Sony Ericsson W810i Walkman Phone Hiss and Distortion
Introduction
This page is a brief explanation of the sound quality problems that W810i Walkman phone owners are currently complaining about - namely distortion and background noise when listening to music. I'm not sure if other Walkman branded phones suffer from an identical problem but there are reports of a similar problem being introduced to the W800i model after a firmware update.
There's been no official comment from Sony Ericsson regarding this problem and my emails concerning this issue sent via www.sonyericsson.com/support have been answered with a stock "there are no known issues with the W810i" response. Therefore my analysis of the technical reasons for the problem are somewhat speculative as I have no detailed information about the implementation of the phone's audio playback hardware. Also note that it's unclear whether this problem affects all W810is (mine is from UK T-Mobile, unbranded using WotanServer and updated with R4EA031 firmware [edit - March 20, 2007]I downgraded to R4DB005 firmware to use qwerty12's acoustic drivers[/edit]).
Update (December 05,2006) : There's now an online petition regarding the phone's poor sound quality - maybe it'll make a difference if enough people sign. It's at:
htttp://www.petitiononline.com/w810i/petition.html
Update (March 20,2007) : Thanks to the endeavours of various individuals it's now possible to minimize your W810's hiss levels by tinkering with your phone's firmware [more...]
Hiss
With just about any portable audio player there'll be background hiss when listening at full volume - but it'll be drowned out by the music so you'll only really notice it during very quiet parts of the audio or the gaps between tunes. If you turn the volume down the background hiss is also turned down - so the level of hiss in relation to the level of music remains constant and it becomes less noticeable the lower the volume.
However with the W810i the background hiss remains the same at all volume settings, so it actually becomes more noticeable at lower volumes.
You can test this yourself using this mp3 (it's just 30 seconds of silence): silence.mp3
- First put on your headphones but don't plug them into the 3.5mm socket on the cable yet - obviously you will hear silence.
- Turn the phone's volume up to maximum and start playing the mp3.
- Plug in your headphones with the mp3 playing at maximum volume and you will hear background hiss.
- Turn the phone's volume all the way down to zero with the mp3 still playing - the level of hiss remains the same.
Why does the background hiss remain constant only on the W810i and not the majority of other audio players?
In a typical audio player the digital audio will be first converted to an analog signal by a DAC (digital-to-analog converter) and then the level of that analog signal will be amplified according to the volume setting - higher amplification results in higher background hiss.
In the case of the W810i it seems that the DAC's analog output remains at the same high level and the volume of the DAC's input signal is adjusted digitally.
Distortion
Adjusting the volume digitally effectively reduces the bit-depth of the digital audio which produces quantization noise. Even at maximum volume with the W810i's EQ set to "normal" there seems to be a bit of quantization noise but it's not too bad (presumably the volume is lowered to give some headroom to avoid clipping with different EQ settings).
At lower volumes this quantization noise becomes more extreme - the sound becomes more crackly - at the lowest audible volume setting it sounds like the audio is being played back with more or less 8-bit quality (this is based on my own subjective listening tests - as I said above I have no technical information about the hardware). You can hear the effects of quantization distortion by playing back this sample on your phone at volume level one: test.mp3 (That's not my voice BTW, it's from Ricky Gervais' Politics DVD
For comparison I've applied equivalent quantization to the sample above while keeping the volume level the same, so you can clearly hear the effects of bit-reduction on the original sound: quantized.mp3
Distortion + Hiss
The distortion on the W810i isn't actually that bad is it?
If you tried playing the test.mp3 above on a W810i at the lowest audible volume setting you might suspect that my quantized.mp3 example is an over exaggeration of the amount of distortion that occurs. In fact the distortion is masked to some extent by the phone's background hiss.
To test the actual level of background hiss in relation to audio level at the lowest volume setting I recorded a 1KHz sine wave normalized to 100% being played on the W810i at both full volume and volume one.
