I just got the answer back on second part of the PR discussion. Please check my interpretation and correct if needed. This relates to which approach is the more accurate or usable, and is now more clearly scenario specific and finally makes some sense to me:

**Approach 1 shorthand:**

All PR(s) at-least 2x

**Xmax**of woofer(s)

**Xmax**.

**Approach 2 shorthand:**

All PR(s)

**Vd**at-least 2x

**Vd**of woofer(s)

**Vd**, so PR(s) total

**Vd**at-least 2x all woofer(s)

**Sd**x

**Xmax**.

**Direct from PE Tech:**

I emphasized my perceived most relevant aspects with italics and bold.

"They are both correct, the

**newer product**simply states the math you can use to determine if you can

**get away**with one PR

**or**if you need two. They describe the same thing, that you need to be able to displace

**double the air volume**, and just describe it in

*different ways*.

Since our

**new**reference series PR's have such a

**large Xmax**, you

*don't*always need to use

**two**PR's. I have had times where the new PR is working with a driver that has

**lower Xmax**and a single passive will work.

That said I have also found when using BassBox to create designs for customers, sometimes using two PR's

**gives me more options**for deeper tunings. Having the

*extra cone area*and being able to add more mass sometimes gives you

**more options**for the design."

So, not surprisingly at all, you crushed it. This also means my original gut instinct (2x Xmax minimum) was at-least the safer approach given my limited understanding.

Let’s see if I’m finally on target with interpretation and a usable, accurate, combined recommendation with scenario specific

included.

**Approach Final Draft:**

All PR(s)

**Vd**

*at-least double*all woofer(s)

**Vd**, so PR(s) total

**Vd**>= 2x woofer(s)

**Sd**x

**Xmax**.

For woofer(s) with

**large Xmax**vs

**Sd**, use 2x

**Xmax**instead, where PR(s) total

**Xmax**>= 2x woofer(s)

**Xmax**.

Is this correct?

If yes, is the wording easily understood?

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