I wouldn't call getting a neat and airtight seal betwixt wood panels and lumpy porous concrete easy compared so, say a madisound kit. I'm more steampunk and like the pipe creations of Linkwitz.
but he'd need an amp somewhere, no? A powered speaker would be cool and absolutely what iPhone users need, but it doesn't appear to have an amp. I do agree that the front input was to avoid connections between the front and back. Safer to ship that way and less likely to be damaged in assembly I don't see it as a problem or anything. Even looks kinda cool if you have the right cloth covered cable..
It seems to me its a clever design by a clever product designer who probably doesn't know enough about speaker cabinet design to make it work well.
BUT I'm thinking in terms of doing it ourselves, better.. then I think it could be a very nice speaker..
He's constrained to using a flexible seal between the "wood panels and lumpy porous concrete" because he's selling a product without the block. We have the luxury of being able to just use a bead of sealant if we make our own wood panels- possibly from a prefinished shelf also at Home Depot? I've spent a lot of time trying to come up with a quick and easy way to make loudspeakers- usually ending up with a large dia. (8" ) length of thick walled PVC pipe similarly sandwiched between two pieces of wood. Trouble is you have to buy 20' lengths of the pipe and it isn't cheap for a piece that size, and probably would be best to rout a groove in the panels to seat it well- lots more work! and weirder looking..
Linkwitz's speakers are excellent but take a lot longer to make than a clone of the conc block speaker. The block speaker could be made in an hour, maybe 3 if all you have is a hand drill and a keyhole saw!
It's quite possible that if you whack the center partition of a block with a hammer you could split off the back half of it, giving plenty of connection between the two chambers. Or a D'apollito arrangement with 2 small mid/bass drivers and a small tweeter!
If it goes wrong you're out a buck or two for a new block!
It seems to me its a clever design by a clever product designer who probably doesn't know enough about speaker cabinet design to make it work well.
BUT I'm thinking in terms of doing it ourselves, better.. then I think it could be a very nice speaker..
He's constrained to using a flexible seal between the "wood panels and lumpy porous concrete" because he's selling a product without the block. We have the luxury of being able to just use a bead of sealant if we make our own wood panels- possibly from a prefinished shelf also at Home Depot? I've spent a lot of time trying to come up with a quick and easy way to make loudspeakers- usually ending up with a large dia. (8" ) length of thick walled PVC pipe similarly sandwiched between two pieces of wood. Trouble is you have to buy 20' lengths of the pipe and it isn't cheap for a piece that size, and probably would be best to rout a groove in the panels to seat it well- lots more work! and weirder looking..
Linkwitz's speakers are excellent but take a lot longer to make than a clone of the conc block speaker. The block speaker could be made in an hour, maybe 3 if all you have is a hand drill and a keyhole saw!
It's quite possible that if you whack the center partition of a block with a hammer you could split off the back half of it, giving plenty of connection between the two chambers. Or a D'apollito arrangement with 2 small mid/bass drivers and a small tweeter!
If it goes wrong you're out a buck or two for a new block!
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More complex but still easy to make https://www.kitronik.co.uk/blog/concrete-speaker-design-nottingham-trent-university/ . Trying to find a picture of some concrete cabinets I saw back in 1986 in a university materials lab.
And one day I hope to find a pair of celestion kingston speakers, which are posh concrete (as is my kenwood kd-550)
And one day I hope to find a pair of celestion kingston speakers, which are posh concrete (as is my kenwood kd-550)
I'm definitely interested in a build - but from scratch, not the kit. Seems essential to take something off the centre partition to link the 2 halves. Surely this would be easy with an angle grinder?
Us kids did some in the mid '50s after being exposed to a new neighbor's incredibly heavy rectangular concrete culvert? box speaker that taught me the virtue/need of mass loading audio systems and pretty quickly busted up, replaced with the DIY Karlson K15 I've periodically mentioned.
Anyway, Jack just drilled a few holes and popped most of it out with a hammer for our scrap yard automobile AM radio oval drivers, though no doubt with the right cutter can be ground out using water as a lubricant/dust suppressor.
