Sorry I know I have just made a few posts, but I have some questions. I am working with another friend stereo, and he has a bandpass box in the trunk of his car. Now I talked to another friend who said bandpass boxes are not for trunks because the trunk acts like a box, and so does the bandpass box or something like that. Is it true that you shouldn't put that type of box in a trunk?
Replies (7)
compvr15s on 04/3/2003 19:04:19
i dont know if thats true or not but i have a heard a few diffterent bandpass in trunks and they didnt sound the greatest. im not sure if it was just the amps being used or if the trunk actually makes a difference. but i know my neighbors mustang hatchback has just a 10 inch bandpass and its loud as hell with 300 watts pushing it. good luck on the install
Buickman94 on 04/3/2003 19:25:03
Ive never heard that bandpass boxes are not for trunks...a lot of people i know have bp boxes in thier trunks.
generally, at least form what ive heard, bandpass boxes cant reproduce alot of frequencies that you would get compared to a sealed box. ive heard them refered to as "one note wonders" because they only hit a few notes well. they are however louder and will give you more spl vs. a sealed box.
Swez on 04/3/2003 20:53:43
BP is a beast of a different kind! You have to really know your stuff to mate the woofer to the box parameters. If you get it wrong, can easily blow the driver with low power, if the box parameters are not correct.
BP is the most efficient sub design available, but are commonly called "one note wonders". Depending on the tuning specs and the sub(s) used... they can get very loud at low amp input power.... but have very narrow bass frequency output levels.
If you go that route, do your homework and find out what the woofer maker has to say about dimensions of front/rear chambers and tuning frequency.
This design is king in SPL Comps.. but in daily driver applciations, sealed or ported boxes are the norm.
Serious research here and Win ISD design profiles are recommended or you may blow the subs and not even know they are in trouble, until it's too late.
If you have the space, a ported enclosure will net better than average results, and less dificult to build. Tuning is key...but not like BP applications.
Swez
GT_man on 04/4/2003 00:29:29
hmmmm....bandpass boxes rule......in trunks tho...it kills the mood.....you see your trunk already acts like a bandpass box..with a sealed box....you have the sealed chamber and then you have the trunk for the other chamber......im not 100% on this but if i understand the consept then thats how it is.....just stick with a well desgined ported box...youll be amazed at what you can do.
Swez on 04/4/2003 16:13:07
In application, the trunk is indeed a secondary enclosure which you have very little control over. This is where we get the term .... cabin gain from.
The larger the trunk (air) space, the more cabin gain effect is noted. If you has a hatch back or seats that fold down, this increases the cabin gain effect and more dB's of SPL are possible from subs. But balance is out the window unless you use EQ.
Again, BP applications are not for beginners. If you get it wrong... they sound awful and the first indication that there is sub trouble, is a dead sub.
Sealed enclosures are the safest, Ported are 3-5dB more output, but BP is notably higher SPL at same power input. Just have to do your homework before pressing on with this design. NOT A GOOD DAILY DRIVER BOX.
Swez
GT_man on 04/5/2003 05:19:06
intresting......thanks Swez for clarifying it for me........does that mean that subs in a SUV require a EQ to sound good? because of the big cabin?
Swez on 04/5/2003 12:59:53
In an SUV, bass is very pronounce and if you are an SPL guy, a very good vehicle for high SPL bass applications.
However, if you are more into SQ and a balanced system approach, then it is good to find the resonance frequency of your vehicle. That will vary from one vehicle to another. Typical resonance range is high 50's to mid-70's Hz. You can find this with a tone generator CD and a calibraded dB meter.
At near resonance frequencies, cabin gain will boost certain frequencies by several dB. Your peak dB readings are the at/near resonance frequencies of the vehicle.
If you find a big spike in dB, may wish to use EQ to bring that spike down to near flat or at least a modest curve, up and down the bass spectrum. Need a good 10 band Slider EQ for this or a Parametric is even better. This only applies to guys that demand high SQ performance across the entire audio spectrum.
Personally, I shoot for high SQ and reasonable SPL. If I can get 105-110dB (max) across the entire audio band and remain somewhat flat in the process... am very pleased with that.
At 110dB, your ears can easily be damaged if exposure lasts more than a few minutes at a time. Reasonable and safe listening range is +90-100dB. Live concert levels are ~120dB near the stage, but taper off to safe levels as we move out from the main stage. Most Pro sound guys try to run the system about 95-105 dB @ 50 feet from stage. That's still plenty loud and safe for all but the fool-hardy nuts that hang at the stage.
