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Discussion Starter #1
Going to be rebuilding my box from the sonotube its in now, moving to an apartment soon, need something more visually pleasing

probably going for a regular box, ~3.5cuft and i want to try dual tuning at ~19-20 and the other at 26 or so, dont know if i want to do like SVS and plug and unplug one to change tuning or just swap over ports from low to higher tune, i cant do too big of a box, so i was looking at doing 2 3", ports become alot more reasonable in size, 1 3" for low tune, 2 for higher tune, or do 2 4" one low and one high

this is going in a college apt, so not going to be listening at high volume, my box now is missing alot in the 28-40hz for music, im used to car audio where you get a big boost there, i miss it in my sono i have now, which is ~3.6 tuned to 19 i believe it was, power now is a ep2500, but probably going to change to a bash 500w plate amp

so sum it up
TC 2000 12 S 4ohm
Bash 500w
dual tuning 19 and 26 ish
sub mounted up front, the ports on the rear, or maybe ports up front
80% movies 20% music probably
box wll be built by me and Rodney, gloss black paint, hopefully will look nice when finished

just wanted to get some recommendations for ideas

thanks guys:bigsmile:
 

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Discussion Starter #3
Here they are off TC's site

TC-2000
Fixed SVC 12"
Qms 3.72
Res Ω 3.12
BL (Tm) 17.20
Mms (grams) 265.00
Cms µN/M 228.00
Sd (m^2) 0.0490
Lp (mH)
Ls (mH)
Rp Ω

Constants
c (m/s) 341.00
d (kg/m³ 1.20
K 9.64E-10

Calculated
Vas (liters) 76.39
Fs (Hz) 20.48
Qes 0.360
Qts 0.328
n0 1.76E-03
SPL (dB) 84.45


xmax is 28mm iirc
xmech is 42mm
thanks
 

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Your idea is not going to work. First of all, the tuning for this sub is too high, you'll wind up with a peaky response. Second, for either tuning frequency, two 4 inch flared ports is minimum. Tuned to 20 hz with one 4 inch port the air speed is 54 m/s. Tuned to 26 hz with one 4 inch port the air speed is 64 m/s. This is way beyond port noise! An option would be to use the passive radiaitors from CSS. They are adjustable from the outside. You unscrew a center cap, add the supplied washers and screw the cap back on. It's that simple. If this interests you at all let me know and I'll run a model on it.

TC2000.JPG
 

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Discussion Starter #5
thanks mike

i have it done now with a single 4" psp flared port, tuned to ~19hz, havnt ran into any problems with it with noise

im looking for that peak in the 30s, so that dosent bother me

ill probably do the 2 4"s, like i said its a college apt, so im not going full out watching movies
 

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Mike

so you think the best way is to use the passive radiators?

The sub right now is on a sonotube 3.5cft and is tune to 19hz with a ep2500, his going to buy a 500 bash amp for the new box.
 

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I would do the PR's to keep the box size down since a pair of 4 inch ports take up a lot of room. I'm not understanding how port noise isn't an issue at over 60 m/s with the sonotube (3.5cft and is tune to 19hz with a ep2500)

Lets see!! He has 4 15" subs on a wall behind his head in his suv and 4000 watts:scared:, I would said DEAF!!!! or BASS HEAD:bigsmile:
 

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Discussion Starter #10
wait,what? i cant hear you!!

also your one to talk about 4 15s...

how about a slot port mike? how many sq in of port would it need on there, would just have to bend it around a bit

or if i was to go PRs, they arnt too good looking, i would want them out of sight, my main goal is a speaker that looks good and sounds good

what im wondering is how does SVS and HSU get such a low tune without running into issues with port length or noise? to my knowledge there is no way to cheat physics

my goal is something similar to this
 

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Discussion Starter #12
i guess try about 20hz or so for slot port, seems fine for a single 12, see if we can get a reasonable length

could you do a design similar to that svs? thats essentially what im going for

http://svsound.com/products-sub-box-newpb12plus.cfm

that one is 25dx19wx21h, if i could do a little bit smaller it would be good, but i might could fit that size, 3 3" ports is the way that one is done
 

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A slot port with internal dimensions of 7" wide by 3" high and 36" long works well with the Bash 500 if the HPF is set at 13.9 hz and 1 db of boost at 20-24 hz. Maximum air speed would be 30 m/s at 20 hz.

