[goonstopher]

I have posted a number of designs that had issues so I want to make sure this is correct:

Hoped to build 2 of these and then 2 more with different size as end tables (4 total!)

Box
Woofer - Rss460-HO 18
Depth - 16 (int) 18.25 (ext)
Width - 47.5 (int) 49 (ext)
Height - 19 (int) 20.5 (ext)
Tune - 15hz

Signal
HPF - 2nd order at 13hz
Power - 800w each (2 wired to 4ohms on 1 side of NU6000)
Cone excursion - 22.3mm at 9hz; 16mm

Port - Think this is too long on 2nd thought
2 square ports - 4" x 4"
61" Long
110hz 1st resonance
max air speed 15.7ms @ 13hz

 

[Samps]

The HO is a 4ohm driver. No way to wire 2 and get a 4ohm load. You could run one off each side of the 6000 with the limiter on but you won't be able to add 2 more down the road and get a good ohm load for the best amp power.

That air speed is lower than it needs to be, which means you should be able to get a better port size/length and still get a good airspeed.

 

[Mrkazador]

Did you account for driver, port, and bracing displacement? Thats around 2cu ft.

 

[goonstopher]

Did you account for driver, port, and bracing displacement? Thats around 2cu ft.

Less than that but yea - External on this was about 7.8

Was thinking to use the port as brace.

How bad are bends in the port?

 

[Samps]

My math says that is 8.3 ft3 without subtracting for the driver and ports and bracing. That's not nearly enough for a 15hz tune. The full sized marty is almost twice that size and it's tuned higher. You can tune to whatever hz you want but the response will not be flat. Before you even start to look at the port size and shape and resonance you need to focus on the box size/tuning/and response. Your 15hz tune is definitely a big arch. To get a somewhat flat 15hz tune you will need a very big box.

 

[goonstopher]

My math says that is 8.3 ft3 without subtracting for the driver and ports and bracing. That's not nearly enough for a 15hz tune. The full sized marty is almost twice that size and it's tuned higher. You can tune to whatever hz you want but the response will not be flat. Before you even start to look at the port size and shape and resonance you need to focus on the box size/tuning/and response. Your 15hz tune is definitely a big arch. To get a somewhat flat 15hz tune you will need a very big box.

I don't care about flat from one - I care about flat from 3 or 4 of them

I get 105 at 15hz using 6'Cu and 107 using 7'Cu which stinks but with 2 in front that could be more like 110-111

If I add one nearfield (or 2) then should have 116 from 15 up

Does that math work?

Goal is to get 116 from 15hz up

 

[Mfusick]

Bigger box is better for a 15hz tune.

 

[goonstopher]

Bigger box is better for a 15hz tune.

Would rather use a smaller woofer than go bigger...

Bigger is not an option

 

[goonstopher]

I am fine with a long roll off...

Maybe I should use 15s but seems fine at 6-7 feet