I was wondering if anyone could comment on the differences or similarities in John's design and the one at PE.
http://www.partsexpress.com/projectshowcase/tubular/index.html
I like the concept of the tubes, I would probably use wooden tubes instead of the pvc. I know that John's design is dependent on the baffle width to acheive the same results. If you changed the part of the crossover that controls the bsc could it be adapted to a tube design? If you attached the tubes to a baffle of appropriate width is John's crossover and design still relevant?
In summary I want to build John's design, the crossover is simpler. However the PE design is more visually interesting. Could the two designs be blended to a degree?
http://www.partsexpress.com/projectshowcase/tubular/index.html
I like the concept of the tubes, I would probably use wooden tubes instead of the pvc. I know that John's design is dependent on the baffle width to acheive the same results. If you changed the part of the crossover that controls the bsc could it be adapted to a tube design? If you attached the tubes to a baffle of appropriate width is John's crossover and design still relevant?
In summary I want to build John's design, the crossover is simpler. However the PE design is more visually interesting. Could the two designs be blended to a degree?
There isn't just a "part" of the filter that controlls the BSD in John's design. His low pass filter, as a whole, shapes the response to compensate for the baffle step. Changing the baffle dimensions would require a complete rework of the low pass filter, which in turn would probably require some major or minor tweaking to the high pass filter to ensure proper phase integration.
Ok, my reasoning is, if you can increase L2 to get more BSC a decrease would give you less BSC, which is not needed since there is no baffle? Concerning your statement about reworking the entire lowpass filter, its just an inducter and resistor, I assume the cap would stay the same? Thats not much to change. I guess what I was asking is if you decreased L2 would you get a desirable reduction in BSC and would you get a desirable result, and if that can't be answered is there a good reason not to try? I don't mind experimenting as I can always make a standard box later.
So, if you add the baffle and attach the tubes to it, keeping the internal volume the same for the speakers, are all things equal at that point?
I'm looking at ways to cosmetically enhance this design, but I'm not sure where artistic license ends and you wind up building a completely different design.
After thinking a moment, would it make more sense to use the PE crossover and redesign the high pass to use the SEAS tweet, if I wanted to use tubes?
BSC is needed all the moreso because there' s no 'baffle'. The baffle prevents the wave from being omni until some frequency at which it 'wraps around', with the 'baffleless", there's nothing to achieve that. So only when the driver starts beaming will it become directional at all, so you have to compensate up to that point.
Hi,
The PE crossover design is poor, no BSC, silly hf impedance.
The Pod Tweeter mounting if its dead centre is about the worst
arrangement possible for diffraction ripple, due to their size its
much less a problem with the bass/mids.
The PE design doesn't really go into driver offsets, but has some.
One possibility is to use perspex panels to join the units. Making
it wider one side of the tweeter than the other will smooth things
a bit and the vertical extensions will smooth things a lot.
The Zaph c/o (and tweeter) is a better place to start with than
the PE design IMO.
Perhaps Zaph could answer the question of near optimum offset ?
/sreten.
The PE crossover design is poor, no BSC, silly hf impedance.
The Pod Tweeter mounting if its dead centre is about the worst
arrangement possible for diffraction ripple, due to their size its
much less a problem with the bass/mids.
The PE design doesn't really go into driver offsets, but has some.
One possibility is to use perspex panels to join the units. Making
it wider one side of the tweeter than the other will smooth things
a bit and the vertical extensions will smooth things a lot.
The Zaph c/o (and tweeter) is a better place to start with than
the PE design IMO.
Perhaps Zaph could answer the question of near optimum offset ?
/sreten.I don't want to build the PE design, I want to build the Zaph design. I want to use the Zaph crossover. All I really want to know is if I keep the baffle the same, can I alter the cabinet behind it. That is, attach some tubes to the baffle to create the enclosure. I can't see where this changes much other than aesthetics.
Cambe said:Hello,
I was wondering what would the low end response be like for the intergrated sub version and how it would compare to the vented floorstander version?
Cambe
Here's your answer, attached. Looking at only the simmed response, the vented floorstander has much more output below 100 Hz. Most would call that alignment bass heavy.
