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Robin Bowes
2004-11-25, 08:56
Hi,

I've begun trying a variety of external DACs with the Squeezebox and I'm
attempting to compare the Squeezebox analogue output with the DAC outputs.

In order to do this, the output level needs to be set the same so the
listening tests are not compromised.

So, I did some measuring.

I created a file of white noise with a level of 0dB (using Steinberg
Wavelab) and set it playing on the Squeezebox. I then measured the
voltage at the analogue outputs of the Squeezebox, an Arcam delta Black
Box 5, and my new Art DI/O.

Now, 0 dBu is defined as 0.775V so I've referenced all my measurements
to that level.

Here are the results;

Description Voltage (V) level (dBu)
Reference level (0dBu) 0.775 0.000
Squeezebox 0.440 -4.917
Arcam 0.800 0.276
DIO 8.400 20.700

These are approximate values as white noise does not produce a steady
signal so I've guessed the voltages at around the maximum of the values
I was seeing on my voltmeter.

Key points to note:

1. The Arcam is pretty close to the 0dBu reference - in fact, allowing
for measurement error, it is pretty much spot on.

2. The DI/O has a specified output level of 20dBu. Again allowing for
measurement error, it is pretty much at that level.

3. The Squeezebox is nearly 5dB lower than the reference level (0dBu).
This would explain why several people have complained that the
Squeezebox seems quieter than their other hifi components - that's
because it is!

Is this a firmware issue? Or is this an inherent limitation of the
Squeezebox output electronics? (I tend to think the former as there are
no output electronics in the Squeezebox - all the processing and audio
control is pretty much all done on a single chip).

Thanks,

R.
--
http://robinbowes.com

Robin Bowes
2004-11-26, 11:21
Submitted as a bug: http://bugs.slimdevices.com/show_bug.cgi?id=689

And cross-posted to the developer list.

R.

Robin Bowes wrote:
> Hi,
>
> I've begun trying a variety of external DACs with the Squeezebox and I'm
> attempting to compare the Squeezebox analogue output with the DAC outputs.
>
> In order to do this, the output level needs to be set the same so the
> listening tests are not compromised.
>
> So, I did some measuring.
>
> I created a file of white noise with a level of 0dB (using Steinberg
> Wavelab) and set it playing on the Squeezebox. I then measured the
> voltage at the analogue outputs of the Squeezebox, an Arcam delta Black
> Box 5, and my new Art DI/O.
>
> Now, 0 dBu is defined as 0.775V so I've referenced all my measurements
> to that level.
>
> Here are the results;
>
> Description Voltage (V) level (dBu)
> Reference level (0dBu) 0.775 0.000
> Squeezebox 0.440 -4.917
> Arcam 0.800 0.276
> DIO 8.400 20.700
>
> These are approximate values as white noise does not produce a steady
> signal so I've guessed the voltages at around the maximum of the values
> I was seeing on my voltmeter.
>
> Key points to note:
>
> 1. The Arcam is pretty close to the 0dBu reference - in fact, allowing
> for measurement error, it is pretty much spot on.
>
> 2. The DI/O has a specified output level of 20dBu. Again allowing for
> measurement error, it is pretty much at that level.
>
> 3. The Squeezebox is nearly 5dB lower than the reference level (0dBu).
> This would explain why several people have complained that the
> Squeezebox seems quieter than their other hifi components - that's
> because it is!
>
> Is this a firmware issue? Or is this an inherent limitation of the
> Squeezebox output electronics? (I tend to think the former as there are
> no output electronics in the Squeezebox - all the processing and audio
> control is pretty much all done on a single chip).
>
> Thanks,
>
> R.


--
http://robinbowes.com

Danny Rego
2004-11-26, 11:39
I would like to know this as well.

Danny Rego


----- Original Message -----
From: "Robin Bowes" <robin-lists (AT) robinbowes (DOT) com>
To: "Slim Devices Discussion" <discuss (AT) lists (DOT) slimdevices.com>
Sent: Thursday, November 25, 2004 10:56 AM
Subject: [slim] Squeezebox output level


> Hi,
>
> I've begun trying a variety of external DACs with the Squeezebox and I'm
> attempting to compare the Squeezebox analogue output with the DAC outputs.
>
> In order to do this, the output level needs to be set the same so the
> listening tests are not compromised.
>
> So, I did some measuring.
>
> I created a file of white noise with a level of 0dB (using Steinberg
> Wavelab) and set it playing on the Squeezebox. I then measured the voltage
> at the analogue outputs of the Squeezebox, an Arcam delta Black Box 5, and
> my new Art DI/O.
>
> Now, 0 dBu is defined as 0.775V so I've referenced all my measurements to
> that level.
>
> Here are the results;
>
> Description Voltage (V) level (dBu)
> Reference level (0dBu) 0.775 0.000
> Squeezebox 0.440 -4.917
> Arcam 0.800 0.276
> DIO 8.400 20.700
>
> These are approximate values as white noise does not produce a steady
> signal so I've guessed the voltages at around the maximum of the values I
> was seeing on my voltmeter.
>
> Key points to note:
>
> 1. The Arcam is pretty close to the 0dBu reference - in fact, allowing for
> measurement error, it is pretty much spot on.
>
> 2. The DI/O has a specified output level of 20dBu. Again allowing for
> measurement error, it is pretty much at that level.
>
> 3. The Squeezebox is nearly 5dB lower than the reference level (0dBu).
> This would explain why several people have complained that the Squeezebox
> seems quieter than their other hifi components - that's because it is!
>
> Is this a firmware issue? Or is this an inherent limitation of the
> Squeezebox output electronics? (I tend to think the former as there are no
> output electronics in the Squeezebox - all the processing and audio
> control is pretty much all done on a single chip).
>
> Thanks,
>
> R.
> --
> http://robinbowes.com
>

Robin Bowes
2004-11-26, 11:49
Danny Rego wrote:
> I would like to know this as well.

Danny,

Login and vote for the bug at
http://bugs.slimdevices.com/show_bug.cgi?id=689

R.
--
http://robinbowes.com

Danny Rego
2004-11-26, 12:16
Done.

The funny thing is...I have been reluctant to get rid of my CD player
because the sound of the squeezebox always sounded "tinny-er", and now that
I know that the output level is just too low for the digital out...that's
probably the only difference I was hearing, and may be the reason some
people think the sound quality of the SB isn't as good.

(It may also be the reason everybody swears by an external DAC here as well)

If they fixed the output level, perhaps people's first impressions of the SB
would be better.

Danny Rego



----- Original Message -----
From: "Robin Bowes" <robin-lists (AT) robinbowes (DOT) com>
To: "Slim Devices Discussion" <discuss (AT) lists (DOT) slimdevices.com>
Sent: Friday, November 26, 2004 1:49 PM
Subject: [slim] Squeezebox output level


> Danny Rego wrote:
>> I would like to know this as well.
>
> Danny,
>
> Login and vote for the bug at
> http://bugs.slimdevices.com/show_bug.cgi?id=689
>
> R.
> --
> http://robinbowes.com
>

kdf
2004-11-26, 12:46
Quoting Danny Rego <danny (AT) rego (DOT) com>:

> Done.
>
> The funny thing is...I have been reluctant to get rid of my CD player
> because the sound of the squeezebox always sounded "tinny-er", and now that
> I know that the output level is just too low for the digital out...

the bug report is about analog out