Hi,
To get full range out of a driver the following is/are typically employed to extend the highs
1) The center of the cone is decoupled at higher frequencies and the cone iis used in breakup mode
2) Stiff dustc cap is used to extend the highs
3) Secondary whizzer cone is used
4) Phase plug is used to break the narrow beam at high frequencies
However, most of the drivers dont seem to focus on achieving constant directivity and polar plots are rarely shown.
So, my question is, can a full range driver be modified as below to get constant directivity. The idea is simple, let the center radiate the highs and as frequency comes down into the mids, have a larger portion of the cone kick in, thereby maintain a constant wavelength to radiating area ratio. Use a 2mm-3mm layer of felt to achieve the damping. Four broad felts are shown in figure but more narrow ones may be needed in practice.
Can the damping be adjusted by trial and error and constant directivity achieved?
Thanks and Regards,
WA
To get full range out of a driver the following is/are typically employed to extend the highs
1) The center of the cone is decoupled at higher frequencies and the cone iis used in breakup mode
2) Stiff dustc cap is used to extend the highs
3) Secondary whizzer cone is used
4) Phase plug is used to break the narrow beam at high frequencies
However, most of the drivers dont seem to focus on achieving constant directivity and polar plots are rarely shown.
So, my question is, can a full range driver be modified as below to get constant directivity. The idea is simple, let the center radiate the highs and as frequency comes down into the mids, have a larger portion of the cone kick in, thereby maintain a constant wavelength to radiating area ratio. Use a 2mm-3mm layer of felt to achieve the damping. Four broad felts are shown in figure but more narrow ones may be needed in practice.
Can the damping be adjusted by trial and error and constant directivity achieved?
Thanks and Regards,
WA
Attachments
I think Manger does something similar.
https://www.inner-magazines.com/wp-content/uploads/2017/08/Manger-driver.jpg
https://www.inner-magazines.com/wp-content/uploads/2017/08/Manger-driver.jpg
The Manger driver is a bending wave transducer and works in an entirely different way (tinkered with them many years ago)...
The diaphragm is flat and 'flexible', the voice coil kind of generates waves travelling to the outside of the diaphragm.
The mods you are describing most likely have to be established in 'trial and error' plus extensive measuring.
Member planet10 has done a lot of things to fullrange drivers and treated them (in a different way). Maybe you can look that up (--> EnAbled was the term I think).
The diaphragm is flat and 'flexible', the voice coil kind of generates waves travelling to the outside of the diaphragm.
The mods you are describing most likely have to be established in 'trial and error' plus extensive measuring.
Member planet10 has done a lot of things to fullrange drivers and treated them (in a different way). Maybe you can look that up (--> EnAbled was the term I think).
The holey grail of a FR is to have a driver that slowly, methodically, and in a well controlled manner, decouple the outside edges and have a smaller & smaller radiating surface as frequencies go up.
Likely the largest contributor to getting a solid dispersion up high is the cone shape. A very shallow cone tends to have greater dispersion than one that is “steeper”. The Alpair 11ms and teh Visaton B200 (or some old isophons) represent these approaches. The Alpair has very good dispersion, the laser beam top end of the B200 requires a phase plug to flatten and disperse the top.
Whizzer cones, IME almost all universally need a phase plug so they no longer have the dustcap as a “tweeter”. I tend to prefer drivers without whizzers.
One can certainring point.ly modify drivers, improving dispersion is hard in many cases, if one is starting from scratch i would choose a driver that is closest to your needs as a starting point.
True constant directiviely is likely not achievable but a nice monotonic decrease in top end reach.
dave
Likely the largest contributor to getting a solid dispersion up high is the cone shape. A very shallow cone tends to have greater dispersion than one that is “steeper”. The Alpair 11ms and teh Visaton B200 (or some old isophons) represent these approaches. The Alpair has very good dispersion, the laser beam top end of the B200 requires a phase plug to flatten and disperse the top.
Whizzer cones, IME almost all universally need a phase plug so they no longer have the dustcap as a “tweeter”. I tend to prefer drivers without whizzers.
One can certainring point.ly modify drivers, improving dispersion is hard in many cases, if one is starting from scratch i would choose a driver that is closest to your needs as a starting point.
True constant directiviely is likely not achievable but a nice monotonic decrease in top end reach.
dave