soundcheck's Touch Toolbox 3.0

[Jeff Flowerday]

What causes the "chipmunk" effect on some radio stations?

soundcheck duscusses it in his install blog.

Sent from my Galaxy Nexus using Tapatalk

[lake_eleven]

Cannot set CPU affinity to more than 0. All other values are disabled. Any ideas?.

[HumanMedia]

So I took the plunge and applied the TT3.0 mods. What do you know, I could not hear any difference between the vanilla unmodded SBT and SBT with TT3.0 fully applied. Now I'm confused, why so much trepidation over some non-existent phantoms?

You are joking right?
You have been following this discussion daily for over a hundred pages, but hadn't even tried TT3.0? and now trolling? Because that would indicate some serious problems, and not with your Squeezebox.

Nah, you almost had me there, of course you are just being a jester to get a rise from your discussion-mates.
Silly me for not getting the sarcasm!

[adamdea]

OK, after checking my source, a post at DIYaudio explaining how Sigma-Delta DAC works (http://www.diyaudio.com/forums/digit...-dac-work.html), I see where is my confusion over here. The article is assimilating S/D DAC to pulse width/pulse density modulation and tells:



After noiseshaping, such DACs might be yielding a resolution higher than 16 bits. Sorry for the misinterpretation.

But this article stressed also that the pulse modulation nature of S/D DACs makes them sensitive to jitter and PSU stability.

That article is 8 years old, but i guess the principles still apply although the impmentations have got better and cheaper. However it's not just the noise-shaping bit that needs to be stressed.
using these techniques you can make a DAC of pretty well arbitrary resolution (subejct to the thermal noise problem). The writer himself refers to DCS DACs having 23 bits resolution. Your point about 24 bit dacs and 16 bits dacs in this context was slightly missing the point.

The designer sets out to make a dac with a particular resolution (be it 16 bit or more). s/he doesn;t want to use an old fashioned ladder resistor multibit type for reasons we don't want to go into. Being an engineer not an audiophile s/he knows that he can convert the input 24 bit data (which may or may not really have 24 bits of information) into data with fewer bits but a higher sampling rate without any information loss. a dboubling of sample rate is the equivalent of adding 6 db of snr or 1 bit. So a 6 bit needs a sample rate of 2**10 (1024) times Fs to get the same snr as the 16 bit data. There is a limit on how fast the sampling rate can be so if he wants more resoltion s/he will need more bits or noise shaping or possibly to use more than one dac. All of this can be predicted and measured.
There are delta sigma dacs now which claim 135 Db or more snr.

It may be that delta sigma dacs are susceptible to jitter arising from the clock or ps of the dac; but that's got nothing to do with interface jitter and therefore nothing to do with the transport or the cable going into the dac (unless the spdif receiver passes on this jitter to the dac chip, which it won't if it's competently designed).

Incidentally it did occur to me when answering your original post, that it would probably not cause you to reconsider the vital importance of tweaking the the transport, if it turned out that the reason you had given for believing that dacs were transport-sensitive was mistaken; I will be delighted to be proven wrong.

[SBGK]

to close the final chapter of this saga

I coverted my rca-rca cables to xlr-rca cables so that the dac1 can output via xlr, I can now use the inbuilt smc attenuators and have set them to 30db. This gives an acceptable listening level with server at 100%, Volloc on and the DAC1 on calibrated output ie no volume control. I always knew the volume control on the dac1 was degrading the sound so this is the last link in the chain.

I can switch to variable output from the dac1 for normal listening.

Surprisingly enough, it does make a difference. So can recommend xlr-rca cables if you have that option.

To all the nasty, bitter and twisted critics of my posts - I forgive you.

I have regularly reset the Touch to the factory reset and built it back up to confirm that the improvements were actually improvements, the base Touch sound is very good, but a bit grainy which TT3.0 takes away.

I have tried a wireless bridge and didn't notice any difference.

I have owned an original Squeezebox and a SB3 and now the Touch.

I'll save my story about Jim Guthrie for another time, suffice to say I enjoy listening to Pink Floyd.

[evdplancke]

Incidentally it did occur to me when answering your original post, that it would probably not cause you to reconsider the vital importance of tweaking the the transport, if it turned out that the reason you had given for believing that dacs were transport-sensitive was mistaken; I will be delighted to be proven wrong.

Since experimentation with my system as on many others proved that tweaking the source had an incidence on SQ, I am trying to figure out why it happens. This is for me the correct scientific approach: trying to modelise results of experimentation, and not believing experimentation is useless because it does not fit into known models. And as you said, I will be delighted to be proven wrong.

[garym]

Since experimentation with my system as on many others proved that tweaking the source had an incidence on SQ, I am trying to figure out why it happens. This is for me the correct scientific approach: trying to modelise results of experimentation, and not believing experimentation is useless because it does not fit into known models.

Without speaking to what you've done (or not, because I don't know the formality of your personal testing), but speaking more generally to things I see at this forum, most of the "experimentation" reported here is not actually an experiment that leads to learning new things that may be generalizable to any other party. Most of what I see reported is from a "sighted" comparison where the person conducting the "experiment" (who is also the subject in the "experiment") knows in advance of any comparison which stimulus is being heard. This may be fun, it's harmless and doesn't hurt anyone, and I have no problems with folks doing it and even reporting their personal nonscientific observations. But this sort of stuff is certainly not an experiment.

[magiccarpetride]

?

[garym]

In scientific terminology, the activities you've described above are called 'fishing for results'. It's a legitimate strategy in scientific circles, because by doing even a random set of repeated trial-and-error activities, one may stumble upon empirically valid set of data. After that, one is advised to devise a more sober set of proper experimental methodology, which is what the previous poster was referring to.

I see how you might interpret what I said this way. I didn't go into complete detail in my response, but at least in my field, experiments without any theory-based hypothesis are not a good thing. Without the theory as a foundation for the hypothesis being tested, I agree this would be a fishing expedition and not valid. Sort of like most of the tests of "tweaks" reported in this thread. Many of the questions for the tweakers posted here are in a sense asking for the theory underlying the hypothesis of "different sound" being tested.

[magiccarpetride]

?