I'm looking at adding a smaller, bandpass design subwoofer for my dining room audio. Currently, I have a very nice set of inwalls, (Phase Technology CI-110ii) being run off a Sonos Amp.
I'd like to add some low end to the system by building a small, (6.5"ish) 4th-order bandpass design similar to this: James Loudspeaker
My dining room shares a wall with my garage and attic above the garage, so I can easily mount it in the attic above the garage and have the port vent into the dining room behind a simple AC vent. Just like the James design, I can have the port tube exterior to the enclosure since it will be in the attic.
I was looking at some of the 6.5" subwoofer offerings from PE, but I don't know what dimensions the enclosure would have to be, nor the port dimensions. I could also do an 8" if it's easier to design since there are more 8" offerings available.
This is just for background music so we can tune it to play lower rather then louder.
Does anyone here have any suggestions for plans and which driver to choose?
Thanks!
I'd like to add some low end to the system by building a small, (6.5"ish) 4th-order bandpass design similar to this: James Loudspeaker
My dining room shares a wall with my garage and attic above the garage, so I can easily mount it in the attic above the garage and have the port vent into the dining room behind a simple AC vent. Just like the James design, I can have the port tube exterior to the enclosure since it will be in the attic.
I was looking at some of the 6.5" subwoofer offerings from PE, but I don't know what dimensions the enclosure would have to be, nor the port dimensions. I could also do an 8" if it's easier to design since there are more 8" offerings available.
This is just for background music so we can tune it to play lower rather then louder.
Does anyone here have any suggestions for plans and which driver to choose?
Thanks!
A 4th order BP system with a 6.5" driver that does 32 Hz to 120 Hz...?
I'm a little skeptical, though I guess it might be possible to achieve with one of those long-through 6.5" subwoofer drivers. And that long vent is likely going to have organ pipe resonances that might end up "coloring" the sound of that system.
If I was going to a 4th order BP build, I'd model and build it as as an offset driver "horn" in Hornresp, and use the offset to cancel out the first out of band resonance peak. This worked out really well when I redesigned my INF10 bandpass subwoofer - The Subwoofer DIY Page v1.1 - Projects : An INF10 Bandpass Subwoofer
I'm a little skeptical, though I guess it might be possible to achieve with one of those long-through 6.5" subwoofer drivers. And that long vent is likely going to have organ pipe resonances that might end up "coloring" the sound of that system.
If I was going to a 4th order BP build, I'd model and build it as as an offset driver "horn" in Hornresp, and use the offset to cancel out the first out of band resonance peak. This worked out really well when I redesigned my INF10 bandpass subwoofer - The Subwoofer DIY Page v1.1 - Projects : An INF10 Bandpass Subwoofer
I've never seen this product from James, but I agree with the sentiments here in this thread from the other posters about possible issues. Being boundary loaded, you COULD get 32 hz from it, but it might not be at the same level of output as the rest of the operational bandwidth; ie- rolled off a bit. You're better off with a solid conduit of PVC or other non-flexible tube.
I'm noodling the DCS165, and with a really long port (30") it's doable with a 17ltr total box if you are fine with bandwidth of 32-44Hz and 92dB at 25W. I'm sure there are other options.
Later,
Wolf
I'm noodling the DCS165, and with a really long port (30") it's doable with a 17ltr total box if you are fine with bandwidth of 32-44Hz and 92dB at 25W. I'm sure there are other options.
Later,
Wolf
Agreed. When you use a 6.5" subwoofer in a 4th order, your extremes are shot by both using small enough sealed volume to not unload, and a tuning frequency that gets you low enough frequency bandwidth, and then not totally making it useless by killing any decent sensitivity numbers. It's not an easy driver size to make work in a bandpass, IMO.
Later,
Wolf
Later,
Wolf
I can make the port out of pvc and make it to any length since it would reside in the attic above the garage. What diameter would it need to be in the above example, if it were 30" long?
Low playing levels are fine. Today I took some readings with my dB meter playing all sorts of music in the dining room. Even cranked, blasting Ozzy/ Metallica, etc, I was only hitting 90dB peaks. Usually we listen to Jazz or house music there at levels in the 75dB range. Maybe 80 if there's a lot of people talking.
Hi freddi,
If you are not sure which chamber or port tube is which, simply press and hold down the S key from any chart to temporarily display the schematic diagram, then click on the slider control adjuster in question to highlight the applicable chamber or tube in yellow, as shown in the attachment.
Kind regards,
David
Attachments
Hi freddi,
Not a problem, provided that I don't have to change any nappies
.
I originally thought about including labels, but as well as showing which chamber and port tube was which, I also wanted to be able to indicate which chamber dimension was being assumed as the chamber depth, and also to show how the port tube area and length were measured. I ultimately decided that the neatest way to do this was to use the yellow highlighting, along with dotted red lines for the relevant dimensions, rather than clutter up the schematic drawing with multiple labels.
Kind regards,
David
Not a problem, provided that I don't have to change any nappies
.I originally thought about including labels, but as well as showing which chamber and port tube was which, I also wanted to be able to indicate which chamber dimension was being assumed as the chamber depth, and also to show how the port tube area and length were measured. I ultimately decided that the neatest way to do this was to use the yellow highlighting, along with dotted red lines for the relevant dimensions, rather than clutter up the schematic drawing with multiple labels.
Kind regards,
David
Attachments
hi wolf_teeth - could you give mote details on that BP4 with the 30" long port? - I could not get a satisfactory bandwidth.
-vents get crazy long with some small drivers - I looked at the low qts Silver Flute 6 and could kinda make a series BP6 but would require an external "carrying handle" vent to link the chambers
-vents get crazy long with some small drivers - I looked at the low qts Silver Flute 6 and could kinda make a series BP6 but would require an external "carrying handle" vent to link the chambers
for low playing levels, 40 liters total or somewhat less for a series BP with the Dayton Classic 8 should give that wanted bandwidth
here's a 20/20 split (maybe 18/18 too)
(I'd like to see the chambers on David's hornresp wizard labeled as get confused)
In this example, you're saying to use a series BP design, with both chambers 20 liters. Where does it show how to design the ports as far as diameter and length?
Are there any other suggestions that may work?
Thanks!
"Ap" indicates port area - "Lp", port length
here's 36 liters chamber volume total (sans driver and ports displacement) with both inner and front ports made from 3" pvc. I don't think the junk around 800 will be bad with the port at a right angle to the driver and maybe some foam in the front chamber.
use 3" ID pvc for the inner port if you can get the 16 inch length to fit between both chambers and clear cabinet walls.
It will be xmax limited to around 10 watts
here's 36 liters chamber volume total (sans driver and ports displacement) with both inner and front ports made from 3" pvc. I don't think the junk around 800 will be bad with the port at a right angle to the driver and maybe some foam in the front chamber.
use 3" ID pvc for the inner port if you can get the 16 inch length to fit between both chambers and clear cabinet walls.
It will be xmax limited to around 10 watts
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