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Message started by Al Pi on 10/05/19 at 18:48:56

Title: The back-loaded horn stands experiment for DM945
Post by Al Pi on 10/05/19 at 18:48:56

Hi,

After sharing with Steve my experimental project with the back-loaded horn stands inspired by the DM947, he encouraged me to share that on this forum, so here I am...

Title: Re: The back-loaded horn stands experiment for DM945
Post by Al Pi on 10/05/19 at 18:50:42

Ever since I learned about the magical simplicity of the Decware genial products, I started thinking about trying to build those back-loaded stands for the DM945, as soon as I get a chance to get my hands on a pair.

Normally, one would just simply purchase the DM947 and have them shipped over the span of several days, at most weeks. But somehow that seemed a wee bit too easy, boring almost... no sacrifice, no pain, just ensure enough "dough" to cover all expenses and taxes, then install and enjoy.

Title: Re: The back-loaded horn stands experiment for DM945
Post by Al Pi on 10/05/19 at 18:52:07

There was also the thought, somewhere in the back of my skull, that I'd forego one of the rare chances to meet The Man, in his audio lab of excellence, where I could experience first-hand all that magic, from all the superlative devices I've been admiring through others' reviews. So, I kept thinking for months how I'd be justifying a trip to Peoria from my neck-o'-the-woods in the Great White North.

It just happens that my other hobby, adventure motorcycling, offers an annual (or at least biannual) opportunity to get away for several days, and going around the great lakes had always been an appealing proposition. So, I ended up this summer, building a vibration-protected "shelf" on the tail of my bike, heading around Georgian Bay and Lake Huron, over on the East side of Lake Michigan, all the way to Peoria, Illinois.



Crazy. I know. In the vicinity of madness & irresponsible, but when options are rather limited, I had to improvise somehow. It turned out rather well. Steve was gracious enough to not laugh at my solution, while seeing my intentions, and I had a wonderful time in his audio lab, enjoying every second of sound immersion facilitated by his ingeniously and expertly designed and built gear.

I then had the pair of DM945 nicely and adeptly wrapped by Sarah, in an effort to save their awesome finish from the elements, also protected them with some memory foam (brought for the purpose), while tying to the tail of the bike, and left:



Title: Re: The back-loaded horn stands experiment for DM945
Post by Al Pi on 10/05/19 at 18:53:16

Once home, after some 3-4 weeks of going through my entire musical collection and re-auditioning over and over my favourites through the DM945 pair (driven by a PrimaLuna Prologue One), I decided it's probably the time to re-enact the experiment of the back-loaded horn stands, which had intrigued me for so long. It had to be done, and Steve was from the get go very encouraging, confirming that the precision of measurements might not be in very tight tolerances, and I'd still be ripping some surprising benefits.

First, the overall dimensions had to be inferred from the DM945 & DM947 specs, which turned out to be rather trivial, especially since Steve so graciously shared those pictures of his initial prototype, then a draft sketch seemed like a good idea to ensure a good usage of a 4 x 8 ft medium-density fiberboard from Home Depot. Getting the MDF cut to the dimensions only required a table saw & mitre-saw of medium performance:








Initially, I thought I might get away with a simplified version of the corner rounding, while replacing the MDF rounding walls of the prototype horn with some cardboard + 1/8' foam board + low expansion polyurethane foam. Nope. No go. The low expansion still had enough force to push through the cardboard while curing, deforming the initial almost perfect corner rounding:





Obviously, some more rigid cardboard might have been able to put up with the foam expansion pressure, but my very initial tests were far from convincing about the very idea of using low frequency sound absorbent materials, in an area meant to reflect the sound column farther down the transmission line.

Title: Re: The back-loaded horn stands experiment for DM945
Post by Al Pi on 10/05/19 at 18:54:27

In fact, it turned out that building the rounding of the corners was not overly complicated, just required dedication and patience in getting the joint angles right for the first one, then cloning the newly found measurements for each one of the remaining ones.







