Triticum Agricolam

Where did you have you + & - test leads attached to? You are probably seeing combined power.

How much power are you running?

Awesome, glad to know it was an easy fix!

Did you make sure they are wired in phase? Easy mistake to make.

So is this a prefab box then?

Its close enough, you may be giving up a little bit of output around tuning due to the smaller box, but I wouldn't lose much sleep over it. How much port area does the box have? An undersized port will cost you a lot more output than the box being .5 cubes smaller than ideal.

Amplifiers are not really my area of expertise, but here is my understanding. Adding more batteries will NOT allow you to turn your gain up any higher. It will just allow you to maintain the same level of output for a longer duration (with less voltage drop). The reason is amplifiers have a maximum voltage they can put out (which is produced by the power supply section of the amp board). Once the output voltage reaches that max voltage this is when they start to clip. Adding batteries will not increase that max voltage, so you won't be able to push your amp any harder, it will just allow you to draw more current for longer.

Well unfortunately there really no way to "get around" it without paying a performance penalty somehow. Welcome to the difficult part of car audio enclosure design :-) Whenever you are dealing with a situation where your space is limited, which is most of the time with car audio, the trick is figuring out what design compromises can be made that will have the least negative impact on performance. No matter what you do, performance is going to have to be sacrificed in some way, we just find to find the best way. One thing you can do is decrease port area. This won't hurt performance at all at low volume, but at high volume it will eat your output for lunch. It can be quite detrimental. Another thing you can do is reduce box volume, this will decrease output around tuning at all volume levels, but it will do so consistently, unlike reducing port area. You can also tune higher, higher tunings require shorter ports, so you will save some space that way, also with higher tunings you can get away with smaller box sizes. The price you pay is decrease low frequency performance. Depending on the type of music you listen to tuning higher may or may not be a path you want to go down. Lastly, you can reduce cone area, by either running smaller subs or running less subs. In your case dropping down to three SA-8s may be something to consider.

Yeah with a single 3" port you would pretty much have a sealed box, whether you want to or not. While 15 sq in per sub may sound like a lot, to put it in perspective Sundown recommends 8-12 sq in for their E-8 sub, and thats and 300 watt RMS sub. You are going to be (potentially) running 2.5 times as much power. At tuning all of the output comes from that port, you don't want to be choking it off. I think your idea of a single 8" port would be great. Here is a calculator that you can use to give you an idea of proper port size: http://www.carstereo.com/help/Articles.cfm?id=31 With high Xmax subs (18mm or greater) that calculator tends to error on the high side, but its a starting point at least.

No prob. When you are working on your design, make sure you use enough port area. It can be tricky to do with these smaller boxes. For a SA-8 on 750 watts I'd use no less than 15 sq in per sub.

1/2 material can work well, but you have to do it right. First off, don't use MDF, use real baltic birch plywood, its a lot stiffer than MDF. Home Depot won't have it, you have to get it from a plywood supplier. I pay about $32 for a 5' x 5' sheet of it. Secondly, you will need to brace it well. Try to keep unbraced spans less than 10". I've built quite a few enclosures out of 1/2" material, it works fine as long as you approach it correctly.

Since this is going under the seat of a pickup that makes it a tougher choice. If you are going to be using a DSP, I'd be inclined to go with the four SA-8s. You can use the DSP to fix their biggest drawback, which is peaky response. An alternative would be to use a couple higher power handling 10"s. A pair of FI SSD 10's would work well too, but then they would have to be down firing, which complicates things.

