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bass-aholic
12-15-2009, 02:53 PM
When following the rule 12-16 inches of port per cubic foot what is the difference between going on the low side of 12 or the high side of 16. Does more port area mean it will be louder? If i have 15.77cuft for 4 15"s how much port area should i have? Thanks in advance!

fasfocus00
12-15-2009, 02:55 PM
When following the rule 12-16 inches of port per cubic foot what is the difference between going on the low side of 12 or the high side of 16. Does more port area mean it will be louder? If i have 15.77cuft for 4 15"s how much port area should i have? Thanks in advance!

do you need a calculator?

Bumpin' Goalie
12-15-2009, 02:57 PM
i believe OP wants to know the diff between 12-16

bass-aholic
12-15-2009, 02:59 PM
do you need a calculator?

No fucktard, maybe if you read the question you would understand what i was asking. If i should go with the 12-13 or 15-16 square inches and what the difference was but thanks for another pointless post...anything to kill time with your pathetic life.

bass-aholic
12-15-2009, 03:00 PM
i believe OP wants to know the diff between 12-16

yes that is correct

SPLluminator
12-15-2009, 03:07 PM
No fucktard, maybe if you read the question you would understand what i was asking. If i should go with the 12-13 or 15-16 square inches and what the difference was but thanks for another pointless post...anything to kill time with your pathetic life.

The low side tends to be more punchy, the high side tends to be more boomy. As for loudness, it depends on the sub, if its got really loose suspension then typically a smaller port is needed if you throw more than rated at it, and some stiffer subs like huge ports to unload completely it also has a lot to do with your setup tho.

bass-aholic
12-15-2009, 03:21 PM
The low side tends to be more punchy, the high side tends to be more boomy. As for loudness, it depends on the sub, if its got really loose suspension then typically a smaller port is needed if you throw more than rated at it, and some stiffer subs like huge ports to unload completely it also has a lot to do with your setup tho.

Alright i understand, Thank you!

PV Audio
12-15-2009, 04:24 PM
No fucktard, maybe if you read the question you would understand what i was asking. If i should go with the 12-13 or 15-16 square inches and what the difference was but thanks for another pointless post...anything to kill time with your pathetic life.
Take it easy, you have no business getting upset.

PV Audio
12-15-2009, 04:27 PM
The low side tends to be more punchy, the high side tends to be more boomy. As for loudness, it depends on the sub, if its got really loose suspension then typically a smaller port is needed if you throw more than rated at it, and some stiffer subs like huge ports to unload completely it also has a lot to do with your setup tho.
I don't know where you heard this, but it is not true. The airspace and tuning of the enclosure is going to determine the frequency response, not the variation of the area of the vent all things considered. There are numerous types of vented enclosures out there, none of which I am going to go into, but they are all based on the Vb as a function of the Vas of the speaker, Qts, Sd, Xmax, as well as the Fs. The port area, not so much.

The larger your port, the less its ability to act as a resonator and the more it begins to act like a transmission line. If you have too much port area, you are going to lose output due to cancellation of the backwave. A smaller port won't make anything punchier or a bigger one boomier. That isn't true.

SSS 18734
12-15-2009, 04:31 PM
You're unlikely to hear much, if any, difference between a box that has 12 in^2 of port per cube as opposed to one that has 16 in^2. The internal airspace of your box will have a much greater effect on the response.

If you're not going for competition, just make the port that fits your space requirements and keep it within those "rule of thumb" guidelines.

basscort2009
12-15-2009, 04:33 PM
pretty much should always use 16 for daily and about 20-25 inches of port for competitions and numbers. 12 is just meh...

Boomintempo
12-15-2009, 04:35 PM
Not to thread-jack here, but I was wondering about port area and a bandpass.

People recommended something crazy like 80 sq in of port area for my bandpass...but I only had room for around 40 sq in of port. The sealed portion is 2 cubic feet while the ported portion is 2.5 cubic feet. The box sounds great, but has me wondering what it would've sounded like if I could've gotten that 80 sq in of port.

thehardknoxlife
12-15-2009, 04:41 PM
I don't know where you heard this, but it is not true. The airspace and tuning of the enclosure is going to determine the frequency response, not the variation of the area of the vent all things considered. There are numerous types of vented enclosures out there, none of which I am going to go into, but they are all based on the Vb as a function of the Vas of the speaker, Qts, Sd, Xmax, as well as the Fs. The port area, not so much.

The larger your port, the less its ability to act as a resonator and the more it begins to act like a transmission line. If you have too much port area, you are going to lose output due to cancellation of the backwave. A smaller port won't make anything punchier or a bigger one boomier. That isn't true.A simple "No, stupid" would have sufficed. It's the CA.com way, I think.

Enough of the technical babble. The difference between 12" and 16" of port per cubic ft is not going to be noticed by a human ear. It probably would with a bunch of woofers but I doubt it even then. Only on a meter.

