Clamped up and all ready for the first welds:
Welder lubricant is a 1/3 of a pint of Moogbrew “Pretty in Pink”, a pink peppercorn infused saison from my local micro-brewery and taproom.
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way to go with that brewskie!! 
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Slow progress this week. It’s been my third on-call week in the last five and a horrifically busy one.
Also, as I feared, 25 x 3 mm is not so easy to bend, so I’m back to kerf cutting and bending, this time using the metal bandsaw:
Excuse the slightly ropey tack welds. I was trying to hold both the filler rod and metal in place with one hand and the TIG torch on the other. It’ll tidy up nicely when I run the weld bead.
Also, I’ve had a setback with my Argon supply. I’ve run out and Linde/BOC now tell me they no longer deliver to residential addresses. So the 11 m³ of argon I was expecting this morning didn’t arrive. I could switch to a smaller cylinder type which I can comfortably handle and fit in the car (the 11 m³ weighs ~85 kg) but the gas cost almost doubles.
In the end, I’ve set up a new account with Air Products and I’m hoping my gas will arrive tomorrow.
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those small welding problems for the DIY market… 
I fear you’re the only one involved… 
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I’ve no doubt it’s also had an effect on a few of the local one-man-band fabricators who work out of their home workshops.
Still, it seems there are viable alternatives.
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The finish on this build is next level, well done Graeme.
For anyone who has attempted a DIY speaker at home, they will know just how much skill is on display here. Such an amazing effort, and you should be super proud. Congratulations.
I would love to ask a few questions if possible.
- Is the shared frequency response a vector average of multiple listening positions?
- Can you share vertical & horizontal SPL response @ 10% increments in room, or contour plot.
- It seems Troels places very little emphasis on constant or uniform driver directivity when designing… it would be very interesting to understand beamwidth integration between drivers. A contour plot would provide some interesting data
- Are you able to share measured harmonic distortion, @ say 85db and 100db. Distortion V’s Frequency?
Cheers
Steve
Hi Steve, many thanks. I’ve certainly challenged my capabilities with this build!
I’ll do my best to answer your questions:
-
The frequency response is a straight RMS average of L & R frequency responses measured at a single listening position (where my head is when sitting in the sweet spot).
-
I should be able to do some more measurements of horizontal and vertical SPL response. Not sure how I would go about making a contour plot though?
-
Indeed, he does seem to place little emphasis on constant directivity, although generally, his measurements of horizontal and vertical dispersion aren’t bad:
Horizontal dispersion: 0, 10, 20 and 30 deg. (Red, blue, green and purple).
Vertical dispersion from 1 metre distance. Starting position = between M and T = red graph. Blue = - 10 cm, green = -20 cm. Yellow = + 10 cm, purple = + 20 cm.
- This I can certainly do.
Might be a few weeks before I can do the extra measurements. I’m feverishly working on finishing the plinths at the moment and we’re off on holiday to Scotland for a couple of weeks. Measurements will need to be done when Mrs Mad Scientist is out, especially the 100 dB distortion ones.
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Apologies for the recent lack of activity. My gas delivery took nearly a week, so I was out of action on stainless welding.
Quite a bit of shifting stuff around to manoeuvre in the new 47 litre, 230 bar, 86 kg Argon cylinder. New regulator, longer gas hose (these things are tall!)) Finally finished the welds on the first plinth. Just the grinding and finishing to do, then on to the second one. But it’ll be a few weeks.
It’s that time of year again. A couple of manic weeks tying up loose ends before our annual holiday back home in Scotland and finally we loaded up the car and set off yesterday.
An overnight stop near Lockerbie in Dumfries and Galloway, and this morning we woke up to a hard frost and a beautiful sunrise:
Worth every moment in traffic jams yesterday!
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great
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Hi @Graeme_Finlayson, I hope you have a great Hogmanay. I hope we see the finished product early in the new year.
Cheers,
Craig
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Thanks. Hope you have a wonderful Hogmanay too.
Having a relaxing one with home made chilli nachos and lethal margaritas.
Mrs. mad Scientist may be hungover in the morning…
I was hoping to have the plinths finished by New Year, but the weather here has been typically English. Wet, windy and miserable. The welding is largely finished, just the grinding and polishing to complete. My revised target is mid-end January…
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keep your own process going my friend, it will be great in the end! (give my love to Stan!)
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Hi @Graeme_Finlayson I have not seen you active so I thought I would check in. I hope you are well.
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Hi Craig, many thanks for your message and well wishes. I’m good, thanks. Life, and especially work have been very busy and particularly stressful of late and free time has been limited. I’m exploring new and healthy ways to adjust and cope. Early morning ice baths are the best thing I’ve ever done for my overall wellbeing of late. They’re not easy 
, but the return more than justifies the investment! I generally struggle with this time of year - short days, long nights and little in the way of proper daylight take a toll on my overall mood and energy, so I tend to withdraw and become a bit of a social hermit.
The stainless plinths are progressing slowly where time allows. In tandem, I’m also concentrating on improving my TIG welding skills.
Roll on the spring!
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Amen to that.
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Good on you to try and find ways to get yourself in a better way. We are not North enough to get as limited light as you during the winter months. We are back on the upswing and have light until 5pm now. I can always have an “ice bath” each day standing outside. 
We have been using the hot tub a bit more at night for similar reasons. Definitely helps with my lower back issues.
Take your time and know we are all excited to see the final product.
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You are not alone, I do exactly the same.
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Take long walks with Stan! He’ll get you through! And finish those speakers - next summer we want to see a new (for normal mortals impossible) DIY project…
There has to be a reason to visit this forum…
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[quote=“Graeme_Finlayson, post:299, topic:242001”]
Early morning ice baths are the best thing I’ve ever done for my overall wellbeing of late. They’re not easy , but the return more than justifies the
Goodness, Greame. You are a “Braveheart”. That takes doing! 
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Thanks for the update @Graeme_Finlayson. Tell us about the ice baths? Do you have a water butt thing in the garden, or just dump a load of ice into the bath? My other half is an open-water swimmer, so there has been some talk about a water butt thing in the garden, but not ice! Perhaps I should mention?? Anyway, thanks for sharing, I hope you are ok! Looking forward to updates when you ready!