help building a box for a hdc4 18

[chava]

Can some one help me with a box dimensions im trying to build a box dat messures 48lx25dx20h tuned to 33 htz

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[Papermaker85 5,000+ posts]

25*25*18 with a port 16.5*3.25*17

 

[Jeffdachef 5,000+ posts]

25*25*18 with a port 16.5*3.25*17

that seems way too small to be for an 18 along with being tuned high too.

 

[Papermaker85 5,000+ posts]

OH **** I though it was a 15..

That box is 4.45 tuned to 36(with the slot port calculations).. Using bbpro with two flush ends and adding 1/2 the width of the port to the length I get 36.88.. What are you getting?

 

[Jeffdachef 5,000+ posts]

OH **** I though it was a 15..That box is 4.45 tuned to 36(with the slot port calculations).. Using bbpro with two flush ends and adding 1/2 the width of the port to the length I get 36.88.. What are you getting?

With torres i'm getting 37hz at 4.3 but i added a 2nd baffle so that took some space and moved the tuning up. Without it, i'm getting basically the same numbers as you.

 

[Papermaker85 5,000+ posts]

My hdc3 15 didn't really like to be tuned under 36..

Seeing as the 18 4.0 after break-in is probably closer to a fs of 36 I would times it somewhere around there as well. If you want more lowend increase box size or port area..

I'd say 37*20*25 with a port 4.25(internal)*18.5*12 gives me 8 tuned to 36.. Do I have to break out the formula and do the math? I know bassbox is suppoesr to be accurate no?

 

[Jeffdachef 5,000+ posts]

My hdc3 15 didn't really like to be tuned under 36..Seeing as the 18 4.0 after break-in is probably closer to a fs of 36 I would times it somewhere around there as well. If you want more lowend increase box size or port area..

I'd say 37*20*25 with a port 4.25(internal)*18.5*12 gives me 8 tuned to 36.. Do I have to break out the formula and do the math? I know bassbox is suppoesr to be accurate no?

Never said you were wrong lol. I assumed that first post was just a typo meant for a 15 too. I got similar numbers too with that one so yes BBpro is accurate. However your port area is on the low side of things and i'd try to account in 2ndary baffles, bracing and sub displacement.

The owner of the black nasty, Andrew McCullough has done a lot of testing with soundqubed subs as well and here are his results for a nice workable range with the HDC series

HDC3 & HDC4 Optimum Enclosure Size - Subwoofers / Enclosures - SMD Forum

I had my hdc3 18s at 12.5 cubes and 16.5 port area per cubic feet at 205 ish sq inches of port and they did well up top and down low to 25hz. Output could be gained with a higher tuning but I my vehicle peaked a bit higher so i tuned a bit lower at 35hz to compensate.

 

[Papermaker85 5,000+ posts]

thanks for catching that though..

54 not enough for daily? don't want the ports Q too low.. its going to fall off really fast. it not like the HDC4 has 30mm xmax. lol

i figured 75 you might be able to do 85 but i don't think anymore than that unless its strictly SPL will benefit..

i tried using alot of port area.. too much isn't a good thing..

well there parameters are ****.. lol

if you do use alot of port area you can decrease your VB to alter your Qt.. your ether loading the cone through resistance in the port or loading through the resistance of the smaller box..

Id like to see the parameters of a broken in driver wit a good tester.

 

[Jeffdachef 5,000+ posts]

It wont fall off that fast unless you listen to 25hz and below.... and they actually like high port area the overall output gained counteracts the roll off to a good degree. Takes a lot to bottom them out even with high port area and they can still play music fine. Kind of why soundqubed and majority of the soundqubed daily and competitors run 16-18 port per cube.

 

[Papermaker85 5,000+ posts]

i have a feeling its because hes getting huge parameter shifts from those not so linear spiders and motors..

 

[Papermaker85 5,000+ posts]

good info though.. last 18 i own was the orginal XXX with the XBL.. loved that driver.. i think i used right around 7 cubes with 80in^2 tuned to 32..

normally with a very stiff spide you can get away with A a larger box for increase efficiency or 2 larger port and decrease box size to help load the driver abit but i didn't think 6.5.

the few woofers i built where built around the more linear techniques/materials possible. also taking in mid parameter shifts from not only operating temperatures but when applying it in excess as well. generally id use a slightly stiff suspension for the high mass drivers as long as i could maintain a QEs lower than .55 while keeping the FS just a bit below intended bandwidth.

how you like those HDCs? i honestly didnt care for mine.. i reconed it with parts i had lying around and now shes better.. lol..

 

[Papermaker85 5,000+ posts]

5031193B-AA65-42CB-AC61-A735AEC0A81E-4784-00000367EAD10ED5.mp4 Video by papermaker85 | Photobucket

1DF18C75-992F-4753-AC0F-D4BEFF75CE6C-4737-00000363BFA25A78.mp4 Video by papermaker85 | Photobucket

that was about 1500 RMS. never put it into production because COP side swiped me and they turned the **** around on me. had one drink and blew over the limit.. needless to say i was out of pocket about 15k..

this pituclar driver perfered port are to box size as well.. FS was 30 and QE was .55.. loaded the driver with a smaller box and had 65in^2 of port area. 3.25 cube.. xmax was like 28mm IIRC 18mm top plate full pole shorting ring and a alum shorting ring faced off the same ID as ID as the topplate it sat inbetween the magnets ID and faced off to the ID of the TP.. i liked it.. wanted abit more motor strength but it was real natural and smooth..

 

[Jeffdachef 5,000+ posts]

good info though.. last 18 i own was the orginal XXX with the XBL.. loved that driver.. i think i used right around 7 cubes with 80in^2 tuned to 32..normally with a very stiff spide you can get away with A a larger box for increase efficiency or 2 larger port and decrease box size to help load the driver abit but i didn't think 6.5.

the few woofers i built where built around the more linear techniques/materials possible. also taking in mid parameter shifts from not only operating temperatures but when applying it in excess as well. generally id use a slightly stiff suspension for the high mass drivers as long as i could maintain a QEs lower than .55 while keeping the FS just a bit below intended bandwidth.

how you like those HDCs? i honestly didnt care for mine.. i reconed it with parts i had lying around and now shes better.. lol..

yeah soft parts arent that great, though my level 5 soft parts arent that great either. For the time I had them, the HDC3s did a pretty good job playing all the musical range i want from decaf to rock/metal when i had it and it get pretty loud to do shirt tricks from basically a D pillar no wall minivan. I just moved on from them. My dc level 5s got a lot louder even on less power at 2 ohms. Still going to have to change up the box a little bit reducing the port area and lowering the tuning for these level 5s down to 32-33hz.

 

[Papermaker85 5,000+ posts]

they use nomex spiders?

 

[DaytonLax14 10+ year member]