"Magic Box" V.2 For an 18"

[sundownz 197]

Took some pics of the process -- thanks to Brandon for helping me get it done in a timely fashion.

* Basic shell complete. We are using mostly cabinet grade Oak plywood (3/4") with some 7/8" ply as well (bottom panel and one layer of top baffle).

* I like to use lots of screws... 2" long models.

* Temporary guide setup to build the port straight

* Outline walls of the port... ready for flexible ply.

* Flexible ply installed to make the flare.

* Coming together !

* Filling in across the flare with strips of wood.

* Wood filler in the gaps.

* Fiberglass cloth and resin applied.

* Top baffles going on.

* Hole cut with counter-sink

* In the Jeep !

---

I installed the only 18" I had laying around in there and it is a hair behind the old Magic Box per watt so far... but this 18" had an extra hard suspension which is terrible in a box this small.

So... based on results so far I expect this box to pull ahead of the old Magic Box once the correct spider configuration is used. It seems to be functionally nearly identically just with more cone and port area (and a bit more volume).

[Kanaworm$ 292]

Ahhh the secret is out now! Box looks great!

[sundownz 197]

The "secret" is a bit more complicated than the pictures might imply... I'd be impressed if someone figured it all out from the pics

I spent all morning the other day reverse engineering the old box since we built it 3+ years ago *laughs* Then I scaled it up and kept the important ratios identical to the old box but a bit larger for an 18.

[sundownz 197]

Results so far with Z v.2 18" D2 with 3 Spiders (too stiff for this box):

420 watts = 144.6

520 watts = 145.5

660 watts = 146.4

830 watts = 147.2

1040 watts = 148.0

1310 watts = 149.0

1620 watts = 149.8

1790 watts = 150.1

1960 watts = 150.4

2340 watts = 151.1

* Let Sub Cool for about 15 minutes *

2530 watts = 151.6

3110 watts = 152.4

3390 watts = 152.7

3530 watts = 152.9

3860 watts = 153.1

4160 watts = 153.4

All results @ 53 Hz / dB Drag on the dash sealed mic position on the TL.

[The enD 467]

Going to beat that 156.1 ?

[sundownz 197]

Going to beat that 156.1 ?

Yah, I think so. When I get more power again.

[ssh 924]

Thats impressive

[kkk4 3]

spectacular

[sundownz 197]

Been playing with it a bit and still not quite up to Magic Box v.1 performance... need to figure out what works best in this box.

Interestingly the 3 Spider Z v.2 was louder than a 3 Spider Nightshade v.1 in this box at equal power (as three NS spiders is a bit less stiff over stroke they are louder in the 15" v.1 enclosure - 2 Z v.2 spiders was roughly equivalent per watt). This leads me to believe I may need to build several 18s to see what configuration is the loudest.

Plan to build a 2 spider model and a 4 spider model and run them all to see what happens.

[sundownz 197]

Oh yah... rounded all outside edges of the box and around the port mouth this morning -- zero change in SPL.

[mrbojang 8]

Nice. I like the idea of the threaded rods for the speaker wiring posts. I'm going to steal it, if you don't mind.

[Randal Johnson 544]

awesome work 4 sure ...

[Adrian_D 520]

Sweet, I'm digging the power vs score tests

How much do you gain by removing all the interior panels ?

[B7L|BL4Z3R 4]

what kind of bolt do you use for terminals?

[draggnwagon 2]

what kind of bolt do you use for terminals?

I know the answer to this one. its bass threaded rod. probley 5/16 or 1/4

[sundownz 197]

Sweet, I'm digging the power vs score tests

How much do you gain by removing all the interior panels ?

Couple tenths... not really significant. It does make it alot easier to work in there, though.

[Derrick824 4]

what kind of bolt do you use for terminals?

I know the answer to this one. its bass threaded rod. probley 5/16 or 1/4

Hahaha, "bass" threaded rod.

[1200 bandit 2]

Nice

[Moparbass28 0]

Nice design and build.

Impressed with power to score tests. Always nice to see you share this info.

[sundownz 197]

Results so far with Z v.2 18" D2 with 3 Spiders (too stiff for this box):

420 watts = 144.6

520 watts = 145.5

660 watts = 146.4

830 watts = 147.2

1040 watts = 148.0

1310 watts = 149.0

1620 watts = 149.8

1790 watts = 150.1

1960 watts = 150.4

2340 watts = 151.1

* Let Sub Cool for about 15 minutes *

2530 watts = 151.6

3110 watts = 152.4

3390 watts = 152.7

3530 watts = 152.9

3860 watts = 153.1

4160 watts = 153.4

All results @ 53 Hz / dB Drag on the dash sealed mic position on the TL.

Swapped to a 2 spider Z v.2 and found my frequency is actually 54 hz with this box :

920 watts = 148.6

1210 watts = 149.3

1510 watts = 150.1

* Sub cool down for 10 minutes *

1890 watts = 150.9

2570 watts = 152.2

2940 watts = 152.4

* Sub cool down for 10 minutes *

3320 watts = 153.0

3650 watts = 153.1

* Sub cool down for 10 minutes *

3850 watts = 153.4

So... SPL per watt is up now. Tried a few things to get my peak back to 53 hz with no luck yet.

[poundindak69 15]

nice box you got there.

Edited May 24, 2010 by lil98cabrio

[Moparbass28 0]

Nice progress.

[SPL_Man 20]

very nice scores for the amt of power being used

i wud like to ask something about the bottom piece of board under the port : does it noticeably flex seeing that nothing is attached on to it at 1 end & will that result in a loss of energy , maybe if u doubled up on that board it should yield even better results ?

im just asking though

[sundownz 197]

very nice scores for the amt of power being used

i wud like to ask something about the bottom piece of board under the port : does it noticeably flex seeing that nothing is attached on to it at 1 end & will that result in a loss of energy , maybe if u doubled up on that board it should yield even better results ?

im just asking though

Can't do it -- won't fit under the window line. I haven't noticed any flex on it either.

[Randal Johnson 544]

awesome #s !!!