Audio (for kite flying)

Part I - Tests (20/02/2005)

Part II - A Problem (16/05/2005)

Introduction

I've long since seen the similarity between flying kites and making music. Recently I've begun to appreciate the pleasure of listening to music whilst sport kite flying.

Using a Nokia 9500 phone as a music player and a stereo handsfree headset as headphones I find that I can lock into the music whilst flying, almost as if the music is the canvas and the kite the brush. High energy music such as The Chemical Brothers or Eat Static helps make the picture a good workout as well. It's also good for conditioning. If I'm flying to music that keeps a definite time (beat) then it's a challenge to do something with the kite at defined intervals, no matter what the wind is doing. Some might call this freestyle.

The limitation with the 9500 is that the audio input / output is by a proprietary pop-port fitting. Nothing else can connect to the Nokia unless it has the Nokia pop-port connector. Being audio minded I wanted to get the best quality out of the 9500 and by acquiring a Skullcandy adapter [Please read Part 2 of this article if you are considering purchasing a Skullcandy adapter as I did run into some issues with it after a month and had to return it] this meant that I could connect up normal headphones and do a few comparative tests. For the tests I tried out a Nokia HDS-3 handsfree headset, a Nokia HS-2R handsfree headset, the Skullcandy adapter itself, Sony MDR-EX71SL earbuds and Sony CD30 headphones.

Click on the images for larger photos.

Nokia HDS-3: A standard Nokia handsfree headset.

Skullcandy: Dual Nokia pop-port / 3.5mm stereo jack source connectors for connecting to one set of headphones.

Sony MDR-EX71SL: Earbud style headphones with earplugs.

Sony CD30: General purpose covered headphones.

I tested two pieces of music, Galvanize by the Chemical Brothers and The Lark Ascending by Ralph Vaughan Williams. The first is a busy modern piece, the second a quiet gentler classical piece.

Both samples were encoded as 128 Kbs MP3's using Cubase SX at the highest quality setting. I listened to about three minutes from each piece somewhere towards the middle.

To start with I tested the Sony CD30 headphones and the Sony MDR-EX71SL earbuds directly by playing the MP3's from the computer. The CD30 helped act as a reference.

In the second test I still played the MP3's from the computer but added the Skullcandy adapter.

For the third test I listened to the MP3's on the 9500 with the Skullcandy adapter.

For the fourth test I listened with the traditional Nokia headphones (HDS-3 and HS-2R).

Results

Galvanize:
The Chemical Brothers

The Lark Ascending :
Ralph Vaughan Williams

TEST 1

PC => Sony CD30

Respectable sound (my reference).

Respectable sound (my reference).

PC => Sony MDR-EX71SL

More definition in higer frequencies. Good bass. Good volume level. Slight hiss noticable probably as a result of the better high frequency response.

The high frequencies of the violins are noticeable.

TEST 2

PC => Skullcandy (3.5mm connector) => Sony CD30

Equivalent sound quality to when the skullcandy wasn't used. The volume control changes the level on the music from the PC but isn't particularly linear.

Equivalent sound quality to when the skullcandy wasn't used. The volume control changes the level on the music from the PC but isn't particularly linear.

PC => Skullcandy (3.5mm connector) => Sony MDR-EX71SL

Equivalent sound quality to when the skullcandy wasn't used. The volume control changes the level on the music from the PC but isn't particularly linear.

Equivalent sound quality to when the skullcandy wasn't used. The volume control changes the level on the music from the PC but isn't particularly linear.

TEST 3

Nokia 9500 => Skullcandy => Sony CD30

'Cloudy' sound. There are, more mid frequencies but the top frequencies are missing.

Respectable quality of sound but lacking in the high frequencies.

Nokia 9500 => Skullcandy => Sony MDR-EX71SL

The thumping bass is more evident. The upper mid / top frequencies are definitely missing.

Nice sound but it is noticable that the high frequencies are missing.

TEST 4

Nokia 9500 => Nokia HDS-3 (with foam pads)

Loud. Good bass. Good frequency response.

Good sound with lots more volume to play with. The middle range seems to be emphasised comparatively more.

Nokia 9500 => Nokia HS-2R (with foam pads)

Weak sound. Little bass. Mono.

Weak sound. Little bass. Mono.

Nokia HS-2R: The only device with an accessible volume control. There is very little bass and the sound quality is weak. Worst of all it plays the MP3's in mono! The radio however is stereo and has a clearer sound, although good reception is vital. Sometimes when listening to the radio it generates a distracting hum which can be got rid of by stepping up one frequency and then returning. It has a clip on the radio tuner and I like the mic being on the lead of one of the earpieces as this means I can position the mic close to my mouth. This is useful when it's cold and one is wrapped up warm.

