New box, over double the port area, sounds the same :/

[kirill007]

Did you find the problem?

[RooTxBeeR]

I haven't heard it myself yet, he said it had gotten louder but not a bunch. Only thing that threw me off was I was expecting it to be louder than my 2 ivx' 15s on barely 700 watts. I know I have double the cone area, but would nearly 5x-7x the power, shouldn't the dd be louder?

[Esgedi]

Did i miss something? This thread started with port area and now we're talking about gain overlap. o__o

I haven't heard it myself yet, he said it had gotten louder but not a bunch. Only thing that threw me off was I was expecting it to be louder than my 2 ivx' 15s on barely 700 watts. I know I have double the cone area, but would nearly 5x-7x the power, shouldn't the dd be louder?

Not really. When you double cone area, if everything's jiving correctly you gain 3dB throughout the range, which is essentially inaudible.. Cone area doesn't really mean anything, what's important is the sensitivity. A 1 or 2 dB difference in sensitivity can make up for double the cone area, and input power is an exponential loss. Going from 500w of input power to 5000w is only enough to double your output, assuming you don't have cabin losses.

[RooTxBeeR]

Did i miss something? This thread started with port area and now we're talking about gain overlap. o__o

I haven't heard it myself yet, he said it had gotten louder but not a bunch. Only thing that threw me off was I was expecting it to be louder than my 2 ivx' 15s on barely 700 watts. I know I have double the cone area, but would nearly 5x-7x the power, shouldn't the dd be louder?

Not really. When you double cone area, if everything's jiving correctly you gain 3dB throughout the range, which is essentially inaudible.. Cone area doesn't really mean anything, what's important is the sensitivity. A 1 or 2 dB difference in sensitivity can make up for double the cone area, and input power is an exponential loss. Going from 500w of input power to 5000w is only enough to double your output, assuming you don't have cabin losses.

That's why I'm confused on it. I'm not expecting to be doing hair tricks or unable to breath when it first hits, but I would expect a single 15 on 3k to be louder than 2 15's with much less Xmax on 500, but it's not.

[Triticum Agricolam]

Lower RMS subs generally have less moving mass, which help increase efficiency as well. So that combined with the great cone area, and I assume a much larger box, it doesn't surprise me the two 15"s do as well as they do compared to the single higher powered 15".

[RooTxBeeR]

Lower RMS subs generally have less moving mass, which help increase efficiency as well. So that combined with the great cone area, and I assume a much larger box, it doesn't surprise me the two 15"s do as well as they do compared to the single higher powered 15".

So would you say if I would want to attempt to make it as loud as possible, what aspect of the box should I go with first? I would think try to shrink the box a little bit and increase the port area. Am I right there?

[reedal]

Decreasing the volume will decrease efficiency, making it quieter, but giving it better mechanical control and a flatter response.

Increase the volume for more output around tuning due to being more efficient, but at the price of less bandwidth, and less mechanical control on the same power.

[Triticum Agricolam]

So would you say if I would want to attempt to make it as loud as possible, what aspect of the box should I go with first? I would think try to shrink the box a little bit and increase the port area. Am I right there?

Its hard to give you a straight answer because it depends on what the limiting factor of the system is now, and everything is a trade off.

So when it comes to port area there really are only two kinds of ports, those that detrimentally restrict airflow, and those that don't. Obviously you want your port to be in the second category. Once it's big enough to not restrict airflow, making it any bigger won't have any effect other than to take up more space. So the trick is making sure you have enough port area to not restrict airflow, but not make it so big it wastes box space. If your port is bigger than it needs to be, shrinking it down so you could gain more box volume could be beneficial, but only if you gain box volume by doing so. If your port is too small, port compression can REALLY kill output, so making the port bigger at the expense of box volume would probably gain you some output, sounds like you have plenty of port area though.