Fortunately, most of the sound passes over their heads . The subs may beat them up a bit... but the mids/highs are usually mounted high above the stage for best audio distribution.
That's all for now,
Swez
Replies (7)
compvr15s on 04/3/2003 19:04:19
i dont know if thats true or not but i have a heard a few diffterent bandpass in trunks and they didnt sound the greatest. im not sure if it was just the amps being used or if the trunk actually makes a difference. but i know my neighbors mustang hatchback has just a 10 inch bandpass and its loud as hell with 300 watts pushing it. good luck on the install
Buickman94 on 04/3/2003 19:25:03
Ive never heard that bandpass boxes are not for trunks...a lot of people i know have bp boxes in thier trunks.
generally, at least form what ive heard, bandpass boxes cant reproduce alot of frequencies that you would get compared to a sealed box. ive heard them refered to as "one note wonders" because they only hit a few notes well. they are however louder and will give you more spl vs. a sealed box.
Swez on 04/3/2003 20:53:43
BP is a beast of a different kind! You have to really know your stuff to mate the woofer to the box parameters. If you get it wrong, can easily blow the driver with low power, if the box parameters are not correct.
BP is the most efficient sub design available, but are commonly called "one note wonders". Depending on the tuning specs and the sub(s) used... they can get very loud at low amp input power.... but have very narrow bass frequency output levels.
If you go that route, do your homework and find out what the woofer maker has to say about dimensions of front/rear chambers and tuning frequency.
This design is king in SPL Comps.. but in daily driver applciations, sealed or ported boxes are the norm.
Serious research here and Win ISD design profiles are recommended or you may blow the subs and not even know they are in trouble, until it's too late.
If you have the space, a ported enclosure will net better than average results, and less dificult to build. Tuning is key...but not like BP applications.
Swez
GT_man on 04/4/2003 00:29:29
hmmmm....bandpass boxes rule......in trunks tho...it kills the mood.....you see your trunk already acts like a bandpass box..with a sealed box....you have the sealed chamber and then you have the trunk for the other chamber......im not 100% on this but if i understand the consept then thats how it is.....just stick with a well desgined ported box...youll be amazed at what you can do.
Swez on 04/4/2003 16:13:07
In application, the trunk is indeed a secondary enclosure which you have very little control over. This is where we get the term .... cabin gain from.
The larger the trunk (air) space, the more cabin gain effect is noted. If you has a hatch back or seats that fold down, this increases the cabin gain effect and more dB's of SPL are possible from subs. But balance is out the window unless you use EQ.
Again, BP applications are not for beginners. If you get it wrong... they sound awful and the first indication that there is sub trouble, is a dead sub.
Sealed enclosures are the safest, Ported are 3-5dB more output, but BP is notably higher SPL at same power input. Just have to do your homework before pressing on with this design. NOT A GOOD DAILY DRIVER BOX.
Swez
GT_man on 04/5/2003 05:19:06
intresting......thanks Swez for clarifying it for me........does that mean that subs in a SUV require a EQ to sound good? because of the big cabin?
Swez on 04/5/2003 12:59:53
In an SUV, bass is very pronounce and if you are an SPL guy, a very good vehicle for high SPL bass applications.
However, if you are more into SQ and a balanced system approach, then it is good to find the resonance frequency of your vehicle. That will vary from one vehicle to another. Typical resonance range is high 50's to mid-70's Hz. You can find this with a tone generator CD and a calibraded dB meter.
At near resonance frequencies, cabin gain will boost certain frequencies by several dB. Your peak dB readings are the at/near resonance frequencies of the vehicle.
If you find a big spike in dB, may wish to use EQ to bring that spike down to near flat or at least a modest curve, up and down the bass spectrum. Need a good 10 band Slider EQ for this or a Parametric is even better. This only applies to guys that demand high SQ performance across the entire audio spectrum.
Personally, I shoot for high SQ and reasonable SPL. If I can get 105-110dB (max) across the entire audio band and remain somewhat flat in the process... am very pleased with that.
At 110dB, your ears can easily be damaged if exposure lasts more than a few minutes at a time. Reasonable and safe listening range is +90-100dB. Live concert levels are ~120dB near the stage, but taper off to safe levels as we move out from the main stage. Most Pro sound guys try to run the system about 95-105 dB @ 50 feet from stage. That's still plenty loud and safe for all but the fool-hardy nuts that hang at the stage.
Fortunately, most of the sound passes over their heads . The subs may beat them up a bit... but the mids/highs are usually mounted high above the stage for best audio distribution.
That's all for now,
Swez
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