Poor Sound Quality

[UK Phil]

This post is just for information purposes. I bought a Linksys NSLU2 a while back and installed Unslung and Firefly on it and bought a Pinnacle (Roku) M1001 as a wireless player which I fed via the optical SPDIF output into a Denon AVR3802 surround sound amplifier. I was streaming FLAC files from the NSLU2 server. The problem was the sound quality was very poor, if I fed my CD player into the same optical input on the surround sound amplifier the quality was way better. This is a major disappointment, to the extent that I’ve returned the M1001 and given up on the project. What concerns me is how either Firefly or Roku are managing to trash what ought to be unadulterated data. This really ought to be like reading a data file where one would never expect to get errors. My understanding is that Firefly re-expands FLAC files to WAV format (so no data lost there) to stream over the wireless connection, if this isn’t the case then it’s a fundamental shortcoming of the whole setup and excludes it from any system that makes a pretence of being HiFi let alone audiophile.

I guess my conclusion is buyer beware, I returned my M1001 and got a complete refund for it but still have the NSLU2, which is OK, but I would have been a very disappointed bunny indeed had I been stuck with the M1001 too. I would have considered it good money down the drain. I may try a Squeezebox3 with Slimserver running on a low power fanless PC at some point but I have to say I’m rather wary after this experience.

[S80_UK]

Hi,

Sorry to hear of your disappointment. However, the Firefly forum is not the right place – since Firefly is a server, it is not itself responsible for any change to the quality of the sound. And since you were using FLAC, there should of course have been no difference.

However, if you go to the Roku forums you will see that there has been considerable discussion relating to sound quality that some (but not all) users have experienced with the SoundBridge M1001. This is apparently due to the fact that the M1001 hardware cannot natively support the 44.1kHz sample rate of CD media (M500, M1000, M2000 don’t have this limitation). Work in investigating / resolving this with a possible improvement to the sample-rate convertor is still geing undertaken by Roku.

Suggestion for Ron… When looking at support for configurable transcoding plug-ins to Firefly, wouldn’t it be cool to be able to decode FLAC to WAV and then also hook in a Sample Rate Convertor for the M1001 users. Not that you don’t have enough to do already… 🙂

[rpedde]

@S80_UK wrote:

This is apparently due to the fact that the M1001 hardware cannot natively support the 44.1kHz sample rate of CD media (M500, M1000, M2000 don’t have this limitation). Work in investigating / resolving this with a possible improvement to the sample-rate convertor is still geing undertaken by Roku.

Hmm.. didn’t know that. Are they using a fixed rate 48k dac or something?

never noticed it, as I have a 500 and a 1000.

Suggestion for Ron… When looking at support for configurable transcoding plug-ins to Firefly, wouldn’t it be cool to be able to decode FLAC to WAV and then also hook in a Sample Rate Convertor for the M1001 users. Not that you don’t have enough to do already… 🙂

Gack!

🙂

[S80_UK]

Hi Ron,

Yes – the DAC clocking appears to be fixed to 48kHz on the M1001 – here’s the thread…

http://forums.rokulabs.com/viewtopic.php?t=7009

To save you reading all 14 pages, the M1001 uses an internal sample rate conversion algorithm. Depending on what they play, how they listen, and maybe on what they paid for their hi-fi, some folks can hear some low-level artefacts from this process. To present some kind of balance, there are many other users of the M1001 hardware that do not hear it. I have M1000 and M2000 and so I am also unable to hear it, but given how I listen I probably would if it was there.

[rpedde]

@S80_UK wrote:

Yes – the DAC clocking appears to be fixed to 48kHz on the M1001 – here’s the thread…

Oof. Yeah, I think I’d be pretty cheesed about that too. I don’t have golden ears, but I can still hear bad upsampling on cheap pc98 audio cards…. and if I could hear that on a piece of consumer audio hardware, I would also be unhappy.

[gordo]

This is a feature of the more recent hardware. m2000, m1000, and m500 do not upsample to 48 kHz but m1001 and soundbridge radio do.

[UK Phil]

Mmmm I guess you’re right this probably wasn’t the place to have made this post as it’s obviously a Roku problem, looks as though its ramifications are rather relevant to Firefly users though, as Ron said, he’d have been disappointed if he were in my situation. Thanks for the responses, I had wondered if it was an upsampling issue as I couldn’t think what else would have caused this problem, other than extreme jitter maybe. As I have the NSLU2 with Firefly on it I may well order an M1000 from Amazon and see if that over comes the problem. If I do I’ll let you know the result.

Phil.

[richdunlop]

@UK Phil wrote:

I may well order an M1000 from Amazon and see if that over comes the problem.

If you’re ordering an M1000 make sure it is an M1000 (connectors under the end caps) before you buy. Roku originally marketed the M1001 as an M1000 when it first came out so you might get a nasty surprise if you aren’t careful. Your best avenue for an original M1000 purchase may be Roku direct or ebay.

[UK Phil]

Thanks Rich I had wondered if it was quite that straight forward, Roku have made a real screw up here haven’t they? That Squeezebox is sounding ever more attractive.

[richdunlop]

@UK Phil wrote:

Thanks Rich I had wondered if it was quite that straight forward, Roku have made a real screw up here haven’t they? That Squeezebox is sounding ever more attractive.

I’ve been a little surprised with some of Roku’s hardware design decisions such as the upsampling and lack of ethernet on the radio. Hopefully they’ll take account of the feedback they’ve had.

For me squeeze isn’t the solution though. If you buy a Squeezebox you have to use Slimserver and I don’t like being locked in to things, no matter how capable. The beauty of the Roku is that it supports so many protocols – DAAP, UPNP, RSP. You have lots of flexibility on the server side in terms of both hardware and software. The Roku / Firefly / NAS combo really is killer for music…

I’m sure that you could pick up an original M1000 on ebay or you may be able to get a refurb M1000 direct from Roku.

[Author]

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