Grilles are done! These took a surpring amount of processes to complete. I'm more happy with the way I went about making them than the actual finished objects. I used a mitre bar with a knob screwed in to push the disc up to a point where it butts up to a stop with slippy tape on and was over the roundover cutter. I put a bit of dry PTFE in the pivot hole and rotated the disc whilst incrementally rising the cutter. I didn't quite get the profile right, I should have used a larger radius but hey. They are done and whilst being more functional than pretty they stop me worrying about my cats obsession with woofer rumble.
hi
can some one give me a clue as to how this diffraction happens and whether a flat baffle with round over would help
below is a measurement of a cd driver with a horn similar to the RCF H100, the upper two are with the horn alone and 45 off hor and the other two are on the actual baffle and the last is the maximum damping with felt gets you...I mean this 3khz hump it changes to a dip when at 45deg hor so a notch filter isn't as much of help since at 45 horizontal it turns into a big dip at 3khz due to the notch filter correction.
can some one give me a clue as to how this diffraction happens and whether a flat baffle with round over would help
below is a measurement of a cd driver with a horn similar to the RCF H100, the upper two are with the horn alone and 45 off hor and the other two are on the actual baffle and the last is the maximum damping with felt gets you...I mean this 3khz hump it changes to a dip when at 45deg hor so a notch filter isn't as much of help since at 45 horizontal it turns into a big dip at 3khz due to the notch filter correction.
Yes, it is not recommended to over-react to the apparent effects of diffraction when looked at from only one angle. Measuring power is one thing you can do. Reducing the diffraction is desirable. It can help to look at the horn as well as the baffle as either might be the problem. Also, the baffle should try to work with the horn.
What horn is it?
I will wager that if you rotate the horn 90 degrees and repeat the polar measurements the response will have less diffraction and will look a lot smoother from position to position. I make a habit to test any horn I use in both orientations to see what is going on.
If the horn does as I mention then it has its own diffraction geometry which is usually to create a wider dispersion. Once you have a full picture you can start chasing down the culprit.
Its unlikely the baffle or cab is effecting it this much as the point of a horn is to direct the waves from the source forward which means it pays little attention to the surface it is mounted on.
Of course, the baffle DOES effect things but not nearly as much as one would assume or expect it to with a direct radiator like a dome tweeter.
More info required - pics of baffle, model of horn, pictures of measurement environment 🙂
I will wager that if you rotate the horn 90 degrees and repeat the polar measurements the response will have less diffraction and will look a lot smoother from position to position. I make a habit to test any horn I use in both orientations to see what is going on.
If the horn does as I mention then it has its own diffraction geometry which is usually to create a wider dispersion. Once you have a full picture you can start chasing down the culprit.
Its unlikely the baffle or cab is effecting it this much as the point of a horn is to direct the waves from the source forward which means it pays little attention to the surface it is mounted on.
Of course, the baffle DOES effect things but not nearly as much as one would assume or expect it to with a direct radiator like a dome tweeter.
More info required - pics of baffle, model of horn, pictures of measurement environment 🙂