Why the difference between Onkyo HF player and Audirvana?

I'm new to hi rez and have been using the Onkyo HF player running on my iPhone or iPad to play hi rez files for the past 10 months. I've used a few dacs during that time and, most recently, a Benchmark DAC 3.

This morning I downloaded the trial version Audirvana player on my MacBook. I'm considering setting up an older Mac mini as a music server and wanted to check it out.

After listening for the past hour I am shocked at the difference in sound. The differences are not subtle. More detail, way better defined and deeper bass, the soundstage is deeper, and the separation of instruments is better defined.

My question is, why does it sound so much better?

Is the signal the DAC is getting from the MacBook is the same as the signal from the iPhone? The cable is the same. Is the difference the player? Does the MacBook have a higher voltage output than the iPhone? I've played 96, 192, and DSD files and they all sounded better through the MacBook.

I know I've only been listening for an hour but the difference I'm hearing is huge.
Assuming you are listening to the output of the DAC and comparing, then the only explanation is that you are adding digital EQ or filtering to the raw digital audio with the software (Audionirvanna EQ/filter is set up with a different EQ from Onkyo). If the digital file reaching the DAC is the same then the sound sill be the same - so try to investigate how to play bit perfect files (no digital filter, no SRC, no digital EQ, no digital volume)
That makes sense. The Onkyo uses an equalizer that you can't turn off. I don't see an equalizer or settings for it in Audinirva.

Thanks for the info.
I also assume the music files are the same on your portable device as your macbook. iPhone or iPad has so little memory, I am surprised anyone would try to use it for hi-res lossless files. Usually iTunes will convert files to 128 or 256 Kbps compressed files when loading a portable device (there is a setting where you can toggle this).
The Iphone was not using ITunes. It was playing hi rez files through the Onkyo HF Player. I have since installed a Mac Mini running Audirvana  to serve the DAC and I'm very happy playing hi rez downloads and streaming Tidal MQA files.

I think the Onkyo player's EQ was the issue. I've been using Audirvana for a while now and have played with the different filters and settings and they all do something to the sound.