See review below for the speaker array, what is not mentioned is the cabinet material which is a resin composite, acoustically inert (no resonance at all) and very solid. The guy who produced them had a unique vision of what made a speaker great.

I have owned these since new bought directly from SD in New Malden, just outside London. I met the man responsible and had an enjoyable afternoon listening to a wide variety of music through the SD3 and SD1. The source was a Micromega CD deck, a selection of valve and solid state amplification and a very large listening area. I originally took home the SD3s but found that they did not light up my lounge the way they had at the dealer. A phone call later and he delivered the SD1s for some extra cash (about 2x the price as I remember at £950).
The difference was dramatic at lower sound levels and I guess that these units are better at normal listening levels and in a domestic setting than the SD3s which seemed to favour higher sound levels - they have the same sonic footprint.
Mine are connected to an Audio Note OTO, streaming lossless MP4 files through a Squeezebox Duet. The sound is detailed and cohesive, the mid range the sweetest I think I have ever heard with fine separation and that rare believability that seems so effortless with good gear. The bass can be a tad loose at higher levels and the lower it gets, electric bass in particular can loose it's character - the type no longer apparent as the volume increases. String bass too becomes a shade overloaded. This may be the equipment as the OTO is only 10 watts it may contribute to this. This is never enough to make me want to change just a facet of the sound. I listen to a lot of older recordings and find these yield much more information than provious setups (Inca Tech Boston Acoustics Pierre Lurne Ariston RD11s) in particular small Jazz groups like Brubeck, Kenny Burrell and Miles Davies really get a great treatment - open, you can here the energy, tempo is rock solid and the fast transients from Brubeck's piano are breathtaking. I am a big fan of these speakers, they deliver the clarity I like, the soundstage is large and the speed is exciting. Pity they are no longer made, he had a vision and realised it through these unique constructions.

Very poweful and big sound. Very revealing. Images superbly. Tri-ampable. Excellent transient response.

Very revealing of source and amps. Rather large. Heavy and difficult to move/place.

Amazing speakers. Incredibly clear and detailed. Brilliant imaging and splendid bass. I use them as monitors for mixing and mastering and they're fantastically revealing. However, they are brilliantly musical too so the revealing nature doesn't make them cold or clinical. They are possibly the fastest speakers I've heard. Transient response is breathtaking with fast, deep bass having enough punch to knock air from your lungs. I bought them off the previous reviewer when he bought an original prototype pair. I wonder if I can find something negative.... Errrrrrrr.... So revealing you'll need a system up to it.

Similar Products Used:

Dynaudio active monitors (can't remember which, but they were in wall and worth about £15,000) Monitor Audio Gold Reference 20 and 60 (Very poor. Technically perfect, but no musicality at all) Proac Studio 125 (musical but hazy details) Rogers LS55 (wonderful speakers, but lacking resolution or dynamics in comparison)

very open sounding, faithfully reproducing any kind of music being generally neutral and vice free.Flexible with regards the ability to tri-wire with different cables

bass can become unruly in smaller rooms especially if close to a rear wall.Size could be a problem for some (1250x360x300mm) and weight 37.5kgs

the SD1 loudspeaker is a hybrid incorporating a ported downward firing bass chamber, a sealed mid unit on an open framed stand sitting above the bass chamber which also houses an open backed ribbon tweeter with the whole caboodle tri-wireable thanks to the easily accesssed crossover sited externally above the bass unit. This strange concoction prduces some of the best sounds i''ve heard .Previous speakers were a bit like watching a film through the letterbox but with the SD''s somebody has opened the door.these speakers aren''t as bell-like as the best panels in the mid-range but,being a full bandwidth speaker they seem more solid in the bass.When the SD1 was first made back in 1985 they sold for £1000 approx (a price way beyond my budget)at the time the venerable Quad ESL63 sold for around £1400 so it certainly wasn''t cheap however the better panels from the states were stratosperically priced.It was only a few years ago that i could afford a second-hand pair.I use them in a lees than accommodating 12''x 10'' room 7'' apart and about the same disstance from the listening position.This arrangement can sometimes lead to the bass sounding overblown depending on the music and volume but i can live with these occasional anomalies

Similar Products Used:

TDL studio 1+2,Epos ES14,Tannoy DC3000 +Cheviots,KEF 105-2