Showing posts with label QRD. Show all posts
Showing posts with label QRD. Show all posts

May 3, 2011

DIY nearfield diffuser panel

Here is a diffuser panel in prototype form that I'm currently testing. I prefer to build prototypes first before coming up with a design that I will build properly.

 
 The process can help with the design. In this case I want to make sure I like the result, and these light easy to make panels can be easily moved to try different placements.

As you can see, it is made with fins of ply and polystyrene wells stuck on with masking tape. They are all parts I had on hand. The panel is around 350 x 400mm and 55mm deep. It is effective to 2k with reduced effectiveness down to 1k.

This particular panel is designed for nearfield placement, around 300 - 500 mm. They will be placed on the rear wall against which my couch sits. In my initial tests I've compared to a bare wall and absorption. I prefer the sound of a bare wall over absorption, as the latter sounds artificially dead. I also prefer the panel over a bare wall as there is an added sense of ambience without adding anything unnatural. The effect with a small area is subtle.

I also have plans for a panel that is 110mm deep which will be effective to1k.

My plans are to add a very large panel to the ceiling and behind the listening couch, with smaller panels distributed around the room.

April 30, 2011

How to design an acoustic diffuser panel

The information here will help you quickly design your own. You may prefer to simply build from a dimensioned plan, however, persist with this quick guide and you will soon have your own custom version that can be sized for your own requirements.

Diffuser primer >

1. Download QRD calculator >

This is a free application that makes it easy.

2. Choose the number of wells for each module

3. Choose either the depth or the lowest design frequency

Choosing one will determine the other. The region above 1k is critical for imaging, hence it is a good idea to aim for your panel to operate to that point at least.

4. Check the listening distance

5. Check the fin width

6. Decide on 1D or 2D

If your panel is 2D then click 2D from the top menu.

Now you have all the information that you need. Grab the calculator and work out how much material you will need. 3mm MDF would work well for the fins, but for the wells you may choose something a little thicker to make it easier. Keep in mind that if 18mm MDF is used, the panels will become heavy and more difficult to mount.

For more information, read the guide written by Collo, who designed this free application.