I have lost my subwoofers spec sheet, but from searching the net at crutchfield they say that the woofer should use a recommended .85cu/ft box and they say this information is straight from Alpine.
BUT
After using two programs for sub woofer box design, inputing various values of the sub including; Fs, Qts, Vas, Xdisp, Z, Diameter they both have given me a value around 1.26cu/ft or thereabouts.
Which value should I use? THINK
Replies (8)
swez on 05/9/2006 10:43:50
The 0.85 cf is mainly for SPL, power bass applications. They can take more power this way, (Sealed) and not have excessive cone excursion at higher SPL levels. This is the spec noted by Alpine.
If you want more deep bass, consider a larger sealed box (1.0 -1.25 cf) for better deep lows, but less power handling abilitilty. Here, you'll use less RMS power, (350-400 RMS/sub) but have more deep bass.
Hope that helps,
Swez
MrBrownstone on 05/9/2006 13:47:10
Every box design has tradeoff values.
When a manufacturer gives you 0.85 to 1.25 cu ft for a box, what that generally means is that you'll get maximum control and mechanical power handling from the smallest box, while broadest frequency response, yet less control, from the larger box.
There is no such thing as the correct, best, or ideal box size for everyone. Simply put, if you want certain characteristics from your subs, you'll have to select the proper box for that.
What are you looking to get out of your subs? You can get maximum sound quality, maximum power output, but you can't get both. In fact, you can get 75% of one or the other...but never 50/50.
WRXallFlex on 05/10/2006 01:25:39
I think that I would most likely be going for sound quality at 75% and spl at 25%, MrBrownStone.
But - using these two sub programs both giving me the 1.25cu/ft value, I am still unsure as to whether I should make the box this size because the Alpine manual for the type R states that the sealed box enclosure should be between 0.7-1.0cu/ft only.
Should I go ahead and use the calculated value of 1.25cu ft? Anyone with a typeR recommend the size which works for them?
Cheers
Victor on 05/10/2006 03:53:34
I have made many kinds of enclosure using the Alpine SWR-1202D, 1204D.
Ported, EBS, BP, and sealed.
For sealed enclosures I have used enclosures from .85 cuft to 1.25 cu.ft. Depending on the application.
Generally 1.0 cuft enclosure for these subs is a good balance between deep low bass, good transients, tight and crisp with considerable power handling too..
Victor....
COFFEE
P.s :- Box size depends a lot on the kind of power you are willing to give to your woofer. I have noticed that the specs given by the most manufacturers ie. in this case. .75 to 1.0 cu ft is suitable to power ranges from +33% or -33% power ratings,
If you giving your sub 500+33%wrms, ie. around 650wrms
use 0,75 cu,ft for better power handling, and to avoid over excursion.
If you giving your box 500-33%wrms, ie. around 350wrms use. 1.0 cu ft , so that ur sub can reach its xmax with lesser power and give u the good amount of spl with lesser power, also since u are not powering ur sub to the fullest, the trade off for the bigger box ( ie. powerhandling) is balanced.
This range is such that it gives you a good share of SPL and Quality. Anything deviating from this will give u either more of SQ or more of SPL, these deviations are subjective and are for different applications..It depends on what you are aiming at, but the manufacturer always has to pull out a recommended enclosure size range for the wide range of people who do not know much about specialised applications..
Hope this helps...
WRXallFlex on 05/10/2006 09:08:56
Thanks victor great to find someone that has had experience with these subs!
I was wondering what would be best a vented or a sealed enclosure if i was
a) going for Sq
b) going for spl
c) bit of both?
In your experience which is better? I would perhaps be going for SQ over spl, and also just to confirm although the manual for the sub states a recommended .75-1cu/ft you have stil made 1.25 cu/ft enclosures and got a good result?
Cheers
lessismorespl on 05/10/2006 10:18:53
Agree w/ Mr. B, there is no such thing as the perfect box, and the manufacturers give specs that are very novice for several reasons, their specs are based on basic calculations which make the sub perform at minimal efficiency.
Victor is probably the most experienced here w/ the Alpine subs, in my experiences, a well made ported/vented enclosure works best for almost any sub I ever used, however, it is best to have a decent amp w/ SSF and a decent crossover(not all amps have the best xovers). W/ all these in combination, you can achieve a decent balance no matter what you are seeking from the sub(SPL, SQL, SQ).
less
MrBrownstone on 05/15/2006 18:11:27
Just keep in mind that you get 75% of one, and that's all you can do.