At full volume the peak background noise level from the phone is about 76 dB quieter than the audio (that's taking into account additional noise generated by my recording hardware, but it's still only an approximate value). At volume one the test signal is 38 dB quieter than at full volume. Therefore at the lowest volume setting the background noise level is only 38 dB quieter than the audio signal.
To illustrate how this sounds in relation to my test sample I've added noise to the quantized.mp3 at the eqivalent level: quantized_with_noise.mp3.
It sounds pretty bad - but remember this is representative of the W810i's sound at the lowest volume, plus I've chosen a sample to specifically highlight the phone's problems. For comparison here's a snippet of music with identical quantization and background noise to the example above: music.mp3 (sample from Go 2 - Let it Burn, Super Eurobeat volume 168
Depending on the type of audio you play you might only notice the distortion as a bit of crackling at the end of a tune when it fades out and only hear the background hiss in between tracks. Here's a music clip which demonstrates the crackling, or "static", sound when it fades out: musictest.mp3 (sample from Aimee Mann - Pavlov's Bell, Lost in Space
Does My Phone Have a Hardware Fault?
It's conceivable but I think not - there's plenty of reports from other people regarding this issue. Eg. here (howardforums.com), here (sonyericsson.com) and here (livejournal.com).
So why do so many reviews praise the sound quality of this phone?
It's possible that the music playback quality of the phone was tested with high volume levels and in an environment with moderate ambient noise, in which case the issues I've described above wouldn't be so apparent.
However it's also likely that the reviews were based on an earlier version of the phone's software which didn't feature this problem - this was the case with the W800i : the hissing problem was introduced with a firmware update as part of a fix for digital clipping at high volumes. In this thread a Sony Ericsson representative is quoted as saying:
"this hissing sound is because of a fix which prevents digital distortion.
This fix have increased the background noise and will unfortunately not be fixed."
If it's a Software Problem Then Can it be Fixed?
In theory yes, although judging by the quote above it seems unlikely Sony Ericsson will issue a fix in a future firmware update. However there is still hope - here is a thread which contains instructions on how to replace specific files on a W800i in order to recreate the audio playback characteristics of the earlier firmware version which didn't have this problem.
Currently it's not possible to perform the same operation on a W810i due to differences between the phones' filesystems, but hopefully it's just a matter of time until there's a similar fix. I'll update this page as more information becomes available.
See below for info on software based fixes.
Why don't I Just Return the Phone if I'm Not Happy With It?
Well now that I've "debranded" it T-Mobile probably wont take it back (maybe it's possible to re-brand it with the T-Mobile version of the software? I'm not sure), but as it happens I am happy with the W810i - on the whole it's pretty good: it's got a reasonable camera, J2ME apps work OK and at fullscreen, the browser has FlashLite support...and as an actual phone it does its job admirably. I'd rather keep hold of it and wait for a solution to this audio problem.
As for minimizing the problem, I got a set of Sennhesier MX500 earphones which have an in-line volume control on the cable - so I can set the phone on it's highest volume and reduce the level with the earphones' volume control which does a reasonable job of dealing with the phone's hiss but it's not an ideal solution.
Tweaking Your Phone's Firmware
There's now a couple of procedures you can use to minimize the background noise during audio playback on the W810 - one method inolves breaking the phone's filesystem encryption using a brute-force technique...it can take several hours.
The second only takes a few minutes, but it's a bit more complicated. Details here:
http://myforum.lasyk.net/showthread.php?t=30945
Here is an alternative explanation of the process:
http://forums.se-nse.net/index.php?showtopic=7330
Before carrying out the process I changed my phone's firmware from the latest R4EA031 version to the previous R4DB005 version - I read somewhere that this was neccessary for the modified acoustic drivers to work...but subsequently I've read that this isn't actually neccessary (TBH it's a bit of a nightmare researching this kind of information...most of it is seems to be in forum threads which are hundreds of posts long...there doesn't seem to be any one page or website which contains all the relevant information about customising the phone).
Anyway, the results are pretty good using the modified audio drivers - there's still hiss but it's now at acceptable levels.