Koss + Yaxi Measurements and Impressions of PortaPro, KSC75 and KPH30i



The Koss suite of on-ear headphones have been around for what seems like an eternity and their popularity continues to grow. More recently, they partnered with Drop to release special edition versions of a few of their products, and they've also released bluetooth versions of their legendary Porta-Pro and KSC35 clip-ons. 

This quick impression will take a look at three of their popular sets which use similar drivers with some tweaks: The PortaPro, the KPH30i, and the KSC75. All of these impressions and follow-on measurements come with Yaxi Pads installed. Yaxi is a Japanese brand that makes pads for a select set of headphones including the Koss line. Their pads are larger and come in colorful choices that give new life to the Koss products and improve comfort significantly.

First off, the KSC75 does use a different driver than the PortaPro and KPH30i. This KSC75 driver features a titanium coating and a different driver housing that has less, but larger holes on the rear. The KPH30i and the PortaPro share the same driver, but the KPH30i is enclosed in a different housing which also has a rear foam sheet on the back of the driver. All of these subtle changes affects the sound between the three.

Sound Impressions



First, off, they all feature warm relaxed sound signatures that are very easy to listen to and offer a really enjoyable tonality at the prices they come in at -- which is $15, $25, and $35-ish USD for the KSC75, KPH30i, and PortaPro, respectively.

The major differences between the three?


PortaPro - most balanced sound signature of the three. Warm presentation, forward, and relaxed treble.

KPH30i - the darkest of the bunch. While it has similar lower end and through the majority of the mid-range, I do find this set to have the most recessed upper mid-range and treble and it show's in the FR as well. The sound is almost muffled in a way, but removing the foam backing from the driver enclosure really helps open up the sound a bit, though it doesn't fully remove the darker tonality while compared to the PortaPro and especially over the KSC75. That said, you get used to this sound.

KSC75 - this one is the most fit dependent of the bunch as it's a clip-on. It can be very tight on your ear or very loose and that can determine how balanced the overall sound, especially the mid-range and low end sound. Despite that, this is the brightest of the bunch, with the biggest treble gain, and sometimes sounding a bit sharp and metallic. The Ti coating on it probably plays a role here.


Fit and Quality

Sound impressions aside, I find the KPH30i the most comfortable of the three. Actually, in some ways, I do find the clip-on KSC75 or the KSC35 (KSC75-style clip-on but with PortaPro driver) to be most comfortable because they dont squish your ears. 

The PortaPro is, by far, my least favorite for comfort. First, the clamping pressure is the highest, and secondly the headband makes you bald. The band slides together and that can snag your hair and pull it out on headphone removal. So those two things combined make this very uncomfortable for me.

The KPH30i fixes this issue by having a more traditional headphone look and adding a comfort strap that helps with any head clamping pain and any top of heat discomfort. On top of that, it doesn't make you bald.

The KSC75 doesn't make you bald either. It may clamp your ear though. Or may fall off unexpectedly. But other than that, I don't have too much problem with it's style.


As far as cables, they all suck. Every iteration of these units, and I've owned a lot of these over the past 20 years -- have had terrible cables. I always take them apart and swap out cables.


So what's the best?

All things considered, I prefer using the KPH30i the most. It's the most comfortable, and I can get used to its darker sound, even if I prefer the PortaPro sound the most. Get it, it's not too expensive and works well for phone calls and quick listening. 


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