Just checking before I order everything and get started.
My current plan is to build a sonosub(24" diameter) utilising partsexpress's dayton quatro 15"(295-560) subwoofer. after a bit of playing around in win isd 7 cu ft tuned to about 20-21 hz(gives a 3 db down of 20 hz without room gain and a pretty flat looking response curve). The porting will be done via two 4" abs black tubes. Can I get away with not flaring them? win isd sais the vent mach will be .04. Since I will be mounting the driver down firing, should the vents come out the bottom or the top? The thing will be powered by the 240 watt plate amp at partsexpress(300-804).
In summary my questions are
1. Is a sonotube suitable for this subwoofer? I dont want it to resonate or flex alot
2. Is my box size and tuning good?
3. Can I get away with two 4" non flared abs pipe ports?(dont want port noise)
4. Vents out the bottom or out the top?
5. (kind of an afterthought) will I need to stuff it?
don't worry about size, I don't care and neither do my parents. I have pretty much as much sonotube as i want and i can go up to a 30" diameter. And if you couldnt already tell I will be using this sub for mainly HT. I value ANY helpful input and feel free to tell me im wrong!
BTW: who else thinks that cow print fabric over the sub would make it look real....beefy?
My current plan is to build a sonosub(24" diameter) utilising partsexpress's dayton quatro 15"(295-560) subwoofer. after a bit of playing around in win isd 7 cu ft tuned to about 20-21 hz(gives a 3 db down of 20 hz without room gain and a pretty flat looking response curve). The porting will be done via two 4" abs black tubes. Can I get away with not flaring them? win isd sais the vent mach will be .04. Since I will be mounting the driver down firing, should the vents come out the bottom or the top? The thing will be powered by the 240 watt plate amp at partsexpress(300-804).
In summary my questions are
1. Is a sonotube suitable for this subwoofer? I dont want it to resonate or flex alot
2. Is my box size and tuning good?
3. Can I get away with two 4" non flared abs pipe ports?(dont want port noise)
4. Vents out the bottom or out the top?
5. (kind of an afterthought) will I need to stuff it?
don't worry about size, I don't care and neither do my parents. I have pretty much as much sonotube as i want and i can go up to a 30" diameter. And if you couldnt already tell I will be using this sub for mainly HT. I value ANY helpful input and feel free to tell me im wrong!
BTW: who else thinks that cow print fabric over the sub would make it look real....beefy?
The Quatro 15" isn't the best driver for downfiring. You can go to the Parts Express website and they have a formula for deciding whether or not a wofer can be used in a downfiring configuration. The rule of thumb is that the driver "Sag" should be less than 5%, the Quatro 15" sag is about 6%.
Thanks about the sag! I completely forgot about that. I have enough room to put it on its side, but it would be alot easier to put it downfiring. Would it be ok? or should I just side fire it?
And your sub is very nice, but im not ready to put that kind of money into a box. but a beutiful install indeed!
also answers to any of my other questions would be very welcome
And your sub is very nice, but im not ready to put that kind of money into a box. but a beutiful install indeed!
also answers to any of my other questions would be very welcome
I don't think the vent airspeed calculations are correct when using multiple ports in WinISD. At least in the version I was using when I tried it. Try using a single port with the equivalent port area af the 2 ports you will be using and you will see the airspeed is different.
Unless this is what really happens and I am missing something, which is entirely possible!
Unless this is what really happens and I am missing something, which is entirely possible!
Thats what i noticed cause it was like .12 with one 4" port(cant remember exactly) and .04 with two :S. anyway, do you think i could still get away with two un flared 4" ports? and if the dayton quatro sub cant downfire i can either side fire it, or maybe a shiva downfiring?(less linear displacement and the extension aint as pretty but still prob unnoticeable)
Great woofer.
Absolutely. Flex will not be a problem with sonotube. Resonation might, but not of the sonotube itself, rather other components in/on the box. If in a normal home and listening room though, resonation of other items in the room will likely be more audible.
The box size is fine. I would not tune higher than 20 Hz though, to keep group delay as low as possible. For that reason, as well as the gain present in most rooms, I personally would tune to about 16 Hz. If you want to walk on the wild side like I do, you could build my 9.7 cubic foot box tuned to 11 Hz. It's down 3 dB at a relatively high 35 Hz, but is down only 11 dB at 10 Hz.
You should be fine. The Adire Audio Shiva is within a gnat's eyelash of having the same displacement capability as the 15" Quatro. Adire recommends a single 3" flared port. Your dual 4" straight ports provide more area.
