A man of taste!
Option paralysis returns. The things look really intricate, which probably means they're good 🤔. How was the bass response? And was it the "Monster" or the "Behemoth"?
Yes, based on Harry Olson's 1940 Type 64-B Studio monitor pg. 60 [52] and reimagined as the DIY Mello Monster.
I had the "small" - both are dual horns, first horizontal back and forth at the top then vertical down up and down as seen in the drawing. However the big one was with two drivers. The bass response was good, however the "small" missing the deep button, which was not the case for the big.
Gotcha. The plans on the site must be for the small one, yeah? If they are, I could go ahead and recreate the them in Fusion360 so there's a more hi-rez version available.
I know that some nicer PDF drawings have been available, but I don't know where to find them. They were published in a danish hifi magazine in the seventies.
Another thing that helped with the deep sound was to cut the suspension away and replace it with sewing thread - also a Duelund modification. He tried the concrete horns with a range of loudspeaker units, but his own conclusion was that modified Bea 8 was by fate the most interesting.
Another thing that helped with the deep sound was to cut the suspension away and replace it with sewing thread - also a Duelund modification. He tried the concrete horns with a range of loudspeaker units, but his own conclusion was that modified Bea 8 was by fate the most interesting.
Sewing thread?? How does that even work?
Regardless, consider me intrigued. Since I won't have the funds to build any speakers until autumn by my estimation, I may as well entertain all possibilities. A while back I talked about "modernizing" a mello monster by making it a bit taller and sleeker, seems that's already been done, and very well by the looks of it.
Gonna go ahead and model these in F360, since the Dallas 2-design is near finished.
this page is unfortunately in Danish, but a google translate will give you the idea.
https://www.vintagehifi.dk/forum/viewtopic.php?t=5614#p51517
I did this modification on the Beta 8 back in the eighties. After cutting the suspension you make three small holes in the metal frame, put one thread through one hole around the coil to another hole. Then another thread through the third hole, around the coil and back to the same hole. Then you can adjust the thread so that the coil moves freely. Remember, as it is said in the danish article, there were lots of Beta eight to buy, and they were relatively cheap - such as 1/4 - 1/5th of a Lowther so we were not afraid of modifying.
https://www.vintagehifi.dk/forum/viewtopic.php?t=5614#p51517
I did this modification on the Beta 8 back in the eighties. After cutting the suspension you make three small holes in the metal frame, put one thread through one hole around the coil to another hole. Then another thread through the third hole, around the coil and back to the same hole. Then you can adjust the thread so that the coil moves freely. Remember, as it is said in the danish article, there were lots of Beta eight to buy, and they were relatively cheap - such as 1/4 - 1/5th of a Lowther so we were not afraid of modifying.
Hey -- you guys may speak funny, but you've yet to mangle written Danish beyond our understanding
Different times indeed.
Since they're my father's I'll hold off on any modifications for now, but being that they've got a few years to them the surrounds may need some work anyways. Good thing he has two pairs!
If I have this straight, you already have the drivers. There is danger in investing untold hours in lily-gilding on unfamiliar designs. What about knifing-up some XPS (etc) and listening to them all before you decide? Just instigating...
🙂
well - Duelund made two versions - a bigger one with two 8" speakers in each. If you have the space you could go for the big one since you have four units. But they are big. I have heard them long time ago. They do of course go deeper than the "small" ones.
But can an XPS enclosure realistically give me a good idea as to the sound of a certain design? Even building an XPS enclosure would strain my monthly budget -- but if it gets me closer to a final decision, I suppose it's worth it.
My primary goal is to build a great pair of speakers to have and to hold until the end of my natural life. I have so many hobbies that are tangential to speaker building (I've built guitars, guitar amps, produce music etc), but I know for a fact that building speakers isn't going to become my primary hobby, and so realistically I'm only going to be able to spend a limited amount of money on it throughout my life.
Time spent simulating and modelling is free, a few square meters of 22mm BB ply is very much not.
There are four avaliable, but I've only been "leant" two. Should the bass be too anemic for my tastes, I'll either just supplement it with a sub or build a different enclosure a few years down the line.
Either way, I doubt that the sound that's there will be anything other than great.
Not because of two drivers, but from the bigger horn. Sgould be ell over 2 x as big as th elittle one to ghet that extention.
dave
Oh, is that the major concern, adequate bass? Well build some BIBs. IMO the most certain way to get lots of bass out of a single fullrange driver.
Not at all -- But the "limited bass" point does seem to come up a often. Personally I'd rather have a speaker that complements the driver where it's capable than a fridge-sized one just to wring out a few dB down low. Does seem to hit a point of diminishing returns eventually.
So far the (simulated) response in the adjusted Dallas horn is looking decent, but there isn't much below ~60Hz. And while the BiB is tempting in its' own way, it's just a bit too... rectangular for me. So, should I have to, I'll hide a subwoofer somewhere out of sight.
Hardly the first though as some of the pioneer's original drivers were made this way, but a good way to DIY PRs. Anybody know how much the driver's specs changed, didn't see them in the various links, docs.
Re ideal horn driver Fs for a given tuning, the pioneers concluded Fb/1.56 to ensure plenty of near zero Xmax power handling, hence ~20 Hz Fs woofers in 30 Hz compression horns.
Dunno about XPS for sub/bass 'anything', but we used banding to wrap/tension my heavy duty corrugated cardboard box Jensen BLH (March 1952), though rope, ratchet straps, etc., will work too. For BW limited sub/bass to its Fhm (max), it's all about mass/stiffness and even then only at high SPLs at/below its terminus frequency.
I would recomend the Schmacks horn, I heard them with JBL 2110 and the bass they put out was terrifying!
BIBs are actually visually attractive. The volume is large, but the footprint is relatively small. My wife likes them more than bookshelf loudspeakers on stands, they are more balanced and "peaceful" to look at. At least in our subjective opinion. I have heard a very good back loaded horn with a sealed subwoofer integrated into the enclosure. The horn reached down to 70Hz or so, the subwoofer 25-70Hz. Sounded great, so that's a viable option as well. You're doing good research, I'm sure your system of choice will sound good.