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

CJ1965 4-20-2018
There’s a reason the graph shown in the web page for db conversion that Erik linked to has a value of -6db for voltage gain/loss and -3db for sound power. One look at the two formulae for sound power and electrical power will explain why if you care to devote the time to examine them closely.

I'm not sure what you are referring to.  The only graph on the page addressing db conversion that Erik linked to is this one, and it just deals with voltage, not power.

In any event, if (as it appears) you are saying that a 6 db reduction in electrical power into a speaker results in a 3 db reduction in SPL at a given distance, rather than resulting in a 6 db reduction in SPL at that distance, we'll have to agree to disagree.

Regards,
-- Al
 

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

Best,


E

Back to the discussion of zero feedback tube amps.  I agree that they may sound good with certain speakers.   The EAR 890 with 70 watts Class A power nearly oscillate when paired with Legacy Focus speakers with their low and non-linear impedance curve.  However, the EAR 890 sounded just fine on the Legacy Signature IIIs which have a smoother curve and 1 ohm higher bass impedance.  Same pre-amp and CD sources, wiring and cabling.  

Geoff-I demagnetize all CDs prior to play with the Walker Talisman.  It's easy and it works for me.  The other tweaks I haven't tried or have an interest in.

Cj1965, I'd suggest you actually do the math. You're working very hard to artfully conflate terms

@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