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4th order bandpass help?


mike12

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 So I have been trying to calculate my first 4th order for 2 orion hcca 10s. I have started with having a seperate sealed chamber for each sub with 0.625 cuft each and a common ported chamber of 2.5 cuft tuned to 45hz. I was just wondering how much port area I would need? Also if the airspace would be fine? Also I went for a 2:1 ratio since that was pretty common, what would be the advantage of going to a bigger ratio like a 3:1? Ive heard these subs like smaller enclosures so I didnt want to get to big. Thanks!

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How much power are you running?

Dont worry about chamber size ratios, you are better to size the chambers individually based on what you want the box to do. 

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

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U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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Is this a trunk car or blowthrough? I'm no expert but I often hear the experts say you are better off just going ported unless you have a reason to do a bandpass.

Sitting around waiting to be installed:

  4 FI X 10

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 AA 3800.1

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3 hours ago, mike12 said:

Ill be running a twisted sounds 3.5k with a 320 amp alt and 2 batteries so I have good voltage i basically want it to have as much output without losing bandwith thats why i wanted to try a 4th order

So 4th order bandpass boxes do several potentially useful things.  They push all the output out the port, which can be very handy for blow throughs and the like.  They let you trade efficiency for bandwidth and vice-versa.  Making the front chamber volume larger makes its more efficient around the tuning frequency (more output) but it makes the output more peaky (less bandwidth).  Reducing the front chamber volume has the opposite effect. Lastly 4th order bandpass boxes let you raise the tuning frequency higher without having to worry about destroying your subs and/or having output fall off a cliff like a ported box would when playing below tuning.  This can be handy since most enclosures have a peak in output around tuning and most vehicles have a peak in cabin gain between 40-50 Hz.  When you match those two up you can get a lot higher peak SPL number.  

Since cabin gain boosts low frequency output, sometimes a 4th order bandpass design can get you wider effective bandwidth since the cabin gain boosts output below tuning where the enclosure is naturally falling off.  It doesn't always work out well though.  Some subs will naturally be more peaky than others in a bandpass box and that's going to make it harder to get a wide bandwidth,  it also depends on how much cabin gain you get in your vehicle and every vehicle is different.  I'm not trying to discourage you, just trying to make you aware of what the challenges may be.  Your HCCA subs are going to be on the more peaky side of things in a 4th order bandpass box. 

 

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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7 hours ago, Triticum Agricolam said:

So 4th order bandpass boxes do several potentially useful things.  They push all the output out the port, which can be very handy for blow throughs and the like.  They let you trade efficiency for bandwidth and vice-versa.  Making the front chamber volume larger makes its more efficient around the tuning frequency (more output) but it makes the output more peaky (less bandwidth).  Reducing the front chamber volume has the opposite effect. Lastly 4th order bandpass boxes let you raise the tuning frequency higher without having to worry about destroying your subs and/or having output fall off a cliff like a ported box would when playing below tuning.  This can be handy since most enclosures have a peak in output around tuning and most vehicles have a peak in cabin gain between 40-50 Hz.  When you match those two up you can get a lot higher peak SPL number.  

Since cabin gain boosts low frequency output, sometimes a 4th order bandpass design can get you wider effective bandwidth since the cabin gain boosts output below tuning where the enclosure is naturally falling off.  It doesn't always work out well though.  Some subs will naturally be more peaky than others in a bandpass box and that's going to make it harder to get a wide bandwidth,  it also depends on how much cabin gain you get in your vehicle and every vehicle is different.  I'm not trying to discourage you, just trying to make you aware of what the challenges may be.  Your HCCA subs are going to be on the more peaky side of things in a 4th order bandpass box. 

 

Thanks! That really helps out a ton! Im sure the best way to learn is by experience but its good to have a base understanding going into something new

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