1. Mixing and tracking are about creating an illusion.

2. You need a room that does not distort/alter the illusion your are trying to create in the monitors.

3. No matter how good your monitors, I think your listening environment is probably the more important issue to address. I give an example. Imagine an important speaker trying to give an address(make a speech) in the middle of a noisy stadium. No point, best to wait until the noise has died down. Its the same with monitors, you do not want a highly reverberant room with minor echoes, adding its own impression to the sound of the monitors.

4. I think you've already nailed the problem, The issue is not the monitors/speakers, it is the room. Here's what I think. In your old room, the monitors were not far from walls, and in spite of your treatment, any monitor placed any where near walls, gets some reflection of bass frequencies added to the sound. Giving you an impression of more bass. Your larger room has much less of the early reflections from walls, "added" to the bass, most likely because your monitors are now further away from the walls. You are probably also sitting at a greater distance from the monitors in your new larger room, which gives the impression of less bass. In a smaller room, the reflection feels a bit like part of the sound - cos of shorter distance - you get early reflections. In a larger room you get less of early reflections, and more of late reflections which sound more like echo/reverb.

Between a rock and a hard place - difficult choice - I would not, at this time recommend either the HS8 or Alpha 80. Why ?

An 8 inch woofer, on both of these will struggle with defining the mid range frequencies, properly. It is difficult to get an 8 inch woofer to move accurately at the kind of speeds that the mid range needs, more so when both of these monitors also use ports which will compromise their bottom end/frequency accuracy, and tightness.

A small anectode. Earlier today I watched someone drive past me with these boomy bassy sound system in their car, loud, but very inaccurate. But he was obviously enjoying the sound - I was cringing inside.

Question - Do you want accurate or boomy.

In addition to the issue of room treatment, I really have little faith in low end monitors, especially ported ones.....Mixing on these is a bit of guess work. Trial and error and lots of referencing on other speakers.

Imagine trying to record music with an out of tune guitar or piano.

Unfortunately good accurate monitors cost money :

I suggest you save up and get something that you may not need to change for at least 10 years :

e.g Focal - CMS 65, Focal Solo 6 Be, or Neumann KH120, or Neumann KH310, or Focal 6 Twin Be, or one of the new raves at the moment - the Amphions - which need a good amp also as they are passive, not active like many other studio monitors.

I appreciate that money is always in limited supply for all of us, but sometimes spending less is simply an exercise in futility, and you end up spending the same amount on two or three poorer quality items over time, when you could have got one that simply does the job, and you never have to think of changing it for a long time, and it would have earned back the money you invested in it, in real money or mixing pleasure. Mixing in a warehouse is also not recommended.

I'm in a similar situation with audio interfaces. I have invested over the years in several and if I had simply bought a good RME interface which certainly costs premium bucks, but I may not need to change it for another 15 years. and absolutely enjoy using it, rather than the competitors products which I bought trying to save money but now face so many limitations......I'll end up buying an RME one day, God willing, so I can finally focus on making music and not concerning my self about limitations and compromises, of less capable audio interfaces.