help with a box ......4 Obsidian V3 12 `s in a blazer.

[mrchuck]

these are what i came up with for those dimensions

first 1





second 1



first one is cramped for space on the subs but the second one works well

[KickinBlazer]

You didn't do the actual port length?...look on the right at the physical port length that's the actual internal port length...the second sketchup ...the inside mouth of the port opens up right on a woofer that might make that woofer unload bad first one would be a better option

[mrchuck]

i kinda thought that too with the second one but the first one you measure down the middle of the port for the length ? if so i got 35.5 inch for that

[KickinBlazer]

No look at the calculator again look at the numbers the physical port length is 25 inches if you would have built it to 33 the tune would be 28hz...lol

[666WMD]

Box Frequency Tuning Calculator - FAQ/Tip Guide
*------------------------------------------------------------------------------------------------*

13 - PLEASE NOTE: 'Physical port length' refers to the length of the wood itself needed to Build the port. This is NOT the same as the effective port, or the port you entered into the port length box that the box will 'see'. You measure on the inside of the port (against the port wall) to measure the physical port, in the same way you measure down the middle of the port to get your actual, or effective, port length.

What that basically means is your port length should be the same length down the middle of the port as what you entered into the port dimensions. The physical port length refers to the material length. KB's calculation says 25" because it thinks the port exits out the rear of the longest panel, not to the side. It believes the port runs down the shortest wall then along the back.

[mrchuck]

i think i got it now

i was looking at the lv/Port Length in green on the bottom right hand corner

[97_eldo]

i think that one sub is too close to the port and may cause problems.
maybe one of the brighter ones can chime in on it and a possible solution

[KickinBlazer]

OK you have a hard decision to make that port will be to close to the woofers and prolly cause unloading you can either choose to port up or tune lower which do you chose?

[mrchuck]

how low of tuning do you think would work ?

[KickinBlazer]

look up on sketchup and see how long the port needs to be to be at least 1 inch past the the woofer cutout closest to the port entrance?

[KickinBlazer]

id say at least another 5 inches maybe more i had to increase the box volume to get it back to safe range for woofers...and the tune would be 28hz...lol that keeps popping up

[mrchuck]

ok ill try yours in a sec this is what i came up with

[IMG][/IMG]

i bumped up depth by 1/2 & the port length by 3 so it looks like this now

[KickinBlazer]

hmm says you bumped port length bye 8 inches not 3...lol so says the sketchup length on bottom right....but looks either would work mine is more narrow in the port department so that will releve some woofer mounting issues

[mrchuck]

ok im working on a sketch up of the last calculations you posted at this point space kinda dont matter i just need to fit all this (amps,batterys & subs) in the cargo area with being able to still see out the rear view mirror

[mrchuck]

what i came up with for the last calculator dimensions ya posted ...

[KickinBlazer]

Either one of those would work ...28hz tuning really isn't that bad of course you won't be as loud as your 2 18's but the 4 12's will be more musical and dig deep tuned to 28hz...talking 22hz deep and cram from 30 to 55hz and taper off above that at least that's how it was in my blazer I wish I never would have gotten rid of that setup..if Ben trying to get that kind of setup sound wise for a long time now

[mrchuck]

so at 28 hz the Ov`s wont be as loud but will hit harder then the Aq`s ?

[KickinBlazer]

Originally Posted by mrchuck

so at 28 hz the Ov`s wont be as loud but will hit harder then the Aq`s ?

maybe not hit as hard but it will sound better dig deeper and be more musical

[mrchuck]

ok got ya but i want to thank you for helping

[KickinBlazer]

No problem

[97_eldo]

nice work kicken

[KickinBlazer]

Originally Posted by 97_eldo

nice work kicken

Thanks eldo ....post Build picks here if you do decide to build it and I forgot to ask is the drivers side open to the sidewalk of the vehicle?