Anyway, Jack just drilled a few holes and popped most of it out with a hammer for our scrap yard automobile AM radio oval drivers, though no doubt with the right cutter can be ground out using water as a lubricant/dust suppressor.
On a somewhat related note, I used to build concrete enclosures with a plywood mold, which worked very well. The front baffle was wooden and set in afterwards with 2 part gray epoxy (jb weld). I went through the hassle of countersinking the drivers with a thin coat of cement over the front baffle, protecting the driver flange edges with electrical tape. The finished product looked like it was made from solid concrete once the front baffle was covered.
You have to fill the concrete mix with some plastic behaving filler material, otherwise the concrete walls will resonate. Back in the 80s over here we had a material expert who figured that out and made quite established monolithic enclosures.
The kit has a recess cut into the back plate, which links the air space of the halves.
The easiest way to duplicate this would be to use a found object that has this recess already built in.
Attachments
A back with a recess is possible. But it can't be hard to take away some concrete. To get tweeter and mid bass close this would be better on the front mid-section of the block.
For the molded concrete enclosures, I would use a wooden baffle board to mount the drivers and make it extra thick, adding a chamfer to the backside so the woofer back wave doesn't get reflected back into the cone. Its more work, but worth it if you want to get the best out of your design. It's very difficult to construct the baffle from concrete with the driver openings properly formed. I've tried this before and it's very hard to get consistent results. You have to factor in shrinkage, which makes accurate countersinking almost impossible.depending on moisture content and mixture ratios.
I used chopped up cotton rope fibers mixed in with the concrete, but had no issues with ringing even without the fibers. It will depend on how much aggregate you introduce into the mixture and the wall thickness you end up with, making the enclosure immune to ringing. Roughly 3/4 inch wall thickness is a good target both for weight and inert acoustical properties as long as you have the proper amount of coarse sand mixed in.
I have experimented with pouring the concrete around the baffle board. This only works if you have one or two grooves cut length wise into your baffle edges to give the concrete something to grip onto. Otherwise you may end up with a loose baffle after the concrete dries and shrinks from losing its moisture along with the baffle itself drying and shrinking.
If you're concerned with air leakage, you can use one of the many concrete sealers available on the market. That will guarantee an air tight seal. A bead of rtv around the inside of the baffle insert will make sure the baffle is sealed.
I used chopped up cotton rope fibers mixed in with the concrete, but had no issues with ringing even without the fibers. It will depend on how much aggregate you introduce into the mixture and the wall thickness you end up with, making the enclosure immune to ringing. Roughly 3/4 inch wall thickness is a good target both for weight and inert acoustical properties as long as you have the proper amount of coarse sand mixed in.
I have experimented with pouring the concrete around the baffle board. This only works if you have one or two grooves cut length wise into your baffle edges to give the concrete something to grip onto. Otherwise you may end up with a loose baffle after the concrete dries and shrinks from losing its moisture along with the baffle itself drying and shrinking.
If you're concerned with air leakage, you can use one of the many concrete sealers available on the market. That will guarantee an air tight seal. A bead of rtv around the inside of the baffle insert will make sure the baffle is sealed.
Sorry, I didn’t mean to say concrete enclosures ring, but in order to get optimal results, use the right mix. Given that, concrete performs remarkably better than standard wood materials. Seen it, heard it. Thirty years ago. Even the shrinking can be controlled so that drivers fit.
Sorry, the twenty year-old who came upon this would be fully lost...they would be left pecking away at their phone trying to link up with a bluetooth connection that doesn't exist. Without such a link, our twenty year-old would be completely lost..."How does this work?...what's this wire for?"
---------------------------------------------------------------------------Rick.......
Living in Costa Rica now, where most houses are concrete block and steel, I can report that an angle grinder is the equivalent to a hammer in the US. An angle grinder with a masonry cutting disk could take out the entire center divider of a block in a minute or two…. But definitely a job to be done outside. Watta mess, but water helps keep down the dust. Removing the divider would also increase the internal dimensions more than you might think.
