Squeezebox Touch VBR Question

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WolfsongAudio

Squeezebox Touch VBR Question
« on: 4 Oct 2011, 09:35 pm »
OK, so after spending 3+ week ripping 1300+ CDs into FLAC using DBPoweramp, I am seeing a wide range of VBR data on my Squeezebox touch.  As low as 500 and as high as 1220, all of which the SQB server says it is transcoding UP to 1441 VBR.  Well enough I guess.  Several threads indicate the transcoding data figures to be a bit of a guess at best. 

Now we move to some 24 bit 96khs recording I have down loaded.  These read as high as 4550 VBR which is being transcoded DOWN to 1441 VBR. 

Is Squeeze Center just transcoding everything to the same 1441 VBR regardless of the actual bit rate?  I am "loosing: something from the 24/96 data? 

I do have the FLAC to PCM conversion set to happen at the server and not the touch.

Any insight or ideas would be helpful

srb

Re: Squeezebox Touch VBR Question
« Reply #1 on: 4 Oct 2011, 11:24 pm »
A CD is 16/44.1 which equates to a constant bit rate (not variable bit rate or VBR) of 1411kb/s.  (Are you sure it is converting to 1441 and not 1411?)  So, that sounds right for your FLAC files from CDs.
 
Your 24/96 FLAC files would have an uncompressed bit rate of 4608kb/s, so yes, you are losing resolution if they are being downsampled to 1411kb/s (16/44.1), if the reported bitrate is even close to being correct.
 
Have you tried FLAC = Native on Squeeze Center?
 
Steve

eclein

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Re: Squeezebox Touch VBR Question
« Reply #2 on: 4 Oct 2011, 11:38 pm »
Wolfsong, you did some or all of the tweaks outlined in that website the guys put up for SB Touch optimization. It looks like it from your last few sentences..???

Do the files sound off??

WolfsongAudio

Re: Squeezebox Touch VBR Question
« Reply #3 on: 5 Oct 2011, 01:33 am »
SBR-  You are correct,  I should have typed 1411 as the bit rate.  I will try the FLAC as Native but will that not cause the FLAC to PCM conversion to happen at the lesser SQB Touch OS instead of my headless server?  The reason I ask is all of the threads that show it is best to allow the FLAC to PCM conversion to happen at the server for better sound.  It would be a PITA to have to switch server preferences every time I want to play a high res file.

WolfsongAudio

Re: Squeezebox Touch VBR Question
« Reply #4 on: 5 Oct 2011, 01:38 am »
eclein,

  I did most of the software tweaks as outlined here and on computeraudiophile.  What I am hearing is basically zero difference between 14/48 and 24/96 versions of the same files.   I have heard HUGE differences between 24/96 and 16/44 and the files I have in both formats seem to be the same from the SQB Touch and I looked at the VBR and it's transcoder info to be the issue.  I am not looking forward to having to swap the FLAC=Native vs. FLAC=PCM setting every time I swap between CD and high res files.

Mike

srb

Re: Squeezebox Touch VBR Question
« Reply #5 on: 5 Oct 2011, 01:55 am »
A.  I was curious what Squeeze Center would report as the bit rate when sending FLAC natively, in case some other setting was causing downsampling.  Did you setup Squeeze Center from scratch yourself or inherit an installation, as I know configurations can be set to always downsample, as one might do if they had a 16/44.1-only capable DAC.
 
B.  I won't pretend to know as much as the more learned Squeezebox optimisers, but are you using the Touch wired or wirelessly?  Another thing to perhaps consider is the slightly reduced network bandwith and less chance of dropouts sending FLAC natively over WiFi, but if you're connected by Ethernet then it wouldn't apply.
 
C.  Finally, aside from what others have said about FLAC to PCM conversion at the server, are you able to hear a difference when streaming FLAC vs PCM on your 16/44.1 files?
 
However you should be able to stream 24/96 as PCM if you want to, so perhaps someone else might be able to zero in on a setting or a configuration file that might be causing the downsampling.
 
Steve

Big Red Machine

Re: Squeezebox Touch VBR Question
« Reply #6 on: 5 Oct 2011, 10:03 am »
What menu sets the resolution in Squeezecenter?  And tab.

eclein

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Re: Squeezebox Touch VBR Question
« Reply #7 on: 5 Oct 2011, 04:54 pm »
Mike, I don't think your going to have to do that. We just got to connect you with the right guys....I'm too new to know for sure and do not want to make your situation worse. Maybe change your questions heading to "S___B___Touch Guys Please help" or something similar so more people see the topic and pursue reading it...there are guys on here that will know this instantly. I will try and round some up for you.... :thumb:

lcrim

Re: Squeezebox Touch VBR Question
« Reply #8 on: 5 Oct 2011, 09:22 pm »
Sorry, I was concerned about this issue too about a year ago and asked the question of John Swenson and Soundcheck. 
I was told to ignore the UI totally. 
I send everything as PCM from the server to the Touch.  As far as changing the bit rate, I experimented w/ upconversion but after comparing it with native bit rate, I removed the upconversion.  You can search on this over on the Squeeze Box Community Forums or on the TT 2.0 thread in DIYAudio.
Larry

WolfsongAudio

Re: Squeezebox Touch VBR Question
« Reply #9 on: 5 Oct 2011, 10:48 pm »
Thanks to all responders.  Here is what I found by switching FLAC to Native.  The VBR goes to the actual bit rate the rip ( recording? * ) was made at.  For instance, the Ride the Lightning ripped from vinyl to a 24/96 track reads at 3995 VBR.  A Led Zep IV ( no source given ) reads at 2956 VBR.  CD files show up all over the map from 400 or so all the way to 1411 with NO transcoding being done. 

