AudioQuest NightOwl and NightHawk Alternate Pad Impressions and Measurements

There's a lot to like about AudioQuest's NightHawk and NightOwl: great comfort, very low distortion, exceptionally flat impedance response. Unfortunately, I found the NightHawk far too dark for me. AudioQuest goes into great detail to justify the tuning of this headphone on this page. I find the information written there about headphone performance and response characteristics simply outstanding. I sure wish more manufacturers went to that much effort to describe what they're doing.

I do have a problem when they start talking about the "HATS effect" in the section titled, "The Solution." To the best of my ability to understand, AudioQuest proposes that since the listener has his own pinnae, they do not need to include the pinna and ear canal effects in their target measurements. They measured a bunch of headphones; found the commonalities of all these cans; and identified them as the HATS effect and subtract them as they develop their target response. Here's an excerpt from the page:

As we discussed previously, head-and-torso simulators (HATS) have their own transfer functions. We do not want the transfer function of the HATS to be reflected in NightHawk’s frequency response. Rather, we want to eliminate it. In other words, for these measurements, we want to know only what the headphone is doing; we are not interested in knowing what the HATS is doing. Remember: While the brain, by applying an inverse filter, can and most likely does compensate for the effects caused by the listener’s own pinnae and ear, it cannot compensate for the effects of the HATS’ own “ears.” Had we included the HATS’ transfer function in NightHawk’s measurements, we would have corrupted the data that describes its actual performance. Similarly, had we included the HATS’ transfer function throughout the course of NightHawk’s development, we would have ended up with a headphone that corrupts the timbre and balance of the audio signal.

I'm not sure I completely follow their logic, but to my mind at some point you have to have an ear of some kind represented in the system when measuring headphones in order to present a somewhat realistic acoustic load. I know that dummy ears aren't like anybody's real ears in particular, but they are a standardized representation that is an average shape of real ears. Somehow in their process, I think AudioQuest threw out the baby with the bathwater and ended up tuning the NightHawk too warm.

Also interesting to me—and this is true of most manufacturers—is that the NightOwl does have significantly different tuning. It begs the question: Which one does AudioQuest believe is right? Did they just respond to market pressure with the NightOwl as many listeners found the NightHawk too warm? Or do they think a closed headphone should be tuned differently? Seems things might morph and change over time. NightHawk designer Skylar Gray has left AudioQuest, though remains a close friend of the company. As I said earlier on, there's a lot to like about the NightHawk; I think there are quite a few worthwhile technical advances in the design. I know there are quite a few fans of the smooth, clean sound. I hope AudioQuest remains committed to their headphone line; I think some tuning changes could breath new life into it for AudioQuest.

At any rate, I did finally get some NightOwls in for measurement, and a full sampling of pads was included. Even though I'm not going to do full reviews, I thought owners would like to have a look at pad performance. Unfortunately, I used the labeling on the pad product packaging, which is different than the terminology on their web site. On the graphs, those labeled Stock Pads is the AudioQuest Protein Leather Earpads; those labeled Classic Protein Leather Pads are the Hybrid Earpads; and the Classic Ultrasuede Pads are the Microsuede Earpads. You can download the full .pfd booklet here.

Here's the frequency response plots comparing the three pads on the NightHawks and NightOwls.



As you can see there's not much difference in the measurements. I do think I heard a pretty clear difference with the Microsuede pads, adding a little more sparkle to the headphones. Funny how things don't easily show up in measurements sometimes. Also felt the Microsuede pads were a bit more comfy.

I was not able to locate any on-line e-tailer that stocked the pads, but AudioQuest told me any of their dealers should be able to order the pads for you. All pads are priced at $49.95/pair.

Bloos's picture

"they do not need to include the pinna and ear canal effects in their target measurements"...
So that's why AudioQuest's headphones sound so bad/unnatural, they failed to logic.

gibtg's picture

I assume if Skylar is no longer working for Audioquest that they've acknowledged their tuning on the Nighthawk was poor and are going in a different direction. What I question is the removal of the damped rear vent however, as much as I enjoyed the Philips Fidelio L1/L2 I thought that design looked clever and innovative for home-use cans for use on contemporary music, but maybe they'll use the opportunity to bring back the venting in a future "more audiophile" design :)

Thanks for the measurements Tyll indicating little change! I appreciate the reliable data and honest subjective opinions! Those are hard to come by from the makers themselves!

brause's picture

How can I trust audioquest, a company that promotes/sells "audio" usb cables in the hundreds of dollars.

