Primary Drive Loudspeaker by Tim de Paravicini

Status
Not open for further replies.
Jump to Latest
#3
Yes, I know it.

.."Basically, it's a dynamic speaker system, with a tweeter and a midrange and a bass unit. The bass unit and the midrange drive a membrane. The bass unit makes a membrane of effectively 12" by 18" (305mm by 457mm) surface area bend and vibrate to put bass into the room. So it has dipole properties. I don't make the drive-units myself and I subcontract the cabinets, but it's still my basic principles."

But I don't understand this sentence:
...The bass unit and the midrange drive a membrane. The bass unit makes a membrane of effectively 12" by 18" (305mm by 457mm) surface area bend and vibrate to put bass into the room...

Maybe a drawing or a picture would help me to imagine how it works....

Tyimo
 
#5
Grown up computer speakers ?

I seem to recall that I saw someone put up pictures of something like this a few years ago. Was it on diyaudio .com ?
It was supposed to be a computer speaker. Basically it consisted of two vertical posts spread a few inches apart with a pvc (?) film stretched between the posts ( both sides). The driver was at the bottom and coupled with the air between the two membranes through a small hole at the bottom.
Rather simply made at that time. Supposed to sound very interesting. It was a dipole of course because it radiated from both sides . Did he get a patent for it at the time ?
There were pictures also with a brief description on how to make it.
 
#11
Hey Dave....

Paul Burton and I started Highwood Audio and we produced a planar speaker driven by a voice coil. Paul left the company and went home to England and had dealings with NXT but I don't know if he had anything to do with Podium.
I know that Dalli built a loudspeaker with conventional dynamic drivers in which the mid and or bass drivers were covered by a sealed layer of mylar. The mylar then became a secondary radiator which was used to control the polar response of the loudspeaker. Perhaps Tim's new speaker employs a similar design. Hard to say with out actually seeing under the grill. Moray.
 
#15
Unless I am mistaken, some ideas seem similar to the Yamaha NS250E.
Semi regid plastic foam diaphram app 2mm thick, covered in thin vinyl.
 

Attachments

  • yamaha_ns250_3.jpg
    yamaha_ns250_3.jpg
    26.2 KB · Views: 553
  • Yamaha_ns250_2.jpg
    Yamaha_ns250_2.jpg
    72.4 KB · Views: 547
#16
So if this scheme is so old , why did it not have a following ? Uneven frequency response, low max spl capability etc ?
Does the basic scheme have any problems ?

This is what NXT are doing...right ? I've never heard one. Then there was the Monsoon computer speakers. They disappeared too....
 
#17
For those interested in Bending Wave Loudspeakers and related stuff,
here are links to threads in the "Planar and Exotics" forum.

http://www.diyaudio.com/forums/planars-exotics/133711-piezo-nxt-type-panel.html

http://www.diyaudio.com/forums/planars-exotics/164414-wave-speakers-how-do-they-work.html



Maybe this Paper is good for a first look on different behaviour of conventional
"rigid cone" dynamic loudspeakers and bending wave transducers.

http://www.randteam.de/_Docs/Aes104 Distributed Mode Loudspeaker simulation model.pdf

This paper is in german, but sometimes a picture says more than
1000 words ...

http://www.wvier.de/texte/NXT_Tonmeistertagung.pdf


Kind Regards
 
#19
Airfoil: Successor of the "Linaeum" tweeter, which in fact is a bending wave transducer.
http://membrane.com/impact/products/prodairfoil_wtpaper.html

German Physiks: Conical bending wave transducer AFAIK based on Walsh invention
http://www.german-physiks.com/

Goebel: Flat panel bending wave transducer in flat cabinet
http://www.goebel-highend.de/en/products/detaille.html

Manger: Flat disc shaped bending wave transducer, operates below its coincidence frequency
http://www.manger-msw.de/

MBL: Maybe not intended to exhibit bending waves above the lowest resonance,
but is at least a "bending transducer"
http://www.mbl-germany.de/

NXT:
http://www.nxtsound.com/index.php

Ohm Speakers:
http://www.ohmspeakers.com

Podium:
http://www.podium-sound.com/
http://www.fairaudio.de/test/stand-lautsprecher-podium-sound-05-1.html

Museatex:
http://www.museatex.com/

Teragaki:
http://www.teragaki-labo.co.jp/products/about_terra-sp3000.html

Bertagni:
http://www.oaktreeent.com/web_photo...ertagni_PL-3_Sound-Panel_Speakers_collage.jpg


There may be further Manufacturers ... feel free to complete the list.
 
Last edited:
#20
Hi

The inventor of the Direct Drive speaker was Brian Mitchell. I evaluated
some prototypes a few years ago before Tim de P adopted it.
The drivers were made by Fane. I dont know if they still are. They
were a flat panel of a matrix like material driven by a shortened cone
from a PA bass driver. The inventor experimented with lots of different
panel materials.

It was supposed to have a bass response better than that which you would expect from a dipole of this size. I believe he was using the driver resonance
to extend bass response. Our measurements did show that there was some
additional bass extension but not enough for our purposes.
 
Status
Not open for further replies.
Top Bottom