Explanation of sub
03-17-2006, 10:06 PM
#11
0 Watt CAFz'r
Join Date: Mar 2006
Posts: 49
Bandpass boxes were designed to add a sub to a home system without the need for a crossover. The box design actually works as a crossover hence the name Bandpass. The problem with Bandpass is all the energy must come through the port, the power handling can be sacrificed, they don't have the impact (kick bass) and it's very hard to hear when you're overdriving the woofer. They are very efficient and do require less power to run.
The box is everything!! You can take a cheap woofer and make it sound okay in the right box and take a great woofer and make it sound like crap in the wrong box.
Is ported better than sealed? It all depends on the woofer. Some work better sealed, some ported.
General rules ( I do mean general):
QTS .2 to .35 Ported
QTS .3 to .45 Either
QTS .45 and up Sealed
Port size, bracing, enclosure shape can all have a huge effect on results.
Installman
The box is everything!! You can take a cheap woofer and make it sound okay in the right box and take a great woofer and make it sound like crap in the wrong box.
Is ported better than sealed? It all depends on the woofer. Some work better sealed, some ported.
General rules ( I do mean general):
QTS .2 to .35 Ported
QTS .3 to .45 Either
QTS .45 and up Sealed
Port size, bracing, enclosure shape can all have a huge effect on results.
Installman
03-19-2006, 12:52 AM
#13
50 Watt CAFz'r
Join Date: Nov 2004
Posts: 167
Originally Posted by Pioneer Guy
However, porting an enclosure does not help you in that aspect. To get low bass, a sealed enclosure is best.
03-19-2006, 01:00 AM
#14
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Join Date: Nov 2004
Posts: 779
Originally Posted by xxPunk0Ramaxx
how so? although a ported enclosure has a faster rolloff below tuning, you can quite easily net better, flatter, lower extension with a ported enclosure simply by tuning low. the only disadvantage is that you require a much larger enclosure to do so and group delay (transient response, whichever term you prefer) increases at lower frequencies.
03-19-2006, 01:14 AM
#15
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Join Date: Nov 2004
Posts: 779
this is not from dan wiggins but
Originally Posted by supergrass2
In a vehicle, a sealed enclosure will ALWAYS best a vented enclosure for low frequency extension. Always.
Most sealed woofer systems start rolling off at 50Hz or so. With the 12dB rolloff below system resonance, and the transfer function of the vehicle - the average end result is a woofer system that extends down below 10Hz flat.
With a vented system, below vent resonance, rolloff is 24dB/oct. In a vehicle, most vented systems exhibit an exaggeration in response from 30-60Hz (average). This exaggerated response at 30Hz, is usually what is considered 'deep' or 'low'. With the steeper rolloff of the vented system, 10Hz stuff will be virtually in-audible and non-existent.
To go low the 'real' way - a sealed woofer system is the ticket.
If you're concerned with output 30Hz and above - a vented system is the way to go.
Many advantages and disadvantages to each option. But to settle the arguement on which kind of enclosure goes lowest - sealed is the answer.
Most sealed woofer systems start rolling off at 50Hz or so. With the 12dB rolloff below system resonance, and the transfer function of the vehicle - the average end result is a woofer system that extends down below 10Hz flat.
With a vented system, below vent resonance, rolloff is 24dB/oct. In a vehicle, most vented systems exhibit an exaggeration in response from 30-60Hz (average). This exaggerated response at 30Hz, is usually what is considered 'deep' or 'low'. With the steeper rolloff of the vented system, 10Hz stuff will be virtually in-audible and non-existent.
To go low the 'real' way - a sealed woofer system is the ticket.
If you're concerned with output 30Hz and above - a vented system is the way to go.
Many advantages and disadvantages to each option. But to settle the arguement on which kind of enclosure goes lowest - sealed is the answer.
Last edited by hofulstrof; 03-19-2006 at 01:17 AM.
03-19-2006, 01:23 AM
#16
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Join Date: Nov 2004
Posts: 779
what i posted above is all from a low bass stand point.
what i will post below is from a sq stand point
quote from grand masta
here are then benefits of low tuneing
1) Minimize the peak in frequency response near tuning frequency.
2) Minimize the peak in group delay in the useable passband of the frequency response.
3) Minimize the possibility that the driver will "unload" during normal use. (Especially helpful if no subsonic filter will be used).
4) Increase mechanical power handling so that more power can be safely used with regular music.
5) Better low frequency extension.
6) Port area requirements are decreased.
what i will post below is from a sq stand point
quote from grand masta
here are then benefits of low tuneing
1) Minimize the peak in frequency response near tuning frequency.
2) Minimize the peak in group delay in the useable passband of the frequency response.
3) Minimize the possibility that the driver will "unload" during normal use. (Especially helpful if no subsonic filter will be used).
4) Increase mechanical power handling so that more power can be safely used with regular music.
5) Better low frequency extension.
6) Port area requirements are decreased.
03-19-2006, 01:41 AM
#17
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Join Date: Nov 2004
Posts: 167
honestly, in car audio (this is a car audio forum, right?) it is not necessary to have any sub that remains flat beyond 20hz at the lowest. there is so little material below even 30hz that this is practically useless unless you like those pipe organ tracks. a ported enclosure can net very flat response with larger spl at lower frequencies with low tuning in the useable range of a subwoofer than a sealed enclosure. you must ask yourself: if sealed enclosures net better low end response, why are many high end home audio subwoofers a ported design?
03-19-2006, 01:51 AM
#18
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Join Date: Nov 2004
Posts: 779
Originally Posted by xxPunk0Ramaxx
honestly, in car audio (this is a car audio forum, right?) it is not necessary to have any sub that remains flat beyond 20hz at the lowest. there is so little material below even 30hz that this is practically useless unless you like those pipe organ tracks. a ported enclosure can net very flat response with larger spl at lower frequencies with low tuning in the useable range of a subwoofer than a sealed enclosure. you must ask yourself: if sealed enclosures net better low end response, why are many high end home audio subwoofers a ported design?
Last edited by hofulstrof; 03-19-2006 at 01:55 AM.
03-19-2006, 02:29 AM
#19
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Join Date: Nov 2004
Posts: 167
Originally Posted by hofulstrof
because home audio and car audio are 2 differnt things.and yes i does depend on which sub you are using. if you are going to deep bass > 25-30 hz i say use sealed but if you just looking for the extra bump in spl arounf the low end 30 hz go ported
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