A Second look at SL's PLUTO

[ScottG]

The first "major" thread can be found here:

SL's Pluto

(This thread though, had a LOT of member "noise".)

The real design interest though is NOT from the stand-point of active or passive crossover, but rather the acoustic nature of the loudspeaker vs. that of SL's other designs (like the Orion) and of course in contrast to other designs like traditional foreward monopoles.

Its interesting that since the last thread SL has updated the Pluto page:

http://www.linkwitzlab.com/Pluto/intro.htm

in particular we have this (starting from the section on afterthoughts):

"..come to the conclusion that uniformity of the polar response is even more important than I had thought previously."

after a bit more analysis on various radiation qualities of differing designs, (and perhaps leading the reader a-stray with the brief mention of baffle step - which has precious little to do with off-axis vs. on axis radiation), he states that the Orion and the Pluto's similarities are with regard to a reduction of room effects provided that the PLUTO is placed closer to the listener. He concludes with:

"Regardless of listening distance PLUTO elicits a significantly more neutral response from the room than the vast majority of box speakers is capable of."

Presumably the reader will accept the *perceived* implied caveat to this conclusion of: .."as long as the PLUTO is placed further into the room". (i.e. Note the sentence that precedes the conclusion, and read the two together.) The problem with such an implied context though is that it CANNOT be there when comparing the PLUTO to the vast majority of box speakers precisely because that majority often excites the room in exactly the same manner (i.e. omni). (..the meaningfull difference is with those speakers with steep crossover slopes and large diameter midranges where the midrange experiences an off-axis amplitude loss that is not compensated for by the tweeter.)

Now you could take his last sentence SOLEY on its own merits and NOT regard it as a conclusion to its paragaph.. but I really don't think so - (why else would it be there in THIS paragraph?).

So then, what am I getting at here? (..and no, what I'm about to say is NOT intended to be SL bashing.)

While SL's design proposal has merit - (that a modest reduction of room effects increases playback quality above the modal region), it has almost nothing to do with why the PLUTO sounds as good as it does. In otherwords, his argument with repect to the PLUTO completely and utterly FAILS. (yes, yes.. I know strong words, just remember though that it is most certainly NOT a character attack.. frankly I can't think of a better overall loudspeaker designer than SL.)

You might ask then, what is the point of this thread? To simply state that SL is wrong here? NO. But to give the reason why, lets look at these statements on subjective quality by SL (while noting inferior component quality of the PLUTO):

"Switching back and forth between PLUTO and ORION can be confusing as to which one is playing, but depends on program material. When deep bass is required then PLUTO gives a hint of its presence, but does not deliver the body. The male and female voice range, though, whether single or in mass, is handled so well that I wonder what the higher cost of the ORION is buying me. I do not sense a lack of very high frequency extension nor of volume capability. Imaging of PLUTO is very precise, the speakers have disappeared, the sound stage is tall and wide, but does not have the depth of the ORION. Overall, PLUTO lacks at times the ease, authority and refined clarity of sound that ORION can deliver on any good program material. Even so, PLUTO has that special quality that allows me to lose myself completely in the sound and to forget about speakers."

In particular look at that statement in the middle:

"..I wonder what the higher cost of the ORION is buying me."

(go ahead, puruse the above subjective statements several times.)

Now this time contrast these statements with component quality and their limitations (PLUTO vs. Orion). What I'm try to suggest here is that the PLUTO (above the modal region) is in fact a BETTER basic design than Orion.

How can this be? If SL knows, (and I don't think he does - or at least hasn't come to "grip" with such a conclusion), then he certainly isn't telling.

I guess then the next question(s) is: Do you really want to know? Do you care about creating the best possible loudspeaker, or are you interested in doing the same old thing?

[AJinFLA]

Hi Scott,

is it possible to read the man's site and not quite analyze it like it was scripture? I mean I've jokingly called it the Bible before , but c'mon. Analyzing and interpreting every single word and concluding what God meant when he said (in english of course) this and when he said that and so forth.
Ok, my preaching of the Lord's words. The Pluto is a specialty item. A big set of headphones that you don't put on your head. They sound great under very specific conditions. They sound not so good if placed where many people would normally have their speakers (2ft from back wall?). He thinks they are very close to the Orions in certain aspects under these very specific conditions. They possibly represent a better value - if used as such. Amen. The gospel according to AJ.
Take from it what you will. Maybe you can just spell out what you are saying? That monopoles are better than dipoles above the modal region? I'll let SL answer for what he is saying. What are you saying exactly? I'm not absolutely clear on either one. I'll let you speak for yourself though. What a concept.

