I have some pure FLACs which I have listened with the Sennheiser HD 215
on iPod, Andriod phone, and Linux box - with default settings.

I could not find any difference anywhere?

Do the storage platforms really matter when it comes to the audio quality
of the FLAC?

What's your take on this?

Storage platform?

Are you comparing flash memory, hdd, cd?

A flac file is a digital file. It simply reads the same data. There will be no difference no matter the digital source.

Of course the storage platform doesn't matter. Digital data is digital data; either the data stream is uncorrupted, in which case the original (digital) data can be reproduced with 100% accuracy, or the data stream is somehow damaged, in which case the storage device must be seriously defective.

The playback device, however, does matter. Remember, you're not listening to a stream of digital data. Nobody is. Instead, we're listening to an analog signal reconstructed from a set of digital samples. That analog signal is the result of a process involving digital-to-analog conversion and subsequent amplification of the generated analog signal.

A cheap playback device may have a DAC chip that's less accurate than DAC chips found in expensive HiFi equipment, and noise from various digital components may be picked up by the analog amplifier components. However, if you find that all your playback devices are of sufficient quality that you can't tell them apart, then clearly your own equipment that meet your specific requirements/needs.

It's not the "storage platform" that makes the difference. It's the playback platform: the different DACs and different (e.g. in impedance) headphone ports that are put in different phones/computers/devices.