Moderator note: this thread split off from here http://www.diyaudio.com/forums/showthread.php?s=&threadid=129625 
Hello Jean-Michel.
Thanks for the hint. (Btw, I´m a big admirer of your work and follow it with big interest and pleasure)
I always considered this flaw from the beginning and decided to find out what it will finally will sound.
The horns were designed on CAD and fem or bem are available to me (structural engeneer), so I played with some versions that took an eye on that.
But: I wanted to give a big merit to the appearance for my eye.
And this way it just looked better to me (for my eyes this just looked "cleaner" or something like that).
I admit: With my constructions sometimes function has to follow form.
But I guess though this, it measures quite good:
(The dip around 6kHz is due to the not optimal crossover of the bms 4590 coax. With a radian 2´´ the horn measures flat)
http://www.miwis-bastelbu.de/Galerien/Hinkelsteine/slides/Hinkelsteine140.jpg
Hi denewma04.
Before casting it in stone, there were prototypes made of fibreglass, papercrete and polymeric concrete.
Finally I made the flowstone-versions and they sound superior to the other versions. (though they all have the same measured response)
Last step in the row was to make a complete prototype-horn from fibreglass and plaster and then take a mold from this, which sonsist of 3 seperate parts.
The procedure is the same as with normal cement.
But the blend is very sensitive, we´re still experimenting.
Ingrdients (percentage still vary):
white cement (high resistance, pressure about 100N/mm², tension without reinforcement 15N/mm²), sand, water, deaerate-additive, flow-additive, glassfibres, pigment if you wish to.
(The base of my TT is of this black-pigmented concrete: click for a pic )
It´s not behaving like common concrete, less resonating, smooth (if the mold is), very rigid.
It can be polished like natural stone, but it´s as difficult as with the natural stone, cause these concretes get very firm.
I use very expensive diamond-tools to grind the flange.
The horns are casted in a bassins, which is flooded with water some hours after the fresh concrete is poured in. The horn stays in the water for 30 days.
To get it out of the mold we need pressure of 10 bar ( appr. 150 psi).
After some time the horns come out of the mold with a silky surface like this (or sometimes it breaks up in parts
)
Everytime I manage to get the horn out of the mold in one piece and without harm, I owe myself a good islay-malt and light up a cigarette.
Cheers, Michael
Hello Jean-Michel.
Thanks for the hint. (Btw, I´m a big admirer of your work and follow it with big interest and pleasure)
I always considered this flaw from the beginning and decided to find out what it will finally will sound.
The horns were designed on CAD and fem or bem are available to me (structural engeneer), so I played with some versions that took an eye on that.
But: I wanted to give a big merit to the appearance for my eye.
And this way it just looked better to me (for my eyes this just looked "cleaner" or something like that).
I admit: With my constructions sometimes function has to follow form.
But I guess though this, it measures quite good:
(The dip around 6kHz is due to the not optimal crossover of the bms 4590 coax. With a radian 2´´ the horn measures flat)
http://www.miwis-bastelbu.de/Galerien/Hinkelsteine/slides/Hinkelsteine140.jpg
Hi denewma04.
Before casting it in stone, there were prototypes made of fibreglass, papercrete and polymeric concrete.
Finally I made the flowstone-versions and they sound superior to the other versions. (though they all have the same measured response)
Last step in the row was to make a complete prototype-horn from fibreglass and plaster and then take a mold from this, which sonsist of 3 seperate parts.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The procedure is the same as with normal cement.
But the blend is very sensitive, we´re still experimenting.
Ingrdients (percentage still vary):
white cement (high resistance, pressure about 100N/mm², tension without reinforcement 15N/mm²), sand, water, deaerate-additive, flow-additive, glassfibres, pigment if you wish to.
(The base of my TT is of this black-pigmented concrete: click for a pic )
It´s not behaving like common concrete, less resonating, smooth (if the mold is), very rigid.
It can be polished like natural stone, but it´s as difficult as with the natural stone, cause these concretes get very firm.
I use very expensive diamond-tools to grind the flange.
The horns are casted in a bassins, which is flooded with water some hours after the fresh concrete is poured in. The horn stays in the water for 30 days.
To get it out of the mold we need pressure of 10 bar ( appr. 150 psi).
After some time the horns come out of the mold with a silky surface like this (or sometimes it breaks up in parts
)
An externally hosted image should be here but it was not working when we last tested it.
Everytime I manage to get the horn out of the mold in one piece and without harm, I owe myself a good islay-malt and light up a cigarette.
Cheers, Michael
Hello Michael,
Could you elaborate a bit why it is needed to submerse the mold under water? This discouraged me a bit..
It would be great if you could put together a tutorial on making these horns. There are just to few articles on manufacturing horns. Angelo did a great job in this regard.
I mean what do you actually use in making the prototype horn? You mention plaster but what is that exactly and what is the process? Do you also use fiberglass for the prototype?
I hope these are not too many questions. I just find your work pretty amazing.
Could you elaborate a bit why it is needed to submerse the mold under water? This discouraged me a bit..
