Linkwitz Pluto + MiniDSP + ClassD

[greenm01]

I've built the Linkwitz Pluto, utilizing a MiniDSP and cheap ($50) 4x100 @ 4ohms Sure TK2050 Class D board. The result is outstanding, even with the board a little under powered with a 24V SMPS. My plan is to upgrade to a few high quality classdaudio boards in the near future, enclosed in a nice chassis with a toroidal transformer.

I made a YouTube video. My cheap pocket camera does not do the accoustics justice, but you get the idea....

/Mason

[Speedskater]

While you can build a speaker that's similar to a Pluto, you can't build a Linkwitz Pluto unless you use all the Linkwitz parts.

[greenm01]

Originally Posted by Speedskater

While you can build a speaker that's similar to a Pluto, you can't build a Linkwitz Pluto unless you use all the Linkwitz parts.

Same drivers. Same filtering (via DSP rather than Opamps). Different amplifier. Not much difference, unless you want to split hairs in regard to branding. Linkwitz himself even suggests to use of DSP in his Linear Audio - Volume 0 article "STEREO - From live to recorded and reproduced - What does it take?"

Originally Posted by Linkwitz

"The active crossover/equalizer filter functions can also be implemented with a digital signal processor (DSP). This could potentially results in superior loudspeaker performance..."

I don't see a problem with updating the design with newer DSP technology and a quality Class D amplifier. The sound is still outstanding, to me.

[5th element]

Well if you use the same drive units and emulate Linkwitz crossover down to the last detail then you've got yourself a Pluto imo. How you implement the xover (providing the filters are the same) is irrelevant, as is the amplification.

[kevinahcc20]

To quote SL, "The function of the ASP could be duplicated with a digital signal processor, DSP, by realizing the poles and zeros of the different transfer functions, and following the same signal flow and gain distribution. Still great care must be taken to have enough dynamic range for each number processing stage to minimize non-linear distortion. Such custom DSP design is not trivial and requires good firmware programming knowledge and technique." so no slam dunk unless the implemetation satisfies all of SL's caveats.

[Pano]

I think it's cool. The Pluto is a nice sounding speaker. Glad to see someone do this.

[ScottG]

Details please with respect to implementing the mini-dsp for this design!

[KyleinCowichan]

He's clearly not trying to fob this off as some kind of exact copy of the Pluto. I think you need to lighten up a little. Also, he's working on this in his house for his own enjoyment so he can call it whatever he wants. Dragging this thread into the dank and miserable depths of a semantic argument about what he can and can't refer to his speakers as is the definition of trolling.

Mason - That's really cool. I just bought a miniDSP and I am very interested in seeing other peoples results programming it. My first try at it was replicating the crossover in my Overnight Sensations. I think it was fairly successful! Perhaps you could post some screen shots of the plug-in settings?

Kyle

[Davey]

It's difficult to match transfer function curves by scaling photographs and estimating.

Mason supplied the .xml file (originally from Kentaro) to everyone on the Orion Users Group. (Still there and anyone can download it.) I loaded it into my miniDSP 2x4 and unfortunately it doesn't match the curves created by a real Linkwitz Pluto ASP.

Kyle,

We try to follow the lead/direction of Mr. Linkwitz for DIY projects like this. He ENCOURAGES this type of project/experimentation, but he only requests that the builder not name the project "Pluto" or "Orion" or whatever. These are projects where the builder has not purchased Construction Plans or circuit boards and/or compensated Mr. Linkwitz in any way. I know this seems a silly concept to some folks involved with "DIY" audio. (Probably like holding back the wind, at this point.)

Cheers,

Dave.

[MrSlim]

Originally Posted by greenm01

I've built the Linkwitz Pluto, utilizing a MiniDSP and cheap ($50) 4x100 @ 4ohms Sure TK2050 Class D board. The result is outstanding, even with the board a little under powered with a 24V SMPS. My plan is to upgrade to a few high quality classdaudio boards in the near future, enclosed in a nice chassis with a toroidal transformer.

I made a YouTube video. My cheap pocket camera does not do the accoustics justice, but you get the idea....

/Mason

Have a look at the L15D or L20D (2092 based Class D) threads, they are a nice economical ClassD solution that people are having success with..