If you have room on the bottom, that's where I'd put them, if only to make the top a nice solid piece and to keep people from dropping things into the port. As for sound quality, I don't think it will make a difference, given the wavelength of a 20 Hz signal.
It's not required, but won't hurt, unless you significantly increase the volume (ie 100% stuffed) or block the ports. My box doesn't have any stuff or damping at all right now, and no complaints, but just for the heck of it I am going to experiment with some acoustic foam behind the driver. With a proper crossover, ie at least 24 dB/octave no higher than 80 Hz, midrange leakage should be very minimal.
Here's my sub for fun. Pictures aren't current, as I have just refinished it in cherry and added a cool grill, but otherwise it's unchanged.
http://www.aaroncgilbert.com/emeraldtitan.html
Aaron Gilbert
Absolutely. Flex will not be a problem with sonotube. Resonation might, but not of the sonotube itself, rather other components in/on the box. If in a normal home and listening room though, resonation of other items in the room will likely be more audible.
The box size is fine. I would not tune higher than 20 Hz though, to keep group delay as low as possible. For that reason, as well as the gain present in most rooms, I personally would tune to about 16 Hz. If you want to walk on the wild side like I do, you could build my 9.7 cubic foot box tuned to 11 Hz. It's down 3 dB at a relatively high 35 Hz, but is down only 11 dB at 10 Hz.
You should be fine. The Adire Audio Shiva is within a gnat's eyelash of having the same displacement capability as the 15" Quatro. Adire recommends a single 3" flared port. Your dual 4" straight ports provide more area.
If you have room on the bottom, that's where I'd put them, if only to make the top a nice solid piece and to keep people from dropping things into the port. As for sound quality, I don't think it will make a difference, given the wavelength of a 20 Hz signal.
It's not required, but won't hurt, unless you significantly increase the volume (ie 100% stuffed) or block the ports. My box doesn't have any stuff or damping at all right now, and no complaints, but just for the heck of it I am going to experiment with some acoustic foam behind the driver. With a proper crossover, ie at least 24 dB/octave no higher than 80 Hz, midrange leakage should be very minimal.
Here's my sub for fun. Pictures aren't current, as I have just refinished it in cherry and added a cool grill, but otherwise it's unchanged.
http://www.aaroncgilbert.com/emeraldtitan.html
Aaron Gilbert
xstephanx said:
I'd side fire it if you can. Personally, I wouldn't use a downfiring woofer unless I absolutely had to, in any case its going to affect the performance. It may not be noticeable, but why chance it?
But, if you really want to downfire it, go ahead. Whats the worst that could happen? You lose some linear excursion capability. If worse comes to worse you'll have to buy a new driver. Not the end of the world.
haha I am very familiar with the emerald titan by now, im just amazed the driver doesnt unload with a tuning of 11hz :S. i would look at your design if it wasnt for the fact that my wains only have usable output down to 100hz(before watching a movie at reference becomes a problem) VERY nice subwoofer. I will port out the top since its in my room, I dont have kids(only 14) or need to worry about WAF. theres less than .2l linear displacement difference between the quatro and the shiva but if the quatro can take down firing ill do it(or i could just put the box on its side). thanks for the input!
Cool, I'm famous, or notorious.
Many people have expressed concern about unloading of my woofer with the 11 Hz tuning. It's not an issue for a couple reasons. First off, unloading typically occurs below the tuning frequency. Not a lot of music/movies have information below 11 Hz! Above the tuning frequency, a vented box is still less likely to unload than a sealed box, up to a certain point at which it behaves exactly like a sealed box. Secondly, I rarely listen to movies at reference levels, typically it's 5-10 dB below that. That means peaks of only 105-110 dB at my listening position from the subwoofer. Since I have measured 114 dB maximum output, I'm usually not there. Third, my subwoofer only receives the bass from the front three speakers, not all seven. Finally, the real clincher, my receiver has a subwoofer peak limiter. It provides a test tone, you crank the volume up until just below distortion sets in, and then the receiver remembers to not send a signal of any greater amplitude to the subwoofer. Works like a charm!
Bummer that your satellites only have usable output down to 100 Hz though! I like 80 Hz or lower for a crossover. Though, I think you could still get a pretty good match if you can keep your subwoofer right up front.
