I purchased these headphones on a whim given my penchant for smooth laid-back headphones (I dislike any bright headphones as my hearing is quite sensitive to treble), these headphones are great in that respect. The bass is a bit pronounced with the Nighthawks with the lower midrange at times sounding a bit cluttered. Male vocals can at times sound a bit muddy, especially if they have a low register voice. The treble is nice and smooth, not at all harsh nor fatiguing.
The design and comfort of the Nighthawk headphones are one of the best I've ever encountered in any headphones. This makes for a very impressive first foray into headphones by Audioquest.
By the way, I also own the Audeze Lcd-3
which definitely sound better, especially with vocals and midrange, but cost over twice as much and are not nearly as comfortable for long periods of wearing, they are way heavier. But both headphones are close in relative sound signature. Impressively, the Nighthawks to me sound in between the Audeze LCD2 and the LCD3, at a lower price point.
I wish the Nighthawk had a higher Ohm rating (they are 25 Ohm) since they are almost too sensitive to use with some headphone amps although if you are not using these with an amp, I suppose this is a good trait. These still benefit from some amping however sound fine directly out of my iPhone.
To reiterate- the design and comfort of these headphones are absolutely tops. They are very comfortable and feel quite light on your head. The earpads are very plush and seem to fit over my ear without any discomfort. The self-adusting headband is very similar to what you find on AKG 702 headphones for example and is quite comfortable. Each earpad is suspended in its own suspension system which also helps them remain comfortable around your ears and also helps to acoustically de-couple them from the headband.
2 headphone cables are included in the box, which also doubles as the foam lined/padded case for the headphones. One of these cables seems nice, and this is the one you're really supposed to use; it seems of an appropriate thickness for a headphone cable, but the other included cable seems like a bit of a joke. It's extremely thin and cheapy feeling. I didn't even try listening to it but Audioquest has stated this one is more durable so I suppose that is the one to use if you are using the headphones while out and about. I have heard it does not sound good however. I wish there was an option for a 4-pin XLR balanced connector or cable however as I wonder how much better these headphones might sound when running them off a balanced headphone amp, which I own. Also, both cables are terminated in a mini 1/8" plug so you need to use an included adapter to plug in to a home system via 1/4".
All this being said, with my engineering background, I just can't get over my differences with the Audioquest company regarding their marketing/selling of cables such as this $2,700. HDMI cable Diamond HDMI Digital Audio/Video Cable W/ Ethernet Connection 5 meters
or a $380 ethernet cable: 1.5m (5') Audioquest Vodka RJ/E (Ethernet) Cable
I cannot fully trust Audioquest because of this yet I believe they have a winner with the Nighthawks if you like bit of a darker smooth sound signature in your headphones. This is a big if, because I know a lot of people will want more treble presence and a bit more detail and a wider soundstage out of their headphones. As for me and my ears, I'm enjoying these a lot so far for all kinds of music.