Hi,
I'm rather intrigued by Linkwitz' Pluto omni speakers. I'm trying to reverse engineer them as I would like to replace the Peerless drivers he's using with some Tangband W5-1611SA (because I have the Tangbands handy).
At first glance, the Pluto looks like a sealed enclosure speaker. So armed with an enclosure calculator and the datasheet for the Peerless 830873, I arrive at a box volume of 3.53 liter.
SL states that the pipe is 4" (10.16 mm) ID, 28.5" (724 mm) long. That's a volume of 5.87 liter.
So playing with the enclosure calculator some more, I arrive at a Qtc = 0.60 for the Pluto as built.
So if I am to build a Pluto-like speaker that fits the Tangband W5-1611SA, would it be reasonable to plug the values above into the calculator and use that as a starting point? Or am I barking up the wrong tree here? I'm not quite sure that my initial assumption of the Pluto being a box speaker is completely valid and would appreciate some input from the more experienced speaker builders here.
~Tom
I'm rather intrigued by Linkwitz' Pluto omni speakers. I'm trying to reverse engineer them as I would like to replace the Peerless drivers he's using with some Tangband W5-1611SA (because I have the Tangbands handy).
At first glance, the Pluto looks like a sealed enclosure speaker. So armed with an enclosure calculator and the datasheet for the Peerless 830873, I arrive at a box volume of 3.53 liter.
SL states that the pipe is 4" (10.16 mm) ID, 28.5" (724 mm) long. That's a volume of 5.87 liter.
So playing with the enclosure calculator some more, I arrive at a Qtc = 0.60 for the Pluto as built.
So if I am to build a Pluto-like speaker that fits the Tangband W5-1611SA, would it be reasonable to plug the values above into the calculator and use that as a starting point? Or am I barking up the wrong tree here? I'm not quite sure that my initial assumption of the Pluto being a box speaker is completely valid and would appreciate some input from the more experienced speaker builders here.
~Tom
You need to do some reading on SL's website!
The speaker has to be active to work properly, or be prepared to build an inefficient power sapping passive crossover to marry the drivers if you plan to go passive. Then with passive you need a LOT of power so forget tubes/valves.
The speaker is a closed box design. It is actively equalized to produce more bass in the low end than would be expected from a small bass mid.
For this purpose you need a very long throw low distortion drive unit.
Pluto uses a low crossover point unsuitable for normal tweeters. The treble drive units needs to not have a faceplate, that will ruin the broad dispersion.
The peerless driver went years ago, it was only used for Pluto 1, Linkwitz is now on Pluto 2.1 with far superior bass performance.
Pluto uses a custom version of a Seas drive unit made specifically for the design. This bass drive unit could be successfully replaced with an inevitably more expensive unit. The treble drive unit should really be the same Aura whisper drive unit. You may get away with a peerless 2 inch fullrange like in the Platon pluto copy but this has more narrow dispersion.
Interesting DIY Pluto and Orion:
Platon
If you do attempt to copy Pluto keep the speaker as slim as the drive unit basket, it is meant to be a point source.
The speaker has to be active to work properly, or be prepared to build an inefficient power sapping passive crossover to marry the drivers if you plan to go passive. Then with passive you need a LOT of power so forget tubes/valves.
The speaker is a closed box design. It is actively equalized to produce more bass in the low end than would be expected from a small bass mid.
For this purpose you need a very long throw low distortion drive unit.
Pluto uses a low crossover point unsuitable for normal tweeters. The treble drive units needs to not have a faceplate, that will ruin the broad dispersion.
The peerless driver went years ago, it was only used for Pluto 1, Linkwitz is now on Pluto 2.1 with far superior bass performance.
Pluto uses a custom version of a Seas drive unit made specifically for the design. This bass drive unit could be successfully replaced with an inevitably more expensive unit. The treble drive unit should really be the same Aura whisper drive unit. You may get away with a peerless 2 inch fullrange like in the Platon pluto copy but this has more narrow dispersion.
Interesting DIY Pluto and Orion:
Platon
If you do attempt to copy Pluto keep the speaker as slim as the drive unit basket, it is meant to be a point source.
Rob, you don't because that defeats the entire purpose of the design and from first listening tests it is absolutly not required although not visible in any diagram or datasheet. If you want more highs then another FR is required. But as things stand now you need to roll off the highs anyway otherwise it will sound too bright.
