Squeezebox Streaming sound quality

With the demise of the smartmix plugin, i’m contemplating a full time switch from LMS to roon (i’d previously been going back and forth). I’ll still miss qobuz, but may be able to cast it and use the transporter’s optical input. i’m already doing the same for Sirius XM.

i’ve noticed however that Roon Squeezebox streaming sounds…different from LMS. to my subjective ear, it’s a little “colder” or more digital. difficult to describe, but there’s a real difference, and i prefer the sound of LMS.

since the files are the same (most of my library is AIFF, with a smattering of FLAC, most in 16/44, but some 24/96 and 24/88) and the device are the same, there must be something in the way roon sends a file to the transporter that changes the sound, perhaps by converting to another format?

i’ve searched the forums and don’t see any info that’s on point. has anyone else experienced the same thing?

As long as Roon is displaying the “purple” bit perfect quality light then Roon is doing nothing to your file but sending the digital bits straight through to the transporter. I don’t have a transporter, but I do have 3 other Squeezebox devices and didn’t notice a difference at all.

yes, the purple light is on.

Then Roon is sending the digital file bit-pefect to the transporter. If Roon does any change to the signal path it is detailed in the playback chain and indicated by a green light.

perhaps it’s transcoding to a different format? how else to account for the difference?

LMS certainly gives you the ability to handle transcoding at the LMS level rather than just passthru of FLAC or AIFF to the Squeezebox device, so it is possible that your LMS setup may be sending something different from what Roon does.

Personally, I cannot hear a difference between Roon streaming and LMS streaming. When I compared them, I streamed to a Sonore uRendu (using the Squeezelite app) to my Devialet. Both sound exceptional. But, of course, I greatly prefer the Roon UI and so no longer use LMS for the most part.

Side question. What are you using for casting SiriusXM to your Transporter optical input?

Try checking out the LMS settings to make sure it the server is not transcoding AIFF to FLAC before sending it to the Transporter.

chromecast audio, using the web interface in chrome and casting the tab that’s playing.

thanks for the info

it actually works just fine. you can’t cast from the iOS apps however; would be better if that were supported.

Qobuz does support casting from its mobile apps, so i’ve started experimenting with that as well. switching between roon & the digital inputs is not straightforward however.

So I checked LMS, and it’s sending AIFF natively, so presumably that’s not the issue. listening some more, I would say that LMS is more dynamic, perhaps a little brighter (not convinced that’s necessarily a good thing), but Roon sounds a little rolled off by comparison.

this is highly subjective i realize, and i’m mostly interested in why there’s a difference at all, rather than the specifics.

My setup sounds exactly the same, but then I exepected it to :smirk:

But in all seriousness, there are a couple of server side settings in LMS that might be audible with your Transporter. There are two roll-off filters - moving to Roon might mean you’ve gone back to the default one having changed it in LMS (I could never reliably tell the difference between them). There’s also absolute phase inversion, which a few people can hear.

i didn’t have expectations either way, but have been back and forth enough on my main system to confirm its there. i’m using the transporter’s analog output.

i have a 2nd system where the transporter is used as a, errrrr, transport into a dac (meridian G61). i need to listen some more to that set up.

but, i’m finding there is some music where i prefer roon- opera and classical vocal in particular sounds very, very good in roon.

i’d read that roon squeezebox streaming converts the stream to a wav file- is this the case?

No, it streams natively.

How did you have the roll-off filter configured in LMS? The default is “fast”, iirc.

not sure- i never touched it, so whatever the default setting is.

Correct me if I’m wrong, but doesn’t the Squeezebox do codex decoding to PCM in in the SB itself (ie. it is sent FLAC/ALAC/whatever files by LMS), while Roon decodes in the core and sends out a PCM stream?

This still should not lead to audible differences IMO, but it is a different modus operandi.

depends on the SB, but the transporter decodes flac, apl, aiff, etc natively. not sure how, or whether, RAAT and Roon Squeezebox Streaming differ.

Output to Squeezebox does not use RAAT.

You are right – I misspoke (and corrected my post). The question remains whether Roon decodes in core and sends out PCM when using the Squeeze protocol, or if it streams the files natively and leaves the Squeezebox to do the decoding?