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South America: Amazon Rain Forest Amazonia, Brazil, 2005-04-22 by Gordon Hempto

In listening to this binaural recording I was immediately struck by the infinite layer of sounds in space that the Planot was able to decode. The ears relaxed and you melded into the forest. When the recording was stopped it was then I became shockingly aware that the forest had shrunk into a point. This recording is my gold standard for realism of tone and space.

Shockingly when using this recording as the source and listening to a single Planot speaker  the stereo image is decoded by a single mono speaker! Yes, a smaller window but the same left and right imaging.

John J. Gaudreault


What struck me when I first heard a recording through John's speaker was that the sound was coming from behind me - even though the speaker was sitting just a few feet in front of me. The complexity of the sound was delightful, and there was no effort involved in hearing even the most subtle parts of the recording.

One of the benefits of listening to live music is enjoying the intensity of the fortes and the subtleties of music is the pianissimos. John's speaker allows you to hear recorded music at such low levels of distortion that I had to ask him to turn the volume down! You can hear all the details, regardless where you are in the piece, at a moderate volume.

When I listened to the Boyz II Men piece, I could hear every breath, every entrance, every note and harmony in incredible detail. As a performer, this got my attention! While we struggle to give the perfect performance each time, we rarely do. There's always something that could be better. Perhaps a sound system of this quality will spur us on to better performances!

Connie Beam

First, there's no doubt the concept works. I'm sure you're pleased at how far a few tiny magnets and one minuscule voice coil has taken the sound. Within it's dynamic capability the sound is remarkably linear and surprisingly spacious. (Surprising because we were listening in mono but even in mono the speaker doesn't tend to reveal it's position.) Bass sounds pretty flat to under 100 cycles with response well under that and high end response sounded very extended. Your measurements of relatively flat response to way beyond 10,000 hz are borne out in the listening. Can't say I can hear to 20,000 hz anymore!

While I'm sure you'll know a lot more about the potential of the technology when you finish a real prototype, a couple experiments we did last night make me optimistic that this could be a wonderful new way to reproduce music. 

I'm sure the crossover-less, single driver nature of the Planot helps in this regard but resolution and transient behavior is important also. The Planot seems to be quite sophisticated from what I could hear...Impressive resolution for a product not even in it's prototype stage...

Doug Robinson

Audition of Planot Speaker Prototype 3     March 27, 2008

In looking over the notes the characteristics that stand out overall are the clean, well defined sound of the various instruments and the vocal tracks. This applies, instrument wise, to either the solo or ensemble performance. The same is true of vocals, solo or multi-voice. 

It should be noted that these selections were chosen for their excellent recorded quality and the complexity of the music. From my first listening to the earlier prototypes the improvement I heard in this most recent prototype is at least quite remarkable. As this is a work in progress and the audition was done in a mono configuration one can only wonder what awaits when the work is complete and a stereo configuration is presented.  

 The only track that did not meet my expectations was Peggy Lee’s Fever. After

some thought and discussion the problem was not with the recording but with my expectations. Since I first heard Peggy do the tune some 56 or 57 years ago, and uncounted times since, it presents a strong case for my listening for what I wanted to hear-again-and did not. Sound great, arrangement fine, all good. I need to listen again without the bias.

I was especially impressed with the clear well defined “you are there” reproduction of the percussion, both as solo and as part of a traditional rhythm section. 

Guitar and double bass were very good. The sound was well defined without any smearing of the notes. This was most evident in the tracks containing plucked and bowed double bass. The decay of a sustained plucked bass note a joy to hear.

The blues rendition using harmonica and organ was awesome. Even in full cry the individual instruments could be picked out and followed. A well recorded and reproduced track.

As for sound stage and instrument placement and vocalist position relative to musicians I am a loss to explain. Based on the mono (or the R+L summed stereo) input source and the physical presence of an obvious single radiating source spacial location is not an expected result. However it is there! It’s an artifact. Maybe. Of what?  Is it a fluke of the listening environment? Figment of the imagination? Maybe all those and more but whatever the source or cause multiple auditions have all produced the same results. Water trickling low left, front to back, bees flying by, high left ( these from an environmental track, not my imagination), vocalist behind the source about a foot and the ensemble behind them with the rhythm on the right, half way to the front.

Don McCutcheon

Mr. St Lucas is a professor of Astronomy and a musician with an interest and skills in audio electronics.

This was an aduition of P3 only.

(P4.5 was dissambled at the time.)



Thank you for having me out to listen to your Planot Speaker last week.  It certainly is the most unusual transducer I've had the pleasure to audition.  

For starters, it was the clearest and most "real" sounding speaker I've ever heard, and I've been critically listening to speakers for over forty years.  When I closed my eyes, I could clearly imagine the environment in which the sound was recorded.  Maybe it was my imagination, but I thought I could also hear stereo (location) information coming from a single transducer.  I am unsure how this is possible.  

Transitions were very clean and quick.  There didn't seem to be the delay time typically associated with conventional speakers.  The attack was very distinct, and the decay was natural and very life-like.  

The only things I would change if I could, would be the lack of audible bass (though I could certainly feel the floor vibrating) and the volume.  For as much power as you were sending through the transducer, I would expect a few more db.  

That being said, this is the most fantastic speaker I've ever heard. It behaves more like a “well-defined line in space”. This is vastly different than a conventional cone or horn speaker point source. I would certainly encourage you to pursue the development of this project.


Charles St Lucas PhD

30 June 2018 

Here are the selections on my Planot Test CD #4.

01) Morning - Grodon Hempton

02) ToyChest - Film & THe BB's

03) Western Wall - Rosanne Cash

04) Yesterday - BoyZ II Men

05)Keith Don't Go* - Nils Lofgren

06) Down at Your Buryin' - George Faber

07) Adagio and Fuge K546 - Ensamble Oriol Berlin

08) Afternoon - George Hempton