As far as box size goes, the bigger you make the box, the more efficient it will be around the tuning frequency and the more output you will get. The trade off here is as you make the box bigger your cone excursion goes up, so you have to be careful with that. Also group delay goes up and the frequency response becomes more peaky, both of which negatively affect sound quality, which may or may not be important to you. As far as box size, output, and cone excursion go, let say you have two boxes, one is 3 cubes and the other is 5 cubes, both are tuned to 35 hz. With the 3 cube box you can hypothetically put 2K watts to it before you run out of excursion, the 5 cube box you can only put 1700 watts before excursion gets too high. The 5 cube box will get louder around tuning on 1700 watts than the 3 cube box will on 2k (at least in theory). Also the 5 cube box will be easier on your amp since it will have slightly higher impedance. However the 3 cube box will sound better and as you get away from the tuning frequency they are both going to have about the same output.

My recommendation would be if you haven't adjusted his gain overlap from 0 to -5 or so, you should do that first. -5 should still be a pretty safe level and will result is almost 4 times as much power going to the sub than a 0 setting would. Things like making the box volume bigger will increase output, but its not going to be by much. You would never hear the difference between a 4 cube and a 4.5 cube box for example.

[RooTxBeeR]

So would you say if I would want to attempt to make it as loud as possible, what aspect of the box should I go with first? I would think try to shrink the box a little bit and increase the port area. Am I right there?

Its hard to give you a straight answer because it depends on what the limiting factor of the system is now, and everything is a trade off.

So when it comes to port area there really are only two kinds of ports, those that detrimentally restrict airflow, and those that don't. Obviously you want your port to be in the second category. Once it's big enough to not restrict airflow, making it any bigger won't have any effect other than to take up more space. So the trick is making sure you have enough port area to not restrict airflow, but not make it so big it wastes box space. If your port is bigger than it needs to be, shrinking it down so you could gain more box volume could be beneficial, but only if you gain box volume by doing so. If your port is too small, port compression can REALLY kill output, so making the port bigger at the expense of box volume would probably gain you some output, sounds like you have plenty of port area though.

As far as box size goes, the bigger you make the box, the more efficient it will be around the tuning frequency and the more output you will get. The trade off here is as you make the box bigger your cone excursion goes up, so you have to be careful with that. Also group delay goes up and the frequency response becomes more peaky, both of which negatively affect sound quality, which may or may not be important to you. As far as box size, output, and cone excursion go, let say you have two boxes, one is 3 cubes and the other is 5 cubes, both are tuned to 35 hz. With the 3 cube box you can hypothetically put 2K watts to it before you run out of excursion, the 5 cube box you can only put 1700 watts before excursion gets too high. The 5 cube box will get louder around tuning on 1700 watts than the 3 cube box will on 2k (at least in theory). Also the 5 cube box will be easier on your amp since it will have slightly higher impedance. However the 3 cube box will sound better and as you get away from the tuning frequency they are both going to have about the same output.

My recommendation would be if you haven't adjusted his gain overlap from 0 to -5 or so, you should do that first. -5 should still be a pretty safe level and will result is almost 4 times as much power going to the sub than a 0 setting would. Things like making the box volume bigger will increase output, but its not going to be by much. You would never hear the difference between a 4 cube and a 4.5 cube box for example.

I want to ask this first, it still is, the larger the more port area, the more output you will have and in turn have less bandwidth. As well you can do the inverse with less port area? Because if so it is the perfect bandwidth currently, don't want to make it any less.

Well when I was asking about that, I meant in the aspect. A new box will be built, not modifying the current to change it. To what you said, I think the only thing that could help this, is to make the box bigger, because as the first sentence asked, if that is true. I do not want to have any less of a bandwidth to it.

[ShadeTreeMechanic]

It depends on what the limiting factor is. If you increased the port area and it made no change then the port is not what is holding it back. You can increase box volume and the efficiency of the port will go up. How would it sound? Only one way to find out for sure.