Koss Porta Pro

The Koss Porta Pro came right in the middle of the 80s, not long after the popularity of portable cassette players and the rise of portable listening use.
It’s a very small and nomad on-ear can, with amazing comfort – adjustable clamp and almost weighs nothing. Can be folded and came with a carrying pouch. Easily driven from a phone. Doesn’t really isolate. The KSC75 is another cheap option from Koss, being open and with clips.

○ Release : 1984
○ Current status : In production
○ Type : On-ear / Open-back
○ Measured weight : 65g
○ Impedance : 60 Ohms
○ Sensitivity : ~103-104 dB/mW
○ Average used price : $15-30

Sound Impression
The Porta Pro is a bit too dark sounding for me, mostly because of excessive mid-bass and rolled-off highs.
It’s -very- midbassy, more than most headphones I have heard so far (although I havent heard consumer bassy headphones in a long time, those usually have lot of midbass).

There is some low-end extension but it doesnt extend well below 60hz. There is more rumble heard than the HD600 but relatively to 100hz the HD600 has better extension down to 50hz.

The midrange is warm and shows some forwardness around 1-2 khz that doesnt bother me particularly (I know that I’m not very sensitive to forward 1-2 khz mids).
Treble is way too recessed for me. I feel that the FR takes a dive after 5 khz and never gets back in line with the midrange around 1khz. Measurements confirm my impressions. It’s not a sparkly presentation and lacks lot of upper-treble. The excessive amount of bass and lower-mids make them sound too muddy sometimes.

Staging in the smaller side but it punches well for the price. I can’t focus a lot on the technicalities (rather good for $30-40) since I don’t enjoy them that much.

I much prefer the Creative Aurvana Live! (version 1) to the Porta Pro. The CAL is around $60 and I prefer the comfort of the Koss, but the Creative is a much more resolving and better sounding headphone to my ears. Better bass extension with control, smoother midrange and more treble energy / coherence. Overall better tonality and timbre. I also prefer by a big margin the KSC75 (though it’s a bit bright) to the Porta Pro, for even cheaper.

Measurements & Resources

You mostly hear from 60hz to 2khz with this headphone. Low-bass is missing energy and upper-mids / treble are quite recessed. Not a lot of air past 10khz (very inaccurate to measure). Yaxi pads and using clips (to reduce clamping) makes the PP sound a bit more even and clear.