Headphones

About

This page is an almost word-for-word copy of an e-mail David Lee from NCMIR sent to me, after I asked him advice about headphones. If you live and/or work in an noisy environment - wether it's due to noisy employees, traffic, loud air-conditioning or other machine noise - and this ambient/background noise is either distracting or driving you insane, you may find this article quite interesting! In my case it's noisy air-conditioning, but time will tell if it drives me crazy or not - I've saved this information here just in case!

Active versus Passive Noise Reduction Headphones

Earphones are a bit of a hobby. They would be more of a hobby, but it's also an amazingly expensive pastime. Based on my meager experience, I'd like to offer some knowledge that may be relevant for reducing ambient noise. The two main types of earphones are active and passive:

• Active headphones aim to cancel ambient sound waves by producing equal and opposite waves that cancel out noise.
• Passive isolation blocks noise by creating a seal with the ear canal, typically with foam or a silicone membrane.

Active cancelation is fairly effective but overall increases sound pressure levels which some people find uncomfortable over extended periods of time. In addition to active canceling of sound waves many active canceling headphones provide some passive cancelation by virtue of creating a seal around the ear with headphone cups. Some find the lack of airflow around the ear uncomfortable. I have a pair of Bose QC2's if you'd like to try these out. Passive sound isolation typically acts like earplugs, not unlike the earplugs you used while swimming. They will often have foam tips that are compressed before inserting into the ear and then expand to fill the ear canal.

A third alternative are custom earphones. These are inverse replicas of your ear canal and create a perfect seal with relatively little pressure. They also attenuate ambient noise quite a bit, in my experience more than either active or canal-style earbuds. The downside to customs is that they are horrifically expensive. They also sound really really good depending on brand/model.

On the low end of customs (like my pair), you can have an existing pair of headphones remolded into a custom shell for about $80 US. In the high end (jhaudio.com) they range from about $400 to $1200 for a pair of headphones. To start out, I'd suggest something cheap. You get decreasing gains with different methods of isolation, especially since hearing is logarithmic in perception.

Headphone recommendations:

• Lower end:
  • Sony Fontopia ear buds. Both Raj and I have these. They go for about $20-40 and offer good bang for the buck. You'll get a little more isolation with Compley foam tips ($15).

• Mid end:
  • Shure SE535
  • Ultimate Ears TF10
  • Westone w3

• High end:
  • JH audio

You can find a terrific number of headphone reviews on head-fi. At the moment, this comparison of several headphones is excellent. http://www.head-fi.org/forum/thread/478568/multi-iem-review-100-iems-compared-westone-um3x-turbine-pro-copper-added-08-18 Link subject to change.

-David Lee

Links:

• http://www.head-fi.org/ - David recommends as having LOT of info
• Headphone - Wikipedia

Acknowledgements: David Lee from UCSD