If you really want something loud, just do a vented enclosure, and don't worry about the quality of sound. Those speakers are fully capable of being as loud as necessary for even intense bass. Anything louder than what you need in a sealed environment, you really don't need to worry about the quality of sound as you've exceeded your hearing's thresholds anyway.
Once you get to 120dB or so, it's all about power and SPL. The only real compromise here for a 75/25 SPL system is a box vented at a low frequency (Say 32-35Hz)...but the amount of boost will be minor.
swez on 05/16/2006 00:55:57
Sealed boxes give a tight, crisp bass response.
If we look at the Qtc plots on a given sub/enclosure, a "Q" of 0.7 will net plenty of deep lows. But, to many (self included) the bass is not well defined and tends to be a bit peaky on the low end. Cone control and power handling also suffer in high "Q" enclosures.
As we move up in "Q", (say 0.85-.90) low bass is still very good, but punch and crispness in upper bass regions is much better and power handling improves. The last guy I worked intensively, used a pair of Alpine R 10's. He used a sealed box, 0.85 cf/chamber and reported his results to be excellent lows, very good punch and plenty of SPL in a sedan, trunk mounted system. He took it over to a high-end "Snob Appeal" shop nearby to demo his system and they were very impressed with his results.
Prior to his completion of the work, he researched many options and the "Snob Shop" tried to get him to buy very expensive JL subs, speakers and amps. When he explained his initial plans, they snubbed his plans and said he'd be better off letting thier shop do the install for about $2,500.00 He spent about $900 on Alpine amps, subs and CDT Comps. The results were stunning.
BTW, this was an older guy. He took his time, installed some Dynamat in doors and rear cargo area as well. In short, if you want a superior sounding SQL system, use quality products, research your options and work the plan.
Finally, if you go ported, one can expect more low bass near the port tuning frequency range selected. (~35 Hz.) The upper bass comes from direct cone radiation. The deep lows, come from the port. A Sub Sonic Filter, (SSF) is needed on ported designs, to protect your woofers from excess excursion and power robbing lows that can damage the most stout of subs.
Swez
BUT
After using two programs for sub woofer box design, inputing various values of the sub including; Fs, Qts, Vas, Xdisp, Z, Diameter they both have given me a value around 1.26cu/ft or thereabouts.
Which value should I use? THINK
Replies (8)
swez on 05/9/2006 10:43:50
The 0.85 cf is mainly for SPL, power bass applications. They can take more power this way, (Sealed) and not have excessive cone excursion at higher SPL levels. This is the spec noted by Alpine.
If you want more deep bass, consider a larger sealed box (1.0 -1.25 cf) for better deep lows, but less power handling abilitilty. Here, you'll use less RMS power, (350-400 RMS/sub) but have more deep bass.
Hope that helps,
Swez
MrBrownstone on 05/9/2006 13:47:10
Every box design has tradeoff values.
When a manufacturer gives you 0.85 to 1.25 cu ft for a box, what that generally means is that you'll get maximum control and mechanical power handling from the smallest box, while broadest frequency response, yet less control, from the larger box.
There is no such thing as the correct, best, or ideal box size for everyone. Simply put, if you want certain characteristics from your subs, you'll have to select the proper box for that.
What are you looking to get out of your subs? You can get maximum sound quality, maximum power output, but you can't get both. In fact, you can get 75% of one or the other...but never 50/50.
WRXallFlex on 05/10/2006 01:25:39
I think that I would most likely be going for sound quality at 75% and spl at 25%, MrBrownStone.
But - using these two sub programs both giving me the 1.25cu/ft value, I am still unsure as to whether I should make the box this size because the Alpine manual for the type R states that the sealed box enclosure should be between 0.7-1.0cu/ft only.
Should I go ahead and use the calculated value of 1.25cu ft? Anyone with a typeR recommend the size which works for them?
Cheers
Victor on 05/10/2006 03:53:34
I have made many kinds of enclosure using the Alpine SWR-1202D, 1204D.
Ported, EBS, BP, and sealed.
For sealed enclosures I have used enclosures from .85 cuft to 1.25 cu.ft. Depending on the application.
Generally 1.0 cuft enclosure for these subs is a good balance between deep low bass, good transients, tight and crisp with considerable power handling too..
