[dcstep]

Quote:

Originally Posted by Crazy88 /img/forum/go_quote.gif Aren't low frequencies supposed to be more difficult for the human ear to hear? From what I remember, more amplitude is required in low frequencies for them to be equally audible with higher frequencies.

Yes indeed, the character changes dramatically after 30Hz or so and then there's another big change at 20Hz, which is where music ends but there is ambiant information that is useful.

Listening to the same test CD through my Vienna Acoustic Beethoven Baby Grand speakers, with a down 3dB spec at around 30Hz, the bass signal continues clearly down to 20Hz, at a reduced level, but not nearly so much as with the AKG. It is useful to listen through a few differenct setups so you can get a bead on what you're listening for.

Dave

 

[KZEE]

Quote:

Originally Posted by SergioRZ /img/forum/go_quote.gif How can the pads be removed? Are there any instructions on how to do this without ruining the pads/cans?

Put pressure on the pad with your hand and then turn it counter-clockwise and it'll come right off.

 

[jh4db536]

im not contesting whether people do or not, nor do i care for generalizing numbers. I'm simply reporting what i get from listening to a test/reference track. I wish i could upload it here so you could hear it for yourself. You'd know exactly what i mean.

You'll see the marked notch when you take the earpads off. Just grab the pads and twist it counter clockwise (it's held on with 4 tabs). It can be offset in 4 different positions. I noticed this was needed when i let my friends try my 701's and it didnt fit their heads until i tinkered with it.

When you have a big head, obviously the tall/thick side of the pad needs to be on the bottom to get that seal (i dont know how it comes stock). If you have a small head the tall/thick side on top usually works. Im personally using the tall/thick side at 9 o'clock. I think it gets the right angle for the sound to go straight into my ears.

Quote:

Originally Posted by SergioRZ /img/forum/go_quote.gif Are we supposed to hear anything at all below 20hz? Besides the vibration of course... I think it is really strange that the 650 is strong making sound at 20hz, and at 10hz is really very weird. How can the pads be removed? Are there any instructions on how to do this without ruining the pads/cans? I have a big head... where is that yellow foam notch?

 

[JaZZ]

Quote:

Originally Posted by jh4db536 /img/forum/go_quote.gif When you have a big head, obviously the tall/thick side of the pad needs to be on the bottom to get that seal (i dont know how it comes stock).

The K 701 is an open (open-baffle) headphone, hence doesn't need a seal.

Originally the thick side is at the back to form angled drivers -- a concept which normally means creating a slightly forward-oriented sound source, to come closer to a natural free-field experience. Turning the pads creates a different sound-impact angle plus a different frequency response. Although the latter may be beneficial (?) in some cases, the former dilutes the angled-driver concept with the goal of a better soundstage.

BTW, a linear frequency response down to 40 (or even 30) Hz is a respectable performance. There aren't many speakers with such a flat and extended bass response, let alone under real-life conditions (speak living rooms) where they develop awful resonances in this range. Also there aren't many other headphones with such an exemplary behavior. (If you hear something with test tones below 20 Hz, it's most likely distortion products.)
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[spinali]

Quote:

Thanks for the idea. I was suspicious about the pads How can I remove the original pads? Any how-to available online? Actually I'd really like to find information oabout how to "dismantle" the 701's and how to recable them..

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You've probably accessed the pads by now. Firmly grip your fingers on the outside of the pads, where it meets the white plastic. Then, push in and clockwise. The pad will open, and you'll see the "sound do-nut" inside. To reassemble the pad, grip the edges of the pad as before, then push in and counterclockwise. You may have to do this a couple times to get it right.

It seems you want to simply tweak the sound signature. There are some great options here, but if you're that sensitive to variations in the sound, an amp like the 3HA gives you exceptional flexibility from one tune to the next.

 

[rhythmdevils]

get k501's and put K701 pads on them. Sounds like a K701 with a little less air, no sibilance, and much more bass. Same soundstage, still really airy, and the mids are so sweet....

 

[ph0rk]

The thing about the headroom graph is they are all "centered" at 600hz.

They would be much more useful if they were set at something like 75db of pink noise, a-weighted. I'm pretty sure all the headphones I listen to would be at different volumes w/ a pure 600 hz tone at normal listening levels, so I don't think it is the best way to center the graphs/compare headphones.

 

[dcstep]

Quote:

Originally Posted by ph0rk /img/forum/go_quote.gif The thing about the headroom graph is they are all "centered" at 600hz. They would be much more useful if they were set at something like 75db of pink noise, a-weighted. I'm pretty sure all the headphones I listen to would be at different volumes w/ a pure 600 hz tone at normal listening levels, so I don't think it is the best way to center the graphs/compare headphones.

Very good point. The 0dB points for th AKGs are about 600 Hz and 20 Hz. Between those points there's a broad 5 or 6 dB hump, which is somewhat typical of all the compared phones. 6 dB is a lot, but it's so broad I think our ears will interpret it as richness.