Tell me though, I assume you're living with parents at 14, how the heck are you watching movies at reference level?! I had to move out of the garage because of over 85dB and barely dreamed of having a subwoofer... Of course, that was back in the days where Dolby Pro Logic was just becoming common and Adire Audio was just a sparkle and Dan and Dave's eye.
Aaron Gilbert
Many people have expressed concern about unloading of my woofer with the 11 Hz tuning. It's not an issue for a couple reasons. First off, unloading typically occurs below the tuning frequency. Not a lot of music/movies have information below 11 Hz! Above the tuning frequency, a vented box is still less likely to unload than a sealed box, up to a certain point at which it behaves exactly like a sealed box. Secondly, I rarely listen to movies at reference levels, typically it's 5-10 dB below that. That means peaks of only 105-110 dB at my listening position from the subwoofer. Since I have measured 114 dB maximum output, I'm usually not there. Third, my subwoofer only receives the bass from the front three speakers, not all seven. Finally, the real clincher, my receiver has a subwoofer peak limiter. It provides a test tone, you crank the volume up until just below distortion sets in, and then the receiver remembers to not send a signal of any greater amplitude to the subwoofer. Works like a charm!
Bummer that your satellites only have usable output down to 100 Hz though! I like 80 Hz or lower for a crossover. Though, I think you could still get a pretty good match if you can keep your subwoofer right up front.
Tell me though, I assume you're living with parents at 14, how the heck are you watching movies at reference level?! I had to move out of the garage because of over 85dB and barely dreamed of having a subwoofer... Of course, that was back in the days where Dolby Pro Logic was just becoming common and Adire Audio was just a sparkle and Dan and Dave's eye.
Aaron Gilbert
I cant listen at reference yet, 85 db is acceptable though, heres the kicker, my room isnt in the basement, its on the top floor(you can hear pretty much everywhere). My dad doesnt care, if I crank metallica he happy as a clam. My mom on the other hand doesnt like it but she does laundry when im playin loud music or watching a dvd. So do you think I could downfire the dayton safely? keep in mind my room is only 14'x10(if im being generous) and doesnt have any openings to other rooms. and aaron Im curious about your form of bracing, think you could stick a penny on end on top run the sub full tilt and the penny wont fall down? and btw i thought reference was 85 db with 115 subwoofer peaks and 105 speaker peaks?(or summat like that)
Must be nice!
Sounds like you have really tolerant parents, that's great! I can hardly believe you are going to use that subwoofer in a 14' x 10' room, you'll hit 115 dB peaks easily. My room is sort of 16' x 21', but then is open to the dining area of about 7' x 7' and two hallways. Really, you could say the room is 23' x 21' with a dividing wall that forms the kitchen. And I still have way more bass than I need, has hit 114 dB on the SPL meter. Anywho...
Oh, and I meant to say I had to move out TO the garage, not out of the garage. And that was when I just had two small speakers with 8" woofers, about four times less air moving capability than the 15" Quatro.
I have never checked into downfiring on the Quatro, let me see if I can find Adire's formula. Ah here we go:
http://www.adireaudio.com/Files/TechPapers/DriverOrientation.pdf
Using this formula, I come up with 5.63% sag for the 15" Quatro, which is just over Adire's recommended 5% maximum to use a woofer downfiring. Shiva by comparison only sags 3.36%. Of course it's up to you in the end, but these are the guys who should know.
As for putting a penny on end on top of my sub at full tilt, I will give it a try! It probably depends on the frequency, because at certain frequencies the whole corner of the room seems to shake. I have all my DVD's on a rack on top of the sub, and the rack shakes too (though fortunately doesn't rattle). But, putting my fingers on any part of the cabinet, I feel so little vibration that it would be hard to believe the sub is working if I couldn't hear it.
Aaron Gilbert
Sounds like you have really tolerant parents, that's great! I can hardly believe you are going to use that subwoofer in a 14' x 10' room, you'll hit 115 dB peaks easily. My room is sort of 16' x 21', but then is open to the dining area of about 7' x 7' and two hallways. Really, you could say the room is 23' x 21' with a dividing wall that forms the kitchen. And I still have way more bass than I need, has hit 114 dB on the SPL meter. Anywho...
Oh, and I meant to say I had to move out TO the garage, not out of the garage.
And that was when I just had two small speakers with 8" woofers, about four times less air moving capability than the 15" Quatro. I have never checked into downfiring on the Quatro, let me see if I can find Adire's formula. Ah here we go:
http://www.adireaudio.com/Files/TechPapers/DriverOrientation.pdf
Using this formula, I come up with 5.63% sag for the 15" Quatro, which is just over Adire's recommended 5% maximum to use a woofer downfiring. Shiva by comparison only sags 3.36%. Of course it's up to you in the end, but these are the guys who should know.