By the time the horn enclosures were ready to migrate from the ad-hoc wood-shop in the garage into the living-room, almost 2 weekends had passed, and I was really aching to hear some real results. After experimenting with the initial cardboard & foam corner rounding non-solution, I wasn't quite sure I'd get much of a difference in sound placing the DM945s on the new MDF horn stands... Man, was I wrong! Very much so, by an order of magnitude  8-)

I spent the reminder of the weekend and next week (some 4-6 hours daily) going again through some of my music collection, confirming and re-confirming the experiment was going beyond what I thought was predictable. There was some effort and sweat involved in getting the DM945 pair from Peoria over 2200 miles, and building my first MDF project with mostly borrowed tools, but it was worth every second, by far...



Title: Re: The back-loaded horn stands experiment for DM945
Post by Al Pi on 10/05/19 at 18:55:56

What turned out to be the most painful stretch in this project, though, was the finishing stage of the project, while learning to spray paint in a decent manner, and finding the right spray-can paint for the amateurish approach I had... and most importantly not being able to listen to my new system for almost 3 weeks. Self-inflicted torture. It needed to be done. It needed to be properly finished to honour the high quality finish of the DM945. I owed it to them [smiley=50.gif]





It slowly and painfully turned out rather well to my eyes, after some desperate re-sanding and re-painting:










It's been a couple of months now since I've been indulging in some of the most satisfying auditions of my old and well known music collection, and some newly discovered gems (using the JRiver MediaCenter Cloudplay). The days have been much longer, while nights getting shorter, and my family is all too often finding me smiling, eyes closed, in front of them. I think it's time I should get out more...

Haven't had a ride on my beloved motorcycle in months, but I'm good [smiley=69.gif]

Title: Re: The back-loaded horn stands experiment for DM945
Post by Radarek on 10/06/19 at 00:10:48

Hi Al

Great project. I'm sure they play as good as they look and they look awesome. I'm in process of building my listening room which put my other project on hold... fortunately I can overlook both from the same spot lol...

Best regards  

Title: Re: The back-loaded horn stands experiment for DM945
Post by Radarek on 10/06/19 at 00:11:59

That's on hold...

Title: Re: The back-loaded horn stands experiment for DM945
Post by Al Pi on 10/06/19 at 16:00:18

That steed of yours is a real beauty, Radarek... maybe one day we'll cross paths too, on some wild and winding roads. Looking forward to see the progress on both projects  :-}

Title: Re: The back-loaded horn stands experiment for DM945
Post by Palomino on 12/20/19 at 13:54:08

Great job on this.  I attempted this a few years ago and got some cabs that worked, but look terrible in comparison.  Really nice work.

Title: Re: The back-loaded horn stands experiment for DM945
Post by Lonely Raven on 12/20/19 at 19:05:44


Beautiful work and attention to Detail on those cabinets!




Title: Re: The back-loaded horn stands experiment for DM945
Post by Donnie on 12/20/19 at 21:19:08

I was going to build a pair of DM's this weekend. Hmmmmmmmmmm

Title: Re: The back-loaded horn stands experiment for DM945
Post by instinct2 on 01/31/20 at 20:24:47

Did you make the isolation stands for the stands?  Those look sweet!

Title: Re: The back-loaded horn stands experiment for DM945
Post by Al Pi on 02/22/20 at 21:49:11

Thanks gentlemen for your nice words.
It's been quite an adventure ever since I bumped into those beautiful aliens, Steve and more recently Randy, who suddenly made me reassess my priorities   [smiley=50.gif]

As for the isolation stands, I'm glad you found them looking "sweet", 'cause they're also quite cheep and easy to come by:
1. Pine-made kitchen cutting board (my wife discarded it several years ago, dissatisfied about some mold build-up on it). Just cut in half, sand it thoroughly, then oiled (optionally it can be stained, too)
2. 8 Set "Golden-Plated Speaker Spikes" from Amazon, pretty cheep too and also easy to stick to the bottom. I quite doubt their impact on the sound (some say it's preferred to not even think to isolate from floor in certain circumstances), but it works pretty well on my old and way-too-floaty hardwood floor (it's an extension room at the back of our bungalow, and the floor is pretty much suspended over a few of joists)

My initial goal was just some way to easily slide the speakers without having to keep adjusting the spikes (for uniform pressure), then I realized I can also give some use to that cutting board I could not just throw away   [smiley=beer.gif]

Cheers,
Al

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