This is just hypothetical as i dont think i have the time or want to do it.... but i was curious as to what the outcome would be. in my home stereo speakers a set of 701 bose speakers. for the bass speakers it has 2 6.5" woofers mounted pointing at each other mayber around 2 inches between them. the area inbetween them is sealed. then each one has a chamber behind it with a transmission line style port behind it.
could this be done in car application with say 8 or 10" subs and what would be the benifits and loss's here?
i only ask because the home speakers net amazingly loud and boomy bass for 6.5" speakers they sound more like each speaker has a really nice 8" woofer in it. they get extrmly low and deep for there size.
well anyway anyone with experience in how and what the benifits are here please chip in your 2 cents this is a design i dont understand and would love to know more about.
Chronos
PS
the one benifit i see here is they great there own back preasure and would have a really snappy response if you did this to some 12" subs. but thats only speculation.
Replies (7)
uochronos on 08/14/2004 04:15:20
noone have any info on this type of design???
P0werLifter on 08/14/2004 14:01:45
The design your describing is an Isobaric design with a ported twist. For home audio its a good idea because you can fit 2 small drivers and a very small enclosure and still have good bass response since.( no one wants to have a huge enclosure in their house for a subwoofer. ) It also cuts out the subtle non-linearaties your sub-bass.
For a car audio application there are really only a few reasons you would really want to use the isobaric design. Information was posted from http://www.jlaudio.com/tutorials/isobarik/index.html
1. The first condition is a common occurence if you decide to change vehicles and keep the sound system or when you out-grow that desire to consume every cubic inch of your vehicle's storage space with subwoofers. You don't want to sell your equipment because you've fallen in love with it and so you begin to look for any way you can to keep it all (after all it *does* sound impressive to say "Hey, I've got 16 eight-inch woofers in the back of my Jetta"). Since iso-loading allows us to use the same number of pistons (a piston is one air-moving unit--think of it as you would the pistons in your engine) in half the space, an isobarik loading scheme might prove very attractive here.
2.The second condition may hold true if you've suddenly acquired a 500W amplifier for your subs and your poor little 125W subwoofers just cannot handle that kind of power. In this case, you might switch from one 125W driver (such as a JL Audio 10W1) in a .875 cubic foot enclosure to 4 of the same drivers (2 isogroups) in the same sized box. This would bump your effective power handling up to 500W -- which, assuming the box was built according to the manufacturer's specifications, should handle the added power just fine.
3.The third condition is pretty self-explanatory...you've got money burning a hole in your pocket and rather than purchase a new set of tires to replace your balding Dunlops, you decide to splurge on stereo equipment and try to put as much stuff into your car as possible.
Hope this helps, If somone has done this design in a car audio setting i would love to hear some feedback as to how it sounded, the SQ and the SPL output.
~Jason
uochronos on 08/14/2004 15:23:15
actualy the box part for my home speakers is huge i estimate from looks of around 1-1.5cubic feet per 6.5inch driver. i thought this was an isobaric system but was unsure.... just couldnt figure it out.
P0werLifter on 08/14/2004 20:42:55
I stand corrected for the "small enclosure for home audio" haha. From the design u posted im allmost 100% positive its isobaric with a ported twist to it.
uochronos on 08/15/2004 02:05:51
probaly is i read up on isobaric systems and the discriptions where all vague. so i was not sure all of them made it sound like one speaker was behind the other speaker... not facing each other. but you are probaly right... either way i would like to see something like this with a port designs with a set of high SQ 12" subs... if it neted as good as results as the 2 6.5's in my home speakers it would be awsome.
however i'm sure it would takes tons of calulation to get it right.
P0werLifter on 08/15/2004 04:36:25
There are different types of Isobaric loading, Piggy back, Back to Back, Planar and Clamshell. The type we are discussing here is the Clamshell design where drivers are facing eachother.
http://www.jlaudio.com/tutorials/isobarik/clam.html has some construction tips, information etc, on the clamshell design and on some of the others i have listed here. On the clamshell design described on that webpage, only one side of the drivers are sealed. (2 Drivers facing eachother, One magnet facing up, one magnet facing down, One side will be enclosued while one magnet is open.)
I think there are numerous ways to design these types of "enclosures" for the lack of a better term.
I would love to hear a set of SQ twelves set up like this. Might be a good project just to experiment and see.
-Jason
swez on 08/15/2004 10:29:15
Bose does like to use unique speaker arrangements. The transmission line effect is their best trump card. It sound like your home system is just that... a pair of small woofers divided by a common panels to prevent cancellations and a transmission line for the rear chamber to reproduce very good SPL bass from the rear of the cones which are in phase with front cone output. Each speaker has its own chamber and transmission line... is what I read into this design.
Isobaric designs are a push-pull arrangement that allows 2 subs to share a very small enclosure space. They can handle more power this way and still provide good bass performance common in larger enclosures. This is more for space saver applications than higher SPL.