You guys think too much.....

SicAudio
12-15-2009, 04:46 PM
I don't know where you heard this, but it is not true. The airspace and tuning of the enclosure is going to determine the frequency response, not the variation of the area of the vent all things considered. There are numerous types of vented enclosures out there, none of which I am going to go into, but they are all based on the Vb as a function of the Vas of the speaker, Qts, Sd, Xmax, as well as the Fs. The port area, not so much.

The larger your port, the less its ability to act as a resonator and the more it begins to act like a transmission line. If you have too much port area, you are going to lose output due to cancellation of the backwave. A smaller port won't make anything punchier or a bigger one boomier. That isn't true.
so very true PV


pretty much should always use 16 for daily and about 20-25 inches of port for competitions and numbers. 12 is just meh...

you do not know much about box designs or Thiele / Small paremeters i take it?
i have seen and built hundreds of small and large enclosures with less than 8 sqin per cubes that had 0 port noise and played just fine. the "port rule" is more typical to spl anyway not daily. the box is a big resonator the more port you have the less control of the cone you have and lower the mechanical power the sub can handle because it unloads faster. with huge ports like 25 sqin per cube you may as well just do an IB build.

PV Audio
12-15-2009, 07:02 PM
A simple "No, stupid" would have sufficed. It's the CA.com way, I think.

Enough of the technical babble. The difference between 12" and 16" of port per cubic ft is not going to be noticed by a human ear. It probably would with a bunch of woofers but I doubt it even then. Only on a meter.

You guys think too much.....
No, the CA.com way is exactly the problem you're exhibiting. Saying "No, stupid" would have done absolutely nothing besides get someone upset for no reason. By explaining how the enclosure works, you can therefore understand how what he reasoned was false. So it comes down to this: if you don't like "technical babble" which is simply how your box works, then don't read it. For those people who want to know WHY a larger port won't be "boomier", then they're free to read it. Following in ignorance is the worst way to learn new things.

If people didn't think too much, you wouldn't have 100% of the things that you use for granted every day, so think about that before you fire up your amplifier or try to crank your starter motor. Someone had to realize that if you put semiconductor pieces next to one another they'll go nuts and create depletion regions and if you run current through a wire it will create a magnetic field which can be manipulated to be used as a motor. Thinking too much is the solution to the problem on this website: thinking too little. ;)

thehardknoxlife
12-15-2009, 07:05 PM
My point exactly. You put way too much thought into what I said. Can you explain the Big Bang Theory also?


Oh BTW, I was joking, but I guess your ego wouldn't let you see that.
No, the CA.com way is exactly the problem you're exhibiting. Saying "No, stupid" would have done absolutely nothing besides get someone upset for no reason. By explaining how the enclosure works, you can therefore understand how what he reasoned was false. So it comes down to this: if you don't like "technical babble" which is simply how your box works, then don't read it. For those people who want to know WHY a larger port won't be "boomier", then they're free to read it. Following in ignorance is the worst way to learn new things.

If people didn't think too much, you wouldn't have 100% of the things that you use for granted every day, so think about that before you fire up your amplifier or try to crank your starter motor. Someone had to realize that if you put semiconductor pieces next to one another they'll go nuts and create depletion regions and if you run current through a wire it will create a magnetic field which can be manipulated to be used as a motor. Thinking too much is the solution to the problem on this website: thinking too little. ;)

PV Audio
12-15-2009, 07:06 PM
Not to thread-jack here, but I was wondering about port area and a bandpass.

People recommended something crazy like 80 sq in of port area for my bandpass...but I only had room for around 40 sq in of port. The sealed portion is 2 cubic feet while the ported portion is 2.5 cubic feet. The box sounds great, but has me wondering what it would've sounded like if I could've gotten that 80 sq in of port.YOur tuning would have changed, and then you would have a completely different output bandwidth. If someone reputable designed it at 40 and someone just shouted out 80, go with the 40. Bandpass design, unlike sealed or ported design, is 70% intuition and 30% math.

PV Audio
12-15-2009, 07:17 PM
My point exactly. You put way too much thought into what I said. Can you explain the Big Bang Theory also?.
You don't get it at all, do you? He stated something as a rule of thumb: larger ports are boomy, smaller ports are punchier. That's not true. I posted why that's not true. You thought me just calling him wrong and insulting him would have sufficed. It doesn't. Can the OP tell the difference between 12 and 16 in^2 of port? No. So no matter what way you look at it, the information given was wrong and I decided to inform him as to why it's wrong. So with that, you can kindly keep your negativity to yourself if you don't want to actually learn something and instead go along with fairy dust tips and tricks instead of what's actually been proven.

