Ported Confusion

[B_Master_Flash 10+ year member]

sealed hits lower notes, although ported will be louder at low notes (peaking at tuning frequency)

 

[MrSwiss 10+ year member]

oh well then crap i guess im going with sealed once again lol

 

[SPL140.2 5,000+ posts]

3db is technically twice the output. To increase output by 3db, it requires a doubling of acoustical power. So, being 3db louder is technically twice the acoustical power.
However, humans have very insensitive hearing...especially in the low subbas frequencies. It typically takes an increase of about 10db to be perceived as "twice as loud".

Going ported will generally give you an increase over sealed of about 3db over the entire bandwidth (all the frequencies being played). However, depending on the box design/tuning frequency and such....ported can have as much as 6-9db more output at a certain frequency over sealed.

So on a termlab i hit 143db and some other dude hits 140 mine is twice as loud?? So say I hit 149 and the dude keeps the 140db so does that mean im 3 times as loud??

 

[kuijo 10+ year member]

Are bandpass boxes completly useless? I know prefabs ****, but what if u made it for the sub. I just don't understand the point of them and have never seen someone in this forum use one.

 

[squeak9798 5,000+ posts]

So on a termlab i hit 143db and some other dude hits 140 mine is twice as loud??

Technically, yes, your stereo had twice the output. Now, does that mean you will sound twice as loud at that frequency? No. Also doesn't mean that you'll be twice as loud over the entire bandwidth...only that you were 3db louder at one specific frequency.

So say I hit 149 and the dude keeps the 140db so does that mean im 3 times as loud??

Again...technically, yes, you had three times the amount of output.

 

[squeak9798 5,000+ posts]

Are bandpass boxes completly useless? I know prefabs ****, but what if u made it for the sub. I just don't understand the point of them and have never seen someone in this forum use one.

Useless? Not all of them. Basically, a bandpass box is simply an "acoustical" crossover (highpasses and lowpasses the sub). Bandpasses are also usually very efficient within the passband (the bandwidth of frequencies that the sub is playing).

4th order bandpasses, when designed correctly, can actually have transient response better than/equal to that of a ported box. So, you can actually acheive pretty good results with a properly designed 4th order bandpass. 6th order typically has very poor transient response, and isn't really ideal to use.

Problem with bandpasses is that they are somewhat tricky to design, and require much larger boxes than sealed or ported. So, you don't see them very often in the car enviorment.

 

[B_Master_Flash 10+ year member]

So say I hit 149 and the dude keeps the 140db so does that mean im 3 times as loud??

try 2 to the 3rd power as loud. (which is 8x) I use the term loud loosely though, you would have 8x the sound pressure, loud is relaitve to the listener. I belive to actually sound 2x as loud you need a 10dB gain.

3x as loud = 4dB gain.

140dB to 143dB = 2x as loud

143dB to 146dB = 2x as loud

146dB to 149dB = 2x as loud

2*2*2 = 8

I hope that wasn't over anyone's head.

 

[audioholic 5,000+ posts]

Keep in mind guys, sound volume isn't something you can measure like water in a glass where 'twice as much' is an obvious amount. What is twice as loud. Its almost as difficult as asking what is twice as pink. There are many different technical definitions of 'twice as loud'. Most say 3db (doubling of amplifier power or cone area). Some say double the 'acoustical energy'. There was an old rule of thumb (sone rule..?) that said humans perceived 10dbs as 'twice as loud'... but that's very frequency dependant.

My point is, 'twice as loud' is debatable amount. 3db's may not seem like a perceived doubling of sound volume, but in one definition it is.

 

[audioholic 5,000+ posts]

IIRC, it's based on the difference in sound pressure (thus Sound Pressure Level), so it is measurable ...
+1 bel (+10 decibels) = twice the pressure difference ...

I can't recall the formula and I don't have the time to look it up ATM ...

I didn't say it wasn't measurable.

You just listed one of the 'twice as loud' theories. Again, there are many.

 

[squeak9798 5,000+ posts]

OMG, Squeak was wrong ??? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif
+9 dB = 8 times the acoustical power, not 3 //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Edit: Should've read the rest of the thread ... B Master Flash already pointed that out //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

And now you see the problems with me trying to post while I'm at work, with people bugging me while I'm trying to post answers to questions //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

Multi-tasking > squeak

 

[Hundreth 10+ year member]

Multi-tasking is for chicks ...

x2

I **** at multi-tasking... bad

I saw a show on the Discovery Channel once where they ran tests on a group of men and women. They put them in situations where multi-tasking was a must, and the women just destroyed them. However, when it came to sense of direction and other stuff, the guys showed them what was good. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[B_Master_Flash 10+ year member]

x2
I **** at multi-tasking... bad

I saw a show on the Discovery Channel once where they ran tests on a group of men and women. They put them in situations where multi-tasking was a must, and the women just destroyed them. However, when it came to sense of direction and other stuff, the guys showed them what was good. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

That explains why women are so good at driving SUVs and talking on their cell phones.

 

[audioholic 5,000+ posts]

They are good at it? Since when?

 

[Hundreth 10+ year member]

Since your mom had to deal with you when you were a baby...

That goes for all of you! //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[DFW40 10+ year member]

x2
I **** at multi-tasking... bad

I saw a show on the Discovery Channel once where they ran tests on a group of men and women. They put them in situations where multi-tasking was a must, and the women just destroyed them. However, when it came to sense of direction and other stuff, the guys showed them what was good. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

I saw that show as well, chicks could have 22 things going on in a kitchen at the same time but have trouble finding their car in a parking lot with 10 cars.

What do you do Squeak, for work?