Reply to thread

Message

<blockquote data-quote="bigbassman" data-source="post: 1815802" data-attributes="member: 542419">good lord what an explosion of..... well... alotta junk //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gifif you decide to go down the road of &quot;sealed box first&quot; testing...&nbsp; you HAVE to use a .707 butterworth alignment, sealed...why .707?&nbsp; because one of its characteristics... is a 12 db per octave rolloff below F3... I think its F3...&nbsp; we&#039;ll try it..now its been well documented that 99% of vehicles exhibit a boost of roughly 12db per octave starting at the corner frequency, which is determined by the size of the cabin, and its characteristics at higher pressure.&nbsp; most corner frequencies are in the 60-80 hz area....so simple math...&nbsp; 12 db per octave - 12 db per octave = 0ish...&nbsp; flat response down to Fb..&nbsp; which in theory will allow the peak hunting to begin...but there&#039;s a couple giant flaws.....&nbsp; one...&nbsp; as stated previously... most vehicles do not have any big peaks.....two.... as pressure increases.... the vehicle will flex, and leak... and that throws a loop into the frequency finding...so in short..&nbsp; sealed box testing at a db level lower then what you&#039;ll be using...&nbsp; is a waste of time...&nbsp; but by all means go for it //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gifnow... onto box efficiency...that&#039;s what you wanna spend your life testing....&nbsp; finding the perfect combination of vehicle, port, volume, and wooferage....unfortunately... there&#039;s no set way that works for everyone....&nbsp; which is why &quot;test, test, test&quot; is usually said 20 times in the course of a thread like this...speaking for myself...&nbsp; my grand prix walled off, didn&#039;t care what it played...&nbsp; it played exactly what I designed it to play....&nbsp; and I&#039;ve adjusted to play nearly every&nbsp; frequency from 30hz, up to 68hz, with no problems..depending on the mic placement, certain tuning arrangements did better, due to wavelength propegation, and cancellation..&nbsp;&nbsp; which again.. is why I&#039;ve spent soo much time testing....Loyd L.</blockquote>

[QUOTE="bigbassman, post: 1815802, member: 542419"] good lord what an explosion of..... well... alotta junk [IMG]//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif[/IMG] if you decide to go down the road of "sealed box first" testing... you HAVE to use a .707 butterworth alignment, sealed... why .707? because one of its characteristics... is a 12 db per octave rolloff below F3... I think its F3... we'll try it.. now its been well documented that 99% of vehicles exhibit a boost of roughly 12db per octave starting at the corner frequency, which is determined by the size of the cabin, and its characteristics at higher pressure. most corner frequencies are in the 60-80 hz area.... so simple math... 12 db per octave - 12 db per octave = 0ish... flat response down to Fb.. which in theory will allow the peak hunting to begin... but there's a couple giant flaws..... one... as stated previously... most vehicles do not have any big peaks..... two.... as pressure increases.... the vehicle will flex, and leak... and that throws a loop into the frequency finding... so in short.. sealed box testing at a db level lower then what you'll be using... is a waste of time... but by all means go for it [IMG]//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif[/IMG] now... onto box efficiency... that's what you wanna spend your life testing.... finding the perfect combination of vehicle, port, volume, and wooferage.... unfortunately... there's no set way that works for everyone.... which is why "test, test, test" is usually said 20 times in the course of a thread like this... speaking for myself... my grand prix walled off, didn't care what it played... it played exactly what I designed it to play.... and I've adjusted to play nearly every frequency from 30hz, up to 68hz, with no problems.. depending on the mic placement, certain tuning arrangements did better, due to wavelength propegation, and cancellation.. which again.. is why I've spent soo much time testing.... Loyd L. [/QUOTE]

Verification