You know, it's almost upsetting to me that people don't want to learn things anymore. I go to school to learn: not to drink, party, sleep around, jump off of buildings into snow drifts (don't ask :D ), but to learn so that I can enrich my knowledge. When it comes to audio, I don't know much, but what I do know I try and share with those who might be confused. If I can help a single person understand what changing port area does to a box, then I feel that I've been successful. If someone doesn't care about that, then that's fine. So again, you can kindly keep your negativity to yourself because I couldn't care less.

If you think that it's arrogant that I'm merely sharing knowledge that I've gathered from texts and from people on here smarter than me, then again, please feel free to keep it to yourself. If you stopped and thought "wait a minute, he's actually going to explain why that rule is false instead of just saying it is, maybe that's a good thing", then maybe people wouldn't be running around saying 10" cones are "faster" than 15" cones or ported boxes are "lower" than sealed boxes or that putting a 10" and a 12" sub playing the same signal in the trunk is going to be beneficial. Maybe. All it takes is someone to actually want to learn something.

I learn dozens of new things about audio from people on here every day. I have long held beliefs that turned out to be false. I am nowhere near a technical genius nor elitist wannabe who thinks he knows everything. Rather, instead of going out into the trunk, I go into the books and read up on HOW and WHY things work instead of just stating that they do. So I say for the final time, if you have a problem with an informative post, or don't understand a term in it, then either don't say anything or ask to clarify. I am trying to help members understand their hobby from the ground up, not the other way around. If you take issue with that, then I guess that's your problem alone.

PV Audio
12-15-2009, 07:18 PM
And if you think that I have an ego after having been the most ridiculed member in this forum's history, then you truly are the densest person posting here.

thehardknoxlife
12-15-2009, 07:28 PM
You don't get it at all, do you? He stated something as a rule of thumb: larger ports are boomy, smaller ports are punchier. That's not true. I posted why that's not true. You thought me just calling him wrong and insulting him would have sufficed. It doesn't. Can the OP tell the difference between 12 and 16 in^2 of port? No. So no matter what way you look at it, the information given was wrong and I decided to inform him as to why it's wrong. So with that, you can kindly keep your negativity to yourself if you don't want to actually learn something and instead go along with fairy dust tips and tricks instead of what's actually been proven.

You know, it's almost upsetting to me that people don't want to learn things anymore. I go to school to learn: not to drink, party, sleep around, jump off of buildings into snow drifts (don't ask :D ), but to learn so that I can enrich my knowledge. When it comes to audio, I don't know much, but what I do know I try and share with those who might be confused. If I can help a single person understand what changing port area does to a box, then I feel that I've been successful. If someone doesn't care about that, then that's fine. So again, you can kindly keep your negativity to yourself because I couldn't care less.

If you think that it's arrogant that I'm merely sharing knowledge that I've gathered from texts and from people on here smarter than me, then again, please feel free to keep it to yourself. If you stopped and thought "wait a minute, he's actually going to explain why that rule is false instead of just saying it is, maybe that's a good thing", then maybe people wouldn't be running around saying 10" cones are "faster" than 15" cones or ported boxes are "lower" than sealed boxes or that putting a 10" and a 12" sub playing the same signal in the trunk is going to be beneficial. Maybe. All it takes is someone to actually want to learn something.

I learn dozens of new things about audio from people on here every day. I have long held beliefs that turned out to be false. I am nowhere near a technical genius nor elitist wannabe who thinks he knows everything. Rather, instead of going out into the trunk, I go into the books and read up on HOW and WHY things work instead of just stating that they do. So I say for the final time, if you have a problem with an informative post, or don't understand a term in it, then either don't say anything or ask to clarify. I am trying to help members understand their hobby from the ground up, not the other way around. If you take issue with that, then I guess that's your problem alone.Whoa dude calm down. You obviously didn't understand my sarcasm, and your interest in my response is quite weird. I was simply implying the fact that the CA.com way is to insult someone without explaining anything. It was actually an applaud to your response. I wasn't insulting your intelligence, but I am questioning your ego.

SicAudio
12-15-2009, 07:57 PM
now now guys don't fight over it i got the sarcasm point and yeah it is the ca.com way pretty pathetic in my opinion lol
and PV u have more knowledge than u think so i say let some ego out its good for ya ;)

PV Audio
12-15-2009, 08:36 PM
Whoa dude calm down. You obviously didn't understand my sarcasm, and your interest in my response is quite weird. I was simply implying the fact that the CA.com way is to insult someone without explaining anything. It was actually an applaud to your response. I wasn't insulting your intelligence, but I am questioning your ego.I got my sarcasm detector from deal-extreme :crap:

Boomintempo
12-16-2009, 07:15 AM
YOur tuning would have changed, and then you would have a completely different output bandwidth. If someone reputable designed it at 40 and someone just shouted out 80, go with the 40. Bandpass design, unlike sealed or ported design, is 70% intuition and 30% math.

I guess my box came down to luck, and I got pretty lucky. Knowledgeable people told me 80 and I went with just under 40 because it was all I could fit.

Luck must've been on my side that day.