Size vs quantity help

[Triticum Agricolam]

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.

[Smoove]

Lots of 10's

http://www.stevemeadedesigns.com/board/topic/118875-audiotistics-astro-64-tens-rockford-fosgate-build/?hl=audiotistics

[somebodyelse]

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.

I'm planning on buying a sundown amp to match subs, but due to electrical requirements I'm thinking of not passing 3000 watts RMS.

I just drew up my box a 3d model and calculated volume after MDF material displacement and I have about 2.5 ft^3. If I made the box more complicated to fit around seat brackets in my crew cab I can claim up to 3ft^3 after material displacement.

If I go with anything bigger than 8" sub then it becomes down facing instead of forward facing and mounting depth becomes important. If it is less than 6" depth it works, and works with 2.5 to 3 ft^3 of air. Its basically a custom truck box in a 2016 silverado crew cab with a rear seat lift of 2 or 3 inches, preferably only 2 inch seat lift.

Ported I can do 4 8" subs of any kind (assuming I have enough box volume)

Or I can do 2 10" subs or 1 12" sub.

Sealed I can still only do 4 8" subs and 2 10" subs, but possibly 2 12" subs if they are less than 7" depth and magnet isn't too wide.

What say you triticum? I was thinking 4 8" sa's would blow away a single 12 or 2 tens if I can handle the power demands.

And also I will be going full active with a DSP, I'm thinking audison bit one, so it is feasable to eq them flat for quality on one setting and then set it to dubstep dirty on another pre set.

[yurvalentine]

Single Havoc 12 ported

[somebodyelse]

Single Havoc 12 ported

I like the specs but I didn't see a mounting depth on the online store, I'll have to search from a PC I think. I also saw the mayhem, a 2500 watt 12 inch sub but I doubt I could make it fit. Would be sick though.

Would The havoc really destroy 4 sa8's? But the cone area of 4 8" is greater than a single 12. Too bad I can't borrow subs, boxes only cost one sheet of MDF for testing.

[Triticum Agricolam]

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.

[somebodyelse]

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.

I'll check out the fi ssd 10" subs maybe that could work too.

One more question. How bad would it be to go with 1/2 inch MDF instead of 3/4. I'm not being cheap it really has to do with available volume, 3/4 inch MDF requires me to lift the rear seat 2.5 inches where I can get away with a 2 inch lift with 1/2 inch mdf.

[Triticum Agricolam]

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.

[Allen Lancos]

Lol... my wife walked by stopped and read the topic of this thread, laughed, started to walk off and said "uhhh size duh"!

Just thought that was funny and figured maybe someone else would get a kick out of it. Her mind stays in the gutter but I love her

[somebodyelse]

I've built quite a few enclosures out of 1/2" material, it works fine as long as you approach it correctly.

Good to know it can be done, I'll try to source some real Baltic birch and add bracing to the design, if it works well I may have a well drafted set of plans to share when I'm done