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Wednesday, August 21, 2013

Maxell HP-CN40

Disclaimer: This is a part of the loaner provided by Inks, a good friend o' mine.

Not only Maxell is not a well-known IEM manufacturer, actually, I have never even heard of this Japanese company until very recently. 

Regardless, one of the main features of HP-CN40 is its oval-shaped nozzle. The manufacturer claim that the shape of the nozzle ensures a tight fit within the ear canal. Due to its unpredictable nature in acoustic design, changing the shape of the bore has never been realized by any IEM manufacturers as far as I know. 

PRO: Linear frequency response & low distortion

CON: Slightly short high frequency extension.

ON SECOND THOUGHT #1: CN40 performs the best when it is slightly inserted into the ear canal, possibly 3 mm away from the reference plane. 

ON SECOND THOUGHT #2: Additional acoustic resistance further cuts the high frequency extension.

ON SECOND THOUGHT #3: Blocking front vents boosts the bass and the resonances located within 3~4 kHz range. 

ON SECOND THOUGHT #4: Since frequency response shaping is already optimized at the oval bore, CN40 is not really hindered by a bore resonance. However, once the stock bore size/length is somehow radically altered, as seen above, the resulting frequency response shall become quite skewed, cutting off the treble extension.

ON SECOND THOUGHT #5: If the resonance at 3~4 kHz can be damped by 6 dB, CN-40 should become very close to the Hi-Fi reference target presented by Harman.


  1. ON SECOND THOUGHT #3: Blocking front vents boosts the bass and the resonances located within 3~4 kHz range.

    Actually the front vents are fake. Inside the driver is closed and only 3 holes from the driver are open at the oval shape.

    1. Oh, thnx Neel. I simply blocked all of them for the "blocked" measurement, and made a single pinhole on the blocked "center vent hole", so the data should be as good.

  2. I tested the CN40 with a filter from a normal/cheap Samsung headset, and it works. The sound is little warmer. I felt that the air pressure also increased in the ear, because of the dense woven fabric.

    = Man can use the filters of their old, non working iem's.

    Do you plan to measure iem's with the stock filter + the Hifiman filter/ handkerchief / non woven fabric thing? Also not only with the different Knowles dampers? Maybe it is easier for people to get these things (handkerchief / non woven fabric / filter from old iem's) than the Knowles dampers.

    And I must say, I really like the "ON SECOND THOUGHT" parts of the reviews. I think, you are the only person, who measures these things. Thank you!

    Do you tested the Hifiman "filtered" sleeve on other IEMs?