In our May News pages we carried news of an addition to the steadily expanding range of products from regular PW advertiser bhi, the HP-1 wired ‘over ear’ folding stereo headphones. bhi also kindly loaned a pair for review.

Headphones in the Shack
I don’t recall having reviewed a pair of headphones since I took over as PW editor almost six years ago. Yet headphones are, to my mind, one of the essential shack accessories and, in my case at least, in constant use. Equally, though, headphones are, or can be, a very personal choice. Some prefer over-ear headphones, some prefer in-ear types. Some like a lead, some prefer a Bluetooth or Wi-Fi connection to allow walking around the shack while operating. SSB operators will often want a boom microphone, although some will prefer to stick with a hand or desk microphone. Some like active noise-cancelling headphones, others prefer heavily padded headphones that keep out noise by passive means. A lot depends on your personal preferences and your operating situation. 

In my case, to put this review in perspective, I almost always operate with headphones, partly because I am primarily a CW operator and find it easier to copy the weaker signals that way and partly to reduce external noise. Indeed, my preferred headphones for several years now have been a pair of Bose QC15 active noise-cancelling headphones. There are two downsides – cost and the need to keep spare batteries to hand when operating for extended periods (a weekend contest, for example, or a DXpedition lasting several days).

Neither do they have a boom microphone although a number of users have found ways of attaching a lightweight boom with electret insert. Noise cancelling, though, can be a benefit in a multi-operator SSB contest or DXpedition environment where it can be distracting as your fellow operators shout ever more loudly while they try to contact that seemingly deaf station they are calling! 

So, it’s a bit of ‘horses for courses’. What I have found is that price isn’t always an indication of suitability. I have, in the past, paid well over £100 for a well-known pair of communication headphones with boom microphone, only to find that they squeezed my head so hard I couldn’t wear them for more than an hour or two at a time – useless for much of the operating I do.

Some Theory
Back in 2006 I was fortunate enough to be a referee at the World Radio Teamsport Championship in Brazil and shared a hotel room with my friend Eric Scace K3NA. Eric has a brain the size of a planet and outside a very successful professional career (he was, for example, one of the key people behind the development of frame relay, a major protocol used within the internet), he has made many contributions to amateur radio. In 2006 his mind was on the physiology of hearing response and what it meant for extended periods of listening to amateur radio signals on noisy bands. A lot of this is written up in two articles he wrote for the US National Contest Journal (see links below) but I can summarise the key points relatively easily.

The ear, just like most electronic devices, has a response that is non-linear at the lowest and highest volumes but is relatively linear over the range of sound levels we encounter day to day. For extended listening, it’s best to keep the levels low, However, the ear gets ‘tired’ when listening for extended periods, for example, in a 24-hour contest, and there is a tendency to gradually ease up the volume control. Eric’s preferred solution was to modify a pair of headphones to maximise the sound insulation so that a pair of passive headphones could, nevertheless, allow listening to the bands at a low level while still being able to hear and copy signals easily and avoiding hearing damage (either temporary or more permanent) if and when there a loud signal suddenly appeared (a static crash or whatever). 

That’s all very well but the headphones he had created were, to put it mildly, rather bulky! The underlying theory is worth bearing in mind, though, when you embark on a long listening/operating session. And I do recommend reading those articles when you have a moment.

http://ncjweb.com/bonus-content/novdec06scace1.pdf
http://ncjweb.com/bonus-content/janfeb07scace2.pdf

Anyway, enough of the theory but I’ve been wanting to cover this for some time in the pages of PW because headphones are something we use so routinely in the shack that we rarely think about them (although I do note that on our CDXC internet ‘reflector’, when someone asks for a recommendation about headphones, a long and heated discussion often ensues!).

The HP-1
The main features and specification of the new bhi HP-1 headphones are listed in the sidebar. There’s not a lot to add – they arrive well-packed and with an adaptor so they will work with both common headphone jack sizes found on our various transceivers (and, indeed, on most domestic audio/visual equipment). 

I like the way they fold up – not necessary for shack use, I guess, but handy when flying, taking on DXpeditions and the like.
My immediate impression on putting on the headphones (before I’d even plugged them in!) was that they are, indeed, lightweight and don’t grip the ears too much. But, at the same time, they do a good job of keeping out extraneous noise (nowhere near what I might expect from my Bose QC15s but at one tenth of the price that’s not surprising!). 

I used them not only for amateur radio use but, given that they have a claimed response of 20Hz to 20kHz (which my ears most certainly don’t nowadays), I tried them out for listening to music (my preferred genre is classical, with its wide dynamic range and range of frequencies).

For extended amateur radio operating (the test coincided conveniently with the ARI weekend contest and the opportunity to review the new FTdx101, which I will report on next month), I found the HP-1 headphones comfortable to the point that you forget you are wearing them and the lead is sufficiently long that you can move about a little or relax in your favourite operating chair. Reproduction of amateur radio SSB and CW is more than acceptable over a range of audio levels.

I also used them to listen to a variety of classical music (wide range of frequencies and large dynamic range) on the Bose CD player I have in my office/shack. Whether they would satisfy the more demanding of music buffs I have no idea but they certainly satisfied my listening requirements.

Conclusions
I rather tend to the view that, for reasons explained earlier, most active radio amateurs can never have enough pairs of headphones.

The bhi HP-1 headphones do what it says on the can(s) and for the price, you can’t really go too far wrong! Indeed, they are more comfortable over long periods than some of the more expensive headphones I have used, they pack up into a handy size for travel use and the sound proofing and audio reproduction are more than acceptable for the price.

The HP-1 headphones are available from bhi for £19.95, including VAT.
www.bhi-ltd.com

HP-1 Features

Closed back foldable dynamic stereo headphones
Comfortable lightweight design
Adjustable headband
Leatherette type soft padded earpads
Frequency Response: 20 to 20,000Hz
Maximum Input: 40mW
Sensitivity: 102dB
Impedance: 32Ω
Weight 155g 
Recommended use: Hi-Fi, TV, Radiocommunications
Cable length: 1.9m
Supplied with 3.5mm to 6.35mm stereo (¼in) jack adapter

This review is taken from the July issue of Practical Wireless. Buy your copy here.