15 vs 18 tumult down firing vs front firing

[Mark_IDT]

I'd like to hear some opinions on the differences if any between the 15 and 18 tumult in a sealed box. Also I'm trying to figure out if I should make it in a down firing box with base plate like svs which would provide nice protection for the driver or just go with front firing. It seems to me like the down firing sub would be easier to setup in a room where you wouldn't be faced with options of pointing the sub into the room or into the back wall or whatever.

[kexodusc]

I'd advise against a down-firing sub. Especially a heavy 18" sucker...You've got gravity working against your speaker, and that won't be a long-term benefit. Build a grill and that should be protection enough. Plus, on that thing, you're pushing a ton of air, and you wouldn't want the back force affecting the cone's movement...I think front firing would be safer and easier for you.

I don't know if you answered this in another thread or not, but how f'n big is your room?

From what I've heard of the Tumult's they are high output subs, but not necessarily considered Adire's best sounding subs though at lower volumes. I personally have not heard one so I can't comment from experience, but intuitively, 33mm xmax is a lot of travel for a that woofer, and it doesn't have the highest sensitivity.

I ran a quick model on the 15" Tumults...At 500 watts you're getting 113 dB of bass power with room to spare, nowhere near hitting peak cone excursion, in fact you're only 1/2 way at 29Hz at 500 Watts...Just for fun I ran 1000 watts too, still not at maximum excursion - it's not everyday that you see the electrical power handling of a voice coil as the limiting factor in a woofer, but that's the case here! This is one serious subwoofer. I'd drop it into a 2.25 cubic foot box, nice and small, you could go anywhere from 2 to 3 cubic feet. F3 is going to be around 34-35 Hz either way. That's deceiving though, your room gain is heavily going to kick in. My 15" sub has an F3 at 35 Hz or so as well, but in my room the measured response I'm actually getting peaks into the high 20's, so my real F3 is around 19 Hz or so.

If I use the typical DIN 45 500 rating, your in room response is easily down to 21Hz, probably even lower.

One thing about these Tumults though, expect them to continue to play loud, and clean above 110 dB. My sub pretty much starts to loose sound quality at 105-106 avereage dB and I wouldn't want lower than 30 Hz peaks above 115dB. For me that's about 20 dB higher than I ever listen anyway, but if I ever want to throw a backyard party, it's something to keep in mind. A Tumult would laugh off 115 dB.

Are you trying to get arrested for distrubing the peace?

[Mark_IDT]

Well it's going to go in my bed room for now which is 13x12 but this is only temporary as I'm forced to live at my parents hous cause I can't work due to a bad car accident I'm still recovering from. When they leave for a weekend I sometime move my stereo into the living room which is 25x14. I'm also going to take it to fraternity parties and possibly use it for a DJ setup. My idea is I can always turn it down and if I ever live somewhere with a big room I won't be left with too small of a sub. I may also let a friend who plays bass in a band use it to get much needed more db's but I'm not so sure if I will do that or not.

So how about the cone size? Any difference between the 15 and 18? I read conflicting so called facts about how size affects sound. Ex: 10's are more punchy and faster and 15 or 18's are deeper sounding and slower. Then again I've read there is no difference just that bigger cones can play lower. So then would bigger cones also struggle to play the upper frequencies?

[kexodusc]

Cone size and it's effect on sound really varies too much from speaker to speaker to generalize I think. I use to think smaller speakers were faster and better sounding, but now I believe it's just the smaller speakers I heard that were better sounding than their larger counterparts.

At lower frequencies, a smaller woofer is going to lose some "speed" as xmax increases when you turn the volume up. The larger woofer won't have to worry about that. Larger woofers need bigger cabinets, and are a bit fussier than smaller ones, and you wouldn't want a big sub in a small room. I think performance wise, larger drivers should be equal to smaller drivers, but offer similar performance as output increases without starting to crap out. Lower response though

That said, I really don't see the need for one of these 18" Tumult drivers for you. Especially if you're going to be moving around a bit. They're a bit more efficient, will play a bit louder, but there's a point where things start getting rediculous. I think a 15" is a pretty safe bet, middle-of the road sub for what you're looking to do. Do you really want to be lugging an 18" sub around, or have on sitting in a smaller room?

But an 18" Tumult definitely has cool factor going on, and is only a $50 more than the 15".
You really need to identify your goals and then pick the right sub, amp, and cabinet to meet them.
Think in terms of response, and output in the expected room sizes. 18" subs in a dorm, apartment, or 13" X 12" bedroom can be a bit, well, in-your-face.

Of course, if you're smart, you'll design the cabinet to serve as a coffee table too. Just don't be resting lamps, drinks, or feet on this when it's on.