It's no secret that I'm not a huge fan of the way most PA setups sound. I dug a little further into the issue as to why that is. Well... other than the fact that most PA setups have too little EQ. Whether that be by design, perference or by the sheer lack therof.
So anyway... this is an equal loudness contour. You might remember it from my "Why the loudness setting sounds better to you" thread. But to recap, we don't hear all frequencies the same. Our hearing is more sensitive to certain frequencies than others. This contour represents what we percieve as "equal loudness". Just looking at it, you can see we are very sensitive to the 1-5khz range (the lower in that curve, the more sensitive we are).
This is a frequency response chart of a random "traditional" 6.5" woofer in full range. Notice how it's FR is relatively smooth with a slight downward slope
beginning ~ 750hz. There's a huge spike @ 5khz, but that would likely be a non issue in a typical CA install due to being off axis and the rolloff caused by that. You're likely to cross these over lower than that anyway.
Now... here's a very
good PA driver. What you'll notice here is the rising response
starting ~ the same spot the "traditional" driver started to trend downward. And with a big, fat peak right at our hearing's most sensitive spot. And a peak ~ 5khz similar to that of the other one. I suppose this might be due to piston size and cone breakup.
What's all that mean? Well... without some clever EQ, that rising response is the reason PA drivers are "shouty", harsh and just plain loud right in our hearing's sweet spot. Whereas the other driver needs less EQ to stay relatively flat.
You'll also notice the low end extension of the traditional driver vs the PA. As in, 50hz vs. 180hz. Yikes. And this is a very good PA driver, mind you. The lightweight parts used in PA drivers to achieve their crazy high sensitivity is a tradeoff. And unfortunately... low end extension is that tradeoff.
Now this is interesting... this is an RTA of another source that I measured just last night. It bore a striking resemblance to the rising respoonse of a PA driver with a very similar peak in the 2-3khz range and a sharp rolloff on the low end. Funny that it has similar high frequency "noise" at ~ 12khz and 15khz too.
Anyone care to guess what that last measured source is?