Jim Tavegia's picture

I have pretty much found that in my home studio that my 2 pair of AKG K271 are my go to headphones for the $200 price point. Much more "accurate" (to me) than my 2 pair of Sony 7506 which I prefer for vocal tracking as the voice is pushed slightly forward and gives singers a better window into their performance, but I would not mix on the Sony's, but for $99 one can complain to much.

I would like to hear the AKG 553's before I bought them as I am tired of buying cans that do not work for "my hearing response", and yes we all hear differently. I did sell my Focal Spirit Pros which were way too dull for me.

I have used this test to get a slight handle on where MY deficiencies are in terms of EQ. It also helped me find out why I find my Sennheiser HD 380's to have a tizzy sound in the lower mids from 200hz to 1khz. This rise in response is very audible compared to the Sony's and much more annoying than the K271's which seem flat to my old ears.

My AKG K701's are my go to cans, but they are open back and cannot be used for tracking. Listening only they are superb and I found mine on sale for $229 years ago.

I will do some research and find out how to take apart the ear cups on my HD 380s and see if I can fill the plastic backs of the ear cups with something to tame them. I think there is a resonance in there, but what it will take to fix it I will have to play with it. I do like the fact the the 380's are solid to 30 hz. This will be my science project and I don't know of any other ear pads that might change much as was found in this sample test of the AudioQuest cans.

Thanks, Tyll, for all you do to help us enjoy headphone listening even more. Little things do matter.

Omid's picture

I would highly recommend that you give the Philips Fidelio-X1 a shot. Unfortunately they're discontinued but you still can find them on eBay or other websites.

JMB's picture

I think it is a difficult decision how much of the ear structure should be part of the measurement system. The argument that all of the outer ear structure is part of normal hearing is completely valid for loudspeakers and normally measurements are done with plain microphones. One can discuss if the directionality of that microphone (mostly omnis) is what we hear in a room. On the other side in ear phones bypass the outer ear.
Exactly how much the outer ear contributes to the sound of over vs on ear headphones will vary but very likely it will be not identical to free field (open vs closed, even influence of size and material of ear pads). So some of the outer ear and especially the pinnae is part of the natural hearing process even with headphones but in a drastically altered form and how much the brain can adapt to that may be very dependent how much aural training that listener has received. So someone how rarely listens to headphones will have a different impression than someone who is constantly trained on one headphone. I guess that why there is so much loyalty to specific headphone designs/brands.
Personally the best headphones I was listening to are off the ear (like AKG K1000). I had long time ago a cheap MB model. These would alter the contribution of the outer ear much less than over ear ones. I am very curious about the upcoming MySphere 3.1

Jim Tavegia's picture

To not personally audition headphones before purchase is a bad thing. Measurements are not an accurate guide as each of us has a totally different response curve that the cans must compensate for and then the cans have their own performance that may not match what we need.

I am also more concerned about the quality control issues from production runs that none of us can truly know about and this is not from just less expensive models.

Long time listener's picture

Couldn't we get a little more info here? Aside from mentioning that the Nighthawk was just too dark for your tastes, and that the Nightowl is tuned significantly differently (how--less dark?) you tell us nothing. The Nightowl has gotten great reviews on a number of sites--including Stereophile. Can't you please in the service of your readers tell us a little more? The recent Sony didn't please you either but we got a lot of information on it. Measurements at least would be good. Thanks

dhavalpatel's picture
Three Toes of Fury's picture

May I ask why you arent going to do a full review of the Night Owl? Is it that the sound quality wasnt at a level which you would normally do a full review or other reason?

The reason for my inquiry is that we are seeing more and more headphones targeting a specific area..i'll call it "mid priced closed". (For clarification im going with $300-$800 for mid priced...i know thats a big range and alot of money but there's alot of cans above and below it, so it works for me). Its an area that im always interested in and wondered how the Night Owls did.

Peace .n. Living in Stereo

3 Toes o Fury

Martin.'s picture

Hasn't Tyll stated that his policy is generally reviewing headphones that are good? I quote:

"Since time is limited, I tend to do only positive reviews—I believe applause rather than harsh criticism is the most productive way to encourage beneficial growth in the headphone category. The only time I do negative reviews is when a very popular headphone has gross problems and consumers need to be warned away."

This is taken from his post, "Manufacturers Guide to Submitting Headphones for Review at InnerFidelity". He also has one called, "To Review, or Not to Review". I have the impression that there has lately been a proclivity towards questioning his reviews to the point of there being something wrong with Tyll's opinions or listening impressions.