In all, a lot of reading in speaker makers handbooks and such, will give you some broad application details if you really want to learn a great deal about many speaker enclsure designs.
Swez
could this be done in car application with say 8 or 10" subs and what would be the benifits and loss's here?
i only ask because the home speakers net amazingly loud and boomy bass for 6.5" speakers they sound more like each speaker has a really nice 8" woofer in it. they get extrmly low and deep for there size.
well anyway anyone with experience in how and what the benifits are here please chip in your 2 cents this is a design i dont understand and would love to know more about.
Chronos
PS
the one benifit i see here is they great there own back preasure and would have a really snappy response if you did this to some 12" subs. but thats only speculation.
Replies (7)
uochronos on 08/14/2004 04:15:20
noone have any info on this type of design???
P0werLifter on 08/14/2004 14:01:45
The design your describing is an Isobaric design with a ported twist. For home audio its a good idea because you can fit 2 small drivers and a very small enclosure and still have good bass response since.( no one wants to have a huge enclosure in their house for a subwoofer. ) It also cuts out the subtle non-linearaties your sub-bass.
For a car audio application there are really only a few reasons you would really want to use the isobaric design. Information was posted from http://www.jlaudio.com/tutorials/isobarik/index.html
1. The first condition is a common occurence if you decide to change vehicles and keep the sound system or when you out-grow that desire to consume every cubic inch of your vehicle's storage space with subwoofers. You don't want to sell your equipment because you've fallen in love with it and so you begin to look for any way you can to keep it all (after all it *does* sound impressive to say "Hey, I've got 16 eight-inch woofers in the back of my Jetta"). Since iso-loading allows us to use the same number of pistons (a piston is one air-moving unit--think of it as you would the pistons in your engine) in half the space, an isobarik loading scheme might prove very attractive here.
2.The second condition may hold true if you've suddenly acquired a 500W amplifier for your subs and your poor little 125W subwoofers just cannot handle that kind of power. In this case, you might switch from one 125W driver (such as a JL Audio 10W1) in a .875 cubic foot enclosure to 4 of the same drivers (2 isogroups) in the same sized box. This would bump your effective power handling up to 500W -- which, assuming the box was built according to the manufacturer's specifications, should handle the added power just fine.
3.The third condition is pretty self-explanatory...you've got money burning a hole in your pocket and rather than purchase a new set of tires to replace your balding Dunlops, you decide to splurge on stereo equipment and try to put as much stuff into your car as possible.
Hope this helps, If somone has done this design in a car audio setting i would love to hear some feedback as to how it sounded, the SQ and the SPL output.
~Jason
uochronos on 08/14/2004 15:23:15
actualy the box part for my home speakers is huge i estimate from looks of around 1-1.5cubic feet per 6.5inch driver. i thought this was an isobaric system but was unsure.... just couldnt figure it out.
P0werLifter on 08/14/2004 20:42:55
I stand corrected for the "small enclosure for home audio" haha. From the design u posted im allmost 100% positive its isobaric with a ported twist to it.
uochronos on 08/15/2004 02:05:51
probaly is i read up on isobaric systems and the discriptions where all vague. so i was not sure all of them made it sound like one speaker was behind the other speaker... not facing each other. but you are probaly right... either way i would like to see something like this with a port designs with a set of high SQ 12" subs... if it neted as good as results as the 2 6.5's in my home speakers it would be awsome.
however i'm sure it would takes tons of calulation to get it right.
P0werLifter on 08/15/2004 04:36:25
There are different types of Isobaric loading, Piggy back, Back to Back, Planar and Clamshell. The type we are discussing here is the Clamshell design where drivers are facing eachother.
http://www.jlaudio.com/tutorials/isobarik/clam.html has some construction tips, information etc, on the clamshell design and on some of the others i have listed here. On the clamshell design described on that webpage, only one side of the drivers are sealed. (2 Drivers facing eachother, One magnet facing up, one magnet facing down, One side will be enclosued while one magnet is open.)
I think there are numerous ways to design these types of "enclosures" for the lack of a better term.
I would love to hear a set of SQ twelves set up like this. Might be a good project just to experiment and see.
-Jason
swez on 08/15/2004 10:29:15
Bose does like to use unique speaker arrangements. The transmission line effect is their best trump card. It sound like your home system is just that... a pair of small woofers divided by a common panels to prevent cancellations and a transmission line for the rear chamber to reproduce very good SPL bass from the rear of the cones which are in phase with front cone output. Each speaker has its own chamber and transmission line... is what I read into this design.
Isobaric designs are a push-pull arrangement that allows 2 subs to share a very small enclosure space. They can handle more power this way and still provide good bass performance common in larger enclosures. This is more for space saver applications than higher SPL.
In all, a lot of reading in speaker makers handbooks and such, will give you some broad application details if you really want to learn a great deal about many speaker enclsure designs.
Swez
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