Kappa 120.9w Need help with my first box design..

[Chrisrizzy]

Right now, I'm running my Infinity Kappa 120.9W in a 1.0 cuft sealed box with polyfill. It doesn't sound bad at all, but it lacks the impact I desire on a 500w RMS Kenwood Excelon amp. I'm thinking of going ported, but I fear losing a fair amount of sq as I listen to a wide range of music. The specs provided by Infinity are: 2.0 cuft with a 30hz tuned port. Port length is 13 and 5/8" with a 4" diameter.

When I comes to enclosures, my audio knowledge kind of drops off lol. I just know ported is more efficient and adds more boom as sealed is tighter and less efficient. With the specifics given, can you tell me how the sub will perform? I'd also appreciate some tips on measuring and building the box since this would be my first time!

-Thanks

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[trumpet 5,000+ posts]

Right now, I'm running my Infinity Kappa 120.9W in a 1.0 cuft sealed box with polyfill. It doesn't sound bad at all, but it lacks the impact I desire on a 500w RMS Kenwood Excelon amp. I'm thinking of going ported, but I fear losing a fair amount of sq as I listen to a wide range of music. The specs provided by Infinity are: 2.0 cuft with a 30hz tuned port. Port length is 13 and 5/8" with a 4" diameter.
When I comes to enclosures, my audio knowledge kind of drops off lol. I just know ported is more efficient and adds more boom as sealed is tighter and less efficient. With the specifics given, can you tell me how the sub will perform? I'd also appreciate some tips on measuring and building the box since this would be my first time!

-Thanks

I modeled the Kappa 120.9W in both a sealed enclosure and a ported enclosure, and for comparison to what I'm running there is also a Dayton Titanic MK4 in 2 cu ft ported at 36 Hz.

white curve = Infinity 120.9W in 2 cubes ported tuned to 30 Hz

red curve = Dayton Titanic MK4 in 2 cubes ported tuned to 36 Hz

yellow curve = Infinity 120.9W in 1 cube sealed

Kappa 120.9W has a reputation for excellent sound quality, and it has a fair amount of excursion potential as well to move some air. While these graphs don't automatically mean X sub will sound like Y, I'm extremely impressed with the sound I'm getting from the Dayton Titanic MK4 on 500W RMS.

Compare the space between the white and yellow curves. It's absolutely massive in any range below what we typically set as a subwoofer's low pass filter. What this means is your deep bass response in 2 cubes ported and tuned to 30 Hz will sound like an entirely different experience. While this image doesn't show SPL, the difference without any boost from the vehicle's acoustics is 6 dB greater in the ported enclosure at 40 Hz. 6 Dee Beez. That's the power of the port. I would expect this to sound pretty great, although you may hear some new or louder rattles.

 

[Chrisrizzy]

I modeled the Kappa 120.9W in both a sealed enclosure and a ported enclosure, and for comparison to what I'm running there is also a Dayton Titanic MK4 in 2 cu ft ported at 36 Hz.

white curve = Infinity 120.9W in 2 cubes ported tuned to 30 Hz

red curve = Dayton Titanic MK4 in 2 cubes ported tuned to 36 Hz

yellow curve = Infinity 120.9W in 1 cube sealed

Kappa 120.9W has a reputation for excellent sound quality, and it has a fair amount of excursion potential as well to move some air. While these graphs don't automatically mean X sub will sound like Y, I'm extremely impressed with the sound I'm getting from the Dayton Titanic MK4 on 500W RMS.

Compare the space between the white and yellow curves. It's absolutely massive in any range below what we typically set as a subwoofer's low pass filter. What this means is your deep bass response in 2 cubes ported and tuned to 30 Hz will sound like an entirely different experience. While this image doesn't show SPL, the difference without any boost from the vehicle's acoustics is 6 dB greater in the ported enclosure at 40 Hz. 6 Dee Beez. That's the power of the port. I would expect this to sound pretty great, although you may hear some new or louder rattles.

Wow! I really appreciate you putting this into Winisd and giving me the run down! Going off of what you said, 2.0 cuft at 30hz is going to be the way to go. This is kind of a stupid question, but how exactly do you build the port... Do I just measure the wood to the desired length and width and I'm good? My apologies, I'm a beginner.

 

[trumpet 5,000+ posts]

Wow! I really appreciate you putting this into Winisd and giving me the run down! Going off of what you said, 2.0 cuft at 30hz is going to be the way to go. This is kind of a stupid question, but how exactly do you build the port... Do I just measure the wood to the desired length and width and I'm good? My apologies, I'm a beginner.

There's no better way to dig into this than to start with the fundamentals:

https://jlaudio.zendesk.com/hc/en-us/articles/224938887-Calculating-Enclosure-Volume-

https://jlaudio.zendesk.com/hc/en-us/articles/221068047-Enclosure-Ports