would Medium Ultracortex fit a 58cm head? (borderline between Medium and Large)

edited July 2017 in Headware

Is there anyone else out there with a head diameter of 58cm used a medium size Mark IV headgear / does it fit?

I ask because I do not see a large Mark IV 16 channel available.

Comments

  • wjcroftwjcroft Mount Shasta, CA
    Slack, hi.

    Please email contact at openbci.com. And post here what reply you get. I'll mention @openbci so they also see this post.

    Did you fill out the Notify Me form?

    William
  • Since this is a non answer I will assume the answer is no a medium will not fit a 58cm diameter head. 

    Anyone else?
  • wjcroftwjcroft Mount Shasta, CA
    You need to email contact at openbci.com and ask them for advise. That is the email for the lab and customer service / fulfillment. Did you do that? 58cm is right at the borderline, so technically it SHOULD fit. But head shapes differ, some are more elongated, some more round.
  • My misunderstanding, I was unaware it was that complicated & looking for a yes or no from anyone w/ previous experience. I have not contacted OpenBCI that was my next step. Thanks for the clarification!
  • Slackconsulting,
    There is an intermediate size available, where 58cm is exactly in the middle of the adjustment range.
    You can buy the "Print it yourself" kit here, and the frame here.

    Choose "Large" from the drop down menu, which corresponds to size "M-L", midway between the OpenBCI M and L size. That will be an ideal fit for you.

    Here is more info about how size is calculated:
    The range is fairly forgiving though because there is 50% overlap
    between sizes. This means that if you have a perfectly average head, all
    three sizes would fit. Small adjusted all the way "out", Medium
    adjusted to the middle of its range, and Large adjusted all the way in.
    While the "range" depends on head shape, there is a specific head
    size/shape for each size headset where the electrode will contact at 50% of bolt adjustment range and 50% spring compression. These are the exact numbers:

    Small (-10mm from Medium)
    48.9cm Circumference
    17.4cm Length
    13.5cm Width
    8.0cm Height (from circumference line)

    Medium- (average head)
    55.2cm Circumference
    19.3cm Length
    15.5cm Width
    9.0cm Height (from circumference line)

    Large (+10mm from Medium)
    61.5cm Circumference
    21.4cm Length
    17.5cm Width
    10.0cm Height (from circumference line)
  • Thank you for the additional information. Generally speaking a medium will in fact fit a 58cm head, at least it did with our experience (with a little room to spare). It is clear to us now that a large would have been too big for our use/testing. Since we were purchasing the un-assembled option the medium worked best for us.
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