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

My Limited Experiences of having been able to hear Quad ESL Speakers in use with a Subwoofer, is that the carefully matched ESL>Subwoofer is is a set up that had a addition of Bass that is detectable, but certainly not an improvement, the Bass being noticeable does not augment the ESL as a Speaker it merely produces a unique type of Bass presentation in conjunction with another Speakers unique Bass presentation.

Remove the Bass from the Subwoofer as a influence on the ESL Bass and what is left is a Speaker functioning with a Bass that is satisfying and not effected by a Bass that is seemingly an anomaly.

It is because of this sensing that the Subwoofer is an anomaly, that has drawn my attention to a Ripole Bass and the Figure of Eight Radiation the Ripole produces. The design seems to lend itself to be much less detectable as a Separate Source for a Bass Driver coupled with the Bass from the ESL.

@dogberry

@mijostyn

I bought an 18" Velodyne servo-controlled subwoofer to replace my Duntech Thors, back when my main speakers were Quad ESL-63. One undoubted advantage is that, by relieving the Quads of low bass, they can play much louder before their protection circuits come into play.

The bigger Quad ESL-2905 has about twice the bass panel area, and does not really benefit much from the Velodyne, which ticks by on level 3 out of 60. Most of what I play is orchestral and the only instruments that go really deep are organs (and maybe venues?)

Oops, I forgot the revolutionary Australian Stuart and Sons 108-key piano which extends the 'normal' piano range by two octaves, all the way down to 16-Hz.  Those low strings add sonority even when playing standard repertoire. The bridge design provides downward rather than sideways coupling, and the pianos are much brighter than popular European heavyweights.

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.