Reverse engineering the SL Pluto

[rob g]

I agree that 500 W would be absurd. See below.

As the woofer uses two bridged LM3886'es, it would have 4*40 = 160 W available. The tweeter would have 40 W available. So 200 W max - assuming the drivers can take it. Is SL, thereby, suggesting that 300 W would be lost in the passive XO should someone build a passive Pluto? That's equally absurd.

~Tom

In fairness what SL actually said was "The two built-in power amplifiers have a combined peak capability as if driving a corresponding passive 2-way speaker from a single 500 W amplifier"

 

[markus76]

I'm trying to get my head around how this speaker works. Understand the engineering that went into it and why it's designed the way it is.

Well, that's pretty easy. Get as few drivers as small as possible while maintaining some SPL capabilities. EQ the whole thing to flat and you're done.

 

[rob g]

Well, that's pretty easy. Get as few drivers as small as possible while maintaining some SPL capabilities. EQ the whole thing to flat and you're done.

Brain surgery, that's easy!
Cut the head open, chop the bit out that you don't want, glue the top bit back on and you're done!

Rocket science!
How hard can that be?, you only want the thing to go straight up, don't even bother me with that one!

 

[markus76]

Brain surgery, that's easy!
Cut the head open, chop the bit out that you don't want, glue the top bit back on and you're done!

Rocket science!
How hard can that be?, you only want the thing to go straight up, don't even bother me with that one!

Exactly 🙂 Just do it. Get measuring equipment and then you're ready.

 

[6.283]

And who knows. Maybe I'll stumble across something that SL didn't think of.

Sorry, Tom. Not meant personally !

Much speaker building is black magic. But it's really only black until someone turns on the light. I'm currently looking for the light switch that's all...

Then you have to do what a man has to do every now and then 😉

But I wonder how the square tube affects the radiation pattern compared to a round tube.

In terms of diffraction the square or even better rectangular "tube" has advantages over circular because the magnitude of diffraction becomes "less". But the circular pipe creates uniform diffraction that can be equalized easily and the circular pipe is less prone to re-radiation.
Anyway, the example is perfectly fine.

So long story short. I'm trying to get my head around how this speaker works. Understand the engineering that went into it and why it's designed the way it is. That's my purpose in life at this point.

Then you have to build something different and fail. Probably multiple times. That means learning; or nicer said: experience 😀 Accompanied by multiple books, magazines, papers and endless discussions in forums about speaker building. And this means reading and understanding and not only reading.
But...don't get me wrong: It is a good way !
And it explains perfectly why the best speaker builders on earth are not exactly 20 years old.

 

[6.283]

Well, that's pretty easy. Get as few drivers as small as possible while maintaining some SPL capabilities. EQ the whole thing to flat and you're done.

Oh brother....

 

[tomchr]

Brain surgery, that's easy!
Rocket science! ...

Now rocket surgery on the other hand.......

Sorry, Tom. Not meant personally !

None taken. 🙂

Then you have to do what a man has to do every now and then 😉

Take matters into my own hands, you mean... 😉

In terms of diffraction the square or even better rectangular "tube" has advantages over circular because the magnitude of diffraction becomes "less". But the circular pipe creates uniform diffraction that can be equalized easily and the circular pipe is less prone to re-radiation.

Oh, DUH. Yeah, that makes sense.

And it explains perfectly why the best speaker builders on earth are not exactly 20 years old.

Well... There is that. That goes for just about any field.

~Tom

 

[markus76]

Well, that's pretty easy. Get as few drivers as small as possible while maintaining some SPL capabilities. EQ the whole thing to flat and you're done.

You probably won't beat Linkwitz in building electronics but with the right measuring equipment and digital crossovers (e.g. acourate) the Pluto mystery should be relatively easy to tackle.
I'm firmly convinced that any speaker's performance is first and foremost defined by good old frequency response. Not only on-axis but on every axis. Virtually no DIYer looks at that kind if data.