I did some more listening to the Stereophile test CD, moving back and forth between my speakers and the AKGs. I pegged the Woo (it doesn't have a ton of gain) so that I could hear every little change. I can clearly hear that midrange hump in the graph, but once we get below 40 Hz the roll off is way, way steeper than that graph. I could tell that by comparative listening between the speakers and the cans. With the speakers I used my Radio Shack SPL meter to set the -20dB white noise tone at 90dB at my listening position. The speakers were +-1dB down to around 200 Hz where the reading bounced around between +-3dB, but staying surprisingly consistant to around 40Hz where the roll off started showing -6dB at 30Hz and -20dB at 20Hz. Not bad really. Still, that -20dB measured from the speakers seemed like way less rolloff in the cans.

No way the AKGs are only -6dB at 20Hz, from their peak in the broad 200 to 600Hz range.

Interesting stuff. I still love the AKGs, but it's informative to understand them better.

Dave

 

[ph0rk]

if it is the same ratshack spl meter I have, it won't do 20 hz well at all - it can do either a-weight or c-weight measurements.

Weighting filter - Wikipedia, the free encyclopedia

 

[dcstep]

Headroom says:
"To perform this test we drive the headphones with a series of 200 tones at the same voltage and of ever increasing in frequency. We then measure the output at each frequency through the ears of the highly-specialized (and pricey!) Head Acoustics microphone. After that we apply an audio correction curve that removes the head-related transfer function and accurately produces the data for display."

Ok, I think I see what's going on. They very carefully take an exceedingly accurate raw reading and then apply an "audio correction curve." That's why we can't replicate the test with our cans, ears and a test-tone series.

What are the odds that a committee of headphone marketing types came up with that correction curve????

Dave

 

[dcstep]

Quote:

Originally Posted by ph0rk /img/forum/go_quote.gif if it is the same ratshack spl meter I have, it won't do 20 hz well at all - it can do either a-weight or c-weight measurements.

'tis indeed. I used C-weighting.

Dave

 

[dcstep]

Ok, I pulled out my UE Pro5s to listen to the Stereophile Test CD and they're clearly flatter below 100Hz and have signficantly more volume at 20Hz, 25Hz and 30Hz vs. the AKGs. Not surprising for IEMs vs. open back design.

What's really interesting is to look at the Headroom frequency response curve for the UEs, since they look surprisingly like all the other Headroom charts. If you go to the UE web site their curves look totally different from Headroom's.

I'll just say that the Headroom charts are very different from what I hear.

Dave

 

[KZEE]

Quote:

Originally Posted by JaZZ /img/forum/go_quote.gif The K 701 is an open (open-baffle) headphone, hence doesn't need a seal. .

Actually an open-baffle design is even more dependent on a good seal than a closed-baffle design would be. If the seal isn't good then leakage will cause cancellations to occur, especially in the lower frequency range.

 

[JaZZ]

Quote:

Originally Posted by KZEE /img/forum/go_quote.gif Actually an open-baffle design is even more dependent on a good seal than a closed-baffle design would be. If the seal isn't good then leakage will cause cancellations to occur, especially in the lower frequency range.

No, it's the other way round. An open baffle* brakes any seal beforehand and makes the system by nature «suffer» from phase cancellations at low frequencies, which have to be compensated for by larger membrane excursions. That's why the so-called seal between earpads and head has virtually no meaning, neither for pumping the sound waves into the ear canal without acoustic loss nor in view of phase cancellation. (BTW: the K 501 is a closed-baffle system.)

* Note that the «baffle» is the plate on which the driver is mounted. A closed baffle separates front and rear sound waves, an open baffle does not.
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[SergioRZ]

Quote:

Originally Posted by jh4db536 /img/forum/go_quote.gif I did the exact same test on it using my IASCA reference cd which is how i came to my conclusions. Track 35 - Sign sweep 1hz to 200hz in 1hz/1second increments. My 650 can make like a helicopter/earthquake just went over my head compared to the 701. The 701 starts making SOMETHING barely audible at ~17seconds~17hz whereas the 650 is going strong starting at ~10seconds~10hz. I can hear a feint clicking sound = the diaphragm/driver vibrating VERY slow at very low frequencies...i hear it vibrating but making no audible sound. That's a VERY noticeable difference to me, i dont need any metering or SPL equipment to figure out what's going on there.

Did the same test with the IASCA CD track 35. You get the clicking sound, and then at around 10hz the 701's seem to start a very faint sound, more a vibration of course, but it is there... it keeps building up stronger, and again there is absolutely no steep change between 10hz and 100hz... it's all very progressive and smooth in the way sound becomes more prominent as the frequencies are upped...

At 15hz the 701's are audible enough (at least what can be expected from 15hz frequency), and at 20hz it's clearly audible. The 701's seem to have all the bass extension that anyone will ever need. But then this is not an "extension" issue... it's more an EQ issue, or a linearity issue...