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Ahh progress!Ok, a few things about your measurement setup. Off the floor like you've got is good! But 5 cm from the driver isn't showing a large enough distance for the dipole behavior to develop, which is why the measurements are rather flat. With no eq applied, a driver in dipole operation like that will measure anything but flat! You will have a peak roughly corresponding to the width of the driver (or baffle), and a 6db rolloff below that. I go about 1.5 meters to see what sort of dipole compensation I will need.Your setup in Holm isn't quite right. What you've got with the complex frequency smoothing is a smoothed in-room response, and you want to see how the drivers behave without the influence of the room (at least for the mid and tweeter, I measure the woofers in-room from the listening position). You want to change the "distance" display on the x-axis of the impulse to "time". To do this go to Options at the top, and go to where it says 'Impulse Axis' in bold. Click on 'Impulse as time (millisec)'. Now click 'Options' next to your measurement, and click the 'Impulse time-window (gating)' spot. At this point, look at your impulse measurement again (this is what Holm is actually measuring, not the FR. The FR is derived from the impulse). See that dotted line that crosses over the x-axis? That sets the gate, which cuts out the room reflections, depending on where you have it set. For me, with the same basic setup conditions as you, I use 4ms. Now you should have a workable frequency response!For some more basics, JohnR has a good guide here: http://www.hifizine.com/2011/03/refining-a-4-way-open-baffle-speaker-minidsp-2x4/He uses a miniDSP, REW, and fuzzmeasure here, but the basics apply. You might also want to check out the free (demo, but fully usable) version of ARTA. I use both ARTA and Holm to make sure I'm on the right track.
And what about that FR? Looks weird, if anything, I would expect fallof at lower frequencies, not a hump...
Give us some data of the Beston driver geometry (baffle height, width and depth, ribbon/membrane geometry and location on driver baffle etc.) and we could see in EDGE where the dipole peaks and notches are to be expected.Rudolf
Haven't thought of modeling driver itself in Edge, great idea! Waveguide as small baffle, and opening in the waveguide as small driver...nice.
gamgee,some comments on your measuring methods:1. Always measure from as near as the situation and the measurement target allows.If you measure a single driver in its baffle, three times the baffle width should be sufficient as measuring distance. Even for a dipole, five times the width would be fully ok. If you measure your Beston from 134 cm, you either have to play it unreasonably loud or you are prone to fetching noise from outside.2. Keep the measured object as far from room boundaries or other obstacles as possible.You have done that already with your Beston measurement. While it is correct to gate your measurement to 130 cm, those 4 ms do limit your low end exactitude somewhat. By moving the mike nearer to the driver, the driver signal will become much louder in relation to the reflections or to noise, and you could safely open the gate to a longer window.3. Don't see more in simulations than the simulation method allows Edge is safe for finding the frequency of the first dipole peak. Its simulated peak height is already questionable. Edge gives a faint idea of the following dipole notch - position only. Everything above that (in frequency as well as dB) is pure math with no relation to reality.Rudolf
Does that mean I should measure naked drivers from different distances, according to their dimensions? For example, BG20 is 20 cm driver and RT002A is 10 cm - should I measure BG20 from 1m and RT002A from 50 cm distance? Nate told me to go for 1,5 m ...
