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x94blair3
2005-09-29, 20:35
This might sound crazy...but...here goes.

I noticed tonight that my a couple of albums in my "sleeping playlist" sounded like garbage. It's hard to describe exactly...sort of warbly?

At the time I was listening to an album from Itunes. I made a mental note to rip the quality of their mp3's (and lack of support for lossless) in my blog in the morning and moved on to the next album. This one was an mp3 album also but from another site. It sounded "better" but maybe not really.

Soo...I moved on to albums I have ripped in flac. And it was noticeably better but still "off". At this point it's driving me insane. And I suddenly think, could it be the volume level I have the squeezebox set to? Sure enough I have it maxed out, so I lowered it to 20 and upped my stereo volume to compensate.

Now even the garbage from itunes sounds "better" although it's painfully obvious that I need to replace the albums with true lossless copies.

I don't confess to know much about electronics, or even the hardcore side of being an audiophile. I love music, I have a crapload of it, and in time I'd like to feel that I've got quality bang for my buck equipment and speakers and plenty of money left over to buy more music. I'll never touch the level of expertise or interest that you guys exhibit.

Is it possible the the maxed volume setting on the SB2 wss contributing to the problem or am I just losing it at 11:32PM? If that is the case, any tips on how to maximize my listening pleasure?

Sorry if this is misinformed or way off the wall...

Nick

pfarrell
2005-09-29, 20:52
On Thu, 2005-09-29 at 20:35 -0700, x94blair3 wrote:
> Soo...I moved on to albums I have ripped in flac. And it was
> noticeably better but still "off". At this point it's driving me
> insane. And I suddenly think, could it be the volume level I have the
> squeezebox set to? Sure enough I have it maxed out, so I lowered it to
> 20 and upped my stereo volume to compensate.
>[snip]
> Is it possible the the maxed volume setting on the SB2 wss contributing
> to the problem or am I just losing it at 11:32PM? If that is the case,
> any tips on how to maximize my listening pleasure?

Yes, it is easy. Hard to know for sure, because there are many ways.
The SB2 puts out a fairly high voltage level. It can over drive
the input, causing distortion at several levels.

If it sounds bad, it is bad.

> I don't confess to know much about electronics, or even the hardcore
> side of being an audiophile. I love music, I have a crapload of it,
> and in time I'd like to feel that I've got quality bang for my buck
> equipment and speakers and plenty of money left over to buy more music.
> I'll never touch the level of expertise or interest that you guys
> exhibit.

Be careful. For most folks, it is all about the music.
Most of the wacko audiophiles started out quite sane, they
just wanted to make the music sound more real.

SqueezeBoxes cause people to listen to more music. I've bought many
times more music recently than I did in the ten years before I got my
first SqueezeBox.


--
Pat
http://www.pfarrell.com/music/slimserver/slimsoftware.html

Mike Anderson
2005-09-30, 00:37
I too would be interested in knowing what the optimal level is for going into my amp (Musical Fidelity A3.2). The SB2 definitely puts out a hot signal at 40; that just can't be optimal.

Fifer
2005-09-30, 00:38
Well said Pat. I spend a reasonable amount of money on equipment with the sole objective of making the music I listen to sound as good and enjoyable as possible. I suspect though, that I'll always spend more money on the music than the equipment as the that is what it's all about. I too have found that I listen to more music since I started using Squeezeboxen. I put it down to that near perfect marriage of sound quality and convenience.

Nick, as Pat says, if it sounds bad, there's probably something wrong. If it sounds better with the SB volume down, then leave it down as the max volume might be overdriving the input electronics of your amp causing clipping and/or other distortion.

Aylwin
2005-09-30, 01:27
I agree with everything Pat's said. Fifer too. Have you tried the latest Slim Server Beta? I'm using a fairly recent build (from maybe a week ago) and I've noticed that the output levels are much lower. I believe they're now optimised so that the SB2 can directly drive a power amp (eliminating the need for a preamp). You might want to give it a try.

By the way, I'm not a wacko audiophile. All of my "normal" friends (wife included) would beg to disagree though. :)

x94blair3
2005-09-30, 05:24
Thanks for the feedback. Let me see if I'm understanding correctly. (I'm only too lazy to TRY and learn..when it's happening accidentally, I actually enjoy it).

In my head (at 11:32 last night), I was thinking perhaps my SB2 at full volume was distorting it's own music output.

But if I'm understanding you correctly...it's more likely that my cheap HT receiver is being fed too much power by the SB2 and it's distorting the output? In other words, it's really my HT receivers fault?

Oh God..if that's the case, it's no wonder you people upgrade every 3 weeks. I can live with the SB2 lower and my receiver higher for a while, but no way I can handle that long term...

And thus it begins.

Nick

usualsuspects
2005-09-30, 05:43
I take it from your original post that you are using the volume control in your receiver, and not the SB? You might take a look at this thread: http://forums.slimdevices.com/showthread.php?t=16209 for a good discussion of SB output voltage issues.

