why expensive streamers

Thanks again Jerry @carlsbad2 

@mdalton - I agree that it would be possible to measure differences between streamers in a test environment that includes a known source and known DAC. But this isn’t really measuring the streamer - it’s measuring the combined system. This could still be useful, but I’m not sure how relevant the information would be for other sources and other DACs. Still, I’d love to see someone do this kind of testing.

But I think for this to be broadly meaningful, a variety of sources (and source content) and a variety of DACs would need to be used, and then a concerted effort made to correlate the resulting measurements with the way the combination sounds. All possible, of course, but probably not very practical.

@carlsbad2  - I assume you are talking about data errors between the streamer and the DAC.

As other’s have mentioned, the data from the streaming servers (whether across the internet from the likes of Qobuz or from a local server) is transferred to the streamer using the TCP/IP protocol which will fix any data errors. If the connection is so flawed that this is not possible, the music will skip or stop playing. No streamer that I am aware of will attempt to fix network data errors.

It is possible to have data errors internal to the streamer or between the streamer and the DAC since these signals (I2S, AES, SPDIF, Toslink) do not include any error detection (let alone correction). USB does include error detection, but no error correction for Isochronous audio data transmission.

I doubt very much that any decent streamer has data corruption problems within the streamer itself, but I do think it is possible that data errors could occur between the streamer and DAC, particularly if the streamer output connection has high signal noise, if long or poorly shielded cables are used, and/or if there is a lot of EMI/RFI present in the environment where the system is located.

I still believe that the larger difference between streamers is caused by timing issues and electrical noise transmitted to the DAC, but this is speculation on my part.

@delmatae I felt the same as you give my technical background. Same exact data should be delivered to the DAC. I went from a Node to an N150 and it was easily noticeable and an improvement. Wife picked out in blind tests. I kept the N150. My expectations that it would be the same sound were wrong. It is true that you have to have a system resolving enough to present the differences and sufficient hearing to detect it - but I did and I don’t have golden ears. Based on what I know, it is my opinion that it reduces noise introduced into the DAC, perhaps due to the linear power supply or other factors. Again, small noise on a digital signal should not matter - but the improvement in sound is typical of what I have experienced with less electrical noise in the chain. I spent about 5% of my system cost on my streamer. I bought Aurender because my buddy goes to the audio shows and said he mostly sees Aurender’s being used. I figured those guys know best.

I am curious at what point a typical digital signal is subject to being processed, changed, or influenced by noise as it travels from a streaming service via modem/router through to the DAC? How about in the case of the following digital streaming set-up:

• Into and out of a server via Ethernet,
• Into and out of a switch via Ethernet
• Into a streamer via Ethernet (or fiberoptic) and out via USB
• Into a DDC via USB and out via S/PDIF or AES/EBU
• Into a DAC via S/PDIF or USB and out via analog cables to a preamp

Obviously the DAC converts the digital signal from digital to analog but which of the other preceding steps has a significant impact on the digital signal?

@jaytor 

yes, it’s the combined system, precisely.  We don’t care what a streamer sounds like without a dac or source, because it has no sound.  So if you say it adds noise to the system - i.e., it conveys noise that manifests thru the dac that can be heard - then you have to test it in the context of the system.  There is no alternative.  And that’s what the tests I’ve seen do.  The results of those tests demonstrate that noise from a streamer can carry thru to the dac, in certain cases, but even in those, it is a question as to whether any marginal increase in noise from a streamer was audible, relative to the noise that was coming from the dac.  In most cases that I’ve seen, with any decent streamer and dac, there is virtually no additional noise that comes from the streamer.  

Candidly, I find extraordinary the reluctance on the part of so many sophisticated audiophiles to follow this basic level of logic and analysis when contemplating spending thousands of dollars on what is really just an accessory (again, putting advanced processing like dsp, reclocking, and upsampling aside).  And as a result of this reluctance, a number of firms have dived into this niche market and, imho, are fleecing their customers.  Don’t get me wrong: their stuff can be beautiful and well-engineered, but without significant sonic benefit.  The only reason anybody should spend alot of $ on these niche players is if they think the UI is worth it (again, imho).  But I’m a Roon guy, so spending another dollar for somebody else’s UI is akin to pouring that dollar down the drain.