Pros :Clothes clip. Volume control. Easily positioned microphone. FM radio.
Cons: Plays MP3's as mono! Sound quality is weak. Nokia pop-port connector easily falls out.

Nokia HDS-3: This generates the highest level of volume than any of the other headset or headphones tested. The bass is good as is the overall frequency response which also includes a more discernable mid-range. The earbud leads wrap around the neck which means that the earpieces will just dangle in a convenient place if they have to be taken out of the ears. I would like to have a clip on the white microphone piece so I could decide where to position the microphone as I don't feel that it settles in the best place naturally.

Pros: Superb sound. Cables wrap around neck.
Cons: Mic position. No clothes clip. Nokia pop-port connector easily falls out.

Sony MDR-EX71SL: The big attraction of this headphone is the earplug style fitting. It cuts out a lot of background noise, so much so that ones own 'body sounds' become more evident as does the sound of the cables brushing against clothing. It comes with a selection of three earplugs. I recommend using the largest ones possible because it helps with bass reproduction. When I listened to the sample MP3's directly from the computer the sound was superb. In my tests I used the Sony CD30's as my reference headset, and in comparison the MDR-EX71SL provided more definition in the higher frequencies. There is a good bass response. A slight hiss is just noticable but this could be because of the higher frequency reproduction.

When used on the 9500 (with the Skullcandy) the difference was dramatic. Upper mid / top frequencies are missing, although the thumping bass (in Galvanize) is more evident than with any of the other headphones. I can only assume that the only thing causing the loss of the high frequencies is the Nokia 9500 itself or the Media Player software.

Pros: Earplug style earbud fitting cuts out background noises. Good sound quality and frequency response.
Cons: On the 9500 an adapter must be used, e.g. a Skullcandy. Also when used with the 9500 the volume level is relatively low.

Skullcandy: The Nokia pop-port connector fits the phone solidly. It locks well and doesn't feel like it will fall off by accident which happens frequently with the HDS-3 and the HS-2R. The additional 3.5mm stereo jack input is surplus to my requirements and gets in the way. I'd rather it wasn't there. The biggest downside to the Skullcandy however is that the volume control on the mic / clip does nothing to the phone volume. This is a big shame. It does control the volume for the 3.5mm jack input, but I don't use that connector. The volume range seems non-linear, maybe an anti-log pot is needed for the design? I like the fact that the skullcandy has a clip so that I can place the microphone where I want. I'm told my voice comes across clear and loud in conversation. The button on the front allows me to terminate a call (and presumably answer one). The Skullcandy made no appreciable difference to the sound quality when it was added to the chain between the PC and the CD30 or MDR-EX71S and is in effect audibly transparent.

You must use something like this if you want to use seperate headphones and retain handsfree capability on the 9500.

Pros: Clothes clip. Microphone. Call button.
Cons: Not designed with this requirement in mind. Overly long cable. Additional input.

Nokia 9500: From these tests it soon became apparent that there is a loss of upper mid / high frequencies in the Nokia 9500, presumably as a result of the 9500's electronics, the Media Player software, or both.

Conclusion

As an MP3 player the Nokia 9500 is functional. If you want to adjust the volume control or skip tracks you have to open the cover. There are no hard buttons on the case for this. Unfortunately the button on the handsfree headsets doesn't allow tracks to be skipped. The sound quality is adequate. If you want the best in audio quality then the 9500 isn't really for you. The upper mid / high frequencies response is poor. To connect to any other headphone requires the purchase of an adapter. The music stops when a call is received but fails to restart when the call ends.

Of course the Nokia 9500 can do MUCH more than just play music files.

The Nokia HDS-3 handsfree headset offers the best overall sound / value for money. The volume is loud and the sound quality good. I recommend using the foam pads on the earpieces as this helps increase the bass range, presumably by helping seal the ear canal. I wouldn't be too surprised to find out that Nokia design their headphones to complement the electronics stage of their mobile phones. Although each 'component' on its own might not necessarily give the best overall sound, combine the two and they may balance. This type of design policy is not uncommon with speaker manufacturers who also design amplifiers. Having said that though the HS-2R is a different story.

For playing audio files the Nokia HS-2R is the worst of the bunch. The sound quality is weak and there is that surprising mono issue.