Fifer
2005-09-30, 06:05
In my head (at 11:32 last night), I was thinking perhaps my SB2 at full volume was distorting it's own music output.

But if I'm understanding you correctly...it's more likely that my cheap HT receiver is being fed too much power by the SB2 and it's distorting the output? In other words, it's really my HT receivers fault?
Yes, except it's probably a mismatch rather than a fault. If you are happy with the sound with the SB2 volume turned down, there's no need to upgrade. I'm pretty sure that Slimserver 6.2 (or if you cannot wait, the latest nightlies) have a programmable attenuation feature where you can adjust the output level so you can comfortably use the entire range of the SB2 volume control (or did I dream that?)

x94blair3
2005-09-30, 10:57
I take it from your original post that you are using the volume control in your receiver, and not the SB? You might take a look at this thread: http://forums.slimdevices.com/showthread.php?t=16209 for a good discussion of SB output voltage issues.

Let me address this question (since I can follow it). Originally I had my SB2 set at max (40 I think it is?) and I had my receiver down pretty low (in the evening when I'm sleeping)..it sounded awful. I've now scaled back the SB2 volume to "20" and of course had to up my receiver volume to make it sound as loud. Now it sounds better.

From what I can tell it appears this is because the SB2 is putting too much "power" (probably wrong term) at vol. 40 for my receiver so then the sound is distorted?

If this is correct, is there any sort of mathematical formula to figure out what volume on the SB2 my receiver would be happiest with? Or maybe it doesn't work that way. If not I guess I can just set my SB2 to whatever volume and crank up the receiver accordingly.

I appreciate everyone's efforts...always happy to learn.

pfarrell
2005-09-30, 11:16
On Fri, 2005-09-30 at 10:57 -0700, x94blair3 wrote:
> Let me address this question (since I can follow it). Originally I had
> my SB2 set at max (40 I think it is?) and I had my receiver down pretty
> low (in the evening when I'm sleeping)..it sounded awful. I've now
> scaled back the SB2 volume to "20" and of course had to up my receiver
> volume to make it sound as loud. Now it sounds better.

So you need to play with the settings to find the best setup.
The term is usually "gain staging" which means adjusting the gain (aka
volume) on each part in the signal chain so that each is in
its optimal zone. This requires tradeoffs, too low causes noise
to be audible, too high causes distortion. And when you have three
or more stages, changing one means impacts the others, so you have
to then change two or three more.

> >From what I can tell it appears this is because the SB2 is putting too
> much "power" (probably wrong term) at vol. 40 for my receiver so then
> the sound is distorted?

It is really voltage, but power is close enough. Right, you
are over driving the input stage of your receiver.
So doctor doctor, don't do that.


> If this is correct, is there any sort of mathematical formula to figure
> out what volume on the SB2 my receiver would be happiest with? Or maybe
> it doesn't work that way. If not I guess I can just set my SB2 to
> whatever volume and crank up the receiver accordingly.

If the gear has real engineering specs, you can theoretically calculate
it. But most consumer electronics plays fast and loose with the specs.
So you get to do it by ear.

I'd start with the SB2 at about 1/3 max volume (quieter than half) and
work up and down to ear. But I don't know what the audio taper is on the
SB2 volume control is, it could be linear or it could be audio tapered,
so I don't know exactly what number is 1/3.

Whatever sounds best is best.


--
Pat
http://www.pfarrell.com/music/slimserver/slimsoftware.html

x94blair3
2005-09-30, 18:43
Thank you. I really appreciate you taking the time to answer me. I'll tinker with my receiver and the SB2 and see if I can find the right combo.

I suppose sometimes it's not as complicated as science, sometimes it just comes down to what sounds good!

Nick

seanadams
2005-09-30, 23:06
The best way to test this is with a full-scale sine wave from the SB2. Very small amounts of clipping are audible on a clean sine input, whereas with music it is only obvious in the loud parts.

In recent firmware revs there is a 1102.5 Hz sine test built in to Squeezebox2. Press "3" on the splash screen to make it run.

Then use the new analog-output attentuation setting, and try dropping the volume a couple decibels. If you notice any difference at all, then it means your receiver's inputs are clipping. Increase the attenuation setting until the sine wave sounds clean at any volume level.

max.spicer
2005-10-01, 00:16
Has the standard output volume of the SB2 been decreased at all? I could swear that I'm having to turn my amp up louder now. I'm just using a standard sb2 directly plugged into amp via an analog cable.

Is there a list somewhere of all the hidden features (that you'll admit to) of the SB2?

Max


The best way to test this is with a full-scale sine wave from the SB2. Very small amounts of clipping are audible on a clean sine input, whereas with music it is only obvious in the loud parts.

In recent firmware revs there is a 1102.5 Hz sine test built in to Squeezebox2. Press "3" on the splash screen to make it run.