I don't think Tyll puts himself as the be-all and end-all of headphones and while his word has weight, there are other professionals who have different, but just as valid, opinions (e.g. Katz's shoot-out). I might have a proclivity to agreeing with Tyll, but it doesn't mean that his word is final for me. What I like about him is that he is never snobbish or condescending towards his audience.

Three Toes of Fury's picture

Wishing skylar all the best in his future endeavors. I was surprised to see he was no longer with audioquest. I have always enjoyed his postings here and footage of him from the shows...seems like a good dude and fan of all things headphones.

good luck sir!

elmura's picture

I'm going against Tylls preference and saying the Freq Response is great except for the 3.5kHz spike. Someone once theorised that 3kHz spikes are necessary for headphones. However, our ears are quite sensitive to the frequencies between 2kHz and 12kHz. Try comparing sine waves at 3kHz and 1kHz to understand.

That flat, deep bass; somewhat flat mids; and slightly declining treble looks great. Flat phase, good square waves, low distortion... especially with the Ultrasuede pads. What's not to like? Curious on its soundstage & imaging....

LytleSound's picture

Each HATS has a frequency response characteristic that approximates that of the average head to the extent possible. Otherwise, if each had its own unique response, they would be useless as simulators. When KEMAR was introduced in the 1970s, its free-field HRTF matched those for real head and ears published by two eminent scientists, Zwislocki who developed the ear canal/eardrum simulator used in the original KEMAR and Shaw who performed detailed measures of the free-field to eardrum transfer function in the horizonal plane. At a minimum, each successive HATS after KEMAR has been designed to match those data.

When an earphone is placed over the ear, as in the case of circumaural earphones such as the Night Owl and Hight Hawk, the response of the head becomes less relevant, for it can be almost modeled as a flat plate with some degree of leakage ranging from minimal to excessive. The ear canal, which in the unoccluded state has the classic response that is flat to 1500 Hz and then rises 12 to 14 dB at 3500 Hz, and then falls off rapidly, acting as a quarter-wave resonator. When the earphone covers the ear canal, its resonance characteristics change. They become more complex and they haven’t been adequately modeled.

However, when an earphone’s response is measured using a HATS, all those resonances are included in the response measured at the microphone of the eardrum simulator. When Sean Olive publishes a preferred frequency response for earphones, that response includes the resonance of the pinna and the ear canal and the effect of the earphone on those. This applies especially to circumaural and supra aural earphones. (It’s different for in-ear monitors since they effectively change the ear canal to a half-wave resonator, pushing the resonance frequency out beyond 7000 Hz, the region of harmonics and the extensions of percussive instruments and where the ear canal transfer function varies greatly by frequency due to the interference of sound being reflected by the ear drum and the breakdown of the signal as a plane wave.) When a half wave of the signal approaches the diameter of the ear canal, resonances are established and act as comb filters, making the response as seen as the ear drum (and HATS microphone) appear very ragged. They may be so different that they will have to be determined for each ear cup style.
Since the response of the earphone as seen at the HATS microphone is supposed to be the same as would be seen at the ear drum of a person wearing the earphone, adjusting the earphone response to remove the “HATS effect” will result in an earphone that sounds flatted or duller or less clear than an earphone for which the response has not been so adjusted. Only setting an earphone’s response to some curve based on measurement in an NBS 9A coupler fitted into a flat plat could be worse.
there might be some justification, if one where trying to adjust the response of the earphone so that it emulated the response of the ear in an open sound field, , but that is a hugely complex task given the complexity of the HRTF in the sound field when 360° of signal incidence are considered.

All that said, a HATS response is an average response and not necessarily yours. KEMAR’s response isn’t mine and I am still in search of a set of earphones that will allow me to hear all of David Chesky’s binaural recordings as true binaural. Sounds from the front show up between my ears, sounds from the rear sound also between my ears, but a little “behind” those from the front. Sounds from the side, including from right and left rear and right and left front appear as they were recorded. Chesky doesn’t use KEMAR, he uses LARS, but LARS uses KEMAR”s large pinnae.

I also know from my own anechoic measurements that while my binaural localization is accurate, I have about 17 dB maximum ear canal gain at between 3400 and 3700 Hz, compared to KEMAR’s gain of 14 dB. But, I don’t want an earphone manufacture removing the HATS effect from their response curve. If necessary, I can trim the treble on my playback system to fit my listening expectations. It’s better to remove what you don’t want than to try to put back what isn’t there because that package always brings along noise.