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<blockquote data-quote="brad.farmer" data-source="post: 217056" data-attributes="member: 547961">Just some general info for those people cracking on my lack of stereo expertise.&nbsp;&nbsp; Checkout what JL Audio has to say on the subject of speaker enclosures (<a href="http://www.jlaudio.com/tutorials/magic/performance.html" target="_blank">http://www.jlaudio.com/tutorials/magic/performance.html</a>).&quot;Sub-30Hz BehaviorSealed box designs and single-reflex bandpasses are much better at controlling excursion at extremely low-frequencies (below 30Hz.) For this reason, they can usually handle more power in these frequency ranges than ported designs and dual-reflex bandpass designs which makes them less prone to low-frequency induced speaker damage. At frequencies below the tuning frequency of the port, a woofer in a ported box (or a dual-reflex bandpass) starts to de-couple. This means that the controlling function of the enclosure begins to disappear. The collapse is gradual rather than immediate, but at some point below the tuning of the port, the speaker behaves as if it were operating without an enclosure and suffers from potentially damaging over-excursion. (This is why it is a good practice to use a sub-sonic filter when running a ported enclosure or a dual-reflex bandpass. Some high-quality electronic crossovers like the AudioControl 4XS incorporate a programmable subsonic filter circuit.) &quot;The point that I was trying to get across is that typically, although there are exceptions, sealed enclosures will play lower than ported enclosures.&nbsp; This is due to the fact that in ported enclosures the sub appears to be operating&nbsp; in an infinite baffle at frequencies significantly below the ported frequency.&nbsp; Can you build a ported enclosure that goes extremely low (10-20Hz) region.&nbsp; Yes.&nbsp; ALthough it takes a ton of box volume and a long port.On the subject of bandpass enclosures.&nbsp; They sound like &quot;crap&quot; if you don&#039;t know how to build one.&nbsp; Building high quality bandpass enclosures is very complicated and should be undertaken utilizing enclosure design software (LEAP or something&nbsp; similar).&nbsp; When it comes to using high excursion subs in bandpass enclosures things can get very squirrelly.brad.farmer</blockquote>

[QUOTE="brad.farmer, post: 217056, member: 547961"] Just some general info for those people cracking on my lack of stereo expertise. Checkout what JL Audio has to say on the subject of speaker enclosures ([URL="http://www.jlaudio.com/tutorials/magic/performance.html"]http://www.jlaudio.com/tutorials/magic/performance.html[/URL]). "Sub-30Hz Behavior Sealed box designs and single-reflex bandpasses are much better at controlling excursion at extremely low-frequencies (below 30Hz.) For this reason, they can usually handle more power in these frequency ranges than ported designs and dual-reflex bandpass designs which makes them less prone to low-frequency induced speaker damage. At frequencies below the tuning frequency of the port, a woofer in a ported box (or a dual-reflex bandpass) starts to de-couple. This means that the controlling function of the enclosure begins to disappear. The collapse is gradual rather than immediate, but at some point below the tuning of the port, the speaker behaves as if it were operating without an enclosure and suffers from potentially damaging over-excursion. (This is why it is a good practice to use a sub-sonic filter when running a ported enclosure or a dual-reflex bandpass. Some high-quality electronic crossovers like the AudioControl 4XS incorporate a programmable subsonic filter circuit.) " The point that I was trying to get across is that typically, although there are exceptions, sealed enclosures will play lower than ported enclosures. This is due to the fact that in ported enclosures the sub appears to be operating in an infinite baffle at frequencies significantly below the ported frequency. Can you build a ported enclosure that goes extremely low (10-20Hz) region. Yes. ALthough it takes a ton of box volume and a long port. On the subject of bandpass enclosures. They sound like "crap" if you don't know how to build one. Building high quality bandpass enclosures is very complicated and should be undertaken utilizing enclosure design software (LEAP or something similar). When it comes to using high excursion subs in bandpass enclosures things can get very squirrelly. brad.farmer [/QUOTE]

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