Koss PRODJ100

A bit about myself - I'm a female student from HK studying in the US. I mainly listen to classical, instrumental and pop, and in general I tend to enjoy headphones that are balanced with a touch of warmth. I also value a wide soundstage, accurate positioning, and to a slightly lesser degree clarity and micro-detail retrieval. I should also mention that I'm not very tolerant towards sibilance and shrill treble in general. 

Alternate link: https://girlinaudiophilia.wordpress.com/2016/05/16/thoughts-on-prodj100/

Introduction

The Koss ProDJ100 is a pair of portable, closed, over-ear headphones currently priced at ~$50 on Amazon. They are known (or not) for their good build quality and bang-for-buck. While opinions on them differ on Head-Fi, I decided to give them a try, as well as compare the stock pads to modded HM5 pads. I won't ramble on and on just so you can finish reading this review without me boring you to death and continue with your life!

Setup used:

Portable: Hidizs AP100

Desktop: Macbook Air –> O2 Combo

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Appearance, Build Quality and Comfort

Being a budget-orientated headphone, the packaging is more of the no-frills approach. You get the headphones, a 3.5-6.35mm adapter and that’s it. If they were more expensive headphones I would complain, but for the price I got them there’s nothing to complain about.

I was surprised by the build quality of the these cans and how sleek they look. For under $100, these seem very sturdy. The outer shells are presumably made of aluminum and have a very nice finish to them – I’ve abused them since I bought them, leaving it in my bag without a case, and they’ve held up very well. I think the hinges are also made of metal, so I wouldn’t worry about them breaking on me. The headband, especially, is what I like the most about these headphones. It’s very well padded and sits on my head very comfortably. The one issue I have is the coiled cable – sure, it’s very well made and sturdy, but for portable use I’d like to have something just a bit more portable. Nonetheless, build-quality wise there’s not much to complain – it seems very well-built and probably would be able to withstand some torture.

The pads deserve some mention, and not really for a good reason. Those with large ears will especially feel the pain – the stock pads are extremely shallow and uncomfortable. I had issues wearing them for more than ~2 hours with the stock pads because of the medium clamping force and the fact that my ears were constantly being compressed by the base of the pads. Many people mentioned the M50x pads as an alternative, but personally I have issues with pleather/leather pads of any kind so I bought some HM5 pads and modded them. That solved the comfort issue. After changing pads, these are fairly comfortable, especially with the velour HM5 pads and low clamping force – I can see myself using them on 16-hour plane rides. Although the velour pads somewhat reduces the isolation, the sound leak is still small enough for these to be used in public areas.

Some glory pictures that are not very professional (sorry!)- 



The nice aluminum cups
 


The headband. If they used the same comfort level on the pads I'd be a very happy girl.


Sturdy hinges - more headphone makers need to learn from this

The mono-stereo switch, something I'll probably never use but neat feature anyway

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Sound Quality

For a sub-$100 headphones, these aren’t bad. Changing the pads did alter the sound signature somewhat – however, I would still characterize both configurations as relatively balanced with a slight boost in the mid regions.

First Impressions:

Slightly harsh and tinny on the upper-mid and treble regions with some sibilance and somewhat boosted bass. Not exactly the best first impression, but people did mention something about burning in. The midrange is pretty clear for something of this price, though. Oh well, I guess I’ll let it warm up (literally) for a bit…

Note: I did find the harshness in the treble to soften after burning in. However, I do think that it may be a psychological effect – take this with a grain of salt! 

Treble:

The difference between HM5 pads and stock pads is small enough for me to discuss them together. Although the sibilance I heard out of the box has subsided somewhat, there is still some sharpness and harshness to the treble – by no means unacceptable though. The highs are slightly grainy but pretty detailed.

Mids:

I don’t really know how exactly to describe the mids… Imagine some honey, really thick and luscious. Then dilute it with some of water and sprinkle some table salt on it. Essentially that’s the mids – it’s not exactly thick and luscious, but not really thin either. In my opinion they do shine the most, but that’s also because I listen to a lot of vocal music. The upper mids are especially prominent, making them a good choice for female vocals. For example, listening to this track showcases to which the upper mids stand out – Solji’s voice sounds very vivid and forward. They are really detailed as well, probably the best I've heard since the glory of FLC8S. But then you can't really compare a $300 IEM to a $50 headphone, right? 

