Undrstm8ed
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Scrambler82 wrote:
buggman wrote:
I like to use either MDF or particle board for my boxes with plenty of internal screw points.
For filling the box, I normally use some poly-fill, the same stuff you'd use to stuff a pillow (from the craft department). You don't want to super pack the fill material, just loosely fluff it inside the box. Not sure if it really "makes the box seem larger" myth but it doesn't seem to hurt, especially in sealed boxes.
Buggman, good to see you posting, was wondering if you left the Ranger/LED Lighting Site. (Looking for something to improve the light output for my Interior Light - Std Cab)
I've been reading about the Poly Fill and it seems that it IS used as a fill to increase the virtual area inside of the box.
The Funny thing is nowhere have I read HOW it does it ! Wasn't any Scientific Sites to look at !
It is said it breaks up the sound waves, causing an affect similar to an increased in volume, LoL !
Instead of building a new enclosure, I cut down the enclosure I got stuck with down to a manageable size for the area behind the seats in my Single Cab.
I calculated the cubic area of the cut off section, easier to calculate on a rectangle than that step needed to fit in the rear wall of the cab Panel.
I started with 0.88 cu. ft., cut off approximately 0.19 cu.ft. (had to recaluate) and ended with 0.69 cu. ft. ! The smaller 8" Woofer needs the same volume as the 10" version, 0.35 - 0.60 cu. ft., I don't think, and do not know for sure, but the 0.09 cu. ft. shouldn't effect the sound.
http://audiojudgement.com/thiele-small-parameters-explained/
This is off my CM308D4's, the link explains each part of the Thiele/Small parameters for those interested in learning more about what they're dealing with of their own parameters better.
Poly-fil by name is actually a brand and seems to have become more of an identifier of products than a single product, much like everyone pretty much calls any sound deadner material "dynomat" and its accepted as such despite over a dozen brands with other well known brand names. As such, Poly-fil fills the virtual area in the box by slowing down the sound waves, thus making the box seem larger. Breaking up soundwaves doesn't really make much sense. The commonly used phrase of "breaking up standing waves" which refers in acoustics to stopping reflections between parallel walls or similarly symmetrical reflective surfaces which cause tonal resonances; most often seen in square or rectangular boxes or enclosures.
As for the removed airspace, ideally in a sealed box application (2nd order enclosure), you should be able to increase power vs reducing the power. A ported enclosure would be different depending on anything else 3rd order and above. I once had a Kicker rep tell me there was no actual difference in a Solobaric vs a Kicker Comp (at that time) with exception of the marketing of the two separated by the fact the Solobaric was sold as a woofer able to work in smaller enclosures, via adding power handling and the in the Thiele/Small/Parameters, the power was nearly doubled as the airspace was just over a 1/3 of a Comp needed airspace. Whether his comments were a 100%, I can't prove otherwise over 2 decades later but I've done well with both.
buggman wrote:
I like to use either MDF or particle board for my boxes with plenty of internal screw points.
For filling the box, I normally use some poly-fill, the same stuff you'd use to stuff a pillow (from the craft department). You don't want to super pack the fill material, just loosely fluff it inside the box. Not sure if it really "makes the box seem larger" myth but it doesn't seem to hurt, especially in sealed boxes.
MDF is denser than particle board and also easier to sand or work with. Neither do well with high moisture and often act like a sponge when they get wet. But few people are willing to spend $58-70 for a 4x8 sheet of Marine Grade Plywood which does have a different sound as would any other Hardwood used. My enclosure is rather difficult in design for a single down firing 8" after swapping in the sport seats awhile back.
I no longer recommend the use of liquid nail in box building.. Wood glue works far better, add 100% silicone to seal enclosures as it doesnt build up a gas while drying and ignite while under pressure and electronically ignited [add facepalm] when test bumping the following day!
I still havent built the enclosure but I think when i do, I may actually make a video of the box/amp rack build as well as take pics, then maybe a follow up as its installed and test bumped.
410customs wrote:
dont forget to subtract the volume of the speaker itself from your 0.88 enclosure, once you drop the woofer in there the cone and cage and magnet take up a bit of airspace, might bring you right to the 0.8 you are after
It's been some time but that falls under Vd, or Peak displacement volume, calculated by Vd = Sd·Xmax if I recall in the Thiele/Small parameters. If you use any type of "box" calculation program, it'll ask for this while calculating enclosure volume and a cut sheet for you.
Last edited on Thu Mar 5th, 2020 01:00 am by Undrstm8ed
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