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Old 4th March 2007, 03:19 AM   #1
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Default whats to be gained from an elaborate box design over a std. bass reflex?

hey

so i couldent find a discussion on this, so here it goes.

what's to be gained from a elaboarate box design over a simple bassreflex box?

the difference of the simple VAS volumed box with a tuning put where its supposed to be, as in contrast to the elaborate, no compromise type of box, using the same drivers and x-overs.

just what manner of difference are we talking about here, really?

if the difference is what i suspect it to be, then i have my design ready to be smacked together, the simple 6'5"+1" type bookshelf thingy. im needing some quality sound now, badly so.

but if theres big improvements to be had by going about a propper design process, then I'm inclined to do just that.

so given the same overlying circumstances, box being the only difference, what improvements are to be had?

- Marius
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Old 4th March 2007, 07:05 PM   #2
pjpoes is offline pjpoes  United States
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This is a very difficult question to answer as it was worded. I mean, a great many ported boxes, for instance, are poorly designed, but this comes from designers trying to get more percieved bass from the speaker than is there, and putting a lump in the response. This is done by using a box that is too small and a tuning frequency too high. Also saves space and allows a smaller length port tube, which may be all that fits in the box.

Now, beyond that, There are advantages and disadvantages to all the different designs. Transmission lines, horns, sealed, ported, etc. It's worth looking around the forums and websites to get an idea what these are. Horn's for instance offer the greatest efficiency, and it is always nice to get more output with less power. It offers other advantages as well, most feel that an efficient speaker does a better job with macro and microdynamics. However, you will noticed that frequently the response isn't as flat with these, and they are large and difficult to construct. They are also harder to design for the average user.

Transmission lines are nice in that you can get a nice extended bass response, good transient response, again, does a better than average job with dynamics, however its only as efficient as a typical sealed box.

Sealed boxes generaly, all other things being equal, offers the best transient response-because of the air cushion, potentially the lowest distortion because of this, and is the easiest to design. However bass is going to be the least extended, and its the least efficient design. There are some sweeping generalizations here too, like the lower distortion and better transient response. Though generally true, its not always, and some here who love their horn loaded speakers especially might disagree.

Ported boxes are harder to design than sealed, but not impossible. With modern software like Bassbox, WinISD, etc it has become very easy for the average user. The only issue becomes understanding the graphs, and knowing how a given response will react in room. Also, they only show you how the bass will be, how the box will effect that, not the upper area, where honostly, a box has less of an effect anyway. None the less, I do think that, as an example, my Focal Midbass drivers sound different in the midrange and upper midbass in a sealed vs ported box. Use some software and design it right, you should be good to go here. I'm a fan of ported boxs for a lot of things, I also like Transmission lines, but don't yet really know how to design them right.
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Old 4th March 2007, 07:44 PM   #3
Salas is offline Salas  Greece
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Listening to an aiding resonance is different than listening to a controlling enclosed volume which is again different than listening to a progressive absorber or to a transformer (BR,IB,TL,HORN). Given that all approaches can be conceived, measured, and executed with same competence and neutral reproduction as the common goal, the more elaborate you get when for a given driver the simpler isn't productive enough, the more rewarded you are going to get. Keep it simple but not simpler than necessary. The logical exercise of the adequate pays off. Adequate for a well balanced performance target considering you, the room, the spare time, the system, the music, the pocket.
It boils down to philosophy in the end if competence is a given prerequisite. That is why very successful schools of design and practices coexist. They are more suitable to different approaches rather than worse or better. The omnipresent BR is simple and delivers bass volume to the masses. Hence a top survivor.
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Old 5th March 2007, 01:15 AM   #4
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What exactly is an "elaborate" enclosure?
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Old 5th March 2007, 10:06 AM   #5
sreten is offline sreten  United Kingdom
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Hi,

If I can add my tuppence worth .......... :

For manafacturers box size is a major issue. Sealed or bass reflex
boxes gives good results in compact boxes and IMO for box volume
vs. performance generally they cannot be touched.

However there is another school of thought where basically more
box volume than the above is available for the drivers. For some
drivers this allows more bass in what I'd term "oversize" complex
enclosures, e.g. TLs, MLTL's, TQWT's, MLTWQT's etc.

Whilst these more complex boxes can get more out of a particular
driver - another approach is to exploit the larger box volume with
a bigger or doubled up bass drivers - back to square one.

Generally for performance per box litre, go for sealed or reflexed.

/sreten.
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Old 5th March 2007, 11:52 AM   #6
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Each box design has its own set of compromises and therefore design or performance constraints. A person has to decide what his or her performance/space/cost/complexity limitations are. That decision will to point to one design over another.
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Old 5th March 2007, 07:15 PM   #7
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Quote:
Originally posted by 454Casull
What exactly is an "elaborate" enclosure?
hello 454casull.

what i ment with "elaborate" design was one of higher build and design complexity, such as a transmission line, a box buildt to eliminate standing waves inside the encloasure, one with internal bracing skeleton for decreased box resonances.

you know..
complex..
>_<

Quote:
Originally posted by roddyama
Each box design has its own set of compromises and therefore design or performance constraints. A person has to decide what his or her performance/space/cost/complexity limitations are. That decision will to point to one design over another.
Hey Rod. thats kinda the phase im in ATM.
i got a spanking in the thread i made concerning the basic design i had settled on. some pretty hefty critique and thats made me rethink my approach.
this is the thread BTW
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Old 5th March 2007, 08:00 PM   #8
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Quote:
Originally posted by pjpoes
This is a very difficult question to answer as it was worded. I mean, a great many ported boxes, for instance, are poorly designed, but this comes from designers trying to get more percieved bass from the speaker than is there, and putting a lump in the response. This is done by using a box that is too small and a tuning frequency too high. Also saves space and allows a smaller length port tube, which may be all that fits in the box.

