Box Problem?

[Jcoleman134 0]

Ok well i built a box for an 18" Fi BL the specs are 42" wide, 22" high, and 22" deep. The port is 5 inches wide and 15.5 inches long. tuning it in the upper 31hz range. The box was like 8.3 cu ft. before woofer displacement. is that too big for a 18" BL with flatwind coil? Because the box doesn't sound good at all. and the woofer gets pretty warm on zx1000.1. I feel like its too big but i could be wrong.

[johnecon2001 82]

Did you possibly wire the voice coils out of phase?

[Jcoleman134 0]

Did you possibly wire the voice coils out of phase?

Thats what i thought at first but i went and pulled the woofer out and double checked everything and it was correct.

[BKOLFO4 29]

Box is a little bigger than I would have made it. Most 18's I have used sound good in 6-7 ft net. For your box, I come up with a tuning around 36 Hz if the port is 20.5 x 5 x 15.5. . .maybe it is not 20.5 high?

If the dust cap is getting hot on 1000 watts, you are clipping pretty hard which is another reason it sounds bad. The dust cap getting hot is not related to the box size. That is a thermal issue.

Brian

[Jcoleman134 0]

Box is a little bigger than I would have made it. Most 18's I have used sound good in 6-7 ft net. For your box, I come up with a tuning around 36 Hz if the port is 20.5 x 5 x 15.5. . .maybe it is not 20.5 high?

If the dust cap is getting hot on 1000 watts, you are clipping pretty hard which is another reason it sounds bad. The dust cap getting hot is not related to the box size. That is a thermal issue.

Brian

Well I got the box design from the re calculator so it might have been wrong. Do you know of a way I can modify the box to make it smaller and make the tuning around like 33 hz? also about the clipping that worries me. When i get home I'm going to have to check both batt's to see what there sitting at. I'm thinking my front battery might be on its last leg.

Also if i was clipping wouldn't that mean im not supplying the amp enough power? i haven't noticed alot of dimming in the lights.

Edited May 15, 2008 by jcoleman134

[KU40 173]

can you describe a little further what "box does not sound good at all" means?

[BKOLFO4 29]

Does the box sound good when you are not a full volume?

Clipping will occur when you are going beyond the amplifier's limits. . . Does not matter what your battery voltage is, you can still clip.

Can you post up the box dimensions, including the port dimensions?

Brian

[Jcoleman134 0]

Its sounding better now. like before it sounded like it was struggling to put out the note. but its sounding better now it just doesn't hit some of the higher notes in songs.

the external dimensions are.. 42" wide 22"high and 22" deep.

the port dimensions are 5"wide 20.5" high and 15.5" deep.

[BKOLFO4 29]

So the port is 20.5" high. . .

You are tuned a little higher than 31 Hz.

Also, the sub has to loosen up a little. About 1 hour of hard playing and it should sound different.

You could add a piece of wood to the port to make it 4.25 inches wide and see if you like how it sounds.

Add it to the inside port wall and run it into the box so it is 5" from the back wall.

Also - What is your crossover set at? Not going to hit higher notes if the crossover is set too low.

Brian

Edited May 15, 2008 by BKOLFO4

[Jcoleman134 0]

So the port is 20.5" high. . .

You are tuned a little higher than 31 Hz.

Also, the sub has to loosen up a little. About 1 hour of hard playing and it should sound different.

You could add a piece of wood to the port to make it 4.25 inches wide and see if you like how it sounds.

Add it to the inside port wall and run it into the box so it is 5" from the back wall.

Also - What is your crossover set at? Not going to hit higher notes if the crossover is set too low.

Brian

Thanks for the help so far man, Ill try putting a piece in there and see. Also the crossover on the amp doesn't really state what you would have it at other than 50 is lowest and 200 is highest and i have it probably no higher than 100hz.

When i play higher notes for example the highest note on Lil Wyte's Oxy Cotton. almost sounds more like rattling then a bass note.

[Jcoleman134 0]

Well i put the board in and it didn't sound any different to tell you the truth.

[BKOLFO4 29]

Well i put the board in and it didn't sound any different to tell you the truth.

I doubted it would, but now you can feel better about having "too much" port area. . .

[Jcoleman134 0]

Well i put the board in and it didn't sound any different to tell you the truth.

I doubted it would, but now you can feel better about having "too much" port area. . .

