dayton quatro sonosub

[xstephanx]

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?

[jonz]

here maybe yu can get some ideas from my finished project...

my sub project

[jjdche]

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%.

[xstephanx]

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

[merlinx76]

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!

[xstephanx]

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.

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)

[aaroncgi]

1. Is a sonotube suitable for this subwoofer? I dont want it to resonate or flex alot

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.

2. Is my box size and tuning good?

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.

3. Can I get away with two 4" non flared abs pipe ports?(dont want port noise)

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.

4. Vents out the bottom or out the top?

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.

5. (kind of an afterthought) will I need to stuff it?

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

[jjdche]

Originally posted by xstephanx
...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)

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.

[xstephanx]

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!

[aaroncgi]

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