I have tried Soundcheck's script and it does work, it does improve the sound. But its only part of a whole environment designed to get the best out of the device.
Important things are to run external server, over a wire, and only send PCM (no flac decoding on the Touch). Thats the starting point. THEN these changes can be applied. Its just doing things like turning off the wifi module, turning off samba and rearranging some process priorities. Nothing drastic or really bizarre. I haven't tried each piece by itself so I can't say which one of these makes the most difference etc. So don't ask. On my tests I found the results from these about the same as unplugging the display. The combination of these changes, unplugging the display and bypassing the output caps was a real home run. The results were stunning. I don't know exactly why these changes effect sound. I tried measuring jitter, but the jitter on the Touch is already so low my measurement system couldn't detect it. That does not mean these do not effect the jitter, it DOES mean I can't afford the right test equipment! The suggestion that all you have to do is run ADM to tell you if there is any change is only valid if the AD converter you are using is significantly better than the Touch itself. From my tests I do know the Touch has significantly less than 50ps jitter. You are going to have to look far and wide to find an AD converter that has say 5ps of jitter so you can make meaningful measurements with ADM. You simply cannot make meaningful jitter measurements of a device with 30ps of jitter with test equipment that has 100ps. The results are completely meaningless. ADM is perfectly fine for detecting things like frequency response differences etc. But if you are making a hypothesis that some code change is somehow causing a change in jitter, and you want to use ADM to see if there is a change in the analog outs, the AD converter used HAS to have significantly lower jitter than the device under test. Personally I CAN hear these differences. Its hard to do quick back and forth tests because it takes a minute or two to apply or remove the changes. I have not been able to do blind tests under these circumstances. There is an interesting side note though. With these changes and the display unplugged the sound is so good that individual changes become far more obvious. For example streaming flac or PCM is very obvious when these are applied and the display is unplugged. With the stock touch it was obvious over the headphone jack, but much less obvious over the analog out. With these changes and the unplugged display its also quite obvious over the analog outs. I have not done extensive listening with the digital out. Its far more difficult to make general statements because there is such a great range of variation in external DACs. On one of my DACs I can't hear a difference, on another I can maybe tell but its tough. Remember that I build my own DACs and go to great lengths to make them as immune to input circumstances as possible, so my experience may be different than others with different DACs. Summary, I can hear a difference with these changes. Whether you can or not is of course up to you and your system. If you don't meet the basic requirements don't even try them. (external server, wired ethernet, streaming PCM) If you don't like the change or you don't hear a change you can ALWAYS reverse it so there is no risk in trying them out. John S. -- JohnSwenson ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=79857 _______________________________________________ Touch mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/touch
