Is Akg k702 really a power hungry headphone ??

[solderdude]

When I bought the K702 from the previous owner he asked me to also measure the 'bass port mod' but kind of forgot ... until today.
So I looked into this (as well as output resistance effects) on this headphone and updated my review.

Some info I will post here as well (to save you from combing the review).
Below the effect of sealing and opening the centre hole in the driver magnet (referred to as bass port mod).

As can be seen a substantial subbass extension is possible. One may wonder why AKG still puts on those damping stickers when they can increase bass so easily. Well the answer is you shouldn't remove that sticker and below is why.

Aside from the stock and 'port open' plot there is a 3rd plot in there showing distortion when used with EQ that mimics the bass extension of the 'port mod'. In fact that EQ lowers bass extension even more. EQ does not increase distortion. All is measured at 90dB SPL b.t.w.
So those contemplating doing the often 'hailed to be great sounding' bass port mod I would say ... don't .. just apply some EQ.

Another aspect is the output resistance which would change the damping factor and make the K702 sound boomy and muddy because the membrane would not be 'controlled' or 'gripped by the amplifier' any more.

Below the frequency response change from 0.2Ω, 10Ω, 32Ω and 120Ω (note the 2dB/div amplitude scale)

Hardly any changes. Even with 120Ω bass increase is around 0.4dB. Not inaudible (120Ω is a LOT) but not obvious either.

How about the ringing of the membrane itself. Is that difference in damping clearly visible in the CSD plot (note from 10Hz to 30kHz) ?

Group Delay is that changed in audible ways ?

Or distortion... does this change a lot when driven from 10Ω or 32Ω and what about 120Ω ?

Nah.. you are pretty safe driving the K702 (and similar AKG's) driving it from most amplifiers.
That said... the output resistance from many power amps/AVR's may well be far above 120Ω and may well become audible.

More measurements in the usual place.
And yes, I know... not an industry standard rig... FR is incorrect... the treble peaks aren't real.. not the correct acoustic impedance etc. etc.
My Measurements May Vary..

 

[Nango]

Never understood the story around this mod until I read your article. Great work (again)!!!

 

[Ufasas]

Not really power hungry, using Sonata S3 Firmware D usb dongle with these headphones, perforated pleather memory foam pads (not the original ones), ASIO driver (Sonata HD Driver), and setting ASIO driver in Media Player, 24bit\48khz in windows 10, works very well. It also worked great on LG v30 quad dac 3.5mm socket, Creative G3 usb dac, and Shanling UP4 bluetooth dual chip dac. K702 was bought used for 60pounds, only replaced earpads and cable, another 10+6 pounds, easiest upgrade ever, these headphones can only compete with my Sony MA900, no other headphones I had could match MA900, as easy to drive as MA900 too.

 

[tdockweiler]

Has anyone on here ever measured a Q701 vs a more recent K702?
Who knows if it's all just marketing or there are some smaller changes.
I know the Q701 does have the Quincy Jones name on it, a green cable and some color options.
I've loved the Q701 ever since I first got it. Was never a fan of my first K701, but my amps were not as good.

Compared it side by side to a K712 and actually preferred the Q701.

I imagine by now the Q701 is no longer sold.
Not many people still seem to talk about it.

For awhile you could get them for $150-200USD I think.
Pretty good deal at the time.

PS bass modded Q701 with K712 pads sounded terrible and un-listenable.
I have no problems with the bass mod with stock pads.

The 65th Anniversary also seemed to have pads that had way less depth than the K712 pads.
Maybe the pads were an earlier revision of the memory foam pads.
The 65th was one of the worst AKG headphones i've heard.

 

[Oukkidoukki]

What are the best pads for k702 if I may ask, mine are totally flat.....i would like to get the cabinet quite far from my ears, sounds more spacy.........driving them o2 jds....sounds pretty damn good........I also have a feeling sound is little bit more relaxed when using internal battery without power cord....am I imagining?........could headphone amps be better with rechargebal battery?.........also , did someone go from o2 to some other amp (with k702)? Was there improvement?......one more, does cabble swap make sound better?

 

[Ufasas]

these memory ones are good for me at least, original non-memory foam were ok, but when i moved head left/right testing if headphones can fall off, it was making creaky sound of plastic, but with memory foam perforated pads it's not creaking, plus sound is fine, not really sure if bass increased, have thought that only mildly, but i still like the sound in games, still fine in music.

PS. Has anyone tried k702 with schiit hel 2 ? how was it in games and music? do you think schiit is overhyped? would it be smoother sounding, further soundstage etc over Creative g3 ?

 

[Oukkidoukki]

Thanks man!

 

[Oukkidoukki]

Also.....been comparing su 8 to o2 to k702 vs. Ipad air 2 phones out to o2 to k702........amazingly little difference.....ipad out is very good...maybe su 8 has little bit more bass and focused middle.....but only little...ipad system is great when out of home........wierdly straight from ipad to k702 is kind of hard in highs so o2 does something good............i havent liked these k 702 so much...they have been in closet and i have been using dt 770 or hd 25.....now i have been reading here.....now i understand their airiness when set up is right......they really are poor mans hd800.....classical music is awesome........now i am intrested about mqa dongle to android phone e1da or lotooo or similar....usb audio player pro streaming mqa....then to o2 and to k702.....maybe even better?.....which dongle is best?

 

[Robbo99999]

What are the best pads for k702 if I may ask, mine are totally flat.....i would like to get the cabinet quite far from my ears, sounds more spacy.........driving them o2 jds....sounds pretty damn good........I also have a feeling sound is little bit more relaxed when using internal battery without power cord....am I imagining?........could headphone amps be better with rechargebal battery?.........also , did someone go from o2 to some other amp (with k702)? Was there improvement?......one more, does cabble swap make sound better?

