Nice! Questions... (Orelo/Orelino)

by Rudy81 , Dallas, TX, Saturday, April 06, 2013, 17:35 (4035 days ago) @ Bert

I'm glad you guys motivated me to set things up again and test a few more options.

I began by duplicating the setup and running a baseline plot to compare with what I did yesterday. Today's setup was extremely close to yesterday's results, and good enough for this task.

I then ran various throat widths to get a better feel for the effect of changing just the throat and leaving the wings angled as I originally built them, or what I call STD for reference in the plots.

The results show that the differences are minimal from 40-250Hz. Between 250Hz and 500Hz, is where the throat size seems to make most difference. As the throat is narrowed, performance improves in that frequency range. Above 650Hz, the inverse happens, as throat size narrows, performance decreases. The good news for me, is that in my range of interest 80-200Hz, the difference is very minimal....although worth consideration.

Based on closely looking at the minor differences, I am going with a 240mm throat opening.

BTW, every one of these plots is raw, un-smoothed and unmodified.

Now, as far as changing the angle of the wings relative to the baffle, I kept the throat at 240mm and tried a few measurements as I closed the opening of the wings. I started with 1320mm, which is the fixed angle of my wings. Then, tried 1193 and 890mm openings.

From 40-150Hz, as the wing opening narrows, the performance decreases. Above 150Hz, performance improves with narrowing wing opening. So, it is a tradeoff one way or the other. Since I am trying to optimize the performance below 200Hz, I will keep the opening as I built it....lucky for me!

And finally, the question of the wings vs. Open baffle and no wings. The results speak for themselves.

Having run all these tests, I am now ready to continue the build. I am modifying my plan and setting the throat opening to 240mm.