Rockville M-4 At .5 ohm (no joke)

[ShowtimeElectronics]

these threads always feel like undercover infomercials.

[kirill007]

this thread..

[SlamminBeats]

Every box is tuned. Prefab or "custom"

Mind = blown

[ShadeTreeMechanic]

After the box is built it can be further tuned with poly fill. The more you add the lower Fb goes until you reach about 1 lb per cuft. Then continue to add to reduce volume and raise Fb above empty. Everyone wants the low bass but the mid bass drivers can benefit from being overstuffed. Poly fill will also make the box sound less hollow. All you really need is a little bit. Ported boxes are a different animal. I will try to post up the equations in a new post. Thanks everyone for your input.

[MrSkippyJ]

You guys are a blast!! I almost spit my coffee through my nose!!

Really though the sealed box is tuned by its volume. Pick your box Q (Qb) maybe .7 for flat response and nice roll off or higher if you want a big bump. Plug and chug the numbers in the equations. You will get the box volume (Vb) for your selected Q, then you get your resonant frequency (Fb) which is what your box is tuned to, then you get your 3db down point (F3) on your roll off. So this is how it can be tuned to 59Hz with a F3 of 44Hz.

Because this is how we figured out how big to make the box to begin with right?

Thanks everyone for your input!

thanks for taking the time to answer! i had to elicit some extra help to clear up a few things but it all makes sense now

[ShadeTreeMechanic]

You guys are a blast!! I almost spit my coffee through my nose!!

Really though the sealed box is tuned by its volume. Pick your box Q (Qb) maybe .7 for flat response and nice roll off or higher if you want a big bump. Plug and chug the numbers in the equations. You will get the box volume (Vb) for your selected Q, then you get your resonant frequency (Fb) which is what your box is tuned to, then you get your 3db down point (F3) on your roll off. So this is how it can be tuned to 59Hz with a F3 of 44Hz.

Because this is how we figured out how big to make the box to begin with right?

Thanks everyone for your input!

thanks for taking the time to answer! i had to elicit some extra help to clear up a few things but it all makes sense now

No Problem! You guys made me think! I have been lurking here and learning a ton for a long time and finally decided to join!

[Miguels]

You guys are a blast!! I almost spit my coffee through my nose!!

Really though the sealed box is tuned by its volume. Pick your box Q (Qb) maybe .7 for flat response and nice roll off or higher if you want a big bump. Plug and chug the numbers in the equations. You will get the box volume (Vb) for your selected Q, then you get your resonant frequency (Fb) which is what your box is tuned to, then you get your 3db down point (F3) on your roll off. So this is how it can be tuned to 59Hz with a F3 of 44Hz.

Because this is how we figured out how big to make the box to begin with right?

Thanks everyone for your input!

but wouldnt it be sub dependent? its tuned 59hz with that sub but put another sub in and will be different.. serious question here

a ported box tuned to 32hz is tuned to 32hz and with different subs it might change but just a bit depending of the displacement of the sub but it wont be much

[ShadeTreeMechanic]

You guys are a blast!! I almost spit my coffee through my nose!!

Really though the sealed box is tuned by its volume. Pick your box Q (Qb) maybe .7 for flat response and nice roll off or higher if you want a big bump. Plug and chug the numbers in the equations. You will get the box volume (Vb) for your selected Q, then you get your resonant frequency (Fb) which is what your box is tuned to, then you get your 3db down point (F3) on your roll off. So this is how it can be tuned to 59Hz with a F3 of 44Hz.

Because this is how we figured out how big to make the box to begin with right?

Thanks everyone for your input!

but wouldnt it be sub dependent? its tuned 59hz with that sub but put another sub in and will be different.. serious question here

a ported box tuned to 32hz is tuned to 32hz and with different subs it might change but just a bit depending of the displacement of the sub but it wont be much

You are correct.

The tuning frequency is very dependent on the drivers Fs in a sealed box.

In a ported enclosure the port is tuned to the box volume, so any driver would do except the box volume needs to be tuned to the driver to begin with. So you would tune the box to the driver and then tune the port to the box. People run into a problem when the box is too small the port will end up being so long it might not fit in the box. For highest SPL you would have the port tuned the same or slightly lower than the box and it will give a big bump at the tuned frequency that might make it hard to match the rest of the system.

Thanks for your question!

[Miguels]

so in other words you cant tune a box. changing subs changes the tuning drastically .. you just cant build it and say its 34hz. you have to build it to the subs perimeters.. think everyone here knows that and also falls within the manufacturers recommendations

a sealed box is just a sealed box and the sub will make the tuning.. i get what youre saying but still not the same tuning as a ported box but shows that even being a sealed box the box has to be custom made for your application

[ShadeTreeMechanic]

so in other words you cant tune a box. changing subs changes the tuning drastically .. you just cant build it and say its 34hz. you have to build it to the subs perimeters.. think everyone here knows that and also falls within the manufacturers recommendations

a sealed box is just a sealed box and the sub will make the tuning.. i get what youre saying but still not the same tuning as a ported box but shows that even being a sealed box the box has to be custom made for your application

The box size is tuned for the frequency you want for a particular driver. If the box is the wrong size then then the tuning will be off.

Pick driver X. Driver X has certain parameters. Decide what you want the response slope to be. This is where you tune it.

Usually a box Q of .7 will give a nice roll off on the bottom end and a certain resonant frequency. Determined by the driver and the Box Q you selected. Some programs wont let you select this and you are stuck with .7.

Suppose that frequency is too low for you. Recalculate with a Box Q of 1.2 and your box gets smaller, and resonant frequency goes up and at a higher peak with a steeper roll off.

Maybe .7 was too high then try .5. This slope is very long and rolls off very nice but the output suffers because it wont be as loud. This box is very big and peaks at a lower frequency.

So in essence you pick the driver and run the numbers. Sometimes a driver is not well suited for an application. Pick another driver and run the numbers again.

Unless you bought a prefab box first. Then you have to find a driver that works in it.

Some people look at the manufacturers recommendations which say the driver works well in a box of 1.5 to 3 cubic feet or something. The buy a box in that range and they are just getting anything and have no idea but it sounds OK. Its OK too if that's all they want to put into it.