Ported enclosure questions

[pimpnyou204 10+ year member]

It would be loudest at if you tuned the enclosure to the subs Fs, I believe. But that's all it is. There are so many other factors.

That was my thought also otherwise their suggested tuning would be solely based on opinion.. It has to be done with real design, tests, and actual advantages no?

 

[Buck 5,000+ posts]

Lol wow I asked aquestion ram doesn't know I'm kinda shocked! But in all serious though aren't most spl comps won at higher frequencies is that bcuz their resonant frequency in the car is that high? If not my thought would be if low tuning is related to more air disruption then that would give u more pressure (spl.) much like a hurricane or tornado when they come by the pressure is much higher. I dont know maybe over analyzing at this point...

It becomes physics at some point. Lower frequencies make vehicles, well, resonate more. Think about how much a vehicle flexes on 30 hz vs. 50 hz. Flex= lost sound. Woofers also have a harder time reproducing lower frequencies than higher frequencies (generally, in my experience).

Basically, hitting higher scores at higher frequencies is easier, that's why I like lows.

 

[Buck 5,000+ posts]

That was my thought also otherwise their suggested tuning would be solely based on opinion.. It has to be done with real design, tests, and actual advantages no?

Yes. Tuning a box to a frequency changes the phase of the frequency that it's tuned to the most. In free air, that frequency would be loudest. The farther away from the tuning frequency you go, the more the phase changes (farther away from 180 degress different than rear wave), which means basically the less sound is produced. That's what a ported box does, if I understand and explain everything correctly. Basically switches the phase of the rear waves of the woofer 180 degrees so that they compliment the front waves of the woofer, thus having more output.

 

[pimpnyou204 10+ year member]

Yes. Tuning a box to a frequency changes the phase of the frequency that it's tuned to the most. In free air, that frequency would be loudest. The farther away from the tuning frequency you go, the more the phase changes (farther away from 180 degress different than rear wave), which means basically the less sound is produced. That's what a ported box does, if I understand and explain everything correctly. Basically switches the phase of the rear waves of the woofer 180 degrees so that they compliment the front waves of the woofer, thus having more output.

So in theory minus a vehicles resonant frequency the further from fs u go the less out put u may possibly have? But a speakers sound is created by friction and frequencies are made by the friction why would a lower note cause a sub to heat up more?

Also is it just me but do amps start to clip more at lower notes than higher ones? Or maybe it's just my test tones..

 

[Slo_Ride 5,000+ posts]

Also is it just me but do amps start to clip more at lower notes than higher ones? Or maybe it's just my test tones..

Probably your electrical, may need mo powa!

 

[Buck 5,000+ posts]

So in theory minus a vehicles resonant frequency the further from fs u go the less out put u may possibly have? But a speakers sound is created by friction and frequencies are made by the friction why would a lower note cause a sub to heat up more?
Also is it just me but do amps start to clip more at lower notes than higher ones? Or maybe it's just my test tones..

I don't see what you are saying with friction.

 

[pimpnyou204 10+ year member]

It becomes physics at some point. Lower frequencies make vehicles, well, resonate more. Think about how much a vehicle flexes on 30 hz vs. 50 hz. Flex= lost sound. Woofers also have a harder time reproducing lower frequencies than higher frequencies (generally, in my experience).
Basically, hitting higher scores at higher frequencies is easier, that's why I like lows.

Hmm that actually makes a lot of sense bcuz fart boxes tend to never flex just vibrate everything like a *****. But if u deaden your entire car like 8 layers thick and super caulked all your doors and windows you probably would get a much higher score at a lower frequency.

The roll off on a sub playing lower than the tuning would cause the sub to bottom out faster correct?

 

[Buck 5,000+ posts]

Hmm that actually makes a lot of sense bcuz fart boxes tend to never flex just vibrate everything like a *****. But if u deaden your entire car like 8 layers thick and super caulked all your doors and windows you probably would get a much higher score at a lower frequency.
The roll off on a sub playing lower than the tuning would cause the sub to bottom out faster correct?

Yes. The port tends to "unload" under tuning frequencies. Don't know why that is, I just know that it is. So that's why we have the F3 lower, and F3 upper.

 

[pimpnyou204 10+ year member]

I don't see what you are saying with friction.

Sounds are made by the motor moving back and forth, this motion causes friction and friction obviously causing more heat. But frequencies (hertz) are measured in the amount of times they move back in forth right? If that's true why would a low note with less motion in the motor cause more heating?

 

[Buck 5,000+ posts]

Sounds are made by the motor moving back and forth, this motion causes friction and friction obviously causing more heat. But frequencies (hertz) are measured in the amount of times they move back in forth right? If that's true why would a low note with less motion in the motor cause more heating?

There isn't any friction in the woofer. The coils slides in and out of the gap (//content.invisioncic.com/y282845/emoticons/naughty.gif.94359f346c0f1259df8038d60b41863e.gif).

I'm not sure with your question, but maybe it has to do with the fact that air is being cycled less, thus having less air around the coil. Just a guess and just a thought. Take it with a grain of salt.

 

[pimpnyou204 10+ year member]

Yes. The port tends to "unload" under tuning frequencies. Don't know why that is, I just know that it is. So that's why we have the F3 lower, and F3 upper.

How much below tuning can u go before needing to filter is that dependent on variables? F3 upper/lower? new subject to discuss lol

 

[Buck 5,000+ posts]

How much below tuning can u go before needing to filter is that dependent on variables? F3 upper/lower? new subject to discuss lol

That can be calculated, but, according to my experience with winisd, you can usually play 3 or 4 hz below tuning frequency. But it all depends on what you are tuned at. The lower you tune, the waves get exponentially longer, making the difference from 50 to 49 much less than 30 to 29.

 

[pimpnyou204 10+ year member]

So it's better to tune lower if u want to cover more frequencies bcuz u can always cover the higher ones but the lower u go with a higher tuning u risk bottoming out?

 

[Buck 5,000+ posts]

Yes. Tuning lower will allow you to play lower. That's why I'm tuned at 27 hz (was supposed to be 28hz, but port was a lil smaller, etc).

Generally a larger box with lower tuning with have a flatter frequency response.

 

[pimpnyou204 10+ year member]

But all with a loss of some spl correct?

Last thing.. Is it true that the fewer amount of ports will creat less turbulence than one larger one of equal area?