AKG N90Q Noise Canceling Auto-Calibrating Over-Ear Headphones Measurements

Click on graphs image to download .pdf for closer inspection.

Plots on this page were taken in Standard Stage mode and with EQ set to the middle position. Tru note calibration was done once at the beginning of the first four FR sweeps in various positions around the ear, and once prior to the last center position FR sweep ensuring best case calibration for other response measurements thereafter.

Interestingly the response curve from 10Hz to about 2kHz matches the shape of the Harman target response (HTR) curve but has only about 40% of the amplitude of the HTR. When EQ is dialed to max (plot seen on page 2 of this review) it does quite closely match the HTR, but the peak at 3.5kHz is about 2-3dB too high.

Raw response above the 3.5kHz peak shows a significant dip 4-6kHz followed by a significant rise to 10kHz and a well shaped, but 3dB too hot on average response in the top octave. For me, I heard this vocals sounding a little stuffed up in the nose, and airy cymbals that had too much tiss and not enough tang.

30Hz square waves show a remarkably horizontal wave top, even with a slight bow upward indicating a small low frequency emphasis. The bass here is potent and nuanced; very well controlled, which can in part be seen in the perfectly horizontal distortion plot into the low bass. (The relatively high distortion number comes from slightly excessive noise in the headphones. Bass sounded very undistorted and clear to me.)

300Hz square wave is nicely horizontal indicating good low-treble to high-mids transition, but initial spike and following ring are troublingly high. I know the research includes an overal warm tilt in the EQ to compensate for distance and directionality of speakers in a room. But I think they've slightly missed the boat on this compensation...at least to my ears. The TruNote calibration always seemed to me to make more right this area of response, maybe they just need to filter it a little more aggressively. This assertive wiggle does seem audible to me.

Impulse response likewise shows a fairly strong subsequent ring. I will point out that the initial transient is very clear. Also observable is about 1.5mSec of latency through the ADC-DSP-DAC loop. This is not enough to be troublesome evidently, a little Google says +/-20mSec is the agreed upon acceptable perception limit.

It seems to me much of the THD+noise measurement here is dominated by the broadband noise from the electronics in the Q90N. Otherwise distortion has few features until a blip at about 1.1kHz. I did feel like I heard some hardness in this area of response, and it did feel like this exacerbated the dry, artificialness to the treble.

I wonder how much of my impression of an unappealing treble is due to all the digital processing going on. I think manufacturers in the future will find that very high bit rate and depth digital processing will yield a significantly improved subjective experience in the up-close and personal world of headphone listening.

Surprisingly, for an electronic headphone, the input impedance is a nice flat 67 Ohms with very little phase shift in the treble. Most input impedances to electronic headphones is in the many thousands of Ohms range. It seems to me, AKG chose to put a load resistor in parallel with the input. I like this approach because most player electronics will be designed to drive this type of load, typical of an average headphone. If you present a high input impedance load to a headphone output of a typical player, it might promote instability in that amplifier. It also lessens the effect of needing a large input coupling capacitor, or its effects on low frequency phase performance.

Isolation is only slightly bettered by the Bose QC35, and extends well into the very low frequencies. At -27dB broadband, this is excellent isolation for a noise canceling headphone.

With 171mVrms needed to achieve 90dBspl at the ear at max volume setting on the headphones, the N90Q will be able to reach very solid listening levels, but some may find it limited.

Harman International Industries, Incorporated.
400 Atlantic Street
Stamford, CT 06901, USA

tony's picture

I thought she would: Dorothee de Becker, I think.

You're on AKG's good side now.

One hell-of-a-review, more thorough than any review I've read ( in the last year ) .

I hope you get an Invite to visit their Austrian Design Center and do a Video ( like the 3 day thing Fremer did at Rega ), meet the design staff, get to see all of their exciting stuff, etc, etc... . Betcha Harmon would get behind that sort of thing now that Stereophile Staff are doing beautiful Video work. ( Print seems rather Static compared to an Active Video supported with written journalism )

Stereophile stuffs got mojo.

Superb work!

Tony in Michigan

ps. I listened to your video report while doing a project, I'll read the "print" context later tonight.

Tyll Hertsens's picture

Congrats on making it through the video, I think it's the longest on I've ever done.

tony's picture

Geez, there's a whole lot to let sink in :

1.) Eq is going mainstream acceptable. Audiophiles ( like Mr.Fremer ) say things like "everything" affects Sound Quality, which is saying that everything is doing a bit of Eq. for gods sake. Our own Herb Reichert is reporting that the very important Rega Turntables is heavily microphonic ( providing a Boogie inducing feedback circuit ) which seems to me to be a mechanical Eq. design.

2.) The Europeans are way out front on Audio Stuff. Graham Nash went Head to Head with our Mr.Fremer on D/A - A/D sound quality proclaiming Digital's excellence. Nash says he lives in the Future! I applaud.

3.) Paper vs. plastic diaphragms . I'm agreeing on paper. Plastic seems "blubbry" sounding to me, I'm not a plastic diaphragm man. Maybe I'm mental on this to the point of not liking Planer Designs as a result. Although Magnapans make nice room speakers for walk-around music systems in the home.

