Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Streaming How to check if your Sooloos network is 'bit perfect'

Hi

It's always good to have discussion but I feel that the discussion has gone well beyond the intention of the test as devised.

This test was designed to show in a scientific way whether or not some of the changes that people have recently discussed about hearing audible differences when changing 'variables' in their Sooloos setups could be due to changes in underlying data - bit for bit rather than timing or other nasties that may or may not influenced the audio during audio replay.

By measuring and comparing multiple 'auditions' of the same track data, it can be shown whether each rendition produces exactly (excluding the bytes expected to change) the same packet data as previous auditions. If the results are exactly the same, then it can be proven that the change to a 'variable' can not have resulted in an audible difference unless the change was due to jitter or other (cable borne or otherwise) external influences, but not in the data as some have implied.

I fully appreciate that a difference may not necessarily result in an audible difference for whatever reason such as redundancy. What is important is that no difference cannot result in an audible change unless that change came from somewhere other than the data.

What the test also aims to show, is that by using a real time packet analyser such as Wireshark, people will see how reliable a wired computer network should be ie so accurate that it may as well be thought of as 100% accurate. By leaving the filtered window running, there should never be any reason to see red marked packets indicating an error. The scenario of packet errors in a hard wired home network should lead the user to question the integrity of their network and do a bit of trouble shooting to sort the problem out.

By running the test multiple times, the chances of two random errors masking each other out becomes smaller and smaller with each run. On the 40 second clip that captured and compared, approximately 3600 packets were collected. If a packet was dropped and thus not captured by WireShark, the chance of a second run having exactly the same error would be 1 in 3600. Even with that, I think it would be fair to say that 1 random error in 3600 samples is not going to result in some of the changes that people are hearing. You can do your own sums what a third run would yield.

I do fully understand that packet errors may not yield audible differences due to error detection and recovery by the Sooloos applications. But, just like error correction when reading from a CD, it cannot be proven whether the error recovery process may or may not have induced audible anomalies.

I just wanted to keep it simple and beyond doubt. 100% consistent data resulted will result in Sooloos having exactly the same audio information to process. It's up to Sooloos to deal with timing and external influences.

NB. The topic of recording and comparing SPDIF output has been discussed multiple times on HH forum.