As far as headphones go the MDR-EX71SL produce a well respectable sound with good frequency range and bass response. Some of this may be down to the fact that the earplugs help cut down the background noise. The earplug effect works well with quieter classical music but the poor frequency response of the 9500 and lower volume output (when used with the MDR-EX71SL) means that classical music can appear quiet even though you can hear it more easily. This isn't an issue when the MDR-EX71SL is used for high energy music.

Summary

For travelling on the tube and to avoid hearing sounds that spill out from other peoples personal music players I will probably use the 9500 => Skullcandy => MDR-EX71SL arrangement. I'll put up with the long lengths of wires and useless volume control in favour of the clothes clip, strong pop-port connector and ability to put the microphone where I want it.

I still like the Nokia HDS-3 handsfree headset for sound quality and I expect I will continue to use it at other times, although the cable is a bit short and the pop-port connector does keep 'popping' off.

During kite flying I have yet to try the 9500 => Skullcandy => MDR-EX71SL arrangement.

There are other earbuds on the market, such as those made by Shure. However these have a significant price tag associated with them and the 9500 wouldn't be my first choice of music player to use alongside.

Finally

At the end of my tests I tried to use the 9500 as a sound source and play its output directly into my stereo using the Skullcandy adapter. Unfortunately the sound is very low and there is a buzzing sound. I think the impedances are totally mismatched. Shame really as I had been wanting to use it in conjunction with my FeONIC Soundbug for a while now.

In case you are wondering the photographs towards the top of the page were taken with the Nokia 9500.

At the end of March I ran into a problem. Music from my 9500 suddenly started to play as mono. By mono I mean that the left and right audio channels came through both ear pieces at the same time. I deduced that it was the Skullcandy adapter after conducting the following tests:

* Music - The music I'm listening to was definitely stereo, it played back as stereo on my computer.

* Headphones - My headphones played back music in stereo from the computer.

* Nokia 9500 - My Nokia HDS-3 headset played music in stereo.

* I rebooted the phone.

* There was no other connection attached to the Skullcandy adapter at the time.

* The 3.5mm stereo input jack on the Skullcandy worked ok and played stereo through the headphones.

* It made no difference if the Skullcandy volume control was up or down or if the mic button was pressed.

* I 'wobbled' the pop-port fitting, but it made no difference.

I contacted the company explaining the problem. They asked me to return it which I did. After waiting a month for a replacement to come into stock I instead decided to source an alternative product and asked for a refund which I recieved.

Skullcandy Alternative

The problem was that I couldn't find a suitable alternative. Fortunately a friend had a HS-8 handsfree which was no longer needed and because the quality of sound and way the earbuds fitted to the ear wasn't to my liking I decided to castrate the earbuds and make my own adapter.

The HS-8 is well thought out but in my opinion it is let down by the ear fitting and sound quality. However the pop port connector is small and fits snugly which means that it doesn't fall off the phone when walking or moving, unlike the HDS-3. The HS-8 also has a clip and two buttons, one of which answers the phone for handsfree and the I'm not sure what the other is for yet.

I unscrewed the casing from the housing and unsoldered the earphones. Next I took the stereo mini jack extension cable that came with the Sony MDR-EX71SL headphones and cut off the 3.5mm female socket along with about 15cm of cable. Unfortunately the wires in the cable is that horrible thin stuff that has cloth type braid mixed in with it. I painstakingly seperated the wires from the braid and gently removed the enamel off the ends of the wires using very fine grade sandpaper so that enough bare wire was exposed to allow me to tin the ends. I worked out the wiring and soldered the new connection on to the HS-8 (click on pic to the left to see the finished product). I chose to gang both grounds (negatives) together inside the HS-8 casing although I noticed afterwards that there is a little bit of crosstalk between channels. Perhaps only using one common ground would solve the problem? Let me know if you try it.

Overall the system works very well and is a vast improvement on the Skullcandy adapter.

External Playback

I've also discovered that my modified HS-8 system allows me to play music out of my Nokia 9500 into other devices with better quality than the Skullcandy (although the frequency response is still limited by the 9500). For instance I have a Tune-Free FM transmitter and during a recent visit to a non-UK country I was able play music out of my 9500 through the modified HS-8 and out from the Tune-Free FM transmitter. I could then listen to my 9500's music through the FM car radio.

The range on these type of low powered FM transmitters is fairly limited and one way to improve it is to add a 1/4 wave aerial. The resultant could look something like the yellow and blue wire in the illustration to the right. The reception range will by improved by anything up to fifteen times.