Latest box design 4 SA-8s

[basscort2009 5,000+ posts]

i had my rockford he2 8s in 3 cubes for all 3 on 1200 rms and they didnt like **** a big box with that much power. u said 4 cubes for 4 sa-8s? thats a cube each like mine. id try to shrink that down to .5-.7 each for a 3k amp. especially a sundown 3k man.

 

[THATpurpleKUSH 5,000+ posts]

I have heard a lot of people advising not going over .8cu/ft with sa8s or you risk mechanical damage

 

[Moble Enclosurs 10+ year member]

They have this stuff on the internet now? Uhhhh. To think, I busted my rump to learn this hands on all these years,lol. That's awesome though! Now, going back to what surreal said, passenger port placement is recommended for this reason, that exists in many vehicle transfer functions, not just modes of operation. In a lot of design I have calculated vehicle gain for, I have noticed it is likely more frequency dependant rather than frequency range dependant when figuring for gain. Here is why....you may find, if calculated correctly, that just below the bandwidth resonance of each exicted frequency, usually from half wavelength, not quarter wave in my experience, exists a dip or a null. This is why when figuring for frequency response, people tune low, because at that resonance is a higher gai before the null, and then the transfer function kicks in at a certain increasing rate until box response dissipates below the cutoof point, in which room gain cannot flatten due to the increased response loss slope passing the common -24dB point. So, by tuning low, you get gain all the way down to below subsonic efficiently and also get the halfwave resonance to match the boxes anechonic resonance of the port for a very high increased output at that given frequency and below. So, the point is, though room gain increases dramatically as frequency decreases, there is a point where it does not help much for output anymore. So, you have to balance the box response with that gain in orrder to see a full range LF response. Now, with passenger side placement, this helps that gain to increase starting at lower frequencies rather than higher frequencies, and all of this (this is the most important part) is room dependant and resides in the actual dimensions rather than a general rule of thumb. So, if you said you are looking for that high spl output in the 30s, then making sure the path between the port and driver, to the listener is greater as to get that halfwave mode to exicte in the 30s range around the ports resonance because this is where the gain will contribute the most, until (depending on the vehicle) it might drop then pick up again, but not as great variation or as quick from one resonance to another as higher frequencies do.

So basically, room gain not a general rule for placement purposes as they don't just dissappear, but can help when figuring for more precise frequency exictation along with the fact that it is different for each vehicle. A lot of people will say that it is too much work or that it is to dofficut to get right, but that is not true if you consider all the variables involved and in your case, we do not know any of them yet. But I will agree with surreal that for lower frequency gain, the furthest distance is recommended for a specific frequency increase. But for response increase, it really depends on more than what we know right now to conclude that exactly. If you want to share your vehicle dimensions, that will help a lot. We can figure for more precise placement configuration for you vehicle.

 

[KyleBechtold 5,000+ posts]

I sketched it up with port passenger side its still a bigger box as I started before I saw to make it small.. this box is 4.06 after port before bracing or 45s so I figure some 2x4s in there should help since its so long.. if that doesn't help I can raise the floor so I can do both batteries on one side and my jack and equip on the other..

 

[KyleBechtold 5,000+ posts]

They have this stuff on the internet now? Uhhhh. To think, I busted my rump to learn this hands on all these years,lol. That's awesome though! Now, going back to what surreal said, passenger port placement is recommended for this reason, that exists in many vehicle transfer functions, not just modes of operation. In a lot of design I have calculated vehicle gain for, I have noticed it is likely more frequency dependant rather than frequency range dependant when figuring for gain. Here is why....you may find, if calculated correctly, that just below the bandwidth resonance of each exicted frequency, usually from half wavelength, not quarter wave in my experience, exists a dip or a null. This is why when figuring for frequency response, people tune low, because at that resonance is a higher gai before the null, and then the transfer function kicks in at a certain increasing rate until box response dissipates below the cutoof point, in which room gain cannot flatten due to the increased response loss slope passing the common -24dB point. So, by tuning low, you get gain all the way down to below subsonic efficiently and also get the halfwave resonance to match the boxes anechonic resonance of the port for a very high increased output at that given frequency and below. So, the point is, though room gain increases dramatically as frequency decreases, there is a point where it does not help much for output anymore. So, you have to balance the box response with that gain in orrder to see a full range LF response. Now, with passenger side placement, this helps that gain to increase starting at lower frequencies rather than higher frequencies, and all of this (this is the most important part) is room dependant and resides in the actual dimensions rather than a general rule of thumb. So, if you said you are looking for that high spl output in the 30s, then making sure the path between the port and driver, to the listener is greater as to get that halfwave mode to exicte in the 30s range around the ports resonance because this is where the gain will contribute the most, until (depending on the vehicle) it might drop then pick up again, but not as great variation or as quick from one resonance to another as higher frequencies do. So basically, room gain not a general rule for placement purposes as they don't just dissappear, but can help when figuring for more precise frequency exictation along with the fact that it is different for each vehicle. A lot of people will say that it is too much work or that it is to dofficut to get right, but that is not true if you consider all the variables involved and in your case, we do not know any of them yet. But I will agree with surreal that for lower frequency gain, the furthest distance is recommended for a specific frequency increase. But for response increase, it really depends on more than what we know right now to conclude that exactly. If you want to share your vehicle dimensions, that will help a lot. We can figure for more precise placement configuration for you vehicle.

vehicle dimensions with an estimated box in there or just vehicle dimensions

 

[Moble Enclosurs 10+ year member]

Awesome! Looks nice man. Let us know how it sounds!

