Disclaimer: This review is not based on any objective measurements. I am merely giving my own subjective
opinion on how these headphones sound, compared to other headphones I have on hand. Your mileage may vary.
I recently bought this fantastic-looking vintage headphone for dirt-cheap on the Polish version of eBay. To be perfectly honest, it was this headphone's looks that attracted me the most and since the price was right, I decided to risk it even though there is almost no literature on how these headphones sound on the internet (I only found some random comments here on Heaf-Fi and on some German headphile sites). Besides, NAD being a big name in audio, I was pretty sure that their headphones wouldn't be too bad. The headphones were in near-mint condition, the seller claimed that they have been used sporadically in a professional capacity back in the 70s and then spent the remainder of their lifetime in an attic somewhere. Based on how good these look, and the fact that the leather earpads are in near-mint condition, I am inclined to believe the seller's story. Had they been used more extensively, the earpads would surely have began to crack, as most old leather earpads do. Besides, there is actually a "made in Japan" sticker on the inside of the headband and the fact that the sticker is still there after nearly 40 years is probably the best proof that these have not been used extensively.
This particular model is the second-highest in NAD's lineup at the time, below the electrostatic Model 20E. It shares the same enclosure with the 20E and based on my research, both these headphones are actually made by Fostex (Foster) for NAD. It is nevertheless also possible that some other Japanese company OEMed these for NAD and not Fostex; however, the enclosures do look very Fostex-like.
The NAD Model 16 is a dynamic, open headphone. It has huge 59 mm drivers and a relatively low impedance of 4-50 Ohms (BTW, nice of NAD to give a meaningful figure here, instead of just the single figure that most other manufacturers offer - after all, impedance varies depending on frequency). It was designed as a premium product in 1975 and its intended use is as a monitor.
Packaging, Looks, Build Quality, Comfort
Everything is packed inside a nice leather box (as seen in the pictures) and the headphones fold flat to fit in it. The box does not look like the most durable thing on the planet but I think if I use it primarily to store the headphones at home, it will still survive many many years. Besides being practical, there is nothing else special about this box. Its nice that they found a way for the box to double as a case but thats it.
The NAD Model 16 is a fantastic looking headphone. Photos don't do it justice as it just looks so much better in the flesh. Moreover, the build quality of these headphones is absolutely superb, and this also contributes to the distinguished looks as the headphone feels very solid. Every potentially weak spot is made out of metal and the enclosures are made out of very solid plastic. The metal is not prone to scratches and neither is the plastic. The headband is entirely metal and covered with a leather cushion that provides ample padding. Headband size adjustment is similarly made out of metal and feels very sturdy. The headphones don't creak or make any other unwanted noises. The earpads are also made out of real leather and are quite plush. The original cable was actually very nice, but it oxidized so I had to replace it.
Comfort is a somewhat mixed bag. The headphones are medium-light (think Shure SRH840) and the headband is very well padded, providing no strain on the top of the head. The clamping force is quite low, perhaps similar to a DT880 Premium Edition. Unfortunately, even though this is a big headphone, the earpads are not circumaural. Instead, they are a bit like a cushion with just a relatively small hole cut in the middle for the drivers. Since they don't clamp much and the earpads are leather, I didn't find sweat to be an issue with these headphones; however, the earpad design can be uncomfortable for those wearing glasses. I found that after about 30 minutes of listening with my glasses on, my ears began to hurt. Removing the glasses fixes this problem completely and the headphones essentially dissapear.
The isolation on these is actually pretty good for an open headphone. I'd say that it actually has a tad more isolation than the semi-open Beyerdynamic DT880. I live downtown and with the windows open, outside noise can sometimes be high enough to prevent me from enjoying my open headphones at the low volume level I like to listen to. This is not the case with this NAD, I am fully able to enjoy listening at a low volume level with the windows open. At the same time, the isolation is not good enough to prevent me from noticing that someone is talking to me. In other words, they have very good isolation that is practical for an urban lifestyle and would also probably work great for office listening applications.
Even though they seal better than most open-back headphones, these are definitely not great for portable use. They are definitely transportable due to the fact that they fold flat and come in that nice box; however, actually using them outside would go against their design. An exception, I guess, is if you'd want to use them in the park or something; however, for typical portable applications (streets, subway, bus, etc.) they are very much not ideal.
Furthermore, while their impedance is indeed low, I found their performance to suffer when driven by portable devices or the integrated sound card in my laptop. They do play loud enough; however, resolution and dynamics are improved noticeably when using an amp, such as my FiiO E17 or my Sony FA30ES interated class A amplifier. There also seems to be less grain when they are driven by an amp, so an amp is definitely recommended to use with these. It doesn't have to be a particularly powerful amp (the E17 only supports cans up to 300 Ohm impedance) but a good amp does improve these to a point that is very noticeable.
The sound is generally neutral, although it rolls off at both extremes, as is common with headphones from this time. I'd say that this headphone is a pretty decent tool for monitoring as it has a fairly flat response overall, with some emphaisis given to mids and upper mids. The bass is also a little emphasized but this is not a warm headphone as the mids have a fairly cold and clear tonality. Generally speaking, this reminds me of the AKG 'house sound', with very clear mids and some accompanying harshness. Soundstage is rather intimate, not much like a typical open headphone. Directional cues are rendered well but the feeling you get when listening to these is like being on stage with the musicians, not like being in the audience.
