I’ve wanted to build these for a while. To cut right to it – for the small outlay of cash - the OSMTS are legit & I cannot speak highly enough of them. The kits are expensive to ship so I built these myself, trying to source all the bits and pieces as inexpensively as possible. Here’s what I found worked best: HiVi B4N drivers x 2 –there are a couple of European dealers, but strangely the cheapest was still with PE, but via ebay - £35 incl. delivery Dayton Tweeters x 2 – Soundimports.nl via ebay again - £30 Crossover parts – HifiCollective, UK – substitute all the Dayton caps & resistors for Jantzen equivalents. The inductors are not kept in stock but can be ordered to the required spec. - £26 Adjustable 35mm ID Port-Tubes – falconacoustics - £7 Wool stuffing – 90p + delivery – Wingham Wool Work Total: ~£100 (Not included: wood, wire, binding posts) I needed to account for metric plywood sizes. I created these quick sketchups to preserve the original baffle size, driver placement & internal volume of the imperial MDF plans but tweak the depth for 18mm ply. I’m using rabbet joints to make assembly easier, much like the PE kit cabinets. But you could just build one easily with butt joints though. Here’s a plan for that: BUILD: Plenty of info already out there so here's just a few pics of the build I took along the way. I decided to make the rear panel removable and add a couple of my own touches. If anybody would like further details about how to do anything I did, please feel free to ask. 1) Frame pieces cut & routed. Allowing overlap of end-grain for final flush trim: 2) Assembly: 3) routing the woofer cut-out (for small baffles I always make a little jig to clamp it without obstructing the router. Screws in the middle prevent movement once final cut is made) 4) cut tweeter hole with forstner bits - 45mm/33mm for exact press-fit. 5) Chamfer rear of woofer hole. Also hit tweeter hole with one too to help clearance of wires/contacts 6) secure baffle with Sapele through-dowels & trim with flush saw 7) Create port hole with Sapele accent to opening and binding post plate 8) Build my first ever crossover 9) Fit crossover & apply gasket to seal rear panel 10) Ready to enjoy. They still need some kind of clear finish or wax. DAMPING: These definitely need stuffing and I think it’s worth playing with the quantity a little bit. I can’t really improve on Paul Carmody’s advice which is to keep adding stuffing until the bass sounds “huge”. You’ll know it when you hear it. Without the stuffing there is a boxiness which diminishes the scale of the speaker and makes them sound a bit weedy & echoey. I started with too much, which made them better fleshed out but also kind of slow. I eventually halved the total amount and teased it out more. I weighed the final amount on some rudimentary kitchen scales and guesstimate it to be not more than around 10g per speaker. LISTENING & COMPARISONS: (OSMT, Rega RS1, Alpair 7.3 DIY - all similar size drivers) using Naim 50wpc integrated amp Vs Rega RS1 Physically, in comparison, the Regas are very lightweight. Sonically they are drier, leaner and also a bit meaner than the OS, with noticeably less bass (especially mid-bass) presence. The OS seem slightly pronounced in this region. The Regas also have a more prominent boxy/resonant colouration which prevents them disappearing in the room as well. They sound a bit cleaner and I feel they resolve more fine detail in the midrange. Unfortunately, the treble has a roughness and grit, which has always bothered me. By contrast, the OS have a very balanced, natural, yet forgiving treble response. I would now place this as one of my top priorities for a speaker. One area I feel the OS fall slightly behind is dynamically. The OS sound just very slightly slow and one dimensional in comparison, while the Regas sound more snappy, lively and impactful - except for in the bass where they are lacking. Vs Alpair 7.3 A single-driver cliché: by comparison, the 7.3s have some magic (realism, depth, nuance and micro-detail) in the midrange that the OS lack. If you listen to ‘Paris, Texas’ by Ry Cooder, the 7.3s resolve more of that fine shimmer of guitars, the decay of the notes, as well as conveying the strings being plucked with varying force & intensity. Just like the Regas, the 7.3s are less effective at disappearing than the OSMTs but that critical vocal area really does a decent job of just appearing centrally and holographically with nice depth. However, the OS are much better in other areas. Firstly, they give me maximum bandwith for my music collection. If you listen to simple acoustic music the Alpairs offer a more interesting experience, but throw something like Radiohead’s ‘Idioteque’ at them and while not being a disaster, they sound a bit of a mess. They really can struggle a bit with complex, multi-layered music. The treble is not as well resolved as the OS and there’s also a bit of roughness and peakiness that I think bears out in the measurements of the Alpair 7s I took before. With the single driver speakers I own, there is the sense of them notably excelling in some areas (which I love) but missing in others, whereas the OS are perhaps a more complete package and a safer choice. OSMTS Final thoughts. The Overnight Sensations are fantastic. I’ve explained some of their weaknesses but where they really succeed is in the way they tie it all together. I found that some of the comparisons with the HD-650 are apt. They have an overall tonal ‘correctness’, decent resolution and a pleasing warmth that makes them an excellent, all purpose budget speaker. Just as with the HD-650, some may find them slightly too warm or a bit ponderous - but for my tastes they are not too far off being just-right. MEASUREMENTS (unsanctioned by SBAF) all ungated, 1/12 octave smoothing. NOTE: conditions were tough. I've been battling with the weather and it was quite windy. It always seems to be noisy.. church bells, birds, pneumatic drills etc. The ground is concrete. I got some quite strange readings but think I have ended up with something usable: 1) Outside - 0 degrees, 1m from mic & floor 2) L+R Comparison 3) Outside - 45 degrees, 1m from mic & floor In room listening position in my test set-up (2m from speakers) THOUGHTS: somewhat better off-axis performance than I saw with the single-driver speakers I built. Some loss of top end but nothing to cry about in my listening while moving around the room I have found these to be very room friendly - again, more forgiving than the fullrangers. In the graph you can see the room causing some boost to the low end which probably contributed to my impression of their extra bass. All in all it looks quite respectable to my untrained eye for ungated measurements in an untreated room. The stands are also a bit low.