Cheers,

AJ

[ScottG]

Originally posted by AJinFLA
Hi Scott,

is it possible to read the man's site and not quite analyze it like it was scripture? I mean I've jokingly called it the Bible before , but c'mon. Analyzing and interpreting every single word and concluding what God meant when he said (in english of course) this and when he said that and so forth.
Ok, my preaching of the Lord's words. The Pluto is a specialty item. A big set of headphones that you don't put on your head. They sound great under very specific conditions. They sound not so good if placed where many people would normally have their speakers (2ft from back wall?). He thinks they are very close to the Orions in certain aspects under these very specific conditions. They possibly represent a better value - if used as such. Amen. The gospel according to AJ.
Take from it what you will. Maybe you can just spell out what you are saying? That monopoles are better than dipoles above the modal region? I'll let SL answer for what he is saying. What are you saying exactly? I'm not absolutely clear on either one. I'll let you speak for yourself though. What a concept.

Cheers,

AJ

And here I thought it was the "devil is in the details"..

In any event the analysis has a purpose, the purpose was to say that SL's argument for the "virtually inexplicable" high quality of the omni design is wrong, and more importantly to hopefully achieve some understanding of exactly what is "right" about an omni above the modal region. Obviously if we don't recognize that SL's assertions were incorrect we would simply say.. OK, whats right with an omni above the modal region is..(see SL's explanation), which is totally counter productive.

I don't know (*sarcasm dripping*), perhaps a better understanding will lead to better DIY loudspeakers?

And thats kinda the point. In otherwords much of the PLUTO's basic design is NOT simply a "specialty item". And I think THIS is the reason that most people dismiss the PLUTO, because they think of it as a quircky little amplified speaker good for a few tricks and possibly a "value" purchase - not as an element of design that could lead to F A R better loudspeakers.

As far as "spelling it out" - I'll say this:

1. SL's PLUTO (if we are to believe that the subjective impressions of SL are correct), for some reason provides nearly complimentary perfomance to the Orion while utilizing substantially inferior components.

2. With regard to #1, why is this the case?

3. Presumably if we discuss and arive at least some plausible explanations for #2, we could then apply that knowledge to creating better loudspeakers.

4. Based on #'s 1,2, and 3 it should be obvious that I'm asking for credible answers (based on thoughtfull logic) from members of this forum, trying to promote a discussion that *could* benefit all of us.

P.S. An omni such as the PLUTO is the antithesis of a typical headphone in just about every concievable fashion except that they are meant to be placed physically closer to the listener than the distance that most people place their loudspeakers.

[sqlkev]

Would anybody agree with me that:
if both speakers with low distortion EQUALIZED to behave the same (flat across the driver's bandwidth), both should sound the almost same?

I personally would like to crank it up sometimes (to realistic/reference level) and move around a bit. Therefore, the Pluto wouldn't do much for me.

Zaph/John,
Ns3 mmtmm or line array coming soon?

[ScottG]

Originally posted by sqlkev
Would anybody agree with me that:
if both speakers with low distortion EQUALIZED to behave the same (flat across the driver's bandwidth), both should sound the almost same?

I personally would like to crank it up sometimes (to realistic/reference level) and move around a bit. Therefore, the Pluto wouldn't do much for me.

Zaph/John,
Ns3 mmtmm or line array coming soon?

Is this all else equal except flat off-axis?

The PLUTO suffers from non-flat off-axis in the treble, therefor moving around would cause at least an amplitude change in the treble (both horizontally and vertically). Can you think of another change that might occur besides high freq. loss off-axis?

[inertial]

Hi ScottG, (sorry for my english)
Very interesting thread.
I believe one big difference pros PLUTO is the rear wave absorbing attempt. It remember me the original concept by L.Dickie (Nautilus).
My friend have some auras and I know it.
I am wondered about no others manufacturers drivers ( and designers) had applied Dickie's idea ( partially).
Subyectively,to my ears , the gap from the cheap aura and the most claimed traditional dome tw is stunning. But if I close (plug) it like a standard chambered dome the gap is missed.
Conclusions? The cheap auras have only one problem: very very low sensitivity. And it is a big problem.
Cheers,

[mac]

Thank you for sharing your insignt.

[dhenryp]

I would rather read an anlysis of how Pluto sounds than how Pluto is described.

[Davey]

AJ, Mac,

Why do you guys respond to a post like this? It's a complete waste of your time.

Davey.

[inertial]

Very kind replies.
Nice to meet you,guys!!!!