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Originally Posted by mypasswordis  Ah, I missed that... what a lame way to inflate numbers.
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Stating dynamic power (or amp headroom) figures can be useful sometimes, but there's no standard (that I'm aware of) that's specified as tightly as the rms 20-20k @x% distortion method. Most home theater amps tend to be spec'd more dynamischly, so be on your toes, it is amongst us. A very rough and ready method to convert to "real" watts is simply divide by two. At least.
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Originally Posted by BoilermakerFan
...dampening at the driver has a great[er] effect on the highs than the bass and ..dampening of the cup has a greater effect on the bass and no effect on the highs.
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Exactly. That's always been the way I've tried to describe it. If I haven't been clear, or if you saw a post of mine that leads you to any other conclusion, let me know and I'll go back and fix it.
Damping simply suppresses (ie, brings back to flat) the typical broad resonant ortho hump in the mid bass that extends into the midrange. It therefore reduces the amount of bass energy but tightens the bass up so that it has more impact and definition-- where before there was bass soup, now you can discern the pitches of bass instruments, follow bass lines in the music, etc. So the bass pops out from the fog, but in terms of amplitude, the average level is lower, even though the peaks are higher. We've taken energy out from under the bloat and re-inflated the peaks, if you will.
It's easier to characterize the main effect of damping, which is to suppress excess midrange and make it sound as if the highs had been turned up. If you damp too hard, you effectively steal energy from the bass and mids and push it into the highs, but you're pushing it into the mid-low treble, not the very top end. Depending on the original FR curve of the driver and the enclosure it's sitting in, this could be a delicate balancing act.
Damping the vents or the back grille of an ortho keeps the backwave under control and that strictly affects the bass. You just have to be careful not to use material that's too dense or you effectively close the cup, and, unless the cup is large, it's bye-bye bass.
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Originally Posted by BoilermakerFan
What's great about the RP18s is that "overdampening" at the driver did not suck out the mids like I noticed with the Yammies, but even 3mm differences in the OD of the felt or cotton discs on the driver is audible. I may try a perforated primary felt disc on the driver backed with the solid felt.
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Sounds like an interesting experiment.
I've only heard one RP 18 and it came pre-modded, but it sounded like a stubborn SOB to try to get that response curve untilted. I know a lot of people have (or had) RP 18s, so if you could post diagrams or photos, several orthonauts would be mighty obliged.
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Originally Posted by BoilermakerFan
Order all three! Just like tubes, you can never have too many pads to roll.
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I was just going to suggest that myself. Stock up. With pads, as we've found from sad experience, what's here today may be gone tomorrow..
Edited by wualta - 9/29/10 at 11:21am
I have yet to hear a can with a truly flat freq. response that was enjoyable and engaging to listen too. My preferred response is strong bass with slightly forward midrange (that can't ever really be EQ'd into a flat signal without 1/3octave active EQs) and present but flatter (as opposed to elevated or rolled off) upper highs that would make the response curve look like a smoothed, channeled, chopped, and stretched "W". A classic late-'40's to mid-50's lead sled for an automotive reference. Of course, my amp is like a 600HP supercharged big block V-8 in that sled and I discovered the adjustable blow-off valve and lake pipe dump switches, so YMMV.
