You're welcome! The design frequency really depends on what band of frequencies you as a user are interested in diffusing. If diffusion in desired in low frequencies, then the design frequency would be lower. Finally, space availability is also important which can decide the design frequency since lower frequencies demand deeper wells which consumes space.

Thank you so much for really explaining this so well! I’m really glad I found this video it should have way more views! My Panels work beautifully in my home theater thanks to you!

A QRD is designed to spread out or distribute sound spatially and temporally without altering its energy. Filling QRD wells with absorptive material will not help to accomplish sound diffusion as sound energy will be absorbed.

Hello@@SrinathSrinivasan and thank you for the reply. So if I understand, the qrd won't diffuse as much sound because the filling is absorbing some of the energy but other than not diffusing as much as it might, are there any other detrimental impacts to the manner in which the sound is diffused?

Thanks! The fin thickness must be as minimal as possible. Increasing fin thickness not only increases diffuser period width and thereby the size but also makes room for some unnecessary reflections.

The well number 0 is present in QRD of any order. When installing QRD assuming N7, it is recommended to use arrays of N7 as using only one will not give meaningful results. So either one can leave the well '0' on one side or split the well '0' evenly along the ends. The latter option ensures that one does not need to worry about symmetry during final assembly. I do not know which manufacturer excludes well '0' altogether but there is a well known QRD manufacturer - RPG Acoustical systems. Their QRD model QRD-734 as mentioned in their website offers well '0' split along both ends. Out of curiosity I used QRDude software to check if there is any difference in keeping well '0' as it is or splitting it along ends and there was no observable difference. You can check the findings in the link in the video description now. Finally my thoughts, even if a manufacturer were to neglect well'0' altogether, they still have to use end-fins on both sides to cover the diffuser sides. In that process, they have just added an approximate well '0' on both sides since the end-fin will have some finite thickness.

Oh thank you very much for your detailed explanation! Now it makes sense... It was my mistake, never noticed that most likely those looking "simmetric" in fact have larger sides to compensate... I prefer the simmetric design, unless is equally good!

First, the diffuser dimensions depend on available space and the frequency range of diffusion you are looking for. Second, a diffuser alone will not create diffusion but the room in which it is placed has to work along with it. For this reason, several measurements have to be conducted in the room to determine the appropriate type.

Does a binary amplitude diffuser (BAD) have the same diffusion properties as QRD or PRD diffusers?

I read information about Binary amplitude diffuser (BAD). It is designed to offer more absorption in low-mid frequencies and less absorption in high frequencies. Some sources claim that it offers diffusion in high frequencies, I do not know if it is true. There also exists no mathematical relations unlike the QRD. RPG Acoustical systems, a well-known manufacturer of QRD, also manufactures BAD, they have not mentioned anything about diffusion coefficients with respect to frequency of BAD in their technical specification sheet.

@@SrinathSrinivasan Thank you🙏