The low end response curve is of lesser importance than the following issues: power handling and distortion. On those 2 very important specs, a single RSS265HF is leaps and bounds above a pair of DA175's. In other words, the integrated sub version is best for those who like it clean and loud.
On the other hand, if you don't listen very loud but you like lots of bass, the vented version could be satisfactory. Or you could build one of the other designs out there using 4 of the DA175's for a little more power handling at the expense of a huge enclosure. Ask around on the PE forum about that one for another option.
Attachments
Hey Folks,
I've read this entire thread and browsed DIY Audio and have been able to get a better understanding of how these come together. I still have a few general questions about the build of these speakers, though.
In the print's listed on Zaph's site here: http://www.zaphaudio.com/BAMTM-cad-sealed.pdf
I've been trying to figure out what the pieces next to the Seas driver are. The leftmost and rightmost portions in the diagram are just triangles to mount the front of the enclosure on, but I see no corresponding lines behind the driver on the front view pictures as there are for the panel mounts. If it's a support mount, were individual pieces of wood used behind each screw hole, or is it a round piece going around the whole driver?
Also, in the middle of the enclosure, are there two holes in the support for the box, or three (one for each speaker)?
And one final question, how have those of you who have made these speakers created precisely smooth and countersunk holes at such a large diameter? The fit of the drivers in Outfitter's pictures is very good and I would like to be able to do something similar, but I've never had to countersink such a large hole before.
Thanks in advance for any help, and sorry for what may be some basic questions. I'm new to DIY Audio but have heard some great things about this speaker design and am looking forward to building my own set in the next few weeks. A direct thanks to Zaph, as well, for having taken the time to compile the graphs and diagrams on his website for everyone to use and enjoy.
-Enrique
I've read this entire thread and browsed DIY Audio and have been able to get a better understanding of how these come together. I still have a few general questions about the build of these speakers, though.
In the print's listed on Zaph's site here: http://www.zaphaudio.com/BAMTM-cad-sealed.pdf
I've been trying to figure out what the pieces next to the Seas driver are. The leftmost and rightmost portions in the diagram are just triangles to mount the front of the enclosure on, but I see no corresponding lines behind the driver on the front view pictures as there are for the panel mounts. If it's a support mount, were individual pieces of wood used behind each screw hole, or is it a round piece going around the whole driver?
Also, in the middle of the enclosure, are there two holes in the support for the box, or three (one for each speaker)?
And one final question, how have those of you who have made these speakers created precisely smooth and countersunk holes at such a large diameter? The fit of the drivers in Outfitter's pictures is very good and I would like to be able to do something similar, but I've never had to countersink such a large hole before.
Thanks in advance for any help, and sorry for what may be some basic questions. I'm new to DIY Audio but have heard some great things about this speaker design and am looking forward to building my own set in the next few weeks. A direct thanks to Zaph, as well, for having taken the time to compile the graphs and diagrams on his website for everyone to use and enjoy.
-Enrique
I use a Jasper Jig for routing holes in the baffle.
Jasper Jig
It attaches to the bottom of your router and cuts perfect cirles. You set it to cut the countersink first, then readjust it to cut the opening.
Jasper Jig
It attaches to the bottom of your router and cuts perfect cirles. You set it to cut the countersink first, then readjust it to cut the opening.
sealed enclosure
I have built the 1 cubit foot sealed enclosure. Does this sealed box require any stuffing or foam ? Also I realize this is a simple crossover, however would anyone have a photo or layout diagram of a completed crossover ? I am very new to crossovers and do not want to screw it up.
Thanks
Tim
I have built the 1 cubit foot sealed enclosure. Does this sealed box require any stuffing or foam ? Also I realize this is a simple crossover, however would anyone have a photo or layout diagram of a completed crossover ? I am very new to crossovers and do not want to screw it up.
Thanks
Tim
An open baffle design would require a completely different filter. An open baffle design would certainly perform better with a wider front baffle, so even if you actively eq'd to compensate for the open baffle losses, the current baffle width that the filter is designed for would not be optimal.
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