I have a DC lvl 4 m2 18 d2 and an american bass hd 3500. bout 1200rms clean. the sub takes 1400 and its underrated. on dc's site they reccomend a 6 cube box. how to i know how much to compensate for the lesser power?

Use what they recommend, 200 watts wouldn't make a difference anyway.

The RMS rating has nothing whatsover to do with how much the sub needs or how much output it will have. The only, and I mean the only thing, the RMS rating tells you is how much power a subwoofer can take on a continuos basis. It tells you absolutelu nothing else...

You need to model to see what enclosure size will optimize your power you already have, if you want to look at it that way. But that is kind of backwards. You should always model for the the most efficient enclsoure you can build (size wise) with the response you desire. Power should be the last thing you decide. If you do it the other way around, you are going about it the wrong way...

what he said

Couldn't agree more with Honda.

One other further clarification. You DON'T change your enclosure due to the power you are running. You are misapplying what you've read. Can, should, will, and do are not all related.

Here is what I look at: (in order)

Space available

Port area needed

Tuning frequency

Once I determine those, I then try a few different designs and see if the cubes is within the mfg "recommended specs". I usually use Torres calculator, then double check by hand.

From there I model the different designs I have come up with.

Despite all this, modeling is still a basic simulation and used to compare the different enclosures and often isn't the same in real world. Also, I seem to build a few designs to see what I like best. I just like building and trying new things. Sometimes it is an improvement, sometimes not so much.

All that being said, if I have a few different designs and are similar in performance, I may lean towards the smaller enclosure with higher power. You may even see some MFG like Sundown even footnote "xx cuft for spl applications". But to aimlessly build it bigger or smaller because of power will typically yield poor results.

* I am be no means a professional designer. I've been into car audio since the late 80's and built I don't know how many enclosures. I know what has worked for me, but may not always be the "best" for someone else with different goals.

Couldn't agree more with Honda.

One other further clarification. You DON'T change your enclosure due to the power you are running. You are misapplying what you've read. Can, should, will, and do are not all related.

I always thought it was funny when people use a smaller enclosure volume for the sole reason being able to use more power.

Here is what I look at: (in order)

Space available

Port area needed

Tuning frequency

Once I determine those, I then try a few different designs and see if the cubes is within the mfg "recommended specs". I usually use Torres calculator, then double check by hand.

From there I model the different designs I have come up with.

Despite all this, modeling is still a basic simulation and used to compare the different enclosures and often isn't the same in real world. Also, I seem to build a few designs to see what I like best. I just like building and trying new things. Sometimes it is an improvement, sometimes not so much.

All that being said, if I have a few different designs and are similar in performance, I may lean towards the smaller enclosure with higher power. You may even see some MFG like Sundown even footnote "xx cuft for spl applications". But to aimlessly build it bigger or smaller because of power will typically yield poor results.

* I am be no means a professional designer. I've been into car audio since the late 80's and built I don't know how many enclosures. I know what has worked for me, but may not always be the "best" for someone else with different goals.

I would think tuning frequency would go above port area needed--since in a round-about-way adequate port area is based on port mach, and port mach happens to be affected by tuning frequency.

But then again I like to look at the overall frequency response.

Edited August 8, 201213 yr by stefanhinote

The only time the power comes into to play is you are building a high efficiency enclosure. Those are normally low power setups and can max out the mechanical limits of a driver prior to reaching RMS. Other then that enclosures play a small roll in the power handling of a driver.

Depending on the driver, the enclosure has a complete role in the mechanical power handling of a sub. Whether you blow the sub by cooking the coil or by tearing the suspension up and smashing the former against the backplate, it's just as dead.

The only time the power comes into to play is you are building a high efficiency enclosure. Those are normally low power setups and can max out the mechanical limits of a driver prior to reaching RMS. Other then that enclosures play a small roll in the power handling of a driver.

I disagree. The RMS rating is meaningless unless you have designed an enclosure that is inefficent enough that you will continually run into thermal limitations before mechincal ones. And don't think mechanical limits mean destruction 100% of the time. This also means you have moved far enough into the non-linear region of the driver's stroke that you are no longer gaining output by applying more power.

Enclosure design is the primary driver of power requirements for a desired output level.