What can I do to improve my 2nd system?

start with :

getting better stands for your equipment and speakers

second subwoofer

room treatments

from there you can tweak things

For the speakers, power amp and CD/SACD player, I have attached semisphere rubber isolators (made by 3M) underneath. Would that suffice? But the audio graded stand is definitely good idea.

I had a old sub by Audio Research (AR SW30) and I hooked both of them in stereo mode using the RCA splitter out of DAC. To integrate them together, I experimented several location and found placing both of them inside the L/R speakers is the best location. And I also need to set the phase on the 2nd sub. to "90 degree" to get them better paired together. However, for some reason, the AR sub seems to have hard time to keep up with SVS pacewise. I may need to purchase the same sub. if going for dual.

Here is my curiosity. I understand the 2nd sub is mainly used to mitigate the hump/null and obtain more even low end frequency distribution in the room. Also, having two subs helps headroom for each of them to play more effortlessly. If my seating position is always at the same spot and I was alone listener 99% of time, given the size of my room do I really need a 2nd sub? I was told by SVS tech a single sub. is sufficient given the size of my room. What are "other" advantages having the 2nd sub?

For room treatment, I was thinking placing the bass traps on L/R corners and the sound absorption panels on the 1st reflection points left and right. On the front wall (behind the main speakers), I have difficult time to do sound diffusion because of the windows but, question, may the blinds work as the diffusers (sort of) to my favor? If not, how about thick lining curtain?  What are the right way to treat that?  

It doesn't look too bad. I'd move the loudspeakers to the very front edge of the stands, move the speakers about a foot more away from the side wall, and hang heavy but open drapes. 

@russ69 That was a very good idea. I was thinking about the heavy/thick drapes behind the speakers but what is "open" drapes?  And what is the purpose of the openess?  Let the sound wave pass through the drapes and be traped between the drapes and window?

The minimum, in order:

1. Thick curtains on the windows. Double layer if you can.
2. GIK Acoustics corner traps with scatter plates in the corners from floor to ceiling.
3. DSP EQ on the sub.

Try crossing the speakers in front of you, that will minimize early side reflections. 

When you realize the advice above works absolutely stunningly consider GIK combination bass trap/diffusors for the side walls as well.

I was thinking about the heavy/thick drapes...

Yes, heavy drapes and you can open or close to varying degrees to get the best sound. 

@russ69 Thank you for the clarification

@erik_squires I was thinking about "upgrading" to the SVS SB 1000 "Pro" version that has the 3-band EQ feature at a trade-off of losing HPF capability.  Later I learned I could add an in-line HPF on the loop back to power amp but had a worry on the quality of in-line filter.  It is a trade-off.  The other option will be the miniDSP that you have alluded before on the other tread.  I need to give it a bit more thought.

Here comes with an interesting suggestion you have "crossing the speakers in front of you..."  To be frank, I have never thought about that.  The most toe-in I have attempted or suggested from other sources is pointing to the listener's position.  The laterally reflected indirect sound is reduced but the speakers become too bright on my face from these Elac bookshelf.  So I gradually reset it back and finally dialed in this slight toe-in angle.  Without the absorption treatment, I actually experienced a bit more spacious sound stage (believe or not).  I read about the "Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms" book by Floyd Toole.  He actually pointed out that some people actually like stronger lateral reflection because of the augmented sound stage and I think that might be the effect I was experiencing with.

Nevertheless, "crossing in front of the listener" is definitely something new and I will try that...

Well, saying you need DSP EQ is kind of an oversimplification of measuring first, then treating, but the miniDSP units are very capable especially for subs.  I would keep your sub and enhance with it.

Speakers vary by a great deal on what their ideal toe-in is.  Focals for instance, to me sound best with zero to just a little toe-in.  You can see in the measurements with some speakers that on axis they may have big peaks and valleys which get a lot smoother off axis.  Toole was also probably thinking of less constrained rooms.  Anyway, it's a total judgement call so try it and let me know if that's a good choice for you.  As a long term solution though consider the GIK acoustics bass traps with diffusor panels.  They will give you a sense of air and space while helping to focus the image and reduce bass standing waves.

OH, also, try listening BELOW the tweeter axis. :) I find this sometimes more pleasant. There’s nothing wrong with that either.  I ended up using Isoacoustics speaker stands which let me tilt the speakers up.

Best,

Erik

Hi, Erik, I will try those excellent suggestions after I get home and embark on the miniDSP journey including room measurements.  I like out-of-the-box thinking and approach doing things.  Also thank you all gentlemen for the advises. 

Doesn't the Parasound need more space for air flow?

one sub can work fine, if you have a single listening position, and the flexibility to place the sub where it needs to go...