Three 3 inch flared ports 38 inches long would work as well with the same HPF and boost on the Bash 500. Maximum air speed is the same, 30 m/s at 20 hz.

If you were to block one of the ports the tuning would drop to 16.5 hz with an air speed of 34 m/s at 16 hz.

Block 2 or the ports and the tuning drops to 11.6 hz with a maximum air speed of 29 m/s at 12 hz.

The air speed doesn't increase much at the lower tunings due to the effect of the HPF.

Here's a SPL graph of the three tunings. Green is three 3 inch ports, pink is two 3 inch ports and orange is one 3 inch port.

TC 2000 SPL Comparison.JPG
 

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Discussion Starter #14
A slot port with internal dimensions of 7" wide by 3" high and 36" long works well with the Bash 500 if the HPF is set at 13.9 hz and 1 db of boost at 20-24 hz. Maximum air speed would be 30 m/s at 20 hz.

Three 3 inch flared ports 38 inches long would work as well with the same HPF and boost on the Bash 500. Maximum air speed is the same, 30 m/s at 20 hz.

If you were to block one of the ports the tuning would drop to 16.5 hz with an air speed of 34 m/s at 16 hz.

Block 2 or the ports and the tuning drops to 11.6 hz with a maximum air speed of 29 m/s at 12 hz.

The air speed doesn't increase much at the lower tunings due to the effect of the HPF.

Here's a SPL graph of the three tunings. Green is three 3 inch ports, pink is two 3 inch ports and orange is one 3 inch port.

View attachment 12966
Thanks Mike,

Thats what i want to do, but can i raise the 1st tuning to a little bit higher? this would also shorten the ports a bit, im not worried about tuning too low, 19-20 is fine for me, but i want something to give me a boost in the 30hz area

which would be better, doing the slot port or the multiple aero's?
 

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Discussion Starter #16 (Edited)
thanks mike,but i didnt make it too clear on there, sorry, i meant the 1st tuning of the 3 aero ports, say all 3=25, 2 =20, and 1 =16 or something along those lines, but i would never really use the 16 setting

edit: 14.5/20.5/25 are all right at like 23.3" long, doing 3.5cubes SS filter at 15hz, looks decent if i did it right

im stuck between doing doing slot port or spending all that money on psp ports
just seems like the flared aero ports would work better on there than regular slot port, even if you manage to do a round over on it, not sure though

also yesterday at work i saw we had 3 of the boston acoustics 12" GTR radiators left, their site dosent give too much info on them but to do with a boston G5, the lowest tune it shows you can get with the included weights is 30hz, i dont know how PRs work, ie:if you use the 30hz setting, does it change as box size changes or is that constant

here is a PDF
http://mobile.bostonacoustics.com/manuals/G5_GTR_Man.pdf

im sure i could get extra weights on there if needed, but as far as weightm, i have no idea

i would rather keep it ported than shooting in the dark with those, but i can get them uber-cheap im assuming, we have no use for them
 

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The 12" GTR only works at those specified frequencies in a 1 cu.ft. box. To see if they would work in your 3.5 cu.ft.box the parameters would be needed.

Green 25 hz 3 - 3 inch ports 23.75
Pink 20.5 hz 2 - 3 inch ports
Orange 14.5 hz 1 - 3 inch port

The HPF on the Bash 500 needs to be changed to 18.7 hz with 1 db of boost from 25-30 hz.

SPL graph:
TC2000 25 hz.JPG

And these are the respective port air speeds:
TC2000 25 hz Air Speed.JPG
 
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