Excuse me I bought a 2 pack 
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had one of those âcalendarsâ once, but it didnât fit in the fridge, so had to open it to store the beersâŚ
Brewdog is not advertising theirs here in NL⌠shameâŚ
The Brewdog advent calendars donât fit in the fridge, so I open the daily door in the morning, put the can in the fridge at breakfast time and drink it in the evening! 
Iâd be too tempted by having them all in the fridge. Theyâd be finished by the 7th of December! 
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Progressing with the stainless now.
First, a 7.1 mm pilot hole with a Cobalt HSS-E drill bit.
Picked up both the 1.0 to 6.0 and the 6.0 to 10.0 sets earlier this year:
On to the holesaw next:
Iâm really liking these new Bosch carbide tipped holesaws. They rip their way through stainless effortlessly.
SAFETY NOTE for the less experienced metalworkers. Using holesaws on sheet material on a drill press is potentially one of the most dangerous activities you can undertake in a home workshop. Itâs vital the material is firmly clamped to the table, the table is locked in position and the material is wedged against the pressâ centre column before starting to drill:
The last thing you want is a sheet of metal spinning around the table at abdominal height when youâre standing in front of it!
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@Graeme_Finlayson I am really enjoying watching you use your mad skills to build these beautiful speakers. One questionâŚwhere or how did you get the detailed plans and/or drawings for these? Iâm just curious if the manufacturer was willing to provide those.
Thanks Jim.
All that Troels provided on his website were these sketches:
There is also a builderâs response page where other builders shared photos of their builds and sketches of cabinet ideas:
http://www.troelsgravesen.dk/PMS_builders.htm
The rest of it was up to my imagination and ingenuity.
And, of course, I took some inspiration from the SF Stradivari themselves too:
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After making the holesaw cuts, I trimmed to length with a cordless metal cutting saw and then roughed the corners etc. down with a 5" grinder, leaving about 1 mm overhang all the way around.
It was then over to my cordless Makita router trimmer with the bearing-guided spiral carbide cutter to shape the stainless to the aluminium template.
First one down, 3 to go:
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I am curious about your crossover testing procedure. I assume that the resistors (for example) are matched within 1%. How closely did the pairs match each other?
I tested all of the components individually with an LCR meter prior to assembly. Tolerances were all pretty much within 1 to 2 per cent.
Transfer functions are easy to measure with REW. More or less the same procedure as speaker measurements bar a couple of resistors to keep the signals within the headroom of the mic input on my Focusrite Scarlet 2i2.
The final test was using REW on the wired-up speakers. No massive nulls at any of the crossover points, so nothing wired out of phase.
Interestingly, the different acoustic environment each loudspeaker finds itself in within a typical room makes a substantially greater difference to the speakerâs acoustic response than any tolerance derived crossover component variation or variations due to the tolerances of the drivers themselves.
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This is one of the most challenging aspects of performing in new spaces, literally learning how to hear each other in a different acoustical environment that might be quite different from the prior rehearsal spaces in the previous hours or days.
Thanks for sharing.
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And we hi-fi buffs think we have challenges!
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Which cables are you going to use?
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I hope only the best pure silver shiny ones! 
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@Graeme_Finlayson would you ever consider going active with something like Hypex Fusion?
A few people have suggested going active. Iâll look into it and try to get a handle on whatâs involved.
If I went that route, Iâd probably just add a third Benchmark AHB2 and run them in stereo, one amp for each pair of drivers.
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There are tons of solutions, but Hypex Fusionâs seem to one of the best (for me thatâs multiple inputs/dac/dsp/amps in one complete unit (shame they donât have an ethernet ready Roon port)), Troels likes them too, and has filters for some of his designs.
@Graeme_Finlayson, I have a pair of Hypex FA122 (2way 120w/4Ohm) literally gathering dust if you wanted to have a play, I could post them, might be kinda pointless with just a 2 way, but Troels seems to use them like this and simply high passes the tweeter on the 2nd channel.
They are currently in a walnut case, a little like a tube amp, with top inputs.
Continued progress.
Stainless clamped onto aluminium template:
Milling the stainless flush with the template:
Another one completed:
All four stainless sheets cut and ready for drilling:
And finally drilled ready for welding:
For the record, carrying out flood-cooled mag-drilling indoors is a really bad idea!
Drilling 16 x 22 mm holes and 16 x 15 mm holes used 3 litres of oil/water emulsion cutting coolant.
Next time Iâll wait until the rain stops and do it outdoors!
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