Hey Franklin.
- Thread starter Dentman
- Start date
That’s a good question and one which may take a long time to fully respond to and explain, but I will try.
First, I am often building hobbyist class systems. This means the design needs to be relatively easy to build and which easily fits the ideal parameter to get the most from the drivers and to get the results desired. As such, complicating the system with an enclosure within an enclosure (smaller midrange enclosure mounted inside the larger woofer enclosure) can be tedious and introduce increasingly more issues during construction. Add to that needing to accommodate small changes to the dimensions of the cabinet panels and parts to accommodate variations in the available materials, such as MDF which is thicker or thinner than exactly ¾ inch or a surprising difference in the volume of the port than the estimated design. Simplification of the enclosures so you get the most from the woofer and the midrange as small adaptations of the design are limited to each driver’s enclosure without impacting the other.
Second, interaction between enclosures is real. It is beneficial to isolate the woofer and its enclosure from the midrange and its enclosure. That way acoustic energy in the form of vibration isn’t impacting the performance of the different drivers. I like the idea of separating the baffle and having more than one layer of MDF between the midrange and woofer.
Third, focusing every single aspect of the performance of each driver based on the ideals for their specific characteristics and frequency range results in better performance. A woofer does better with a wider, larger baffle than a midrange, than a tweeter. The round-over on the edge of the baffle is more important on the tweeter than on the midrange and pretty much unnecessary on a woofer. So, being able to focus 100% on the most ideal characteristics for each driver results in better performance from each and thus for the entire system. A good example of this is the ideal dimensions of a bass enclosure will result in a box with a baffle not tall enough for the midrange/tweeter portion of the system. If you increase the height to accommodate the mid/tweeter speakers, the width or depth has to be reduced and thus the ideal dimensions are lost and now you have to deal with complex bass performance issues caused by a tall narrow enclosure. I’d rather make the enclosures all ideal since it is easy.
Fourth, since most of the speakers I design and build are hobbyist style and compromised or opinion based decisions are made before hearing the results, I like the idea that I could replace any one of the drivers in a 3-way system in case I am less than satisfied with one, or a new and obviously better performing driver is released. With a separate enclosure for each driver, you can replace one with another pretty easily if it makes sense. If swapping drivers, all new enclosures need to be designed and built. I’d rather just do one simple enclosure than a large and complex multi-driver enclosure.
Fifth, the size and weight of a proper 3-way single box system will be significantly more difficult to move, build, handle, and deal with than three separate modular enclosures stacked up on each other. I’d rather carry 6 lighter boxes up the stairs than 2 massive ones.
Sixth, and less commonly an issue, with separate bass bins you have more flexibility in the placement of the large bass enclosures than with the midrange/tweeter models. For ideal stereo imaging, there really is one single most ideal placement for the midrange and tweeter in the room while the bass bin can be moved to the left or right by as much as foot in either direction (depending on the crossover frequency) without impacting the stereo image. That means if the ideal placement for the mid/tweeter is closer to the screen, the width of the bass enclosure won’t block the screen if they are independent. If the speaker is one huge integrated box, one might have to decide between the ideal sound or the box blocking the screen, or close enough to be distracted by how close the speaker is to the screen.
Those are the basic reasons I prefer to build a separate bass box from the midrange/tweeter. And, since I know the pragmatic benefits of this sort of design, I have become enamored with it when I see it done by speaker companies, like the old KEF, current B&W, Wilson Audio, and other companies who agree.
First, I am often building hobbyist class systems. This means the design needs to be relatively easy to build and which easily fits the ideal parameter to get the most from the drivers and to get the results desired. As such, complicating the system with an enclosure within an enclosure (smaller midrange enclosure mounted inside the larger woofer enclosure) can be tedious and introduce increasingly more issues during construction. Add to that needing to accommodate small changes to the dimensions of the cabinet panels and parts to accommodate variations in the available materials, such as MDF which is thicker or thinner than exactly ¾ inch or a surprising difference in the volume of the port than the estimated design. Simplification of the enclosures so you get the most from the woofer and the midrange as small adaptations of the design are limited to each driver’s enclosure without impacting the other.
Second, interaction between enclosures is real. It is beneficial to isolate the woofer and its enclosure from the midrange and its enclosure. That way acoustic energy in the form of vibration isn’t impacting the performance of the different drivers. I like the idea of separating the baffle and having more than one layer of MDF between the midrange and woofer.
Third, focusing every single aspect of the performance of each driver based on the ideals for their specific characteristics and frequency range results in better performance. A woofer does better with a wider, larger baffle than a midrange, than a tweeter. The round-over on the edge of the baffle is more important on the tweeter than on the midrange and pretty much unnecessary on a woofer. So, being able to focus 100% on the most ideal characteristics for each driver results in better performance from each and thus for the entire system. A good example of this is the ideal dimensions of a bass enclosure will result in a box with a baffle not tall enough for the midrange/tweeter portion of the system. If you increase the height to accommodate the mid/tweeter speakers, the width or depth has to be reduced and thus the ideal dimensions are lost and now you have to deal with complex bass performance issues caused by a tall narrow enclosure. I’d rather make the enclosures all ideal since it is easy.
Fourth, since most of the speakers I design and build are hobbyist style and compromised or opinion based decisions are made before hearing the results, I like the idea that I could replace any one of the drivers in a 3-way system in case I am less than satisfied with one, or a new and obviously better performing driver is released. With a separate enclosure for each driver, you can replace one with another pretty easily if it makes sense. If swapping drivers, all new enclosures need to be designed and built. I’d rather just do one simple enclosure than a large and complex multi-driver enclosure.
Fifth, the size and weight of a proper 3-way single box system will be significantly more difficult to move, build, handle, and deal with than three separate modular enclosures stacked up on each other. I’d rather carry 6 lighter boxes up the stairs than 2 massive ones.
Sixth, and less commonly an issue, with separate bass bins you have more flexibility in the placement of the large bass enclosures than with the midrange/tweeter models. For ideal stereo imaging, there really is one single most ideal placement for the midrange and tweeter in the room while the bass bin can be moved to the left or right by as much as foot in either direction (depending on the crossover frequency) without impacting the stereo image. That means if the ideal placement for the mid/tweeter is closer to the screen, the width of the bass enclosure won’t block the screen if they are independent. If the speaker is one huge integrated box, one might have to decide between the ideal sound or the box blocking the screen, or close enough to be distracted by how close the speaker is to the screen.
Those are the basic reasons I prefer to build a separate bass box from the midrange/tweeter. And, since I know the pragmatic benefits of this sort of design, I have become enamored with it when I see it done by speaker companies, like the old KEF, current B&W, Wilson Audio, and other companies who agree.
It could be done, but there are still benefits to separates.
D
Deleted member 133
Guest
On this point I could not agree more.
In my younger days schlepping an 80 lb awkward-as-heck speaker up and down my basement steps was no big deal. But the other day I moved a pair of CM/1030s back to the basement and wondered how many more such trips I might have left in me. I used them for my Canada Day party. Next year I think it will be the Totem Sttaf from the living room.
Jeff
Dentman
Well-Known Member
MakeMineVinyl
Well-Known Member
TitaniumTroy
Well-Known Member
Thanks for a good post Flint, I am familiar with most of the principles you espoused. However it's good to see it get reinforced, so I can get an even better depth of understanding. Also makes it easier to remember when it's distilled down in one read.