Odd bit here:  I THINK the non transcoded setting sounds better on both 24/96 files AND 16/44.1 files.  More open and better timber.  Greater decay of notes and more dynamic contrast.  More PRAT and Jump as it were with a better sense of space in recordings that have it ( IE live stuff in big rooms ).  The 24/96 stuff shines more at the frequency extremes.  Bass has more weight and impact ans cymbals more shimmer and ring with less grit.  Not subtle on the high res. files.  Still pretty obvious on the CD files.  BTW all of this is via the un-modded SQB Touch analog outs.  I have a Musical Fidelity M1 Dac on the way to play with to see if it will eclipse my Ayre C5Xe.  Can't wait!

The Touch is connected via ethernet so wireless is not in the picture. 

Larry,  By setting the FLAC designate to Native am I still doing the PCM conversion at the Server?

*Now the $64K ?  Why/how are the bit rates on my CDs so all over the map?  400 to 1411 with literally hundreds of them at or under 800?  All a guess by Squeeze center and of 0 consequence?  A result of poor "rips"?  Bad CD mastering?  Sony and Phillips LIED to US? :evil: :duh: :scratch:

lcrim

Re: Squeezebox Touch VBR Question
« Reply #10 on: 5 Oct 2011, 11:15 pm »
Larry,  By setting the FLAC designate to Native am I still doing the PCM conversion at the Server?

*Now the $64K ?  Why/how are the bit rates on my CDs so all over the map?  400 to 1411 with literally hundreds of them at or under 800?  All a guess by Squeeze center and of 0 consequence?  A result of poor "rips"?  Bad CD mastering?  Sony and Phillips LIED to US? :evil: :duh: :scratch:
Hi:
No
The User Interface is nonsense in this area.  To whit:   http://forums.slimdevices.com/showpost.php?p=579980&postcount=10
No offense but I'm going to contnue sending PCM from the server to the Touch.
Larry

WolfsongAudio

Re: Squeezebox Touch VBR Question
« Reply #11 on: 5 Oct 2011, 11:21 pm »
Larry,

  No worries.  I will do more critical listening when the DAC gets here.  It should also help that it indicates the sample rate it is being fed so I should then have more confidence in the results.  So when your system plays a 24/96 file, the "transcoding" down to 1411 does not "harm" the sound?

mfsoa

Re: Squeezebox Touch VBR Question
« Reply #12 on: 5 Oct 2011, 11:34 pm »
Hi Larry,
Does this (the untrustworthy display) explain why people are saying that the Touch won't play at the slightly higher bitrate of Pandora One?
Or does the Touch truly not recognize the 192K bitrate?

Thanks

WC

Re: Squeezebox Touch VBR Question
« Reply #13 on: 5 Oct 2011, 11:45 pm »
What would it do with the MOG 320k bitrate?

Big Red Machine

Re: Squeezebox Touch VBR Question
« Reply #14 on: 5 Oct 2011, 11:47 pm »
Where are finding this VBR data?

lcrim

Re: Squeezebox Touch VBR Question
« Reply #15 on: 6 Oct 2011, 12:00 am »
(Mike)mfsoa:
Pandora should be available both paid and free through MySqueezeBox.com  I personally don't mess w/ internet radio because it sucks.  A 192 kb stream is much less data than 24/192.
Red:
You need to look at the SBS interface and double-click a playing file in the right hand window, more information will be displayed in the left hand window.  The bit rate is totally bogus so what's the point?

Larry

WolfsongAudio

Re: Squeezebox Touch VBR Question
« Reply #16 on: 6 Oct 2011, 12:43 am »
Larry,

MFSOA?

lcrim

Re: Squeezebox Touch VBR Question
« Reply #17 on: 6 Oct 2011, 01:17 am »
mfsoa is a member here who I know to be named Mike.  I was answering his question.
Larry

JEaton

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Re: Squeezebox Touch VBR Question
« Reply #18 on: 6 Oct 2011, 02:18 am »
The bitrate figure is simply a factor of the compression ratio of the lossless Flac file. It's not a "guess", it's the actual bitrate at which the file streams across the network in its native format.

The user interface may not display it in a very helpful manner, but it's accurate. It doesn't take into account whether or not you're decoding the file at the server and streaming PCM, and the 'VBR' designation is somewhat meaningless.

A two channel, 16-bit, 44.1 kHz uncompressed audio file would be streamed at 1,411,000 bits per second, or about 1411 kbps. If a file is compressed to exactly 50% of its original size then the bitrate shown will be 705.5 kbps. If a file is compressed to 60% of its original size, then the bitrate is 846.6 kbps, etc.