DevilDriver

Fuckin eh, man...

Mindless Self Indulgence - Straight to Video

That cone and surround look incredible.

7" mid with ~10mm of excursion and extension over 3khz would be nice.

And for SSA, it is more meaningful traffic as well. For example, if a rush of people come to the site all at once after being linked from a larger site, that increases your traffic in the short term. But is that helpful over a long period of time? Not really. Several studies have indicated that "swarm" traffic is not a good thing, but consistent growth is great. I look forward to better and better results here.

Congrats! Pics?

The responsible side of me thinks you should stick with engineering. It is a mentally challenging job with high financial rewards. At the same time, my free spirit side says do whatever comes to your mind. I am an engineering student and I love it. Math, physics, gym, and computer science have always been my favourite classes, and now I am actively involved in three of those categories. Sometimes it just takes a while to figure out what you want to do. If I had gone to university right out of high school, I would have wasted a years worth of tuition, so take your time and find something that fits.

I would love for CDT to do an 8/3/1 set so badly.

Lol, I got a funny email from a friend who is a troll. "Who is this SSA and do they have a website?"

This is a routinely asked question: "How long does the vent tube need to be if I use an n" flared port?" Granted, there are a few calculators out there that will calculate this for you, particularly if you're using some of the widely available manufactured ports. Here's a good example of a calculator available to you: http://psp-inc.com/psp-inc.com/public_html..._calculator.cgi But what if you have hand-formed your flared ends? Better yet, let's assume you are a dork like me and prefer to hand calculate a lot of things (believe it or not, the extra effort is worthwhile in the long run, but that's a rant for another day). Without getting too into depth on the actual derivation of the formula, here's what you need to know. Where: Lv = length of the vent tube (in meters) N = number of ports (unitless) c = speed of sound (in meters/second) Rm = mouth radius of the flare (in meters) Rt = throat radius of the flare (in meters) Rf = flare radius (in meters) Fb = frequency of port resonance (in Hertz) Vb = size of enclosure (in cubic meters) V = Volume of air in the flare Rm = Rf + Rt and V = pi*Rf*Rm*Rm - (pi*pi*Rm*Rf*Rf/2) + (2*pi*Rf*Rf*Rf/3) and for a vent with two flared ends: Lv = N*c*c*Rt*Rt / (4*pi*Fb*Fb*Vb) - 0.85*Rm - 0.613*Rm - 2*V / (pi*Rt*Rt) and for a vent with one flared end: Lv = N*c*c*Rt*Rt / (4*pi*Fb*Fb*Vb) - 0.85*Rm - 0.613*Rt - 2*V / (pi*Rt*Rt) I KNOW you are happy to have a lot of equations thrown at you, but this is actually relatively simple to sort out, as far as equations go. First, let's fill in the blanks I know the answer to in our simulation. We'll assume I have already measured or calculated the radius of the flare, throat, and mouth. Lv = length of the vent tube (in meters) N = 1 port c = 340 m/s at sea level Rm = mouth radius of the flare (in meters) Rt = 0.05m (approximately 2 inches) Rf = 0.025m (approximately 1 inch) Fb = 10 Hz Vb = 0.284m^3 (approximately 1 cubic foot) V = Volume of air in the flare As you can see, we are down to only three things that need solving! First, let's solve for Rm. As mentioned previously: Rm = Rt + Rf Rm = 0.05m + 0.025m Rm = 0.075m Now we move on to solving for V. This one is a bit more complicated, but still easy when we know all of the variables. V = pi*Rf*Rm*Rm - (pi*pi*Rm*Rf*Rf/2) + (2*pi*Rf*Rf*Rf/3) V = 3.14*0.025*0.075*0.075 - (3.14*3.14*0.075*0.025*0.025/2) + (2*3.14*0.025*0.025*0.025/3) V = 0.0004415625 - 0.000231084375 + 0.0000327083 V = 0.0002432 Ok, now we're getting somewhere! Let's get to solving for Lv where both ends are flared! Lv = N*c*c*Rt*Rt / (4*pi*Fb*Fb*Vb) - 0.85*Rm - 0.613*Rm - 2*V / (pi*Rt*Rt) Lv = 1*340*340*0.05*0.05 / (4*3.14*10*10*0.284) - 0.85*0.075 - 0.613*0.075 - 2*0.0002432 / (3.14*0.05*0.05) Lv = 289 / 356.704 - 0.06375 - 0.045975 - 0.0004864 / 0.00785 Lv = 0.81020 - 0.06375 - 0.04597 - 0.06196 Lv = 0.63852m Lv = 25.15" At last, we know how long the vent tube must be. There is one last step which you might find interesting. Let's say you model up an enclosure (who hasn't?). Using a straight port with a 2" radius, you notice that the vent speed is approximately 15m/s. What will be the new vent speed, now that we have flared ports? Using the values for Rt and Rm that we determined previously, we can easily calculate the change in exit velocity. Vt = 15m/s Vm = Rt*Rt*Vt / Rm*Rm Vm = 0.05*0.05*15 / 0.075*0.075 Vm = 0.0375 / 0.005625 Vm = 6.67m/s That's quite a change! From % perspective standpoint, that's a decrease of approximately 56%! Hopefully you enjoyed the little math lesson. Whether this is practical for you to learn in depth or not, it is definitely worth reading and maybe picking up some theory. If someone asks you any questions about calculating flared ports, you can answer intelligibly. Cheers!