True. I'm thinking now that its just the box and the box position. maybe trying to put an 18" where my back seats were wasn't the greatest idea..

[Jcoleman134 0]

BKOLFO, Would you be able to throw me a box design together?

[BKOLFO4 29]

sure. . . PM me what you are looking for.

[shizzzon 461]

Even though Fi may recommend 12-14sqin per cube of port, this also has a factor of how much power u have available too.

the purpose of having a large enough port is to prevent audible turbulence for your daily driver.

Now, with that large of box, you would normally have quite a bit of power available.

That statement has no reference to a single sub, just box in general.

So with only 1kw of power, port area can be quite smaller in this scenario.

If you were to have a turbulence calculator, it will help greatly!

I'm not home right now but I think u may be able to get away with only 45sqin but don't quote me on that until I confirm it!

[Jcoleman134 0]

Even though Fi may recommend 12-14sqin per cube of port, this also has a factor of how much power u have available too.

the purpose of having a large enough port is to prevent audible turbulence for your daily driver.

Now, with that large of box, you would normally have quite a bit of power available.

That statement has no reference to a single sub, just box in general.

So with only 1kw of power, port area can be quite smaller in this scenario.

If you were to have a turbulence calculator, it will help greatly!

I'm not home right now but I think u may be able to get away with only 45sqin but don't quote me on that until I confirm it!

I wish i had a turbulence calc but i don't. :/

[///M5 2,833]

Doesn't play the high notes but is crossed at 100hz....woah, it is a sub, playing beyond 50hz isn't necessary. By some mids for god sakes.

[Jcoleman134 0]

Doesn't play the high notes but is crossed at 100hz....woah, it is a sub, playing beyond 50hz isn't necessary. By some mids for god sakes.

Thats not the problem. im not wanting it to play 100 hz but wouldn't you think that it would play a 50hz note without sounding horrible.

Its not that i go around bumping 50hz test tones all day but id atleast like to be able to play a higher note in a song with out being embarrassed when someone heres it.

Edited May 17, 2008 by jcoleman134

[shizzzon 461]

Oh, if ur problem is the high notes then I see 1 or 2 problems here.

Port area is fine for higher notes.

U r tuned lower than necessary to get in the 50s-60s loud and I also believe u could get a lot louder in that range if the box was smaller as well. The very minimum, 5 or 6 cubes net would have been a lot better

[Jcoleman134 0]

Yeah i do believe i went a little over board with how big the box is. but i also noticed it doesn't seem that loud in the lower hz range either. almost like its struggling. I really do think a better planned out box would solve my problems.

[johnecon2001 82]

If you want to play higher notes, piece together a 3-way front stage with a large midbass. That's what's going to do those notes for you.

[Jcoleman134 0]

If you want to play higher notes, piece together a 3-way front stage with a large midbass. That's what's going to do those notes for you.

Its not that i want go play a lot of higher notes, for example i just want to at least be able to play Lil Wyte - Oxy Cotton with out the highest bass note sounds terrible.

Edited May 17, 2008 by jcoleman134

[KU40 173]

just to cover some bases........Is the box sealed well besides the port? Having an airleak will make it sound bad, usually like a tapping or rattling while being quieter as well.

Is there a bass boost on anywhere (either on the amp or the head unit)?

does your head unit have a low pass crossover for the sub that's on?

You can try putting stuff inside the box to take up space to see if that's the problem. bricks, wood, etc.

how do you have the box oriented? You couldn't just be hearing rattling from your car trunk or lift gate?

[Jcoleman134 0]

just to cover some bases........Is the box sealed well besides the port? Having an airleak will make it sound bad, usually like a tapping or rattling while being quieter as well.

Is there a bass boost on anywhere (either on the amp or the head unit)?

does your head unit have a low pass crossover for the sub that's on?

You can try putting stuff inside the box to take up space to see if that's the problem. bricks, wood, etc.

how do you have the box oriented? You couldn't just be hearing rattling from your car trunk or lift gate?

Yeah the box is sealed. i have caulk all on the inside of the box to make sure there wasn't any leaks.

Theres bass boost on the amp.

To tell you the truth im not sure if the head unit has a low pass crossover. its a Pioneer Premier 6900ub.

its like a different type of rattling. doesn't sound like metal rattling. it sounds kind of like a buzz.