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Another noobie question: what are the comparative pros/cons for active and passive subs? Clearly, an active sub has a built-in or included amp. Why would I want a passive one when my receiver can only push 120W of power per channel? Thanks.
 

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Usally passave is use to tie in with the speakers so it works with the speakers taking over the low end. Almost all amps have just a sub line out, non amplifed. You really need a regular sub with the amp built in because they draw so much power. besides in HT the sub is it's own channel and can't be passave unless your using another external amp.
 

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Most of the high performance passive subwoofers are designed to work with their own dedicated amplifier....just an amplifier separate from the enclosure. The most common reasoning for passive subwoofers is to keep sensitive electronics away from the constant vibration associated with being mounted to the enclosure.


Tom V.

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When talking real subwoofers, I prefer passive. I like my sub enclosure as rigid as possible, and no cut-out area for the plate amp gives me a warm fuzzy feeling. :)


BTW, when I say "real subwoofers", I mean non-HTIB subwoofers. If you are looking for a HTIB, run away as fast as you can from one with a passive sub.


Sorny
 

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some plate amps for sub just so crappy they burnt up in a year or two


now using a 2 channel power amp to power 2 passive subs, perhaps this is better way of doing it and as TV says getting rid of those vibrations away from sensitive electronic components
 

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I've always preferred passive subs and, until recently, used them exclusively.


The reason for my partial change is that I got a complete JBL Performance Series system, which comes with two PS1400 units, which are 14" subs with 400 Watt built in amps and with crossovers to the accompanying PT800 towers. Obviously, I'm going to utilize these amazing speakers.


Nonetheless, I still have a passive sub for my LFE channel. It's a 12" Fosgate Audionics CSS200. The reason I keep it in the mix and the reason I like passive subs is that I can choose the type of amplification, and I can keep the sub away from the heat of the amp (and the amp away from the effects of the sub). My LFE sub is driven by the same kind of amp I use for the other channels in the system, so I know it's fed the same clean, reliable, MOSFET, soft clipping power of the other channels.


While the JBL subs have very clean, powerful amps, too, I do wish I could have chosen my own power source.
 

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>>>When talking real subwoofers, I prefer passive. I like my sub enclosure as rigid as possible, and no cut-out area for the plate amp gives me a warm fuzzy feeling
 

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In line with the comments on not knowing what an internal amplifier is doing, there are some benefits and detriments in passive subwoofers. First, 95% of powered subwoofers employ some form of EQ and output limiting. Limiting may be either in the form of actuall electronic limiting circuitry, or in the nature of the amplifier, where many of the lesser cost amplifiers I have seen will sputter out when asked to deliver even rated output at low frequencies.


A passive subwoofer requires that the subwoofer works as intended without external processing. One benefit is that you know exactly what sort of limiting is or is not being employed. Maybe 3-5 years ago when Aerial Acoustics came out with their SW-12, I quickly tracked down the difference I was hearing to be limiting being used in the subs I was comparing it to. Many powered subwoofers claiming sub 16Hz performance are employing a great deal of EQ, and will compress or limit under common usage.


Simply put, passive subs allow you a little more knowledge of exactly what is in the chain, where testing or knowledge of the components and design are the only way to know if an internal amplifier is doing anything funny.


One of the reasons people find it so difficult to compare powered subwoofers by specifications is that the specifications do not characterize the overload or limiting nature of the sub, and what level that occurs at. This characteristic can be a HUGE part of the subjective quality, yet it of course varies with the level of playback.
 

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Clarification: There are speaker companies; Triad included; that offer active (powered) subwoofers, but offer them either with the amplifier onboard or outboard.
 
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