BsEMS

well.. you shouldnt get anothe sp4. b/c on a stock alt (unless you add a HUGE battery bank back there) you wont be able to power 2 sp4 sufficiently.

Before you do any changes.. ie new box, wall, adding a sub, changing amps.. UPGRADE YOUR ELECTRICAL. THeres no way your getting the spec'd rms out of that amp if you havent done all of the following. 1. BIG 3 wiring upgrade. 2. Added at least 1 extra battery. 3. Installed an high output alternator. And then Id say get yourself a 3500 watt amp. AQ, SAZ, or M3B. You will experience serious gains and it will sound like you have a new system all over again. :cheers:

Ohh ok, I have an sp4..and my design is on the forum.. its a basic slot port.. I keep it simple, clean, and LOUD!

You should have already invested in a fire extinguisher if you have any type of high(er) powered audio installation. Shit happens.

Me personally, I only used two charts to design my box. Rear port velocity, to show what the speed of air would be exiting the port at each frequency, and the graph that displays the output bandwidth. The others I didnt find usefull, or I just didnt understand quite well enough. With those two you can play with your tuning and see how it effects the output bandwidth of the design, and how much stronger/weaker the port velocity is at your desired range of frequency.

Nice design! From the 1st box designs.. i dont get the"4th port wall" area.. what the point of having that little box'd out area? THen i see its changed in your 2nd dwg.. .but as far as the 45degree corner slabs.... ive read that they actually hurt spl numbers when put in corners that have nothing to do with helping the port flow.

I got it to work. Must have been the jobs' computer internet limitations.

Im going to try and be brief.. since I'm at work. (One of the very few sites I have access to!) I used WinISD to play with output numbers. Of those, I valued port velocity::frequency ratio. And I tried to configure a flat response bandwidth while keeping my desired tuniing @ 29hz. Quick specs: 1. Its a trunk build ( 4 door camry) 2. substage amp VFL 150.1 3. Rear firing design // 15" SP4 with electrical to boot. 306A - 274A alt (Hot). 306A Peak (cold) . 178A Hot @ idle I can post more details on Port volume later, I left the last dimension of port length at home. But what your seeing is port depth 17.25, height 15.5, length is somewhere between 26.xx to 28.xx. I cant remember off top. What has been changed though is the front wall 2nd baffle will be extended to the left to eliminate that 1" gap between it and the interior port wall. And also will be changed the front enclosure wall will be cut to extend over the right side wall and left slot wall. So when I fasten the walls the screws will sit parallel with the subs linear force, not coming in from the sides of the enclosure walls. I dont think I'll need any bracing. With the 2900 watts...and not a large sized box with the slot port acting as bracing all I will do really is glass the kerfs. And if I want overkill Ill reinforce corners with more GRP. All thats left for me to do is build a prototype enclosure from cardboard and make sure she fits through the opening of the trunk. And possibly make the radius of the inner port wall larger to make it less of a degree turn to create a smoother flow of air. If you dont like my dwg.. tell me, I dont care lol. Im open for any and all input. Thats how we learn isn't it. Whether you have 1 post or 100000 posts.. im game for listening to opinions.

I guess a single page pulled from a book with a couple pictures is a lot to read these days.If you clicked on the link you would see a page refrenced lol LOL. man when I clicked the link it took me straight to the cover page. And yes..there was two pictures on it! B-)

I'd love to sit and read all of that. But cant right now. What chapter or page references what we're discussing?

Minor change- I will tune a bit higher @ 32-33 hz. Doing this should gain overall output and lose very little low end.

 How is this so? I assume kerfing the inner port wall (opening) would kind of act in a expanding wave type deal. But if only at the edge..how would an inch or so distance of port opening kerf be more effective than kerfing the entire inner wall(s) of the port? My goal with kerfing is to create a more efficient path for air to travel, increasing port air velocity and lessening resistance from the traditional 90degree L-Port design. I am not an engineer in fluid mechanics but I would think it would be more beneficial to decrease turbulence at the mouth of the port. Any bends throughout the port length are typically cut at a forty five degree angle to reduce turbulence. Which is standard practice for many speaker enclosure designers. What is most important is that your port is properly designed for your enclosure. Is there legitimate turbulence at the mouth though? I dont know. I assumed since it is coming from a confined space into an open space that turbulence(resistance to flow?) would be minimal at the mouth. But yes, I did try to calculate port volume as accurately as possible for my setup.

