many are probably rated in an anechoic chamber. If a manufacturer "rates" response down to 20hz, but I put the sub into a ported enclosure tuned to 50hz, I can promise you it won't play 20hz well....at all. Likewise, if they rate response only down to 30hz in an anechoic chamber, then I put the sub in a sealed enclosure in my car, it may have flat response down to 10hz due to the transfer function. Wrong. Low frequency extension (output) is dictated by factors such as Vd (how much air the sub can move) and Qtc (or box volume & tuning frequency, if a ported enclosure). High frequency extension dictated by Le; or voice coil inductance. A large sub will not necessarily have high Le, and therefore will not necessarily lack in high frequency capability. Don't believe me? Look at pro audio...they have 15" and 18" [I]mid[/I]woofers. Just the same, you can have an 8" with very poor high frequency response....why? Because of a high Le. If you are playing the sub balls to the wall....yeah, maybe. But that's solely for balance of the frequency spectrum..so that the bass isn't overwhelming the rest of the music spectrum. But then again, you could always just lower the output of the sub [IMG]//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif[/IMG] Erm.....No. Large subs can play higher frequencies fine (Le allowing, ofcourse). Ask audiolife on here about his pair of 15" IDW's...he lowpassed them at 90hz, and qualified for IASCA world finals with such [IMG]//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif[/IMG] Again, high frequency extension is dictated by Le, not subwoofer diameter. [/QUOTE]

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