new to car audio, need help

[SickVette]

PaulD...you refer to the bandpass as a higher order. Technically that is not true. Cabinets were started to be labeled in orders due to their simularity to a certain order xover. So calling a bandpass a "4th order" is really using an applied term that was given through time but not a true definition. I guess you could call it slang. Now bandpass enclosure have been given a bad rap in SQ circles due to they are really intended to provide a high amount of output at a given frequency. The higher the output at that frequency the narrower the bandwidth. But if you widen the bandwidth the frequency spike will drop and you can have a good sounding bandpass. Or as was said you can use a very strong midbass driver(s) to fill the gap to the midrange. On the flip side if you build a bandpass to have a wideband you are defeating the purpose of using that type of enclosure and creating a overly large enclosure. One that will give the same results as a smaller ported or sealed enclosure. Either way you can still build a bandpass enclosure that has good sound quality charcterists...I know. I have done it. Do I recommend it....no. Personally I prefer sealed enclosures but that is entirely different conversation.

[Haibane]

And that right there tells me exactly what I was trying to get across, but also a few things I didn't know, like how you could have a good level bandpass.

[aznxthuggie]

Originally Posted by sr20de4evr

Bandpass boxes can sound good, just like Paul and Vette have said though, it needs to be built (and above all, designed) very very well. Most people have only heard prefab bandpass boxes, just like prefab ported boxes these are 1) not built for the specific sub (normally) and 2) built to get very loud at a few frequencies to give the "wow" effect, while ultimately giving you a horrible response curve. Just like with ported boxes, if you want to build an effective bandpass box with good sound quality, you have to design and build it yourself, the only difference is the bandpass will be much harder than the ported box.

Now, back to the facts, aznxthuggie - building a box is easier than you think, give it a try, you might be surprised. Lets see, all the enclosure sizes we give are in cubic feet, by definition this is a cube where each side is one foot long. To get the volume of the box you just take the lengths of the sides (in feet), making sure to subtract the thickness of the wood, and multiply them together, thats it. If you have a box that is 2' x 1.5' x 1', it will be 3 cubic feet, pretty simple. Then you just add in a little extra volume (make the box a little bigger, how much bigger depends on the specific sub you're using) to account for the space taken up by the sub itself, and you're golden.

hmm lets say i do find out what kind of box i need, and the dimensions and everything, since i am going to buy wood frmo home depot, do u think it'll be easier if i just pay them to cut it, i think its a little $ per cut, they do all the cutting, you give them the specs/dimensions? also.. what do u have planned for your audio overhaul? or will we know when your done heh

[sr20de4evr]

Originally Posted by aznxthuggie

hmm lets say i do find out what kind of box i need, and the dimensions and everything, since i am going to buy wood frmo home depot, do u think it'll be easier if i just pay them to cut it, i think its a little $ per cut, they do all the cutting, you give them the specs/dimensions? also.. what do u have planned for your audio overhaul? or will we know when your done heh

Home Depot cuts aren't very accurate. I'm sure if you give the guy a few extra bucks and tell him to make it exact he will, but normally they just get it close and cut away. The few cuts I've had them make have all been 1/8 to 1/4" off, which will REALLY screw up your box.

And I'll post a thread when it's all done, ordering the first piece in about 3 days and it should take around a month to finish (it sucks building a system from paycheck to paycheck).

[SickVette]

sr20de4evr....is correct and it is very sad too. Since all the Home Depots here have panel saws, which are much more accurate,safer,and easier to use than a table saw. It is really sad that most of the employees can not make a square cut with one.

[n_samedi]

wow, thanks for the responses guys. i didnt mean to bring up so much drama, lol, but i appreciate all your opinions. thanks again.

[aznxthuggie]

Originally Posted by n_samedi

wow, thanks for the responses guys. i didnt mean to bring up so much drama, lol, but i appreciate all your opinions. thanks again.

heh its ok we do this all the time, im a newb also =D

[PaulD]

Originally Posted by SickVette

PaulD...you refer to the bandpass as a higher order. Technically that is not true. Cabinets were started to be labeled in orders due to their simularity to a certain order xover. So calling a bandpass a "4th order" is really using an applied term that was given through time but not a true definition. I guess you could call it slang

Actually, it's a very accurate term - a fourth order box has a roll off very similiar in nature to a 4th order crossover. It's just a natural transition. The very nature of the thiele/small parameters was to model a box/speaker program as electronic components in a circuit. It can very accurately predict the performance of a box/speaker in a large room. The trick has been to take into account that a car's bass sysytem is enclosed in a realitively small enclosure.

[n_samedi]

Originally Posted by SickVette

Damn I forgot something. n_samedi on your sisters car there are a few things you can try on the trunk that are free.On the two outer corners of the trunk there are rubber stoppers. Those are adjustable. The latch in the center is adjustable also. What you can do is adjust those three things till the trunk close very tight. You have to lower the latch part that is inside the trunk and first raise the rubber stoppers. When you get the latch lowered to the point where you can still latch the trunk you lower the stoppers to push the trunk back up a little so it is flush with the quarterpanels. Then ofcourse you can use sound deadning materials.

that worked so well, thanks. the latch didnt move too much but i think its the rubber stoppers that did the trick. there is no more rattling and my sis isnt embarassed to turn her sound up! thanks!

[SickVette]

sweet n_samedi....glad it worked for her.