4.) I'm seeing two powerful "Forces" waving over all things Audio: DSP and MQA. Generic have a DSP system that optimizes for any listening position in the room ( it has a small microphone that you move to where you want to sit to listen, their DSP readjusts the entire system to that spot. It's an affordable device ) .

In this detailed review you seem like a flat pebble skipping across a pond, touching on a wide range of advancements. Exciting stuff!!

Stereophile seems populated with Analog writers that have 7 decades of media collection ( like me ), that's momentum but I can't see folks getting excited about Nina Simone's variations in sound quality from her various vinyl releases or the horrible sound quality from most of the vinyl thats ever been released.

Thank you for taking the time and effort, you're stuff is where all the action is.

Tony in Michigan

hfvienna's picture

.. most probably, due to the fact that Harmann Kardon will closed this center April 2017 (announced 4 month ago) , sending away all former designers with a rumoured offer of about 1500 bucks per month and working place in Hungary. But if you love this N90 you will not be harmed that much, because this was designed anyhow in US and China, not Austria/Vienna. And Harmann is now Samsung , so things will be very much different anyhow.

tony's picture

Phew, I'll take this as "Bad News".

Thanks for reporting.

Tony in Michigan

Feilong4's picture

First off, just watched your video review. Excellent in-depth review!

Secondly, tried clicking on the measurements to expand it but seems to say that the page cannot be found.

Tyll Hertsens's picture
Yeah, we switched FTP servers late last week and there were some hiccups. Should be working now.
steaxauce's picture

I just got a pair of these yesterday, and I think they're pretty phenomenal. The pair I have seems to be defective--it has a pretty high level of background noise--but other than that I think they're very good and I'll definitely be getting a replacement.

I have an HD800 that I've equalized pretty carefully, starting with Sonarworks' curve, and the N90Q sounds surprisingly close to those out of the box. I probably know what you mean by the "digititus" comment and complaints about the slightly hard sounding upper mids and treble. It's hard for me to focus too closely on the sound of these headphones with the background noise my unit has, so maybe I can get some better impressions once I get a replacement pair, but so far I think any deviations from neutral are a lot smaller than what I've heard from any passive headphone, especially closed back.

My equalized HD800 sounds a bit better than these, but without EQ, I'd definitely take the N90Q over my HD800, Sony MDR-Z1R and the Ether C Flow I used to have. I absolutely consider them competitive with top passive headphones.

We all have different heads and different HRTFs, so the headphone frequency response that sounds flat for me may not sound flat to you. Could it be that Harman/AKG tuned these for what they consider an "average" ideal response, and my ideal FR is closer to what's used in the N90Q than yours is? I ask because it just seems odd that Harman wouldn't have been able to get what they consider to be a flat response when they're using DSP.

By the way, how close are the different EQ settings to equal loudness contours? Could that be their purpose?

GNagus's picture

Is it enough to affect lip syncing in movies, TV shows, po....YouTube videos?

Tyll Hertsens's picture
No. You need about 20mSec to start having an effect.
Phoniac's picture

Your extensive description of the implemented crossfeed matches the standard bs2b (Bauer Stereo to Binaural) effect 100%. See here:

Tyll Hertsens's picture
You bet, this stuff has been around a long time, and I've heard lots of them. The N90Q imlementation is the cleanest of the bunch I've heard so far.
ulogin's picture

Tyll, you said you heard "digititis" and uneven treble, and as such N90Q is not really competitive with other headphones at this price point. Now if I read your review correctly, all these problems were observed without TrueNote being activated, right? If so, wouldn't it be fairer if assessment is done with the feature being activated, given the main selling point of N90Q is TrueNote?

Tyll Hertsens's picture
No, all subjective impressions were done with fresh TruNote calibrations. It was definitely worse with TruNote misscalibrated, but it doesn't entirely go away after calibration.
ulogin's picture

Fair enough. I still think it would be fairer if your assessment about N90Q's competitiveness is done by comparing with closed-back headphones. These sound better to me than other closed-back headphones I have tried, including Ether C Flow, LCD-XC, SRH1540, PM3, etc.

Corsair's picture

Thanks for your diligent work on that review That was extensive and very interesting. I've been trying to get the balance right between external noise blockage and sound quality. There are more than a few choices out there. Many thanks.

peterj's picture

Many thanks for your review. I purchased these headphones after reading your review and I am really pleased with them. I agree with virtually all of your comments.
They are not as good as my Mr Speakers Ether with my big rig but for general/portable use they are wonderful.

I tried them with my Smyth Realiser A8 just for fun and the sound was terrible - too much processing!

rumzell's picture

The AKG K 490 NC is probably the best value for money if you are looking for an active noise reduction headset. Its sound performance is really impressive for this price and the noise cancellation works very well without degrading the audio quality. It is clearly a good deal if you are used to listening to your music in noisy environments

Mihalis's picture

I dont think you are right that you can connect to an iPhone. The lightning to usb connector gives a "too much power used" error and would only work with a hack (which some say includes including an entire hub in the chain.) This hurts portability which is the point (for me at least) for these headphones.