Greetings Rob. Stick around for a while: you have great taste.

I prefer Second Cup and tea over coffee.

Any cyanoacrylate based glue should do fine. http://www.partsexpress.com/webpage.cfm?&a...p_ID=3&SO=2

It shouldn't be that much of the end process either, especially if you're making a quality, affordable sub. Don't pay attention to him I mean, show me an affordable subwoofer that doesn't use widely available stock parts and look similar to many other subs. The appearance really shouldn't matter much, and me personally, I prefer that look.

They should be posting results on the springfling website in the near future (springflingcarshow.com). If you need to know soon, send an email to Doug (organizer) at [email protected] or you should be able to get the results from IASCA over the phone at (386) 322-1551

As far as port noise and vent velocity, that is perfectly fine. I think you'll find that a fairly long port will be required (almost 30" long) to reach an Fb around 35 Hz.

They are great amps, but I was told by a friend with Carver that there was a conflict between PG w/ their Xenon line and JL Audio w/ their R.I.P.S trademark.

Break it down into sections. Top section of the T: v(1) = l*w*h v(1) = 20" * 48" * 9" v(1) = 8640"^3 Bottom section of the T: v(2) = l*w*h v(2) = 20" * 36" * 6.5" v(2) = 4680"^3 Total volume v(t) = v(1) + v(2) v(t) = 13320"^3 v(t) = 7.71ft^3

Here is an interesting thread that might get you on your way: http://www.soundsolutionsaudio.com/forum/i...?showtopic=2690

Almost forgot about Memento and Equilibrium. Absolutely stellar movies.

The port came out quite nice and your wood work looks pretty good. Now what are your plans for finishing it? Good looking enclosure!

I thought it was upload, download to a server. Where as Kazaa, Morpheous, excetera are upload, download from random people on the internet who happened to be online at the time. Nope. Sean whatever-his-name-is was a lowly college student who could never afford the server costs that would be involved in that. For example, I pay around US$80 for a dedicated server; 512mhz RAM, 160GB HDD, 100mbps (which is actually capped closer to 50mbps, but still very affordable for the bandwidth), and is totally unmetered. You would need several 100 of these to host the type of traffic that Napster was doing back then. When I get another invite, I'll send one your way. All of that stuff is on OiNK just waiting for you

Looks good so far, Aaron. People are naturally going to call it other subs because of the affordable stock parts, but I look forward to seeing and hearing more!

Just a few thoughts of my own here. Yes, increasing the length of the coil will increase efficiency; it increases BL. However, it can also increase Mms, which will decrease efficiency. There is a point of diminishing returns where you are much better off to increase BL and, conversely, efficiency by adding to the "B" portion of that equation. A positive effect of adding length to the coil is increasing Mms (yes, it is positive as well). Increasing Mms will also lower Fs, which is very handy for those who dig their low frequency response. The last negative effect of increasing L is the increase in inductance, which impacts your high frequency response and your transient rise response. For subwoofers in general, I hate efficiency ratings. If I'm using a subwoofer, I want something that can produce low frequencies adequately in a small enclosure, and here comes Hoffman's Iron Law to trounce on my dreams. I would love to increase BL or drop Mms to increase efficiency, but this will also be damaging to my Fs. If I'm buying a subwoofer, I honestly don't care how efficient it is; there are several high efficiency subwoofers that sound awful from the inherent damage that a low Q subwoofer can audibly produce. Good stuff all around!

No, a copper coil should decrease power handling minimally.