Making the most out of the power and available airspace!?

[Chase Wallace]

2 minutes ago, Joe X said:

It's bass box pro but it's commercial, what I pointed out at the end is that you actually save space (1.25 net) going with two 10s rather than one 15, if you don't mind the cost the two tens would be the space saving alternative in this case.

Yeah, you have a perfectly good point and that's what's reversed my thinking on using bigger subs. I can get more cone volume with less airspace. In THIS situation though the two EV3 10's cost less than a single SA-15. They are also easier to fit in the tight spaces of this box design. Also I have to factor in the cost and if I'm only using say two 15's then those 15's need to handle about 2000 watts each or even slightly more as my amp tested out at over 4800 RMS certified.

Subs that can handle 2000 RMS  cost an insane amount. The EV2 10's cost about 87$ where as the higher end subs that can handle 2000+ watts are like 500-700$ range. It's actually cheaper to buy say eight 10's in this situation because the 10's I would use would be discounted. So this is a rare situation where multiple subs would be cheaper. When trying to use 1-2 subs that single sub needs to handle 4000rms and two subs would need to handle 2000 watts each. Subs with a power handling that high are super expensive. One sub that's rated for 2000 watts cost around 700$ Eight EV 10's that are discounted cost roughly 700$

[Triticum Agricolam]

8 minutes ago, Chase Wallace said:

Yeah, you have a perfectly good point and that's what's reversed my thinking on using bigger subs. I can get more cone volume with less airspace. In THIS situation though the two EV3 10's cost less than a single SA-15. They are also easier to fit in the tight spaces of this box design. Also I have to factor in the cost and if I'm only using say two 15's then those 15's need to handle about 2000 watts each or even slightly more as my amp tested out at over 4800 RMS certified.

Subs that can handle 2000 RMS  cost an insane amount. The EV2 10's cost about 87$ where as the higher end subs that can handle 2000+ watts are like 500-700$ range. It's actually cheaper to buy say eight 10's in this situation because the 10's I would use would be discounted. So this is a rare situation where multiple subs would be cheaper. When trying to use 1-2 subs that single sub needs to handle 4000rms and two subs would need to handle 2000 watts each. Subs with a power handling that high are super expensive. One sub that's rated for 2000 watts cost around 700$ Eight EV 10's that are discounted cost roughly 700$

You don't need 2000 watt RMS rated subs to handle 2400 watts of amp power.  Quality 1500 watt RMS rated subs would work with your amp just fine.  Music is dynamic so your subs would only be seeing the full 2400 watts for brief periods of time, if ever.  

There are plenty of 1500 watt rated subs that are under $300 a piece, which would put your total cost under what eight E-10s will cost you.  

[Chase Wallace]

41 minutes ago, Joe X said:

It's bass box pro but it's commercial, what I pointed out at the end is that you can actually save space (1.25 net) going with two 10s rather than one 15 and get the same output.

I see, the problem with that is more or less power handling and money. I think you oversimplified it by not saying which cost more. A subwoofer that can handle 2000-4000 watts cost an insane amount. I think you're getting into the 1000$ +range for subs that can handle that much power. The 8 EV's cost right under 700$ Where as if I were to get 2 15's then with a 2000 watt rms  power rating they will probably cost 800-1000+ range. In this case I would be spending around 1800$ for on 2 subs. The 8 10's would cost lest than say two 15's rated for 1500-2000 watts and the 10's have a good bit more surface area. I mean when we look at subs that can handle 2000+RMS they cost way more and it starts getting more cost effective to use more and cheap subs.

[ShadeTreeMechanic]

Personally I wouldn't hesitate to give a sub double its rated power in a properly tuned box. With impedance rise taken into account, the subs won't see the amps full output. 

[Chase Wallace]

Guys I'm not completely new to this. I have a DD-1 to set the gains right and I'm not afraid to over power a sub either. I was just trying to get the point across that I would need more expensive subs if I'm going to sent the full power of the amp to 1 or 2 speakers. I'm fine with sending 1200 watts to an SA v3 or 2400 watts to the Xv2 series but my point was that if I deiced I was going to just use two subs and give them 2400 I would use the X v2 or ZV3 if I stuck with Sundown. There is a huge difference in the price of the EV series and the ZV3. This is all so off topic from what I was trying to ask though.

[the_garynator]

On 5/25/2017 at 11:03 PM, Triticum Agricolam said:

Ok, so when comparing four subs vs eight.  Lets assume you are using the same subs.  Lets assume you have four 10" subs in a 6 cubic foot box vs eight 10" subs in a 12 cubic foot box.  Tuning is the same. Your four subs are D2 coils so you can wire them to 1 ohm at the amp, your eight subs are D4 coils so they are also wired to 1 ohm load at the amp.  Other than that the subs are identical.  The setup with eight subs SHOULD be about 3 db louder because you have twice the cone are AND twice the box volume.  In practice it probably won't be exactly 3 db louder, but it should be somewhere in that area.  

Now you were talking about using different subs in your "four vs eight" comparison.  With different subs things are...different.  Generally speaking lower power subs tend to be more efficient due to their lower moving mass, there are exceptions though.  This would PROBABLY shift the advantage even more towards the eight sub setup.

You are making an error in your cone area calculations.  The problem is the radiating area of a sub isn't the same as it nominal diameter.  A 10" sub has a cone that is more like around 8-1/8" in diameter, there is some variance between different models of subs.  At 15" sub has a cone that is around 12-3/4" in diameter.  So when you are comparing cone area between different sized subs, here are the numbers that are more accurate:

8" sub = 32.5 sq in

10" sub = 48 sq in

12" sub = 79 sq in

15" sub = 125 sq in

18" sub = 188 sq in

Not all subs are exactly the same, depending on the size of the surround there is going to be some variance between different models of subs with the same nominal size, but those numbers will give you a lot more accurate comparison.

Are you using the physical cone diameter to calculate those numbers? Because radiating area generally should be the diameter of the cone and half of the surround from everything I've seen. This is why the cone area loss for subs with ridiculously huge surrounds, like some sundowns, isn't a huge disadvantage since the radiating surface only loses half of added width of the surround from its diameter.  I.e. radiating surface diameter of a 12" with a 1" wide surround would be 11" and a 12" with a 2" surround would be 10". 94in^2 vs 78.5in^2.

[Chase Wallace]

Guys using WinISD, I'm having trouble trusting the results I'm getting from it. It seems when I change the sub diameter in the parameters it doesn't change the plot graph at all... in fact I just changed a bunch of the parameters and still got no change in the graph. What gives?

[Joe X]

Post which subs are you considering and some screenshots of the results you are getting, parameters and plots to see what's going on.