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

I share with @lewm and @mijostyn admiration for the Magnepan ribbon tweeter, which is found in the Tympani T-IVa’s. The planar-magnetic midrange driver of the T-IVa (unfortunately single-ended), however, is somewhat veiled, especially in comparison with just about any and all ESL’s as well as the p-m midrange driver of the Eminent Technology LFT-8b and 8c, which is of push-pull design and construction, a big deal.

There are a group of guys active on the Planar Speaker Asylum forum who replaced the T-IVa’s midrange driver with eight of the fabulous NEO 8 p-m drivers, which with a little fiddling fit into the slot in the frame of the T-IVa’s for that Magnepan midrange driver. Mated with the Magnepan ribbon tweeter and the two Tympani bass panels (Harry Pearson made his "super speaker" using those bass panels with the Infinity EMIT and EMIM drivers), the resulting loudspeaker is reported to be significantly more transparent than the stock T-IVa.

While the Eminent Technology LFT-8b may not be up the level of the SoundLab ESL’s, they cost only $3200 a pair. That is just about the same price as a pair of Magnepan MG1.7i’s (also with a single ended midrange driver), which imo (and that of Steve Guttenberg) is not in the same league as the LFT-8. One problem with the LFT-8 is that the crossover point from the p-m midrange driver to the ribbon tweeter is located at 10kHz, with 1st-order filters. Those filters characteristics coupled with the short wavelength of 10kHz leads to the inevitable comb filter behavior of the driver interaction. I trust I don’t have to explain comb filtering. I’d love for Danny Richie to get a hold of a pair, and design a crossover with filters at, say, 2 to 3kHz.

Guttenberg found the sealed enclosure 8" woofer of the LFT-8 to mate very well with the planar-magnetic driver, but an 8" woofer can be expected to play only so low, and not at lifelike spl. However, since the crossover point between the woofer and midrange driver is at a very low 180Hz, the GR Research/Rythmik Audio OB/Dipole Sub (you can disregard the opinion of @mijostyn---he hasn’t heard it)---which is capable of playing up to 300Hz---can be substituted for the stock woofer. The resulting combination provides 100% open baffle/dipole operation, with deep, clean reproduction from 20Hz to 20kHz. Guttenberg found the sound of the LFT-8 to possess the best characterisics of ESL’s and planar-magnetics, without their (in his opinion) failings. Since getting my pair of LFT-8b’s, my Tympani T-IVa’s and QUADS have been relegated to a spare room.

@dover yes, I listened to it most of the day yesterday. The sound was definitely less harsh, better, but after listening to 5 records that I know really well I best describe the overall performance as flat, flat in terms of excitement and visceral involvement, less dynamic than todays best cartridges. It is also way more sensitive to surrounding electro magnetic fields resulting in more background noise than all of my other cartridges. It is also more microphonic than all of my other cartridges. How it compares to other $500 cartridges I can't say. The high output cartridges that I have listened to lately including the Clearaudio Charisma and the Soundsmith voice are superior in every way sonically. The Soundsmith Voice was also playing through the phono stage of the DEQX Pre 8 in a system centered around Magico S7s and the pair sounded wonderful. This is not the fault of the phono stage. My other cartridges, all low output are played through a Channel D Seta L Plus which I am thrilled with. 

@audioquest4life It is the new microridge version and I have absolutely no complaints. It and the Lyra Atlas Lambda SL are, in my system the two best cartridges I have ever used. I am going to try the My Sonic Lab Ultra Eminent EX as it has the lowest impedance of any cartridge I know of. The Seta L will do both voltage and current mode. In current mode the cartridge with the lowest impedance wins and I am betting that it will outperform the Signature Platinum, a good cartridge, but not as exciting as the Hyperion or the Atlas in my system. 

@pindac That is an assumption that is simply not true. You can not compare the reproduction of very low frequencies with higher frequencies. Matching subwoofers so the system is completely unified is not easy. It is not any more difficult with dipole speakers as long as the crossover point does not go much over 100 Hz. The benefit in terms of distortion and headroom/dynamics in ESLs can not be overstated. 

@lewm Acoustat 2+2s run correctly with subwoofers out perform 57s in every way and you have to throw a Javelin at them to cause any damage. I used a single Sowter 1:100 transformer on each one along with my own adjustable bias supply. Their one weakness is their horizontal dispersion is very limited almost as bad a Roger Sanders speakers. 

@richardbrand  That is some piano.

Next time you try subwoofers please use at least two. Not only will your ESLs play louder, but if you cross higher at 100 Hz, distortion levels in the ESLs will drop noticeably. The problem is getting the subwoofer to disappear. At 100 Hz you have to use very steep filters at least 8th order. The only way to do this cleanly is in the digital realm. The benefits far outweigh any detriment. There is loads of low bass in good classical recordings. Large indoor venues breath at low frequencies, then there is the Tympany, Organs and massed strings. In order to get realistic low frequency performance in a residential space 20 Hz has to be boosted up to 10 dB. This will cause serious problems in most speakers, but not subwoofers. Done correctly subwoofers will give you the FEELING of a live performance while improving the performance of the main speakers. Unfortunately, it is much easier to screw things up then get the desired result and the manufacturers do not help.

@bdp24 You definitely do not want to mention comb filtering around me, it could put you in mortal danger. I spent two months trying desperately to stop it as it was confusing the computer in my DEQX preamplifier. The solution required about 50 hours of shop work and you can see it on my virtual system page. It was initially designed by Dr Roger West. I modified the design by making it a foot wider and using 8" wedges instead of 6" wedges. Dr West calls it SALLIE, Sound Attenuation of Low Level Interference Effects. They worked. 

@lewm The Sound Labs makes that impression on everyone who sees them. Nobody is use to seeing monoliths like them. Just because they are HUGE does not mean they make great low bass. They make great mid bass. I stand by my opinion. Just 15 minutes listening and I will change your approach to HiFi forever especially since you are already 75% of the way there.

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.