The 59mm drivers are more than capable of delivering bass-head bass in songs that have it (dubstep, hip-hop etc.); however, the bass does begin to roll-off at about 70 Hz and the general tonal balance of the bass is neutral. This means that songs that do not have huge bass will not sound very bassy on these headphones. With EQ, I feel that they have some of the best bass I've heard in a fully open headphone. It is fairly detailed and impactful, and it also is well seperated from the mids, which allows for these headphones to be EQed well, without warming up the mids or masking anything. Without EQ, the NAD Model 16 has less prominent bass than the Sennheiser Amperior, Audio-Technica ATH-M50, Beyerdynamic DT990 PRO, Ultrasone PRO900, Audio-Technica ATH-ESW9 or Koss Porta Pro. It has about as much bass as the AKG K550 or the Shure SRH940, and actually also a somewhat similar overall tonality; however, the AKG K550 has more extended bass and better-defined sub-bass without EQ (both the AKG and Shure also sound clearer).
It's obvious to me that the mids are the definite calling card of these headphones as they are quite forward. Guitars in rock music have that powerful, Grado-like energy that is so awesome for this kind of music. As far as I can tell, the mids are quite flat all the way up to about 6 Khz, where things get a little peaky at times, and vocals have some very occasional sibilance issues that are more likely caused by the recording than the headphones themselves. If there is one word which I would use to describe the mids here it is 'raw'. They are so forward and in your face that every single little element can be heard very clearly; however, their neutral and somewhat cold tonality, combined with the fact that they are not warmed up by the bass, makes the eperience potentially too 'compressed' sounding. One thing that I noticed that sounds a bit off is the vocals. They sound a little muddy; however, I believe that this is actually what vocals are supposed to sound like - a lot of modern headphones are tuned to make vocals seem overly emphasized (by attenuating vocal-crucial frequencies or having ringing in that area?). This means that the NAD has more of a genre bandwidth than many modern headphones and will sound just as much at home with classical music as with modern, compressed rock.
The treble is actually my favorite aspect of this headphone. Let me explain. The treble is very crystal-clear and has almost no decay that I can detect. It reminds me a lot of how many Audio Technica headphones handle the treble. There is not a lot of air in the treble, compared to many other open headphones; however, the treble is so crystal-clear that it makes up for this. It is prone to some sibilance on certain frequencies (my best guess is around 7-8 kHz) but I have not found it to be problematic for most music. Basically, although the treble has some minor issues, its overall clarity makes up for that. There is also a modification that can help tame the treble a little bit that I will describe later. Furthermore, the upper-treble rolloff that these headpones have means that these are quite forgiving to badly-compressed tracks. I will admit that the treble is marred by some ringing; however, in this case, the ringing simply makes it sound more clear. Truly, this is wonderful stuff and makes every cymbal crash a great experience of hearing the wonderful clarity. Without EQ, this is a somewhat bright headphone and the treble is fantastic. With this said, the treble of the Sennheiser Amperior, Beyerdynamic DT990 PRO and Grado SR225i is more emphasized than on the NAD Model 16, so this is not really a super-bright headphone either.
Using the +4 setting on my FiiO E17, these do not sound at their full potential as mid-bass is boosted a little too much for my taste. The same thing happens when I turn my bass knob up by a few dB on my Sony FA30ES integrated Class A amplifier. The bass boost in Rockbox - same story. It is far better to use a proper parametric equalizer to bump sub-bass (below around 100 Hz) up by a few decibels (I found 3 or 4 dB to be ideal). while leaving the mid-bass alone. This results in a flatter overall response but with nicely audible and physical sub bass (kick drums provide a nice sensation of motion) and doesn't affect the mids as badly (increased resonance from mid-bass results in more ringing in high mids).
As with many retro headphones, some modifications are possible that make these more competitive in today's world of modern headphones. The very first thing I did when I received them is replacing the cable. The old cable has clearly oxidized a little bit and the huge plug attached to it similarly had some conductivity issues. I recabled these headphones with a Prolink Futura cable, which is a well-shielded OFC cable. Recabling has not affected the sound in any way that I can hear, but it was also one of the easiest recabling jobs that I have ever attempted. Inside the cups, NAD actually installed metal holders for the cable, which make it very easy to hold them in place and also act as strain relief.
The NAD Model 16 is a very simple open construction that doesn't really leave much room for resonance within the cup, the drivers are separated from the outside world by a very thin layer of damping material and a thin, perforated plastic cover (think old DT880). I was considering removing the damping material to see what that would do to the sound; however, they seem to be glued to the cups so I chose not to remove them just yet as it might not be easily reversible.
To tame the treble a little bit and reduce sibilance in female vocals, I have found that adding a layer of foam in front of the drivers (between drivers and ears) goes a long way to make these sound less harsh and bright. I used the material from Beyerdynamic's DT700 series of headphones. It is just a thin layer of foam and you can see it clearly in the photos attached to this review.
I used a Sennheiser HZR-64 variable resistor to add some additional resistance to the cable. This seemed to tame the sound a little more and decrease distortion. Perhaps using an Etymotic 75Ohm adapter cable would be a good idea, or one could add any other resistor to the cable. I am considering installing a 75 Ohm resistor inside the enclosure, but I need to do some more listening to determine whether this is indeed such a good idea
Even after nearly 40 years, these headphones are surprisingly good value. I'd be comfortable in calling them decent mid-fi headphones that are more than capable of competing with some of the best mid-fi headphones out there. I'd be comfortable comparing it to a Sennheiser HD598, for example, although I do think that the classic mid-fi trio of Beyerdynamic DT880, Sennheiser HD600 and AKG Q701 does offer slightly better sound over all. With this said, there are certain things that the NAD does that even these relatively modern and far more expensive headphones can't do as well as it does (bass is IMO better). NAD's motto on the packaging is "Listen happily ever after" and they clearly meant it.
Edited by jupitreas - 4/4/13 at 3:51pm