Then use the new analog-output attentuation setting, and try dropping the volume a couple decibels. If you notice any difference at all, then it means your receiver's inputs are clipping. Increase the attenuation setting until the sine wave sounds clean at any volume level.

seanadams
2005-10-01, 00:33
Has the standard output volume of the SB2 been decreased at all?

Nope.


Is there a list somewhere of all the hidden features (that you'll admit to) of the SB2?

Max

These are not documented because they can change at any time, and are generally only for my own testing purposes. Right now we have:

(press this button on the Slim Devices screen)

"add": resets to factory defaults
1: reprogram xilinx
2: begin factory test (useless except with factory test system)
3: sine wave test

Those are the ones I know of anyway. Dean has been known to slip an easter egg in from time to time. :)

max.spicer
2005-10-01, 00:59
Dean says the standard output volume has been dropped. See http://forums.slimdevices.com/showpost.php?p=55293&postcount=1. Who's right then? Or am I wrong?

Max


Nope.

ceejay
2005-10-01, 01:07
Dean says the standard output volume has been dropped. See http://forums.slimdevices.com/showpost.php?p=55293&postcount=1. Who's right then? Or am I wrong?

Max

I don't think that Dean was saying that the standard output volume had been dropped. What he was saying, I think, is that the scale on the new attenutaion feature has been changed from linear to logarithmic, so that the volume at intermediate points on the scale would be lower than before - though the maximum would be the same.

Ceejay

seanadams
2005-10-01, 01:46
I'll double check this - I think this is just a misunderstanding of that post.

if 100% volume is not -0d then it's broken, but I don't think that's the case.

dean
2005-10-01, 11:39
Sorry if my post was unclear. 100% (aka 40 on the player display, 11
on the web interface) is still -0dB.

The older volume mapping was neither linear nor logarithmic, rather
it was the best mapping we could do with only 8 bits of resolution
and still have audible differences at every step from 0 to 40 on the
display. So, the steps at very low levels were audibly large and at
high levels where audibly small.

What we changed was that we added higher resolution volume control
(fixed point 16.16 multiplier). We did not change the 24 bit output
resolution.

With the new higher resolution control, we're able to make the volume
control logarithmic where 1% steps down are -0.5dB.

This means that there's a difference between the old mapping and new
one and it's generally at a lower volume than before.

Sean also recently added a preamp output level setting which sets the
maximum analog output level, so when we're at 100% the voltage level
can be adjusted lower in the case that your analog input to your
amplifier/preamp needs a lower maximum value. That setting is also
in dB.






On Oct 1, 2005, at 1:46 AM, seanadams wrote:

>
> I'll double check this - I think this is just a misunderstanding of
> that
> post.
>
> if 100% volume is not -0d then it's broken, but I don't think that's
> the case.
>
>
> --
> seanadams
>

Mike Anderson
2005-10-02, 10:13
I can get the sine wave tone, but how do I adjust the volume on it?

seanadams
2005-10-03, 07:31
I can get the sine wave tone, but how do I adjust the volume on it?

Player settings -> Audio -> Preamp Volume Control

After entering the setting you need to hit volume up on the remote for it to take effect.

The main volume control is not applied to the sine wave test, only this preamp control.

Note that you can still play music in this mode - it just plays the sine wave (instead of nothing) when there is no music playing.

Davey
2005-10-03, 10:28
For those of you interested I did some quick tests that show the new volume control mapping. Please excuse the primitive Excel graphs. :)

http://home.comcast.net/~dreite/SB2/SB2outputlevels.xls

For those that use the analog outputs and the volume control as their primary I think this is a nice improvement in useability.

Cheers,

Davey.

rme
2005-10-03, 15:01
Thanks for the graphs.

Question though,

Is the 0-40 settings on the left of the table the sb2 volume setting on the player or is it the preamp volume adjustment level for the player in Slimserver?

For example new vout = 0.186 then is the number 24 in your table = Slimserver preamp volume set to 24 and SB2 volume = 40 or ss preamp volume not set and sb2 vol = 24?

Sorry, I don't remember what the correct terms are on the slimserver beta as I have reverted to 6.1.1

Davey
2005-10-03, 17:56
Yeah, sorry. I'm such a wizard with Excel graphs. :) Take a look at it again.

The 0-40 settings refer to the volume setting on the graphical display on the player. I didn't make any change to the "preamp volume control" setting....it's at the default setting of zero.

Cheers,

Davey.

rme
2005-10-08, 06:30
The 0-40 settings refer to the volume setting on the graphical display on the player. I didn't make any change to the "preamp volume control" setting....it's at the default setting of zero.

Davey.

Can we infer from the graph then that if you set preamp volume control to 10 (-10db atten), then the output at sb2 player volume setting 40 would change to 0.588 vout instead of 1.86 vout (full output)?

Also then, if preamp vol out set to 10, would the level at sb player volume setting 35 be an additional atten of -6.26db for a total db atten of -16.26 and vout of 0.286?

Just wondering as my amp has input sensitivity of 388 Mv.