Sunday, 24 February 2013

MEASUREMENTS: Logitech Squeezebox Touch. [Updated 2013-06-22]


I got this unit late last year lightly used when Logitech announced the Touch's discontinuation. I notice it is quite hard to get one of these now and they're commanding quite an elevated price on eBay!

- Internal DAC chip: AKM4420

Setup: i7 computer system - same as Essence One. Analogue output from Touch going into the E-MU 0404USB for measurements.

Oscilloscope measurement of 1kHz square wave, 0dBFS off the analogue RCA output:
Nice clean waveform. 2.92V peak voltage. No significant channel imbalance noted.

Standard linear phase oversampling digital filter impulse response (16/44). Absolute polarity maintained.

RightMark Results:
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Mostly better results all around compared to the SB3. Frequency response within tighter range over the 20-20kHz spectrum, noise levels 1 dB lower in the 16-bit domain (as if it could go any lower!?), and about -4dB lower with 24-bit data giving the Touch DAC about 17.5 bits of dynamic range. Interestingly, the stereo crosstalk is a bit higher in the Touch vs. SB3 by about 6-8 dB (remember, it's still down at -90dB).

Notice no significant difference between WiFi and wired through the ethernet.

Frequency Response:






16-bit audio vs. 24-bit audio. Looks good. Less bass drop-off than the SB3 with my equipment.


Noise Floor:




 THD Graphs:




Jitter (Dunn J-Test, WiFi):
16-bit:

24-bit:


Analogue outputs look very clean.

Summary:
I guess the only surprise is that the stereo crosstalk is higher in the Touch than the SB3. Otherwise, audio quality seems superior - it can obviously handle 96kHz natively (up to 192kHz with the EDO plug-in as a digital transport), and flatter frequency response especially in the low bass could be audible.

Again, assuming the WiFi strength is reliable and you're not constantly rebuffering, I see no indication that sound quality is negatively impacted by going wireless.

Subjectively, I like the Touch's sound. These days, it powers my bedroom system with SONY amp and Tannoy mX2 bookshelf speakers I got about 10 years ago. For what it is, I can't complain about these analogue output results - very competent! Although you can get better measuring noise floor, dynamic range, etc. with an outboard DAC, the Touch in its stock form is already very impressive and it would be wise to do some A-B testing before thinking an expensive DAC will improve the sound much!

For what you get, the bang-for-the-buck from this little device is fantastic and a shame really that it has been discontinued.

3 comments:

  1. Thanks for the measurements. Would the bitfrost shiit uber dac provide a superior sound. Seems as though many say "no." I am running Aragon pre and power amps through a fully restored dq10 speaker set up with stereo subwoofers. Thx. Tom

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  2. Thank you for the measurents. I am thinking about upgrading Squeezebox Touch. It is connected to Harman Kardon HD970 as a DAC. Is there a DAC under 500$ that is much better then SBT or HD970? Thank you.

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