Cheers
Oliver
Hi Oliver,
Maybe my memory is faulty, didn't you discuss adding a tweeter with this Speaker?
Anyway that is good to hear, if you can get away with equalization alone.
Perhaps you should link this discussion with the omni popularity thread!
Maybe my memory is faulty, didn't you discuss adding a tweeter with this Speaker?
Anyway that is good to hear, if you can get away with equalization alone.
Perhaps you should link this discussion with the omni popularity thread!
Nope 😉
That's the goal. It might even be possible to get away without reflector but first things first.
Well, I can't really add anything to the original question. Omnis are pretty popular here And if I would do anything into this direction
then I would try to make them more popular since they're worth it.
...but since I am here anyway, I have a few comments on topic:
Tom, the TB W5-1611SA has an underhung motor and I am not sure it can produce enough punch below 100Hz. If you believe data in datasheets then it might. However, it would easily find its limits in excursion capability, which are required down there. So you would have to add a sub, which is primarily not required with Pluto. Also, the PP cone is too floppy for usage without sub. Then you need either a rigid metal or otherwise stiff cone. Dried paper, Nomex and Kevlar come to mind.
The "special" Seas unit is really the best out there for the money since years.
In short:
If you want to listen to music and be done then you should buy plans from SL. The speaker is absolutely worth the money. If you want to fiddle and learn, well, then nobody can stop you anyway. But then be prepared to do measurements otherwise you will not hit the mark.
Cheers and have fun !
Oliver
Tom, the TB W5-1611SA has an underhung motor and I am not sure it can produce enough punch below 100Hz. If you believe data in datasheets then it might. However, it would easily find its limits in excursion capability, which are required down there. So you would have to add a sub, which is primarily not required with Pluto. Also, the PP cone is too floppy for usage without sub. Then you need either a rigid metal or otherwise stiff cone. Dried paper, Nomex and Kevlar come to mind.
The "special" Seas unit is really the best out there for the money since years.
It does but the magnitude is such that it will most likely not make a huge difference in listening tests since it counters with a smoother roll off.
In short:
If you want to listen to music and be done then you should buy plans from SL. The speaker is absolutely worth the money. If you want to fiddle and learn, well, then nobody can stop you anyway. But then be prepared to do measurements otherwise you will not hit the mark.
Cheers and have fun !
Oliver
I see Demokrit has become a two way now, just not in the direction I imagined!
This might make a nice surround speaker for multi channel omni with Pluto.
This might make a nice surround speaker for multi channel omni with Pluto.
I think you're jumping to conclusions here. I'm very well aware that the Pluto uses an active XO to
1) compensate for driver resonances/squiggles in the frequency response
2) extend the low end
Nothing says I can't do that as well. I'm well versed in analog filter design and own the test equipment needed to engineer them, so no issue here.
What I don't know much about is speaker design. That why I posted this thread to start with. I have the W5-1611SA's and was wondering if they could be used in a Pluto clone. I'd probably use the AURA tweeters for the same reasons as you point out.
I'm not looking to start a tube vs sand yelling match. How much power is needed depends entirely on the desired SPL in the room where the speakers are located. Along with speaker efficiency, of course. I'm not looking to rock my house off its foundation. If an LM3886 can power the Pluto, I'm sure a 6L6 Push-Pull stage would be able to do so as well.
The guys at the Parts Express Forum actually made a passive Pluto. No word on efficiency - at least not according to my quick glance-over, but the frequency response is pretty nice...
That's more along the lines of what I was looking for in an answer. Thanks!
Ah... That's the sticking point. Yeah, the Tangband has an Xmax of 3 mm. I think that's 3 mm peak = 6 mm p-p, but that's probably the physical limitations of the motor and not the limit for low distortion.
Well, yeah.... 🙂 I was hoping to learn a thing or two in the process. Who knows. Maybe I'll use a DSP for the XO. Who knows. At this point the project is in the idea stage.
~Tom
Oliver,
Did you do any polars for your deflector/speaker combination? I just measured a quick and dirty deflector on a B200 today and it didn't look too promising.
Did you do any polars for your deflector/speaker combination? I just measured a quick and dirty deflector on a B200 today and it didn't look too promising.
