understanding how boxes work..

[shynegrynd07 10+ year member]

//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

im not totally clueless in ca.. i install systems around town and install electrical stuff in cars.. it's kind of a hobby along with body work.

i just don't understand how a box can effect how the subs sound.

my questions:

difference in ported and non ported boxes?

is it the pressure displacement or air change that makes the bass come in?

bigger cars=deeper bass?

difference in sound between ohms? like, whats the difference between .5 ohms and 8 ohms? i can wire for different ohms using charts online and stuff, but i would like to understand what exactly im doing.

i know that some subs require bigger boxes to sound their best and other need smaller and some need ported, etc. why is this?

do fiberglass boxes sound better than wood?

and i think that's about it. sorry if they are dumb questions, but idk who to trust when they explain these things to me. a lot of people just make up answers to these questions due to their lack of knowledge

thanks:naughty:

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[SW9152 10+ year member]

check out http://www.the12volt.com

 

[SW9152 10+ year member]

oh and http://www.bcae1.com is good too

 

[Chevyaudio 5,000+ posts]

yes read those two sites...they will pretty much explain everything a lot quicker than we can type it out.

 

[shynegrynd07 10+ year member]

alright, cool. i'll look into them

so are ohms basicall the measure of the electrical current going to the sub?

 

[skadude016 5,000+ posts]

alright, cool. i'll look into them
so are ohms basicall the measure of the electrical current going to the sub?

or resistance

 

[shynegrynd07 10+ year member]

or resistance

so it's right to say that .5 ohms is better than 4? it all depends on what you're running?

or is it fair to say usually the lower the number the better the sound?

 

[skadude016 5,000+ posts]

so it's right to say that .5 ohms is better than 4? it all depends on what you're running?or is it fair to say usually the lower the number the better the sound?

neither is better. if you have an amp that puts out its most power and stable at 4ohms. then 4ohms would be a better choice than .5

if your amp is stable down to .5ohms with enough juice to back it up then go .5 ohms //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

but usually the lower the ohm load the more amps it will pull

 

[Chevyaudio 5,000+ posts]

an ohm load is merely the amount of resistance that a load presents to the amplifier.

Though many amplifers have a lower THD (total harmonic distortion) at higher loads (ie: the THD would likely be lower on said amp at 4 ohms as aposed to 1 ohm). Other than that the ohm load has no effect on the sound of the driver, other than the fact that more than likely it will probably be louder because in most cases the lower the load the more power the amplifier will put out...that is unless the amps have regulated power supplies.

 

[Prowler573 5,000+ posts]

When talking about the drivers that comprise your substage there's really much (if any) noticeable difference in sound from one resistance to another.

Comparitively few amps are even stable when shown a 1/2 Ohm load whereas pretty much every amp in existence is stable at 4 Ohms.

The variance in resistance will dictate how much output a given amp will produce - assuming that the amp in question will offer stable operation at the resistance load you plan to present it.

Ergo - if you will refer to the equipment listed in my signature, the monoblock I use for my Geo gives one output @ 4 Ohms, it increases when shown a 2 Ohm load and then increases again when shown a 1 Ohm load. I wouldn't feel comfortable trying a load under 1 Ohm as it isn't particularly designed for it.

The monoblock going in the BudgetMobile gives one output @ 4 Ohms and will increase when shown a 2 Ohm load. That particular amp won't even do a 1 Ohm load much less under that.

 

[shynegrynd07 10+ year member]

great, that all made a lot of sense //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

sooo

ohms :check:

how boxes work :workin on it:

 

[Skip01 5,000+ posts]

Everest, F. Alton - The Master Handbook Of Acoustics [McGraw Hill 2001]

Download this book of a torrent and read away

 

[audioholic 5,000+ posts]

An ecnlosure creates an 'airspring' behind the cone. This, coupled with the suspension characterisitics of the speaker, will affect the sound characterisitcs of the system. Furthermore, going bu the t/s specs of the driver, enclosure sizes and alignments can be calculated that would give a predictable response.

So what this means is, given the proper knowledge of the speaker you are using, you can design/build an enclosure that will tailor its output and frequency response to fit your system's needs.

The space, its size and shape, will affect perceived system response. Build a sub system, then place it in a concert hall and play it. Now go sit it in your closet and play the same material... it will sound different. Wave interaction from the system is affected by environment, as the sound wavs created by the sub bounce around and interact with each other, it changes the perceived sound.

The basic difference between sealed and ported boxes is a ported box is designed and built to utilize the sound waves coming off the rear of the cone to reinforce the direct radiating sound coming from the front of the cone. This reinforcement is not linear however, how much it reinforces is dependant on the frequency of the material being played, and the design/tuning of the box. There is also the problem of the front and rear sound waves will always be slightly out of phase with each other, due to the rear waves having further to travel to reach your ears than the front. This problem can be minimalized, but never eliminated, in a ported box.

Sealed boxes do not have that delay issue of course (called group delay), but it also lacks the added output boost given by the rear waves in a vented/ported system. Sealed boxes rely solely on direct radiating sound from the speaker cone. As the cone moves in and out in the box, it creates high and low pressure zones inside the box, resisting further cone motion and attempting to return the cone back to its home position.

Hope these random thoughts helped.

 

[shynegrynd07 10+ year member]

iiiinteresting. that is helpful. i dont think anyone understands 100% how it all works, but you all seem pretty close