slot port question

[Derek_K 0]

ok. i built my boxes (still unsure about the subs), and the port came out looking funny. I'm almost sure, but just to be extra sure, i figured someone could help me out. when i ported my boxes, i took the cubic inches of a different boxe's port (3 cubes at 34 htz) and used the same on my 3 cube box (also at 34 htz) the difference is that it isnt as deep, but longer... even though the dimensions are different, because they both have the same cubic inches of port, it's still tuned to the same freq, correct? thanks

[vladd 26]

I didn't really understand what you did, lol. How about telling us what size the box is and what size the port is? ie 3 cubes is the size of the box and the slot port is 3x24 and 20 inches deep

[Kyle Richardson 0]

Umm, confused here too.

[Derek_K 0]

Umm, confused here too.

<{POST_SNAPBACK}>

sorry-

The box is 3 cubes, and i took the cubic inches of an older 3 cubes boxe's port and basically just switched the #'s around to come up with a new port with the same area of the older one.

[///M5 2,833]

That may or may not have worked. What was the port and what is it now??

[Derek_K 0]

That may or may not have worked.  What was the port and what is it now??

<{POST_SNAPBACK}>

it was 14.5x1.25x15, and i switched it to 13.75x2x10

[///M5 2,833]

Sorry, but those aren't the same. You aren't making this easy as you are leaving out a lot of information. I am making the assumption that the internal dimensions of the port are what you gave me and that the 3cuft stays constant either way. In other words since your info is incomplete, I am assuming that your ports are on the outside of your box. From the numbers you gave, neither box was tuned to 34Hz like you stated: more like 40 and 28--but that is very dependent on how you read your question as well.

[Derek_K 0]

Sorry, but those aren't the same.  You aren't making this easy as you are leaving out a lot of information.  I am making the assumption that the internal dimensions of the port are what you gave me and that the 3cuft stays constant either way.  In other words since your info is incomplete, I am assuming that your ports are on the outside of your box.  From the numbers you gave, neither box was tuned to 34Hz like you stated: more like 40 and 28--but that is very dependent on how you read your question as well.

<{POST_SNAPBACK}>

well i took the box dementions from pre-made boxes for memphis subs- just a bunch of dimentions written on a chart giving the optimum box volume and tunings for all of their subs. i got them from a friend that works at an audio shop. the box was 3 cubes, ported at 34 htz... the port dementions it asked for was 14.5x1.25x15.... so if that isnt correct dimentoins then i'm not sure what to do.....

but the box i BUILT is 3 cubes and has a port demention of 2x13.75x10 (and yes, the slot port is on the same side of the speaker).... so what is that box tuned to? (the box is 3 cubes AFTER port displacement)... if there is any other info u need please let me know, because it's going to help me set my amp's xovers and filters.

[Derek_K 0]

Sorry, but those aren't the same.

[vladd 26]

i'm thinking yours is about 39hz and it would have been 28 following his directions. Exactly as m5 stated before.

[///M5 2,833]

I will stick with what I stated before; however, there is a big difference between gross volume and net volume and you haven't clarified what you are using. Also, everything is not just linear you can't go making assumptions like you are as mathematically they don't work. It sounds to me like your help at the "audio shop" you refer to does not know what they are doing and if you want your sub to sound its best my recommendation would be to scrap the box you have and pay NeonRyder for plans for one that will work. That nominal investment will save you a bunch of time, make your sub sound the best, and costs way less than it is worth. Having the wrong box for a sub = teh svck!

[vladd 26]

agree with m5 100% the box that i just built for my ava....its amazing how much low end it lost. Its tuned to 25hz but ended up being wayyyy too small and i lost a ton of low end. I had more low end with my 35hz tuning (new box ended up less than 2cubes, old was over 3)

good plans = good sound