Now, beyond that, There are advantages and disadvantages to all the different designs. Transmission lines, horns, sealed, ported, etc. It's worth looking around the forums and websites to get an idea what these are. Horn's for instance offer the greatest efficiency, and it is always nice to get more output with less power. It offers other advantages as well, most feel that an efficient speaker does a better job with macro and microdynamics. However, you will noticed that frequently the response isn't as flat with these, and they are large and difficult to construct. They are also harder to design for the average user.

Transmission lines are nice in that you can get a nice extended bass response, good transient response, again, does a better than average job with dynamics, however its only as efficient as a typical sealed box.

Sealed boxes generaly, all other things being equal, offers the best transient response-because of the air cushion, potentially the lowest distortion because of this, and is the easiest to design. However bass is going to be the least extended, and its the least efficient design. There are some sweeping generalizations here too, like the lower distortion and better transient response. Though generally true, its not always, and some here who love their horn loaded speakers especially might disagree.

Ported boxes are harder to design than sealed, but not impossible. With modern software like Bassbox, WinISD, etc it has become very easy for the average user. The only issue becomes understanding the graphs, and knowing how a given response will react in room. Also, they only show you how the bass will be, how the box will effect that, not the upper area, where honostly, a box has less of an effect anyway. None the less, I do think that, as an example, my Focal Midbass drivers sound different in the midrange and upper midbass in a sealed vs ported box. Use some software and design it right, you should be good to go here. I'm a fan of ported boxs for a lot of things, I also like Transmission lines, but don't yet really know how to design them right.
Pjpoes! thanks for your in depth reply!

when i was messing around trying to find a design to mate my drivers with i played a lot with winISD and ended up with a 8 liter box tuned at 58Hz, a quick and easy solution, one i thought was going to give good resoults, and mix in well with my subs. I kinda was given the boot on that one and as i'v said in my previous post im back to scratch. And now i have to choose again.

Quote:
Originally posted by salas
Listening to an aiding resonance is different than listening to a controlling enclosed volume which is again different than listening to a progressive absorber or to a transformer (BR,IB,TL,HORN). Given that all approaches can be conceived, measured, and executed with same competence and neutral reproduction as the common goal, the more elaborate you get when for a given driver the simpler isn't productive enough, the more rewarded you are going to get. Keep it simple but not simpler than necessary. The logical exercise of the adequate pays off. Adequate for a well balanced performance target considering you, the room, the spare time, the system, the music, the pocket.
It boils down to philosophy in the end if competence is a given prerequisite. That is why very successful schools of design and practices coexist. They are more suitable to different approaches rather than worse or better. The omnipresent BR is simple and delivers bass volume to the masses. Hence a top survivor.
Salas: your not going to give me a quick easy answer by deciding for me either i see

Quote:
Originally posted by sreten
Hi,

If I can add my tuppence worth .......... :

For manafacturers box size is a major issue. Sealed or bass reflex
boxes gives good results in compact boxes and IMO for box volume
vs. performance generally they cannot be touched.

However there is another school of thought where basically more
box volume than the above is available for the drivers. For some
drivers this allows more bass in what I'd term "oversize" complex
enclosures, e.g. TLs, MLTL's, TQWT's, MLTWQT's etc.

Whilst these more complex boxes can get more out of a particular
driver - another approach is to exploit the larger box volume with
a bigger or doubled up bass drivers - back to square one.

Generally for performance per box litre, go for sealed or reflexed.

/sreten.
Hey Sreten. this were my initial thoughts: to get as much as possible out of a designt as easy as it could be, but no simpler.

the best performance while keping the box small with good and clean sub intigration, i landed on a bassreflex.

Bass was never something i aimed to get out of my 1x6.5 design, as i got 2x12' XLS subs to deal with that.

_________________

well, going to have to sleep on the subject for now, allthough my feelings on the subject i wanted to raise is that diminishing returns sets in quickly in a situation like the one raised. And as said, differing box design topoligies are different to each other, not necicarily better. situation of use dictates the best solutions so that kind of leaves me back to a closed\bassreflex box

thanks for your replys gentlemen, they are appreciated.

-Marius
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Old 5th March 2007, 10:27 PM   #9
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Quote:
Originally posted by demogorgon

Hey Rod. thats kinda the phase im in ATM.
i got a spanking in the thread i made concerning the basic design i had settled on. some pretty hefty critique and thats made me rethink my approach.
this is the thread BTW
No, not a spanking, I've seen some spankings around here and that doesn't come close. You just got some constructive criticism.


I started to read your original post in the link you provided and couldn't get through the whole thing. You need to decide what your performance goals are and determine if you can afford them, if you have the space to acommodate them, and if you have the skills and/or resources to realize the design. ...or you can go out and buy a nice kit just to get something going while you decide what you really want.
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Old 6th March 2007, 12:53 PM   #10
sreten is offline sreten  United Kingdom
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Quote:
Originally posted by demogorgon


.....the best performance while keping the box small with
good and clean sub intigration, i landed on a bassreflex....

-Marius
Hi,

FWIW sealed is nearly always better for subwoofer integration / use.

/sreten.
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