I have installed 2 apps, Tidal and USB Audio Player Pro. The EQ doesn’t scale well because the player has very little digital headroom. If you try to increase frequencies it is very easy to clip the signal. For example, sometimes I an in the mood for bass and a slight to moderate increase in the lower frequencies causes clipping and therefore major distortion. My Cowon allows for a huge increase in bass that allows me to be a bass head. I have 2 great headphones for bass – the Fostex TH900 and the JVC HA-SZ2000. The worst EQ dap I own is the Ibasso DX100. This Onkyo is the second worse. Heck, even my old antique Sony NW-HD1 had a more functional EQ and that was over 10 years ago.
There is NO digital headroom in modern music recordings. The only way to EQ is down, unless you tweak your system using things like ReplayGain to lower the digital signal before processing. But audiophiles hate stuff like that (“where’d my bit perfect recording go??”) so Onkyo doesn’t do it.
1. Automatically apply a fixed negative preamp to the EQ (makes the music quieter the moment you push the EQ button, everybody thinks the EQ makes the sound muffled. FiiO did this and nobody uses their EQ either)
2. Quietly apply a fixed negative preamp ALL the time, even when EQ is off. Again this throws away bit-perfectness.
3. Do (1), but automatically increase the master volume to compensate. FiiO did this for the X1 and people complained why the max volume decreases with EQ on. Still one of the best solutions so far. But, I don’t think this is possible to do (or at least very complicated) on an Android platform.
4. Quietly apply a digital soft limiter to the EQ, so you don’t hear obvious distortion. Now a digital soft limiter shouldn’t change the signal at all when you’re not clipping, but when you’re clipping the soft limiter does its work by dynamically compressing your music further. Only a band-aid to the problem to be sure.
In short, EQ is between a rock and a hard place when facing people who expect it to break the laws of digital audio. The only solution is to learn how to use it properly.
You can easily bring the whole EQ curve down below clipping on the Onkyo app by dragging down on an empty part of the graph (i.e. not dragging directly on the curve).
Also, the EQ / spectrum graph flashes red when clipping happens in real time. That shows you when you need to bring the EQ setting down.
For comparing the flat output vs an EQed setting (which would be quieter, if you follow the instructions above to avoid clipping), I advise adding a new Preset that’s just the flat default line but dragged down to match the EQed volume. This way you can compare the settings at equal volume and let your ears judge more fairly whether the EQ setting is making an improvement or not. Yes you’re not doing bit-perfect output with the lowered flat setting, but if you believed that compromises audio quality you should not be EQing in the first place…
I know there there is no digital headroom in the music/audio file, I was speaking about the dap itself and the playback software. What you are saying basically that in all digital audio platforms a software based eq cannot be applied that works well. That is not true. There is a software work around for implementing an eq properly and the same method is used for digital volume control so one doesnt start losing bits when listening at low volumes. In the audio processing, by adding extra bits would allow for plenty of digital headroom. Instead of processing in 16 or 24 bit registers, it would process in higher bit depth registers before sending the data to the dacs. ESS uses pretty much the same method for its volume control.