Bass:

This is where I felt pad-switching really made a difference. The stock pads made the bass somewhat heavier and there was a noticeable bump in the mid-bass region that I didn’t really like. However, even with the bump, the bass wasn’t overly prominent and was fast enough for the music I listen to. With the modded HM5 pads, it brought the sub-bass further up but pushed the mid-bass down, resulting in a more linear bass response that I liked better and made the mids shine more (which is what I live for anyway – liquid-gold mids!)

Across the spectrum:

This is another place where I found that the pads influenced the sound. With the stock pads, the headphones sound more closed-in – it was a good, well-rounded soundstage for a pair of closed headphones, but I would immediately feel closed-in after listening to open or even semi-open headphones like the HD668B. Switching to the HM5 pads, I didn’t get as good of a seal, so the soundstage got wider and the headphones opened up a bit more. I personally like the space and air of the HM5 pads, but YMMV (of course). Overall, I would characterize these as pretty balanced and neutral headphones that are perhaps slightly mid-centric.

Sources:

These are hella picky. I made the mistake of listening them unamped out of my phone and cringed at 1. the bad quality of the 128kbps mp3 that Spotify kindly provides to poor students like me, 2. the sibilant highs and 3. how closed in everything sounds. These headphones need POWER. Running them out of AP100 was a lot better, they sounded more balanced and less harsh – it was a nice pairing overall. Pairing them with the XDuoo X3 made the sound somewhat warmer and the treble less harsh, but much of the detail was smoothed out so I preferred the detail of AP100 to the smoothness of the X3. Of course, the desktop setting brought the best out of the DJ100 (IMO), providing enough power to drive these. They sound the most balanced from my desktop setup with no frequency overpowering others (which is kind of sad, considering I bought them for portable use…).

Pads(!):

I’ve already discussed the way HM5 pads affected the sound, so this is just on how exactly I “modded” the HM5 pads. Per the DJ100 thread’s instructions, I turned the pads inside out so the pleather backing (on the back of the velour, just between the thin fabric driver protection layer and the cushions) was facing out. I then carefully cut out four small holes (top, bottom, left, right) so that the memory foam inside the pads were exposed. It may be placebo, but I felt like this brought the bass back up a bit and added a bit of warmth to the sound that wouldn’t be present with stock HM5 pads (they did kill the bass and made them so harsh that I would scream).

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Conclusion: 

These are good headphones for the price. Sure, it’s not perfect and I never expected it to be, but it did do the job well. I’m not sure I would recommend them at their MSRP, considering you still need to get pads to bring the best out of them. They aren’t exactly the best at portability and treble quality (IMO), but for the current street price I’d say these are pretty good everyday headphones if you need something to bring around and torture, as they provide a decent all-rounded package.

This is a great inexpensive headphone with one of my favorite sonic signatures. It's one of the few headphones I bought twice when I tried much more expensive headphones being disappointed and realizing what I had lost.
 
One of the things I look for in headphones is how vocals are represented and these probably beat out most 200 dollar headphones in vocals department. But these are not one focus headphones. They're for studio use so they are well balanced everything is tight and well represented. If you're looking for the humming type of bass found in Beats headphones, you won't get them here. If you're looking for crazy sibilant highs that crackle, they were smart about that too, they stop well short of that cliff in fact maybe that's it's hidden flaw.
 
Maybe the mids are slightly more represented over the highs than they should be. Maybe it's human nature to look for flaws in all things. Maybe the Japanese were right. Wabi-sabi. An imperfect rougher sound signature may be more desirable. I don't know but all headphones should start with this level of vocal clarity and build around it. 

I got mine for $35, and I can't figure out why. They sound perfect to me, with forward mids, clear vocals, and bass that thumps, but isn't in your face. Simply put: if you find these for under $80, snatch em up!