 

[basscort2009 5,000+ posts]

tea 4 cubes is gonna make those subs bottom out alot man. try 3 cubes after all displacements. plain and simple, not gonna give you a 3 paragraph novel post to read, 3 cubes tuned to low to mid 30s and you will be fine. are you going to any SQ shows? how bout spl shows?

 

[Moble Enclosurs 10+ year member]

vehicle dimensions with an estimated box in there or just vehicle dimensions

Just vehicle dimensions. Displacement can be figured for on my part, but get box dimensions interior and exterior as well for other information. Have you not figured for a response, and just built this to fit or for appeal?

 

[KyleBechtold 5,000+ posts]

tea 4 cubes is gonna make those subs bottom out alot man. try 3 cubes after all displacements. plain and simple, not gonna give you a 3 paragraph novel post to read, 3 cubes tuned to low to mid 30s and you will be fine. are you going to any SQ shows? how bout spl shows?

I posted with that picture that I made it a 4.06 before seeing the recs for a smaller box.. The easiest way would be to raise the floor and recalculate the port inch by inch until I get the size needed..

No I don't go to shows minus to watch every once and a blue moon.. I do it for my own enjoyment.. I am planning 34-35 and can build a port extender if necessary..

 

[Moble Enclosurs 10+ year member]

tea 4 cubes is gonna make those subs bottom out alot man. try 3 cubes after all displacements. plain and simple, not gonna give you a 3 paragraph novel post to read, 3 cubes tuned to low to mid 30s and you will be fine. are you going to any SQ shows? how bout spl shows?

Hey, that novel is going to help people. There is a lot more information to be known that this about proper audio, so be glad I'm sharing it.

 

[basscort2009 5,000+ posts]

I posted with that picture that I made it a 4.06 before seeing the recs for a smaller box.. The easiest way would be to raise the floor and recalculate the port inch by inch until I get the size needed..
No I don't go to shows minus to watch every once and a blue moon.. I do it for my own enjoyment.. I am planning 34-35 and can build a port extender if necessary..

my point to plain and simple. i like that moblenclosurs is giving complex advise but i dont think its needed unless super serious about sq or spl. other wise build simple and it will sound good. otherwise ur gonna pay a **** ton for designs and builders to get it right for you. and yea 4.06 but after all displacments thats still like 3.5 cubes or so. too big bro

 

[KyleBechtold 5,000+ posts]

Just vehicle dimensions. Displacement can be figured for on my part, but get box dimensions interior and exterior as well for other information. Have you not figured for a response, and just built this to fit or for appeal?

This is my first box so I had no Idea what I was doing.. Had atleast 2 threads asking for opinions/help offered to buy designs etc so I said f it and measured it out and started figuring out tuning... I have heard any where from .4-1 cuft so I just aimed for the biggest I could so I could cut it down if needed.. I know how to tune a ported box and some woofer/port placement techniques for certain vehicles.. I confused this port with a side firing port and put it on the the wrong side.. coulda got that sorted but actual response Idk how to use the sub's Ts with a program to figure out a box that way

 

[basscort2009 5,000+ posts]

Hey, that novel is going to help people. There is a lot more information to be known that this about proper audio, so be glad I'm sharing it.

your info is good i just think too complex for this setup. good info though for sure

 

[Moble Enclosurs 10+ year member]

I posted with that picture that I made it a 4.06 before seeing the recs for a smaller box.. The easiest way would be to raise the floor and recalculate the port inch by inch until I get the size needed..
No I don't go to shows minus to watch every once and a blue moon.. I do it for my own enjoyment.. I am planning 34-35 and can build a port extender if necessary..

As far as recalculating inch by inch. That's awesome. If you have time for it, it will prove helpful without having to calculate much, lol.

 

[KyleBechtold 5,000+ posts]

my point to plain and simple. i like that moblenclosurs is giving complex advise but i dont think its needed unless super serious about sq or spl. other wise build simple and it will sound good. otherwise ur gonna pay a **** ton for designs and builders to get it right for you. and yea 4.06 but after all displacments thats still like 3.5 cubes or so. too big bro

he is just trying to help so threads like this don't need to be made as often I appreciate his help although 85%+ of it is a foreign language to me.. I am trying to catch some of what he is saying.. as for the 4.06.. Like I said the first two times it was BEFORE I saw the recs to make it smaller.. I will calculate displacements and slowly raise the floor up until I get it where I need it as the port size will also change with the box getting smaller