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Tom,
Any posts here or any forums I try to write in the knowledge that others may read them and find them useful.
The reason I stated that anyone doing a proper passive copy of Pluto should forget tubes is because most users would try something like the pluto styled speaker you sent the link to. few people have the funds, space, or the amp's for valve bi amping!
Properly done Mr linkwitz says Pluto would require 500 watts for a passive crossover, I'm sure you would agree that is an absurd figure for what is effectively a mini monitor.
Pluto uses 3x lm3886 not one. They are bridged for the bass driver and single unit for treble.
Of course Push pull 6l6's, KT66's, EL34's or whatever would be just fine operating after an active crossover for a close copy of Pluto.
I hope your project goes well.
Any posts here or any forums I try to write in the knowledge that others may read them and find them useful.
The reason I stated that anyone doing a proper passive copy of Pluto should forget tubes is because most users would try something like the pluto styled speaker you sent the link to. few people have the funds, space, or the amp's for valve bi amping!
Properly done Mr linkwitz says Pluto would require 500 watts for a passive crossover, I'm sure you would agree that is an absurd figure for what is effectively a mini monitor.
Pluto uses 3x lm3886 not one. They are bridged for the bass driver and single unit for treble.
Of course Push pull 6l6's, KT66's, EL34's or whatever would be just fine operating after an active crossover for a close copy of Pluto.
I hope your project goes well.
Again, that depends on the SPL you're trying to get out of these speakers. I and a friend of mine took some measurements using various tools (RMS voltmeter, wave analyzer, spectrum analyzer, oscilloscope, etc.) to figure out what the power requirements would be to achieve a reasonably loud SPL. We actually - to our surprise - worked out that our typical listening levels (75-ish dB(A)) required only a few mW of power. This was with typical box speaker with about 85~87 dB/W*m rated efficiency.
Actually, my buddy went on to building op-amp based "power" amps in the <500 mW (yes, milliwatt) range for his nude dipole speakers. He doesn't need more than 90~95 dB(A) SPL so why design for more?
That may be true, but in my opinion whether something is affordable should be left for the individual builder to decide.
I tend to balk at blanket statements so perhaps I'm being overly sensitive. I prefer to explore the options and do a little research before I make a decision. But that's just my style.
I agree that 500 W would be absurd. See below.
The LM3886'es are running off of +/-30 V supplies. According to the National LM3886 datasheet, that will give you 38 W (typ), 30 W (worst case) into an 8-ohm load. The drivers SL is using are 8-ohm drivers. The numbers in the datasheet are for +/-28 V not +/-30 V so you'll get a few more mW... Big whoop. Let's just say 40 W per LM3886 to make everyone happy.
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.
The other question is whether one could make a few tradeoffs. So maybe the 4.3 kHz notch filter gets left out of the tweeter channel. Maybe some other tweaks. This could potentially give a speaker that isn't optimized to the Nth degree like SL's Pluto but still sounds damn good. It wouldn't be as efficient, but would it be efficient enough?
Or maybe do parts of the XO passive, the other active... Options, options.
~Tom
and the H1480 has 12mm p-p, linear with the largest effective piston area on the market for a 5". So you get the idea 😉
No, typically distortion rises if the coil leaves the gap. Needless to say that the distorion of the H1480 is well controlled and at low levels.
Here is a nice build with miniDSP.
Why would you do that ? Just to make it yours ?
No, no, no. Pluto is minimalistic already.
Try to tweak something that is according to its intended use and specs close to perfect.
Tweaking Pluto is like pumping money and time into something with questionable improvements.
The time and money is best spent to make it look nice. This woofer column e.g. has something I think. Ok, the wood is a question of taste but the shape is good.
Tom, sorry, ' don't mean to dilute your thread. Maybe sooner or later we go play somewhere else.
if you are in the northern part of Switzerland, then you know what weather we have
I have indoor measurements to find the proper cone position but will not show them. This is like measuring dipoles indoors; doesn't really work well.
Hopefully tomorrow I can measure outside. Then I will post some new pictures.
I saw your diagram. Seems the paper is acoutically too transparent with different densities in the circumference ?
Did you optimize the cone position at all ? Here 0.5mm up or down does make a difference visible in the graphs between 7KHz and 20KHz.
