Calculation RMS Power for a Subwoofer... For a woofer which is not built yet. Only design is ready.

[Haunz 10+ year member]

Drivers are normally rated in 'program'. (ie. RMS voltage available x RMS current available x duty cycle of music)

Pink noise is normally used to rate the thermal power handling of a driver, as it is approximately equal to the duty cycle of music.

There are several IEC standards for thermal power handling. I would look those up.

 

[hispls 5,000+ posts]

Thanks for your reply.
We use EP200 and some other adhesives from US. We work with Hernon and CP Moyen.
For serial production, we use glue from China and Taiwan.
For bubble problem, yes we know that very well. We also had some solutions for that.
So for the calculation RMS, you count layers just only one side of the VC, correct? or you double that, because it is circle?

I don't think glue for assembly is so much of an issue (triple joint, surround to frame, spider to frame, etc.) I have had good luck with several different CA glues and I've seen people using several other types of adhesives to make subs that can withstand some extreme punishment. I understand the epoxy used to wind and bake the coils can make a difference and often Chinese coils will unwind "slinky" sooner than similar size American made ones.

As far as I know Precision Econowind is the top name for voice coil winding but they are not cheap and there is a long wait to get an order made (also shipping to and from USA may be cost prohibitive). Hopefully you can find someone reliable to build coils elsewhere. Honestly I suspect if someone could build a factory to custom wind coils they would quickly have more work than they could handle. I'm sure loudspeaker voice coils are not the only project those places get.

Simply using a thicker steel former should prevent outgassing issues, round wire also adds some resistance to this problem, at the expense of some efficiency but round wire coils will also save cost and have been used successfully in many top quality loudspeakers.

Count only one side for using this method for estimating power handling. For the record this formula was passed along from engineers at Emminence (you've probably heard of them, they make a few loudspeakers). You will notice it's pretty consistent with ratings you'll find from Sundown. I have had this conversation with Jacob who is also of the mind to rate your speakers conservatively enough that they're almost impossible to break within your rated power. This has done well by way of the reputation his speakers have built.