Please Read and express your feelings and opinions....

@almarg

My comment was seconded in that thread by Erik_Squires, who is particularly knowledgeable and experienced in speaker design.

You are far too kind. I’m not as knowledgeable as many others, and I certainly make my share of public mistakes. I hope that despite this I leave plenty of room for people to enjoy what they enjoy without imposing my own biases.

I’m sure after this endorsement I’ll suffer a relentless series of public mistakes to make up for it. I will say that I often use XSim to double check my math. Speaker building is not my day job and I am far rustier than I used to be on this, so whenever I’m in doubt, I whip up a sample circuit, and pull up the relevant charts to validate my work. I encourage others to do the same, and frankly, if you have speaker building (or even mere speaker wiring) questions, take your questions and XSim schematics over to DIYAudio:

http://www.diyaudio.com/forums/multi-way/

where the XSim author, Bill Waslo, and many many other more knowledgeable and opinionated speaker builders hang out.

I daresay you’ll find many there who know more than me, but certainly not any with stronger opinions! :)

Best,


E

What is this sound power I keep hearing about this week on Audiogon? It seems new and interesting. Oh look, donuts ... 

Best,


E

@almarg

Namely that if the input power to a speaker is changed by a given number of db, SPL at a given listening distance will change by the same number of db

It’s frankly hard to tell what cj was talking about, but I think what his problem was he couldn’t wrap his head around the delta dB being the same across V, W and SPL and that this was expressed in the separate coefficients (20 vs. 10) used in the dB formula. In the same way you can have different power calculations, and each be correct:

P = V x A
P = ( V x V ) / R

Honestly, if these formulas weren’t equivalent, I’m not sure amplifiers could work! This tight interrelationship just blew cj's mind.

On another note, Erik, thanks for injecting some sorely needed humor into this thread, with the donuts post :-)

Haha! I thought everyone missed that.

Best,

E

@geoffkait 

This problem is so acute that in some fields they have a sub specialty. 

Translational medicine for instance aims to bridge the gap between patient treating doctors and medical researchers. Improving how information flows from one to another. 

https://en.wikipedia.org/wiki/Translational_medicine

In my day job about half of what I do is this, translating between software developers, reliability engineers and business people so that the teams are fully engaged and unblocked. 

The rest of the time I'm just a jerk. 

Best,


E