[colinallcarz]

After reading some of this thread, I think I might have to give AKG more of a chance. I picked up the K553 from Massdrop and wasn't very impressed with the sound.

 

[metal571]

After reading some of this thread, I think I might have to give AKG more of a chance. I picked up the K553 from Massdrop and wasn't very impressed with the sound.

I'm selling my K550 in favor of the 271. It definitely isn't their best effort. (a 553 I heard sounded identical to my 550)

 

[metal571]

New measurements from Tyll I just saw posted:
 
AKG K240DF (mine): http://www.innerfidelity.com/images/AKGK240DF.pdf
AKG K240M: http://www.innerfidelity.com/images/AKGK240Monitor.pdf
AKG K702 65th: http://www.innerfidelity.com/images/AKGK70265thAnvEd2014.pdf
 
Looks like the Monitor really is like a DF with actual bass. The only thing his measurements aren't showing clearly is the glare at 6k I experience with the DF - you can see some kind of slowness on the 300 Hz wave though, but the higher frequency overtone in the impulse response is perhaps showing up a little, though I can't see it on the Monitor. I didn't notice any peakiness at 3.5k despite the graph - driver is probably very fast through that region.

 

[ericj]

  New measurements from Tyll I just saw posted:
 
AKG K240DF (mine): http://www.innerfidelity.com/images/AKGK240DF.pdf
AKG K240M: http://www.innerfidelity.com/images/AKGK240Monitor.pdf
AKG K702 65th: http://www.innerfidelity.com/images/AKGK70265thAnvEd2014.pdf
 
Looks like the Monitor really is like a DF with actual bass. The only thing his measurements aren't showing clearly is the glare at 6k I experience with the DF - you can see some kind of slowness on the 300 Hz wave though, but the higher frequency overtone in the impulse response is perhaps showing up a little, though I can't see it on the Monitor. I didn't notice any peakiness at 3.5k despite the graph - driver is probably very fast through that region.

 
Which version of the Monitor? 

 

[metal571]

   
Which version of the Monitor? 

I don't think Tyll is that well versed in 240s to know which production version it was. Maybe if someone knows who sent the unit in?

 

[ericj]

I don't know the sonic differences, but there were, what, 3 or 4 different designs that carried that name over the course of about 30 years. 

 

[nick n]

Also wonder about pad condition on those.

 

[metal571]

I can say that the DF he measured there has mint condition pads, because it was my pair. The Monitor measures how I would expect...more bass but a similar signature as the DF otherwise.

 

[ericj]

I think the differences in treble response are worth noting. Since a difference in those peaks is largely what diffuse field equalization is about. 
 

 
 
I have a DF, and a 1st generation Monitor, and an early sextett. And an early 141 monitor. And i had a late sextett, and a late 141 monitor. i also have a k260 pro, k270 playback (270 playback #2 just entered the country today!), and a Realistic Pro 50 which is a K250, so i feel like i have a pretty good understanding of AKG's high-impedance monitor sound signature. 
 
I also have a number of DF-equalized Beyerdynamic cans. 

 

[metal571]

Yeah the DF would sound about exactly neutral (except for the horribly rolled off bass) if it didn't have so much ringing at some frequency. Can't tell what that frequency is cause Tyll doesn't believe in CSDs, but it's easily visible on the 300 Hz square wave and to my ears sounds like it originates somewhere in the low treble. To my ears, the HD 600 is the most natural sounding headphone I've heard yet, while the HD 800 and DT880/600 are the closest to a DF curve. I'm not a huge fan of DF headphones though, the treble sounds too dry to me. I like to have a slight recession around 6k, not a bump or only a mild rolloff from the upper midrange peak in an uncompensated response. Just my preference. I understand the whole DF compensation and what not, but it just doesn't sound like live instruments in my experience.

 

[ericj]

I will have to do some A/B of the DF and other variations. I don't recall my DF being all that lite on bass, but i don't think of most of the pro-grade AKGs as being bassy. 
 
The K270P can handle organ drone, tho. 
 
Speaking of which, when it rains it pours - got my new-to-me k270p in from austria today and it's great. Just stinks of hand lotion and needed foam discs. The pads are even good. One of the aluminum rings has almost fallen off, but is still intact - i might tease it off so that i can glue it down properly (hanging on in one spot only). They generally are near-new, surprising for how old they are. Old enough to have the ribbed cable. and even that is in better shape than i have seen before. I have begun treating the cable with 1Z Gummi Pflege Stift (rubber care stick). 
 
And i just paid $25 shipped for someone's miswired k270s on ebay, which i will fix up and listen to a bit. Word from fitz and other akg fanatics is that it's not so great, so i will fix it up and try it out, and maybe cannibalize it to rebuild my old k270p. 
 
There are more sets of k270p on ebay.de for people who are interested. Also a few sets of k290 surround. I'm tempted to get one and plug it into my sennheiser lucas surround dsp. 

 

[vid]

 
a Realistic Pro 50 which is a K250

 
The pro 50 is not the k 250. The pro 50 is more clearly with the sextett lineage, the k 250 was pushing towards the df, and with my hrtf does a better job of neutrality in the midrange than the df. Typical sextett ringing in the treble, still.

 

[GREQ]

 
The pro 50 is more clearly with the sextett lineage

I don't disagree with you, but I found the Pro 50 sounds subjectively more like a K250 than a K240 Sextett (I've had 2 sextetts, one bass heavy, one bass light)

 

[vid]

My theory is that the later sextetts had the same or very similar driver as the k 250/241; in other words, that akg's move from free field to diffuse field around that time bled into the changes they were making to the sextett. What version of driver is in the pro 50, I don't know, but still, the pro 50 came with the sextett namesake passive radiators, while the 241/250 pioneered the sound ports that the df took off with. This should be enough reason, in any case, to not say that the pro 50 is the k 250.

 

[GREQ]

Makes sense.
It's one of the few headphone lines that has this kind of strange unique evolution period with so much variation between seemingly identical or similar models.