Remove any flexible footers from under any and all of your speakers. You want the speaker to be held firmly in a fixed physical position. Otherwise energy put into the speaker by the amplifier is partially being used up to move the speaker, rather than to move the speaker cones. This results in smearing. I know there are many who like to put cushiony devices like Springs and sorbothane, etc pillows under their speakers, but in my opinion this is plain wrong. The practice is encouraged by dealers and manufacturers, because of course it sells product.

The above principle is another reason to get better speaker stands, and when you get them make sure your speakers are firmly anchored to them. I’d even put some lead weights on top of the speakers.

@lewm that is an interesting position on vibration isolation for speakers. As more and more high end speaker manufacturers are using devices like the ISO Acoustics Oras as standard equipment for isolation.

I will stick with what the QLN and Magico engineers built into their product. Also can not deny the science in the Townshend ISO platforms.

May be the case for ELS speakers and ribbons..

I have no idea what QLN or Magico do.  Can you elaborate?  I cannot believe that either company would countenance placing rubbery supports under their speaker cabinets, but I am all ears.  I have a better idea about Townshend ISO platforms.  They seem to constrain speaker movement while also claiming to isolate the cabinet.  I am not preaching against isolation. I am preaching against mushy or springy feet that allow the cabinet to move in response to a musical transient.  How could that be a good thing?  Has nothing to do with the type of speaker, in my thinking.

Not all speaker manufacturers….but if ya throw time and phase out w trash, what’s a bunch of doppler distortion ? It’s product specific, in the OP system, might help…

Guess you need to look at their websites as well as PSB……

I agree the spongy stuff is not ideal. But the times they are a changing as is engineering.

So far as I know, Newton’s 3rd Law of Motion still operates in the modern world, Relativity notwithstanding. What changes are the stories that audio entrepreneurs dish out to lure customers.

@lewm You intrigue me to dig into the decoupler/isolator subject. Here are articles, some support it and some don't. Please take it with a grain of salt. I went through several bookshelfs, starting from my 1st (NHT SuperOne 2.1) 25 years ago, Tannoy Mercury F1, Sony SSCS 5 and currently this Elac. I placed the IsoNode isolator underneath without a second thought back then because, just like many others, I heard noticeable difference in bass, tighter and cleaner. The effect on the subwoofer is even more pronounced. I think very few audiophiles will debate the benefit of using damping isolators under the subwoofer. I compared the $50 SVS Soundpath isolators with $3.5 a set of four damping isolators you could get from Walmart.  Very subtle different.  As a band bass player a band in college, I could testify that is not a placebo effect.  

I place the similar IsoNode isolators under the gears including CD/SACD player to reduce the vibration.  With that, the gap under the player has increased to 1+ inch to help dissicipate the heat from Parasound to answer @slaw, although I do agree a audio grade rack placing them individually will be more ideal.  BTW, the heat from Parasound PA is much less than the Cambridge IA I had for being a similar class A/B design.

https://www.pro-tools-expert.com/production-expert-1/2019/5/23/speaker-isolation-fact-or-bullshit-we-have-the-results-from-the-poll?mc_cid=2a1503e520&mc_eid=f10a2ce15b

http://ethanwiner.com/speaker_isolation.htm

Without first hand examination of these devices, it is hard to say whether they preserve a rigid mount of the speaker while also providing some isolation, or whether they permit too much motion at the speaker base.  I did take a look at the Magico website. The footers on their speakers actually would seem to add stability to the cabinets, while also attempting to isolate the speaker from the floor.  If so, I certainly have no issue.  Like I said, I take issue with rubbery or springy speaker mounts.  But springy could work OK if the springs are very compressed under load so as to minimize the potential for amplifier energy to generate cabinet motion. I suppose it's a trade-off.

the wall color for sure

get headphones with a dedicated amp....will be better sound than your current system.

@erik_squires Finally got home after a long drive.  Play "The Wild Heart of the Earth" by Cécile Verny Quartet from Fear and Faith (album) to test out the "crossing in front of the listener" idea.  Immediately the first impression is the shrinkage of the sound stage.  Switching back to slight toe-in position and everything gets back to normal.  Sorry, Erik, as much as I appreciate the thought, I am not sold on this thinking outside the box idea.  However, with the height of the stands, I was actually listening below the vertical axis of tweeter all the time when I lean back on the recliner.

@stringreen I do not disagree the magic power of a good paring of headset and dedicated amp.  However, I could not endure wearing headset or In-ear even for half hour.  The discomfort from even a high-end headphone just sets off my enjoyment of music listening.   

Better speakers. Not that yours are bad. Just a good area to improve. 

Any suggestion that can work well with Parasound?

Nevertheless, "crossing in front of the listener" is definitely something new and I will try that...

Crossing just in front or just behind the listener works most times.

@russ69 Maybe you did not see my response to Erik. Crossing in front of the listener shrinks the soundstange, at least in my room.