Building a sub box

[seq4x4]

No dramas, So what do these figures actully mean?
Lg Sealed 1.25
Qtc 0.977
F3 45.76
As i want to build it right the first time as i have way to many projects on the go to buy extra wood incase of stuff up.

 

[Tasmaniak]

Lg Sealed is not a T/S term, it just means large sealed enclosure: 1.25cu.ft.

F3 is an easy one - every driver has a frequency where it's performance starts to decline as it attempts to play lower and lower. This gradual decrease is considered to start when the frequency response graph shows a lower freqency 3dB below the rest and every frequency below that is ALWAYS lower. No more peaks and troughs. The frequency that this starts at is called f3.

Qtc - Man, I'm not sure how to explain this one...Technical explanation, The Q is relative damping of a driver (sub) and the "tc" is the resonant frequency of that driver in that sealed enclosure. Not to be confused with Qts which is the damping of the resonant freqency of that driver in an infinite baffle (free-air) scenario.

Erm, not really sure how to explain Qtc in simpler terms. It took me a bloody long time to wrap my head around it! To be perfectly honest, in your situation, I wouldn't worry about it. The biggest one you need to know is how many cu.ft.

 

[seq4x4]

Thanks for your help. I wasnt quite sure how to read it. Nice little box to build i think. Just waiting on the subs to arrive. Thanks!

Just one more question. After the math i need a H35.6, W35.6 D36.6cm box. Is it required to have insulation in it as i have a large amount of it laying around. Or can i half the box and add that?

 

[Tasmaniak]

Looking at that qtc, I would be inclined to keep that size and put some padding stapled to the walls and leave it at that.

 

[Tasmaniak]

Hey just a thought that many people forget... Are those dimension the inside of the box or the outside? Remember, your MDF is 18mm thick so effectively your box just grew 36mm in height, width and depth.

 

[seq4x4]

Those are the outside mesurements taking into account for a 16mm mdf. However due to them being out of stock of the sound streams their sending me 2 Rockford Fosgate P1 12" instead.

 

[Tasmaniak]

ooOOoo they are actually a really nice sub for their money. And I think they are worth a lot more then the Soundstream from memory. If your more then capable of building the enclosure... take those boys vented. Little more complex to build but I can work out the dimensions for you if get me the max dimensions the box can take. Calculating port length can be a bitch (not CAN but IS a bitch lol)... also need boot opening width lol.

 

[seq4x4]

Is ported so much better? I thought sealed was the deal?
By building a ported box i dare say this would be perfect to use? RE AUDIO - Box Calculator

 

[Fun_Bucket]

Ported or sealed is up to you, you need to decide. No point is buying a driver and then wondering what to do with it. Buy the driver you want, for the sized enclosure you want, for the type of application you want. Paramaters are only part of it, once you put the driver in an enclosure those paramaters change.

 

[Tasmaniak]

I personally use Bass Box Pro still....Not sure if there is anything newer out there or not. Can't teach an old dog new tricks I guess.

To get the most out of the subs with your amp.. then yeah, I would be leaning towards vented.