I used 3M undercoating (for underneath a vehicle, basically a rubberized spray coating) on the interior of the speakers, then I put rockwool around the diameter of the inside, however I "packed" it in there, which I believe had the largest effect on dampening any vibrations though the line-x also helps too - I will have to record 'knocking' on the tanks to demonstrate their 'deadness'. I broke my phantom power supply last night, i was trying to calibrate my microphone with an electric spark, and to get the noise floor quieter (6db/oct rolloff from spark sound) I tried hooking it to a battery, it has an 18vac input... it didn't work
I should have a new phantom supply in a few days so I will make a recording and do more measurements then.
I did not use anything to dampen any resonances of the pipe... its just the pipe
Since the speaker transducers are isolated from the speaker enclosures via sorbothane the already acostically dead enclosures are further isolated from any energy produced by the transducers. THEN, the vinyl-steel cables also seem to not be particularly conductive acoustically, then also, since its 3/4" pipe, thats quite a bit of mass - my point: I have found that any resonances/ringing from the pipe is insignificant. I intend on doing some measurements eventually, and since I like to perfect things, may end up stuffing the pipes with rockwool.
The N7r's should be good to 3-4k, if you can bi-tri amp your system and use a processor that would be optimal of course since you could EQ them a bit and achieve a pretty clean 8k
The amp is awesome. See their site (labgruppen.com) for more info; I got it off ebay, I was very lucky to find it at the price I got it for, they definitely are expensive, however, my setup consists of computer -> spdif cable to amp ->amp ->sub+speakers! so in a sense, you don't have to buy two amps (speakers and sub amp) and also the dsp processing is also included, so yes, expensive, but it really takes care of all but the source and the speakers [transducers], I have the 4 channel model of course.
You are in luck, a few days ago (the 21st) I did some EQ'ing and I have a pre-eq and post-eq measurement saved! The measurement is for the right channel (left and sub muted), on axis, ~6" from the acoustic center of the transducer (I made a 'jig' to consistently position the mic too, I will have to put pics up of that). The EQ'ed measurements are actually *measured* results, not predicted by REW. I was not finished eq'ing... so understand there is some variation in the high frequencies in the eq'ed measurement.
How are you liking the Neo10's I saw those (exist) after I built the N7r's, I want to mess around with planar speakers at some point here
Graphs! - the x-over was set to 48db/oct lin-phase @95 hz I believe... I think I changed the x-over to 62.5 hz for the post-eq stuff
Purple is pre-eq: blue is post-eq
<- this hyperlink will take you to the picasa web album of the graphs so you can see full-size