A blue tooth receiver is pretty easy to find at Parts Express. Youth of today will also assume the ACA amp and heatsink is already attached to the back panel..
A blue tooth receiver is pretty easy to find at Parts Express. Youth of today will also assume the ACA amp and heatsink is already attached to the back panel..
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As a twenty-something, you're right in expecting most to be oblivious. However, the issue is more that these people have never really seen anything beyond their all-in-one, spoon-fed, good-for-a-year junk. Once you've introduced many of these people (at least those that I've associated with in any real capacity) to "better" they'll gladly dive in head first to find more of whatever that was, how it works, etc. It's not that they can't be bothered, it's more that new and shiny perpetuates that wireless minimalism trend and we're out in the background somewhere with this stuff with no reason for them to know what is going on.
The real problem is more that you're going to need to sit them down with some good gear, well executed, and say, "Here's what you can do" if you want any hope of pushing DIY on them. DIY is not an entry point for people that haven't already been bit by the audio bug.
So I don't really get this speaker... It's not going to perform particularly well for the guy that wants to DIY something good, nor is it going to appeal to the guy that doesn't really know about audio/DIY because it is passive, it is wired, it isn't convenient relative to that bluetooth thing, and it isn't particularly attractive when it's sitting there all wired up unless you're after that super obvious "I made that" aesthetic.
Yes, you're so right on many levels. I've given up trying to explain a proper realistic music listening experience to millennials. 99.9% don't get it and never will, unless they have some sort of comparison to reference, which doesn't exist anymore in the mainstream of today's brain dead, ADHD and overstimulated society. The epiphany moment that opens their eyes to what used to be such a common thing to appreciate back in the day won't take place unless they put down their damn smartphone and pay attention to what's actually physically going on around them. Most kids don't even have their own formed identity or self asteem anymore because they're tought not to think for themselves and believe in the fake garbage their brainwashed with from the constant bombardment of online crap.
Being dissolved in the abyss of fake virtual reality, character and behavioral manipulation from social media and asking Google for advice on simple grade school knowledge based questions is creating stupid brainless zombies. These people are the empty, depressed and sad souls that now so commonly roam this earth. Its simply pathetic and tragic. This world is doomed and screwed...
End of rant.
I bet people reacted the same with the introduction of recorded music vs. live performance or introduction of the motor car when people rode horseback. 😉
My guess: in the broad variety of human kind there will always be people preferring a niche. And since world population rises, the niche gets bigger too. Btw I'm thankful for the modern times when I think back of the old days and the painstakingly slow way we had to acquire knowledge then.
My guess: in the broad variety of human kind there will always be people preferring a niche. And since world population rises, the niche gets bigger too. Btw I'm thankful for the modern times when I think back of the old days and the painstakingly slow way we had to acquire knowledge then.
It’s not that it’s going to be outright bad (though the concerns over the port and routing and driver chambers are valid reasons to question the potential performance) but I don’t expect it to be priced at a point that leaves it competitive with some existing lower budget DIY kit options. Yes, that’s based in nearly nothing, but I don’t expect it to be cheap enough to warrant the quirks of this unless clamps and glue terrify you. I’d love to be wrong on the pricing side of things. It’s just that whole industrial design thing leads to crazy prices for unnecessary minimalism pretty often.
But ultimately, I don’t have any hard evidence it won’t perform well (though the intent of that comment was not to say it flatly wouldn’t perform well, rather that it wouldn’t have an especially appealing price to performance ratio for the DIYer looking for a good kit, especially one that will gladly jump to an alternative if it’s a better deal), but I’d be happy to see someone with the tools to do so measuring such a kit and proving me wrong by showing that it’s a monster and whatever price it carries is of little concern.
But ultimately, I don’t have any hard evidence it won’t perform well (though the intent of that comment was not to say it flatly wouldn’t perform well, rather that it wouldn’t have an especially appealing price to performance ratio for the DIYer looking for a good kit, especially one that will gladly jump to an alternative if it’s a better deal), but I’d be happy to see someone with the tools to do so measuring such a kit and proving me wrong by showing that it’s a monster and whatever price it carries is of little concern.