I think the best pads for the K702 would be the original genuine pads, as that way you can guarantee that they won't mess up the good soundstage of the K702.....also Oratory will be measuring my K702 really quite soon and if you use different pads then you wouldn't be able to use his EQ with confidence/validity. This is where I bought new genuine K702 pads, but they're expensive, it's a bit of a rip-off, but for my favourite headphone it's gotta be done:
https://www.thomann.de/gb/akg_k_702_ear_pad.htm
Note that's the price for just one earpad and you need two of course!

 

[Oukkidoukki]

Okey, thanks man!

 

[Ufasas]

Testing K702 with Asus Strix Soar SNR 116 dB 6pin PCIe card for the first time today, sound is busy, no cardboard box like, warm, full, while listening to mp3 320kbps and youtube too. Sounded amazingly full with Rotting Christ latest songs compilation

Update: On Low Impedance mode in Drivers it was too quiet, Medium Impedance - just about right

 

[Ufasas]

Anyone tried this software with k702? does it make any improvements?

 

[Oukkidoukki]

When dac ,amp and wires are spot on does k702 really need an eq?....mine don’t at least.....there is nothing to fix.....before dac amp and wire upgrade I thought they were shit....now suberb. Edit. I dont mean headphone wire, i mean other cables. My headphone wire is original.

 

[solderdude]

It just means your brain has totally adjusted to the sound signature of your K702.

 

[Robbo99999]

Anyone tried this software with k702? does it make any improvements?

I wouldn't recommend Sonarworks, they use their own target curve and "non-standard" equipment to measure the headphones which is not backed up by proper research, I don't think it's particularly valid. First port of call is to try an EQ to the Harman Curve which you were shown over here: https://www.audiosciencereview.com/...as-been-measured-by-oratory.22992/post-766514
Oratory has measured the K702 this week & published the measurements & EQ. If you don't like the sound try tweaking the bass level or other filters - Oratory describes which filters to adjust at the bottom of his pdf file for the headphone.

 

[Ufasas]

I wouldn't recommend Sonarworks, they use their own target curve and "non-standard" equipment to measure the headphones which is not backed up by proper research, I don't think it's particularly valid. First port of call is to try an EQ to the Harman Curve which you were shown over here: https://www.audiosciencereview.com/...as-been-measured-by-oratory.22992/post-766514
Oratory has measured the K702 this week & published the measurements & EQ. If you don't like the sound try tweaking the bass level or other filters - Oratory describes which filters to adjust at the bottom of his pdf file for the headphone.

Thanks already bookmarked and preparing for the Oratory style tweaks, only experimented with Asus drivers default presets, where bass is boosted 6 to 9dB, and for music I liked all the presets that gave bass boost to K702 (non original cable, non original pads too ) , for FPS gaming, audio gods forbid, not touching a single frequency, it's perfect as it is, just sometimes adding Asus compressor, that slightly brightens the footsteps

Waiting for some velvet non-original pads to be coming soon (possibly angled ones, photos shows angles, but hell knows what you get from China, lol) !

 

[Robbo99999]

Thanks already bookmarked and preparing for the Oratory style tweaks, only experimented with Asus drivers default presets, where bass is boosted 6 to 9dB, and for music I liked all the presets that gave bass boost to K702 (non original cable, non original pads too ) , for FPS gaming, audio gods forbid, not touching a single frequency, it's perfect as it is, just sometimes adding Asus compressor, that slightly brightens the footsteps

Waiting for some velvet non-original pads to be coming soon (possibly angled ones, photos shows angles, but hell knows what you get from China, lol) !

Sacrilege! But each to their own!

 

[Ufasas]

Got delivery, i'm lucky, they angled, not perfectly, but I like the sound, very good for rock music, but can't tell the difference, liked the sound with all 3: original worn out, pleather perforated or velvet, so I don't know, 8$ per pair, what can I ask more

Have I shoved them correctly: Thick part towards back of my head, and thin part towards my eyes?

 

[Jimbob54]

Got delivery, i'm lucky, they angled, not perfectly, but I like the sound, very good for rock music, but can't tell the difference, liked the sound with all 3: original worn out, pleather perforated or velvet, so I don't know, 8$ per pair, what can I ask more

Have I shoved them correctly: Thick part towards back of my head, and thin part towards my eyes?

Yes, wide part behind ears, angled in towards front

 

[jensgk]

I am now using Moode Player to do headphone EQ and Crossfeed with my AKG K702. It works great.

My audio chain is:
Flac-files/Spotify Connect/Airplay/mconnect Qobuz(uPnP) -> Raspberry Pi 3B running Moode Player 7.2.1 -> Topping E30 -> Topping L30 -> AKG K702 headphones.

I am using the new CamillaDSP, available in Moode Player.

I have made the following setup files:

headphone_AKG_K702_EQ_CamillaDSP.yml is pure headphone EQ, using the crinacle settings from AutoEQ.
headphone_AKG_K702_EQ_CamillaDSP_w_xfeed.yml is the same EQ as above, but with a Crossfeed filter behind.

To upload them, choose Configure -> Audio -> CamillaDSP Edit -> Pipeline configuration: UPLOAD
Then upload the two files one by one, and press SAVE (top of CamillaDSP Config page)
To use them, just choose the file under CamillaDSP Config: General -> Configuration dropdown list, and press SAVE (top of CamillaDSP Config page).

They are available here, if anyone is interested: https://github.com/jensgk/akg_k702_camilladsp_eq