Hi Markus,
if you are in the northern part of Switzerland, then you know what weather we have
I have indoor measurements to find the proper cone position but will not show them. This is like measuring dipoles indoors; doesn't really work well.
Hopefully tomorrow I can measure outside. Then I will post some new pictures.
I saw your diagram. Seems the paper is acoutically too transparent with different densities in the circumference ?
Did you optimize the cone position at all ? Here 0.5mm up or down does make a difference visible in the graphs between 7KHz and 20KHz.
I agree, we should open a new thread. I'll open a new one if you would like to share your measurements too.
Hi Markus,
sure; always willing to share.
Maybe find a thread title, which allows others to share real life experiences and facts in form of measurements and papers so that it would rule out hearsay and wild guessing. Concluding is allowed, though 😀
The popularity thread has too many speculative elements and the original question has been answered as best as it can be by opinions. Since then it has become an "all you ever wanted or don't want know about omnis soup" (with some good points, though that hopefully come up again, including some of yours).
Also, a definition of omni speaker might be helpful although that already has potential for the folks go wild 😀
Challenging, I know but maybe this way people can learn from it and become more interested since these speakers can be build pretty easy and fit into many rooms.
OK with you or do you have a different scope in mind ?
sure; always willing to share.
Maybe find a thread title, which allows others to share real life experiences and facts in form of measurements and papers so that it would rule out hearsay and wild guessing. Concluding is allowed, though 😀
The popularity thread has too many speculative elements and the original question has been answered as best as it can be by opinions. Since then it has become an "all you ever wanted or don't want know about omnis soup" (with some good points, though that hopefully come up again, including some of yours).
Also, a definition of omni speaker might be helpful although that already has potential for the folks go wild 😀
Challenging, I know but maybe this way people can learn from it and become more interested since these speakers can be build pretty easy and fit into many rooms.
OK with you or do you have a different scope in mind ?
Hi Oliver,
I've opened this new thread. Hope you don't mind that I've used a picture from your site.
I've opened this new thread. Hope you don't mind that I've used a picture from your site.
Tom,
Pluto is a pretty highly evolved design & it seems unlikely that casual mods/driver substitutions would provide improved performance...more likely the opposite. If it were me I'd 1st build Pluto to spec and spend some time listening before heading off in a modded direction. I haven't heard Pluto, but I have Orion+ 3.3.1 & if they sound as similar as people say they must be sweet!
Pluto is a pretty highly evolved design & it seems unlikely that casual mods/driver substitutions would provide improved performance...more likely the opposite. If it were me I'd 1st build Pluto to spec and spend some time listening before heading off in a modded direction. I haven't heard Pluto, but I have Orion+ 3.3.1 & if they sound as similar as people say they must be sweet!
I know several owners with both speakers and I keep being told in PM's (from owners with both) that Pluto 2.1 sounds virtually identical on most material to Orion+ 3.1. Apparently 3.2 sounds a little different.
I usually say to them it will depend on what volume you like to play and how big your listening room is, ymmv. What this tells me is tonally and in terms of detail there is little to choose between them. I expect big rooms and symphonic works at full bore seperate the men from the boys. It seems the guys with rooms that qualify as just about big enough for Orion may as well have built just pluto.
Exactly the point I was trying to make.
I've seen that one. I'm not a fan of the miniDSP, though. I would rather choose my own DAC for example. I would also add upsampling to 24/96 or 24/192. For that an ADAU144x SigmaDSP would be more attractive.
I'd like to get the LM3886 out of there. I prefer the sound of my tube amps or my LME49811+STD03 amp to that of the LM3886.
I don't like mindless assembly of kits. I've had a soldering iron in my hands since I was about five years old. I can assemble kits in the dark. I would rather understand the engineering behind something and then implement it. And who knows. Maybe I'll stumble across something that SL didn't think of. Or a trade off that I would make differently.
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...
I like the overall look, though I find the wood a bit too busy for me. As you said... Personal taste. But I wonder how the square tube affects the radiation pattern compared to a round tube. It's supposed to be a point source, but then you introduce these reflecting planes. Hmmm. I'm not convinced here.
I much prefer the slender and smooth examples on SL's website. Like this one. Of course the sexy chrome metal and glass piece of art speaker near the bottom of the page is just phenomenal - at least in terms of industrial design.
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.
~Tom
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