As for putting a penny on end on top of my sub at full tilt, I will give it a try! It probably depends on the frequency, because at certain frequencies the whole corner of the room seems to shake. I have all my DVD's on a rack on top of the sub, and the rack shakes too (though fortunately doesn't rattle). But, putting my fingers on any part of the cabinet, I feel so little vibration that it would be hard to believe the sub is working if I couldn't hear it.
Aaron Gilbert
Oh and yes, you're right on reference.
It, home THX (and also Dolby Digital) reference levels are specified as 85 dB average, with 105 dB peaks. It used to be 105 dB for all speakers including the subwoofer, but now I have indeed heard the 115 dB figure given for the subwoofer. I don't know if that's a Dolby specification, THX, or both, or whether the various levels of THX (ie Select, Ultra, Ultra2) differ.
My system falls just short of the 115 dB figure.
Aaron Gilbert
It, home THX (and also Dolby Digital) reference levels are specified as 85 dB average, with 105 dB peaks. It used to be 105 dB for all speakers including the subwoofer, but now I have indeed heard the 115 dB figure given for the subwoofer. I don't know if that's a Dolby specification, THX, or both, or whether the various levels of THX (ie Select, Ultra, Ultra2) differ.
My system falls just short of the 115 dB figure.
Aaron Gilbert
first of all
Thank you very much aaron, and nice saab
I'm guissing since its only.63% im probly good downfiring, if not? i tip it sideways, not a big deal and i know its gonna get LOUD. So far i havent heard a system that can hit the low note on 3-6 mafias late night tip(song) and i know after i get this thing workin, ill reach FAR under that note. Plus ill have the nicest HT system in all my classes
Thank you very much aaron, and nice saab
I'm guissing since its only.63% im probly good downfiring, if not? i tip it sideways, not a big deal and i know its gonna get LOUD. So far i havent heard a system that can hit the low note on 3-6 mafias late night tip(song) and i know after i get this thing workin, ill reach FAR under that note. Plus ill have the nicest HT system in all my classes
Penny test results.
xstephanx,
Well, I finally tried a penny standing on end on top of my subwoofer at full tilt (at least 300 watts) just now. It will stand up, but for how long depends on frequency. It only seems to stay up a few seconds at 20 Hz, but much longer at 5 Hz. I took some pictures, but the woofer is moving too slowly to show up on the camera as movement at all, so I figured that wouldn't prove anything. Maybe I'll take a video later.
It would seem that the problem is not vibration of the cabinet panels, but rather, movement of the entire freakin' box back and forth in opposition to the woofer! Now this box, as I probably mentioned, weighs about 130 pounds, and also has all my DVD's on top, at least another 35 pounds. I am using four casters, not spikes, but my carpet is quite thick and so the bottom doesn't move. Now I can see the advantage of having dual woofers, on opposing sides of a cabinet! In my case, barring adding a woofer to the back, I suppose I could screw the box into the wall joists. I don't think spikes or screwing it to the floor would be the answer, as it could still rock back and forth on those 'joints'. This may be one big advantage for a downfiring woofer, perhaps, since it's cabinet is trying to move up and down.
Aaron Gilbert
xstephanx,
Well, I finally tried a penny standing on end on top of my subwoofer at full tilt (at least 300 watts) just now. It will stand up, but for how long depends on frequency. It only seems to stay up a few seconds at 20 Hz, but much longer at 5 Hz. I took some pictures, but the woofer is moving too slowly to show up on the camera as movement at all, so I figured that wouldn't prove anything. Maybe I'll take a video later.
It would seem that the problem is not vibration of the cabinet panels, but rather, movement of the entire freakin' box back and forth in opposition to the woofer! Now this box, as I probably mentioned, weighs about 130 pounds, and also has all my DVD's on top, at least another 35 pounds. I am using four casters, not spikes, but my carpet is quite thick and so the bottom doesn't move. Now I can see the advantage of having dual woofers, on opposing sides of a cabinet! In my case, barring adding a woofer to the back, I suppose I could screw the box into the wall joists. I don't think spikes or screwing it to the floor would be the answer, as it could still rock back and forth on those 'joints'. This may be one big advantage for a downfiring woofer, perhaps, since it's cabinet is trying to move up and down.
Aaron Gilbert
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