I seriously considered dowel rods.. but only b/c i see a lot of builds with them. But if I take into account the largest "empty" space of my box w/o bracing is going to be around 33 x 12 inches of area. Theres no way that small space will need extra support, especially if the sub isnt going to be mounted on top the box.

I've already built a mock-up. And the only adjustment I made was having total height at 16.75 instead of 17. And it fit like a muthfreakin glove. 40" wide fits just perfect into the trunk opening. I bought some cheap 3/4 cello foam from Home Depot, got a straight edge + a retractible blade. And cut, taped it to perfection. It turned out to be a solid representation of my enclsure... all dimensions falling within 1/16 to 2/16 tolerance (due to the density of the foam board and the cleanliness of the cuts)

How is this so? I assume kerfing the inner port wall (opening) would kind of act in a expanding wave type deal. But if only at the edge..how would an inch or so distance of port opening kerf be more effective than kerfing the entire inner wall(s) of the port? My goal with kerfing is to create a more efficient path for air to travel, increasing port air velocity and lessening resistance from the traditional 90degree L-Port design.

wait a minute.. ( i just caught up on the thread). You DONT want to unscrew the sub and LOOK at the spider and or tinsel lead / cone connection point? you must not really be worried about it. The woofer showed you signs of malfunction..but you ignored them and didnt evaluate the problem other than writing emails to FI. Now it has worsened to a point where there is a safety issue within your vehicle...and you STILL dont want to unscrew it and see what is happening? I really hope you car stays safe, but If i were you, I wouldnt put my health, my cars health, my sound systems health, in jeapordy soley because im too lazy to remove the sub and re check wiring.

"judging by the amount my lights dim there is quite a bit of current flowing" I think this means your current ISNT flowing correctly. Becuase its drawing power from the cars power bank, somewhere that it shouldnt. Let me rephrase that..it might not be flowing incorrect, but it damn sure isnt flowing efficiently.

That funny, because I was very pleased with how my sp4 was shipped.. foam surround protector, lower foam magnet seat, plastic bag, birch crate and even the cardboard box was in very good condition. I guess it depends on what FedEx loader/unloader handles your sheit. I dont know if it complies, but maybe Fi should mark their boxes fragile? Even though its crated and protected.

what nemesis said. I'd put it back in the box exactly how it came, take a thousand pictures in sequence of you removing it from the box. Of course keep all packaging stuff.. then test it out completely.

I ordered on March 1st... and will lay eyes on it tomorrow finally. The wait isnt bad at all if your patient..and it sounds like you are. But I can say that you wont wait as long as I did, they have new customer service support and i believe they are recovering day by day from being jammed with orders. So if you believe them, then you should be guaranteed to get it before 7 weeks. Can you upload your WinISD image of the box design? I ordered the 15 sp4..and too have used winISD to calculate box design. Mine is tuned to 29.... Im going to post about it and the enclosure dimensions to get 2nd opinions, b/c when looking around... a lot of ppl have huge port areas. While mine doesnt seem to be as large.

Look into the rules and regulations on how to perform an insurance claim with FedEx. Dont call and ask them, do it on your own. I know when I claimed insurance w/ UPS (when they damaged my AGM battery) some of the things you had to have (and im going off memory) was: a certified box that was regulated to hold that amount of weight, 2-3" padding around, less than 1" space between box and item inside (after padding) and stuff like that. Make sure you read ALL of the rules. Then take pictures of how the sub was packaged correctly. And if it wasnt, maybe Nick and FI could send you some pictures of one that IS packaged correctly. Then you could open that claim and possible help FI helf you get a sub replaced w/o having FI or yourself pay out of pocket. It may take a few weeks, but if your determined then go for it.

FedEx is the best of the 3. USPS UPS FedEx. I shipped a PS3 wrapped in bubble and foam.. and the recipient said the box arrived with a 4-5" hole in the corner of it. As if it was dropped on it corner several times, got wet, then ripped up. UPS is the worst company to use. ALWAYS use the highest shipping insurance..and make sure you read the rules on how to package using them b/c there's specific clearance levels that you have to be within on the interior of the pkg to be accpeted by there insurance claims. Its a hassle.

OUCH. I hope it works out for you bro. I understand the anxiousness of waiting weeks and weeks..then the feeling you had when you saw the crack.

So what happened to Shawn He didnt say, and I didnt ask. I dont think its our business why he isnt working THE tposition anymore. As long as my shi*t is on order and in route..that all I needed to get half mast

Your port length is 34