The Shure V15 V with a Jico SAS/B stylus VS The Soundsmith Hyperion MR and Lyra Atlas SL

Mijostyn, I always get the impression that you read but do not take the time to understand what I and others write. How can you really know that Acoustat 2+2s outperform a stacked Quad 57 with all the modifications I described? I am quite sure you’ve never heard the Quad system, because it is one of a kind. Whereas, I have many hours listening to both the modified Quads and Acoustat 2+2s. Yes, I am offering a subjective opinion based on some aural data. And then you add in that if by chance the Acoustats were found wanting, it must be because they were not properly driven. Your mind is closed.

Then in your last paragraph you tell me what I already candidly admitted about the bass response of my Sound Labs, even keeping in mind that we once calculated that my speakers have a greater radiating area than yours and so almost assuredly do better in the low bass than yours do without subwoofers. At the same time, I recognize that you went for the smaller panels because you knew in advance you were going to use subwoofers. You got the right version for yourself, and I got the right version for myself. Nothing wrong with that, and I am sure you have more extended bass response than I do. I still sleep at night.

Seems you are hearing the Shure V15 in much the same way that I heard the V15 in my system 40 or so years ago (probablyi version III); flat response but dry and a bit dull.  I didn't keep it for very long. This does not mean that all vintage cartridges are inferior to very expensive modern LOMCs, categorically, at least in my opinion.

@mijostyn My Velodyne 18" subwoofer is digitally controlled, with digital crossover and servo control of the cone for under 0.5% harmonic distortion.  It has 8-band parametric equalisation and 1250-Watts RMS power.  If I am not careful, it rattles the windows and brick walls too much.  It adds about two octaves to the Quad 2905 but most of that is felt, not heard.  Like you, I am a big fan of walking around to see how the audio image holds up.

On swept tones, the sound is dreadful as various room modes kick in.  Additional subwoofers would help, but musically I am in my own sort of heaven!

@mijostyn Assumption ? Please Clarify 

I usually am doing my best to share only my experiences had and an very subjective assessment will be attached, if I feel it is worth the mention.

As always, I don't expect anybody within the Current Thread to endorse my input, it is quite obvious the common posters are not able to cojoin.

My Input is directed to the onlookers of the thread or future thread visitors, who  might get some value from the content added. 

I was once a Visitor, then a Regular Onlooker and developed into a valuable contributor.  

@lewm You apparently do not listen to me either Lew. I was one of the very first people in the entire world to mess around with stacked Quads. It was the brainchild of Mark Levinson and John Curl. It was called the HQD system. Levinson marketed an Oak stand that held the stacked Quads with a little window in the center for the Decca Ribbon tweeter. I'm sure you can find a picture. We had the full system set up at Sound Components in Miami. I have talked endlessly about the poor reliability of both the Quads and the Decca. It was powered by six  25 watt class a amps. God knows how much power they put out in B mode. I have WAY more experience with Quads then you will ever have. I have taken them apart, exchanged elements and blown them up a second time. On the other hand you have no experience with Acoustats. Granted, the methods supplied by the manufacturer to drive them were somewhat crippled, but the panels were genius. They were the first ESL panels made that you could not burn out. All they needed to shine was a good transformer, the right amp and subwoofers.

@richardbrand Having low bass is a lot of fun. Digital electronics do make it much easier to to get to the point where the subwoofers are invisible while still supporting the low bass. I promise you that if you get a second and digitally high pass your main speakers you will be even more amazed by a factor of four. 

@lewm Which reminds me, I find your speakers to look fat and bulbous (Captain Beefheart). The dimensions are wrong, but take just four inches off the girth and they become graceful. Screw the bass, it's WAF that counts. Anyway, go here https://www.stereophile.com/content/mark-levinson-hqd-loudspeaker-system. The article mentions a dealer in Florida. That was us and we did have them sounding great....for a few minutes until we blew something. The system was doomed from the start. It was way too difficult to set up and way to fragile. You are right, I have a very closed mind. 

@pindac The way I read your comment above was  if you used a subwoofer that radiated like the main speakers, both dipoles, it would be easier to integrate the subwoofers correctly. That is the assumption that is not true. It is logical to think that way, but subwoofers and main speakers are apples and oranges. The considerations for the best performance are vastly different.