This thread is so informative (and uniquely so) that it would be a disappointment if it didn't develop into its own website, or at least become well-organized like InnerFidelity (or perhaps become part of it?). The consolidation and organization of the information in this thread and its evolution could become one of the most, if not the most, valuable information databases for selecting one's next pair of headphones, and moreover keep the competition more honest Regardless of what happens, at least I hope the measurements continue. Thanks Purrin for the enlightening information.

Thank you. Unfortunately, judging by the number of page views per day, I don't think a lot of people really care or really understand what I am trying to do. (The LCD# threads are far more popular!) I know however that I have a small audience that has expressed appreciation and that's who I do them for.

Impulse Responses

These are just as interesting too. In addition to the CSDs, we now have a more complete picture.
 
SR009

 
AD2000

 
LCD2r1

Wow, the AD2000 has a great response. Curious how the 009 almost seems to bounce back up rather than ring back and forth.

Quote:

purrin said:

The decay is only one aspect of "fast". There is also the attack which isn't seen here but rather in the impulse response and square wave 

 
There are also secondary considerations of "fast" that involve how clean the entire spectrum is after the decay. The 009 is the only one of the above that doesn't have a lot of crap. Also subject to interpretation would be what level would be considered audible? The dark blue? The light blue?
 
I'll pull up the impulse responses of all three.

Click to expand...

Exactly.  I also thought the HD800 looked pretty clean as well.  Toss that impulse response in there as well, it sure sounds faster than the LCD2 despite whatever anyone thinks about treble.  Absence of treble isn't giving me congestion on fast, complex tracks w/ the LCD2.  Not to mention I've seen about 4 different LCD2 Impulse response charts already that perform differently.
 
I wonder if that 009 response attributes it with that airy, ethereal sound.  I wish we could measure the HE60.

Too lazy to run a impulse response according to the same graph parameters in Excel - I deleted that file.
 
Anyways LCD2r1 vs HD800 impulse response comparison:

Blue = HD800
Red = LCD2r1

Quote:

rhythmdevils said:

The overhead graphs make it look like the AD2000 driver is faster than the SR009 despite the much faster decay of the 009.  Is that your reading as well?  Kind of hard to believe.

Click to expand...

Now that I'm pouring over the data, I'm glad you caught this. A lot of the measurements (at least the top down graphs), need to be redone. I didn't account for adjusting the differences between the microphone and the drivers. The headphones with drivers closer to the microphone will appear to decay faster (especially on the overheads). This is a result of how the calculations are handled.
 
Oops. Sorry. The good thing is that the raw data I have can still be re-used. The ringing behavior and how the waterfalls drop down are still accurate. It's just matter of shifting the same structures backward or forward in time.

AKG K340

This one is an oddball. Part electrostatic, part dynamic.

 

Pre-measurement impressions:

These vintage AKGs are hard for me to get a grasp on. I haven't been good at predicting their plots.
 
Bass lite. Zero low bass. Treble emphasis. Tizzy around 10-12k. Broad valley from 4-7k? Sounds like there is a 1.5k ridge - the only area of significant ringing. Otherwise it sounds extremely fast in the treble. I'm betting a very clean waterplot from 5k on up to 12k. Trebly, but doesn't hurt - very unique in this respect.
 
These really lack dynamics, especially down low, but they have an interesting sweet sound when the volume is turned down. Kind of a night-time low volume mellow trebly can, which is what I've been using them for the last two days. I've actually been grabbing these and the Sextetts on occasion. These two AKGs are interesting, although I doubt they ultimately would be keepers for me.
 
These are no FR plots. The waterfall plots below only go down to 200Hz not 20Hz.
Closed headphones require compensation below ~2kHz which is not applied in these plots.

 
The ridge is at 2.5k. I thought the midrange ringing wasn't as honky and was closer to 1k - just the nature of the presentation of these cans. Didn't hear the thin slice ringing at 4.5k, but I have a tough time hearing ringing around 5k anyways. Very clean from 5k onward as I predicted. This is a very nice attribute which I believe kept me coming back to these cans despite the treble emphasis.
 
BIG THANKS TO RD FOR SENDING ME A BOX OF GOOD STUFF. (I still have the little Yamaha supra-aurals to measure)

Lol, me and RD talked about the coherence issue between the two drivers awhile back.  Seems you can see the two distinct red humps separated by a nice ringing ridgeline.  We both liked them though as far as thinking they had something potentially special, just failed in proper execution.

PS1000

We all know about these (in)famous Grados and how they sound. A few people have asked about CSDs for these and RD was kind enough to provide me with one of his own plots:

In your impulse reponse plots, why does the SR009 pretty much stop at 0 on the way down, while the others shoot past 0?  Is it because they have more moving mass to halt? 

 
Quote:

n3rdling said:

In your impulse reponse plots, why does the SR009 pretty much stop at 0 on the way down, while the others shoot past 0?  Is it because they have more moving mass to halt? 

Click to expand...

 
That's a good hypothesis. Let me look through my other data, i.e. ESP950.
 
 

Interesting...
 

ESP950 Impulse Response

Red = ESP950 driven by Koss Energizer
Blue = ESP950 driver by SRM323
 
Wow! Looks like stats do things a little bit different than dynamics.

 
Quote:

purrin said:

Thank you. Unfortunately, judging by the number of page views per day, I don't think a lot of people really care or really understand what I am trying to do. (The LCD# threads are far more popular!) I know however that I have a small audience that has expressed appreciation and that's who I do them for.

Click to expand...

I love this thread so much.    
I've learned more about headphone sound from this thread than any other thread or topic on head-fi.  Thank you.
 
I never realized that ringing was such an issue in headphones or caused so much of a spike.  That spike gets smoothed out of all of the FR graphs I've seen and the FR graphs don't show the decay effects at all.  Now I know what's going on.  I've heard "weird things" and spikes but never knew what to attribute them to.  No one ever told me that weird stuff was ringing.  I didn't even know what ringing was so how could I attribute it to what I'm hearing?  Now I know (painfully in some cases).
 
The graph of the D7000 was especially ear opening.  Now I know why my D2000 has so much treble with some amps.  I refuse to listen to the D2000 on my Schiit Asgard.  Toooo muuuuch treble.  Ouch.  I gravitate to "amps that suck" to tame the Denon treble.  Some amps that aren't so revealing somehow manage to tame the Denon treble to a level that doesn't annoy me.  I don't know what's going on there.  Does an amp that sucks somehow decrease the ringing or does it somehow blur or mush things around the ringing enough so that it doesn't annoy me as much?
 

Hmm, looking at Tyll's impulse graphs it doesn't really look like the Stax he measured are particularly lopsided in impulse response compared to dynamics and orthos... I know they're not quite the same, but still, hmm...