Big question, how much power are you going to run? That is going to greatly affect what subs you should pick and how flat of response you can achieve. Here are some things to think about: 1. Ported boxes boost output around tuning. Once you get about an octave above tuning, the port has no effect. So at 70 Hz a 25 Hz tune is going to sound exactly the same as a 32 hz tuning. 2. The larger you make a ported box, the more boost in output you get, but only around tuning. If you want smoother frequency response, making the box smaller is one way to do that. 3. If you care about frequency response, don't run 8" subs unless you can't fit anything else. The problem with 8" subs is if they have moderately high power handling (which for 8"s is anything above 300 watts RMS, IMHO) they generally have really stiff suspensions and high motor force to cone area ratios, both of these things are bad for getting smooth frequency response. Compared to larger subs 8" subs will also have limited Xmax due to the fact that you can only fit so big of a spider on them. I'll say it again, there is no reason to run 8" subs if you can fit something larger. 4. If you are after smoother frequency response there are several ways to accomplish that goal. - Run larger subs, larger subs GENERALLY have lower motor force to cone area ratios, makes it easier to get smoother frequency response. I'd take one 15" over two 12"s or three 10"s almost every single time. - Make the ported box smaller. Smaller ported boxes boost the low end less, making it much less likely you will end up with peaky response. - Run sealed. With a sealed box you don't get any low frequency boost. The low end roll off of a proper sealed box closely matches the cabin gain you get in most vehicles, giving you pretty flat frequency response. - Do like strangeduck suggested and run a ported box and EQ it flat. This is the mostly complex option, but its also the most flexible. You can get whatever frequency response you want and you can change it around really easily. Just keep in mind its easy to turn down peaks with EQ, its almost impossible to fix dips in output though. DSP/EQ is pretty cheap these days, you can get a miniDSP for a little over $100. This is what I'm doing in my own vehicle. If I were in your shoes I'd probably try to cram two 12"s subs in a ported box if at all possible (what's the max dimensions of your space?), if its not go for two 10"s. I'd be picky about what subs I used and I'd probably use EQ to dial in exactly how it wanted them to sound.

Get WinISD, its free, you can get it here: http://www.linearteam.org/download/winisd-07x.exe For box layout you can use SketchUp, its also free.

I have an E12v2 that I have been very happy with. My build is more SQ focused but I'm using mine in a 1.5 cu ft box tuned to 28 Hz on about 600 watts of power. Works great.

I haven't had the issue yesterday or today yet, so maybe its resolved. Time will tell. I'll post back in here if it happens again.

So I've been having this ongoing issue where I can't reply to posts or PMs. I'll type out my reply but when I click the "Post" button I get the little status bar at the top of the screen, but nothing ever happens. After a minute or so the status bar goes away and its like I never clicked "Post" at all. I would say I have this problem at least 50% of the time I try to reply to something. Its SUPER frustrating. The really odd thing about this problem is it only happens on my desktop computer. On my laptop (or phone) I NEVER have the issue. I mostly use Chrome on my desktop, but I've tried IE and I have the same issue. I've tried clearing all my cookies for stevemeadedesigns.com but it made no difference. I thought it might be some weird DNS caching issue so I tried clearing my DNS cache/rebooting, didn't help either. At this point I'm at a loss, it been going on for quite some time (over a month) and everytime it happens I want to stab something. Does anyone have any idea what my issue might be? Has anyone experienced this before? Ironically when I first tried to post this thread it failed. im having to post this from my phone.

+1 to what Reedal said. Also, another thing to keep in mind is running a sub on a 1000 watt amp, and actually putting 1000 watts to it aren't the same thing. How much power its actually getting and the overall power handling of a sub are incredibly situationally dependant, which is one of the reasons SOME people can get away with putting what seems like a lot more than RMS power to a sub.

I haven't looked at the specs but it may be that sub has lower Vas (tighter suspension). Lower Vas subs need smaller boxes, though they also have lower efficiency due to that.

Nice! I totally have dust collector envy now. I'm just using a modified Harbor Freight one. I have a couple Glu-bots and I love them! They aren't the best for everything but now that I'm used to using them I'd never give them up.

I've used Rage Gold Extreme and Z-grip. Both are WAY better than Bondo. The Rage Gold seems to go on a little smoother than the z-grip, but I'm not sure its worth the extra expense. Z-grip seems to do the job pretty well.

That's awesome you got it playing, you will have to let us know how it sounds when you get it all dialed in!

That's awesome! Could you tell me what song that is please?

No, your other option was to sell the 12" and get two 10"s so you could do it right, but hey man, it's your journey. Hopefully it works out OK for you. Keep the pics coming.

I agree with CJ18 and I think some type of slot ported box is going to be your best bet. You have a lot more design flexibility with slot ports so you should probably be able to fit enough port area in there vs what you can do with an aero port. Also, due to the way common wall slot ports work, a slot port will be shorter than an equivalent aero port of the same tuning.