Victor....
COFFEE
P.s :- Box size depends a lot on the kind of power you are willing to give to your woofer. I have noticed that the specs given by the most manufacturers ie. in this case. .75 to 1.0 cu ft is suitable to power ranges from +33% or -33% power ratings,
If you giving your sub 500+33%wrms, ie. around 650wrms
use 0,75 cu,ft for better power handling, and to avoid over excursion.
If you giving your box 500-33%wrms, ie. around 350wrms use. 1.0 cu ft , so that ur sub can reach its xmax with lesser power and give u the good amount of spl with lesser power, also since u are not powering ur sub to the fullest, the trade off for the bigger box ( ie. powerhandling) is balanced.
This range is such that it gives you a good share of SPL and Quality. Anything deviating from this will give u either more of SQ or more of SPL, these deviations are subjective and are for different applications..It depends on what you are aiming at, but the manufacturer always has to pull out a recommended enclosure size range for the wide range of people who do not know much about specialised applications..
Hope this helps...
WRXallFlex on 05/10/2006 09:08:56
Thanks victor great to find someone that has had experience with these subs!
I was wondering what would be best a vented or a sealed enclosure if i was
a) going for Sq
b) going for spl
c) bit of both?
In your experience which is better? I would perhaps be going for SQ over spl, and also just to confirm although the manual for the sub states a recommended .75-1cu/ft you have stil made 1.25 cu/ft enclosures and got a good result?
Cheers
lessismorespl on 05/10/2006 10:18:53
Agree w/ Mr. B, there is no such thing as the perfect box, and the manufacturers give specs that are very novice for several reasons, their specs are based on basic calculations which make the sub perform at minimal efficiency.
Victor is probably the most experienced here w/ the Alpine subs, in my experiences, a well made ported/vented enclosure works best for almost any sub I ever used, however, it is best to have a decent amp w/ SSF and a decent crossover(not all amps have the best xovers). W/ all these in combination, you can achieve a decent balance no matter what you are seeking from the sub(SPL, SQL, SQ).
less
MrBrownstone on 05/15/2006 18:11:27
Just keep in mind that you get 75% of one, and that's all you can do.
If you really want something loud, just do a vented enclosure, and don't worry about the quality of sound. Those speakers are fully capable of being as loud as necessary for even intense bass. Anything louder than what you need in a sealed environment, you really don't need to worry about the quality of sound as you've exceeded your hearing's thresholds anyway.
Once you get to 120dB or so, it's all about power and SPL. The only real compromise here for a 75/25 SPL system is a box vented at a low frequency (Say 32-35Hz)...but the amount of boost will be minor.
swez on 05/16/2006 00:55:57
Sealed boxes give a tight, crisp bass response.
If we look at the Qtc plots on a given sub/enclosure, a "Q" of 0.7 will net plenty of deep lows. But, to many (self included) the bass is not well defined and tends to be a bit peaky on the low end. Cone control and power handling also suffer in high "Q" enclosures.
As we move up in "Q", (say 0.85-.90) low bass is still very good, but punch and crispness in upper bass regions is much better and power handling improves. The last guy I worked intensively, used a pair of Alpine R 10's. He used a sealed box, 0.85 cf/chamber and reported his results to be excellent lows, very good punch and plenty of SPL in a sedan, trunk mounted system. He took it over to a high-end "Snob Appeal" shop nearby to demo his system and they were very impressed with his results.
Prior to his completion of the work, he researched many options and the "Snob Shop" tried to get him to buy very expensive JL subs, speakers and amps. When he explained his initial plans, they snubbed his plans and said he'd be better off letting thier shop do the install for about $2,500.00 He spent about $900 on Alpine amps, subs and CDT Comps. The results were stunning.
BTW, this was an older guy. He took his time, installed some Dynamat in doors and rear cargo area as well. In short, if you want a superior sounding SQL system, use quality products, research your options and work the plan.
Finally, if you go ported, one can expect more low bass near the port tuning frequency range selected. (~35 Hz.) The upper bass comes from direct cone radiation. The deep lows, come from the port. A Sub Sonic Filter, (SSF) is needed on ported designs, to protect your woofers from excess excursion and power robbing lows that can damage the most stout of subs.
Swez
Copyright ClubKnowledge 2009 * All Rights Reserved
