Is DEQX a game changer?

Actually, you should have no issues if you use the PreMate to drive everything (once the mods are done).

A delay on low frequencies via the Chord DAC will not be an issue - just measure the subs at the listening position separately to the other channels & then delay mid/high by comparing impulse responses & subtracting the slowest (subs) from the fastest (others). 

I used to have a Chord DAC64 which was very nice but sold it on a few years ago. Other than that I've not used their products (don't use the inbuilt DAC's on either of my DEQX processors either)

Good to hear. Do you think it will work if I add an mscaler before the Dave as well? This device specifically has a video option because the signal is delayed up to about 1.4 seconds due to the processing power when listening to music. I don't want to use the video option with the deqx for music listening, as it doesn't upscale as much.

People who are familiar with the Dave but unfamiliar with the deqx are telling me to get rid of the deqx and go straight to mscaler and Dave. However they don't understand how much the deqx helps with timing and room correction so that isn't an option for me. I like the deqx tech that much and there is nothing really put there that can compare to it at the same level. So I need to figure it out and hoping the deqx can be flexible enough  to do this.

Another option I guess I could remove the subs for my p1 profile? Do you know, if for example, I can set the p1 profile for no subs, so the deqx takes the full range of the speakers for music, so the digital signal has the bass frequencies? Then on p3 I have a sub present for the low lfe frequencies for movie watching? This is what I do at the moment p1 for music and p3 for movies.

I am hoping the deqx can be set up this way as well without adding another configuration and having to switch between them in the application. 

After you add the mscaler/Dave, then measure the speakers & subs and use these impulse responses to set delay. DEQX will measure what it hears from the speakers, irrespective of what is in between it/them.

Because I don't have details of your specific speaker wiring your previous posts infer that there are two sets of cables to each speaker - one for mid/high and another for the 'subs' (ie woofers - your post says ...."in my case I will need "single amp with stereo subwoofer" as I have two subs - they're built into my speakers")

If you set P1 with the subs disabled, then bass frequencies may not be present as the cabling feeding the subs will not have a signal. It all depends on the frequency range of your speakers without the 'subs'.

Yes you are correct. I have my speaker cables connected and they Are doing the highs and mids. I have an rca connected to my subs taking care of the low frequencies. Deqx set it up with the rca doing sub duties but I can have full range through just a speaker cable. 

My speakers are designed to go full range without an rca connection. They included an rca for home theatre and movies and having more options for Setup.

 I am hoping the deqx can run p1 with no subs full range and then when I switch to p3 for movies it will include the subs for the bass section and the speaker cables for mids and highs,without having two sets of deqx configurations. 

What speakers and dacs are you running with your hdp5 and hdp3? Sounds like an active Setup to me. 

Yes you are correct. I have my speaker cables connected and they Are doing the highs and mids. I have an rca connected to my subs taking care of the low frequencies. Deqx set it up with the rca doing sub duties but I can have full range through just a speaker cable. 

My speakers are designed to go full range without an rca connection. They included an rca for home theatre and movies and having more options for Setup.

 I am hoping the deqx can run p1 with no subs full range and then when I switch to p3 for movies it will include the subs for the bass section and the speaker cables for mids and highs,without having two sets of deqx configurations. 

What speakers and dacs are you running with your hdp5 and hdp3? Sounds like an active Setup to me.