Monday 25 April 2022

Homemade 'cat ear' wind noise reduction devices

After several prototypes, these are my homemade wind noise reduction devices that I now use on my bike helmet straps.  I'm really pleased with how they wo
rk. The biggest benefit is not, surprisingly, related to actually hearing things better. Instead, the biggest benefit is actually that it never seems like you're cycling into a headwind.  That alone dramatically improves how enjoyable a ride is.  This blog post describes how I developed them, the four iterations of prototype I went through to get something that worked, but that didn't look too stupid.

These type of wind noise devices have been around for some time.  This article published about 10 years ago by James Huang on Bike Radar describes the original Cat Ears, which I think were the first wind noise reducing devices like this.  The intended benefit of reducing wind noise is to enable the rider to better hear other sounds.  Personally, I've often found it difficult to hear what my riding friends are saying due to wind noise, and so back in 2018 I was keen to get a pair.

Unfortunately, when I was looking to buy some of these a few years ago, the official Cat Ears weren't sold here in the UK, only in the US.  Alternatives were available though, so I bought a pair of Wind Blox devices.  These were good at reducing wind noise, but I didn't like how thick in profile they were.  Instead of being a fluffy material, like Cat Ears, the Wind Blox devices are a foam filled wrap that had a thickness of about 1cm.  The problem I found was that the arms of my cycling glasses didn't fit over the top of them, due to their bulk.  I tried putting the arms underneath the straps instead, but then the noise-reducing effect didn't work.  It seemed that they needed to be flush against my face to cut out the noise.

At that point, I decided that I'd try to make a pair of Cat Ear devices myself.


Homemade Cat Ears Mk.1

This was my first attempt.   I made these out of pieces of black Lycra material from a pair of worn out cycling shorts, some Velcro strips, and a piece of black fluffy faux fur material bought from HobbyCraft.  The fluffy material cost a few pounds for the smallest quantify I could get, which was a 10 x 100cm piece (far more than I needed) from one of their fabic rolls.  The various pieces were glued together using contact adhesive.

Although they worked well, I admit they look ridiculous.  I was encouraged though, that when I tried using them on a road ride, the noise reduction worked really well.  I just needed to find a way to make them smaller, so I wouldn't get funny looks from people.


Homemade Cat Ears Mk.2


I tried to find a way to attach the fluffy material directly to the helmet strap.  I didn't want anything permanent though, so adhesive was out to the question. I tried using safety pins, but even small ones caused the strap to ruck up, and so the straps wouldn't lie flat against my face.

I decided to try using pairs of strong Neodymium magnets, which I bought form eBay for a few pounds.  By bonding 4 magnets to the back of the fluffy material, I could then use another set of magnet on the other side of the strap to hold it in place.

In many ways this worked very well.  The Mk.2 was much less obtrusive and stupid looking t
han the wider Mk.1, as shown in the photos of the left.

The magnets had a tendency to be attracted to their neighbours though, so the whole strip would occasionally collapse in on itself into a fluffy ball, needing the be carefully unravelled.  I also had a slight concern about having strong magnet close to my temples for prolonged periods of time.  A quick search on the internet about adverse effects of magnets on brain activity/health didn't reveal any known problems.  However, I still felt slightly uncomfortable and decided that I didn't want to take a risk with strong magnets next to my head.

Back to the drawing board.


Homemade Cat Ears Mk.3

For my next attempt, I tried to re-use a helmet strap device that comes with most Planet X helmets.

I had a couple of these spare, lying around already, because I don't use them.  They have a Velcro closure, so my hope was that it would be a simply job to bond the fluffy material to the outside.

Unfortunately, these devices were slightly padded, as shown in the photo to the left, making them slightly thicker in profile than I really wanted.  Also the Velcro wasn't particularly strong, so they tended to come undone quite easily.

For these two reasons, I gave up on the Mk.3 version.



Homemade Cat Ears Mk.4

Finally, with the Mk.4, I feel now that I have a device that works well.  In many ways it's very similar to the Mk.1, using the same Lycra off-cuts and Velcro.

Where it differs from the Mk.1 though, is how it wraps around the helmet strap.  In this respect it works more like the Mk.3.

The sketch below shows how the Mk.4 wraps around the helmet strap, versus the Mk.1.   This allows it to be no wider than the helmet strap, and therefore more discrete.

The lycra material is very thin, therefore the profile remains quite thin.





The photo below shows all of the materials that were used:

  • Lycra material, cut from an old worn-our pair of cycling shorts.
  • 3M 12mm Hook and Loop Tape.
  • Fluffy material from Hobbycraft
  • Impact adhesive.





Benefits

The noise reducing benefits are quite noticeable, as also noted by James Huang when he reported on them in his article.  A fair amount of wind noise remains, but what they do really well is to cut out the high frequency 'tearing' noise of the wind.  What remains is a lower frequency 'whooshing' sound of the wind.

On group rides I've done, I've found it easier to hear what my friends are saying, although this is perceived improvement is admittedly rather qualitative.

The most interesting thing I discovered though, which I wasn't at all expecting, is that it's now quite difficult to tell now when I'm cycling into a headwind.  I still go slower into a headwind, of  of course - it doesn't change that - but I didn't realise that as cyclists we must use the volume of the wind noise to judge the airspeed, and therefore the presence of a headwind.

This improvement, never feeling like I'm cycling into a headwind, is undoubtedly the greatest benefit and one that makes any ride more pleasant - Who likes that feeling of cycling into a headwind, right? 


3 comments:

  1. excellent ..thanks for sharing ..I shall make some soon . Much appreciated, Bill in Devon

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  2. These are uber cool!!! I love the idea as they also give you the "Elvis" look. Not sure if Elvis ever road a bicycle though......? ;-)

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