It would be great if you could put together a tutorial on making these horns. There are just to few articles on manufacturing horns. Angelo did a great job in this regard.
I mean what do you actually use in making the prototype horn? You mention plaster but what is that exactly and what is the process? Do you also use fiberglass for the prototype?
I hope these are not too many questions. I just find your work pretty amazing.
Michael, thanks for the info. I am also in the planning stages of a DIY turntable and have been giving a great deal of thought to making the base out of concrete as you have done. It looks beautiful. More research on that will be required. I'd love to copy your horns, but it's a bit out of my league, currently.
Great work on your website.
Great work on your website.
Hello.
Yes, the prototypes are made of fibreglass and plaster, there are several products in the boat-building, model-making and car-tuning-shops.
The mold has to be submersed under water, because concrete is hydraulically hardening and it is building crystalline CSH-phases, which means it is binding the water chemically. To much water will not be bond, to less water and you won´t get all c and s to an h so to say. (it´s difficult to me to explain this in my bad english, sorry)
This very special concrete must be mixed with only a wter/cement value of appr. 0,15 which is very low. This guaranties very less microholes in the structure lateron, because there is very less water which is not chemically bound and therefor cannot evaporate an leave tiny holes. The concrete has to me mixed nearly one hour, before it gets creamy. The first 20 minutes you think "this won´t ever be a fluid" because its like dust first. This is crazy high-tech-cement.
Putting the mold under water gives you a better surface, a more stable replication of colour (depends on temperature and microholes in the surface) a stronger concrete and it prevents a big amount of shrinkage (dehydration-shrinkage as well as the further shrinkage process). Another effect is to keep the temperature of the hardening concrete low, which is also good.
Less shrinkage means less microcracks etc.
If you dont put it under water, it is nearly impossible, to get it out of the mold. There is still one molding hanging from the ceiling with on horn in it, we couldn´t even get it of with a jackhammer.
But all this doesn´t work with usual concrete. Usual concrete also has less good sound signature, it rings way more than this one.
This concret is about 7 times more expensive, has highest strength, is self-compressing and you will have to use additives like deaerate-additive, flow-additive, etc. The blend is very delicate. The additives have to be weight out by gram.
You can search for furniture made of this concret etc. on google.
See this:
flowstone and this broschure
Cheers, Michael
BTW: The speakers shown above are from a friend with my horns on top.
This are mine:
and another one from a friend who made the concrte horn-project together with me:
His speakers as well as mine are supported each by two tapped horn subs, which are not shown (partly build in the walls or kept under curtains etc.)
Yes, the prototypes are made of fibreglass and plaster, there are several products in the boat-building, model-making and car-tuning-shops.
The mold has to be submersed under water, because concrete is hydraulically hardening and it is building crystalline CSH-phases, which means it is binding the water chemically. To much water will not be bond, to less water and you won´t get all c and s to an h so to say. (it´s difficult to me to explain this in my bad english, sorry)
This very special concrete must be mixed with only a wter/cement value of appr. 0,15 which is very low. This guaranties very less microholes in the structure lateron, because there is very less water which is not chemically bound and therefor cannot evaporate an leave tiny holes. The concrete has to me mixed nearly one hour, before it gets creamy. The first 20 minutes you think "this won´t ever be a fluid" because its like dust first. This is crazy high-tech-cement.
Putting the mold under water gives you a better surface, a more stable replication of colour (depends on temperature and microholes in the surface) a stronger concrete and it prevents a big amount of shrinkage (dehydration-shrinkage as well as the further shrinkage process). Another effect is to keep the temperature of the hardening concrete low, which is also good.
Less shrinkage means less microcracks etc.
If you dont put it under water, it is nearly impossible, to get it out of the mold. There is still one molding hanging from the ceiling with on horn in it, we couldn´t even get it of with a jackhammer.
But all this doesn´t work with usual concrete. Usual concrete also has less good sound signature, it rings way more than this one.
This concret is about 7 times more expensive, has highest strength, is self-compressing and you will have to use additives like deaerate-additive, flow-additive, etc. The blend is very delicate. The additives have to be weight out by gram.
You can search for furniture made of this concret etc. on google.
See this:
flowstone and this broschure
Cheers, Michael
BTW: The speakers shown above are from a friend with my horns on top.
This are mine:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
and another one from a friend who made the concrte horn-project together with me:
An externally hosted image should be here but it was not working when we last tested it.
His speakers as well as mine are supported each by two tapped horn subs, which are not shown (partly build in the walls or kept under curtains etc.)
And this concrete behaves like alien stuff.You know this fluid Terminator from T2 ?
When you take the concrete after 1h of mixing, you still can make dusty breadcrumbs when grinding it in your hands (because of so less water in it). It feels very strong an rigid, you cant squeeze it through your fingers.
The breadcrumbs fall on the floor and after one minute they start to to converge, one minute later they contract to one flat spread mass, like this sh.. is living.
It needs time to flow and to self-compress.
The first ten minutes when the horns are in the mold, a lot of bubbles ascent and the concrete itselfs gets rid off all the air in it.
I´m a strutural engeneer and have seen some concrete, but never one strange like this.
Michael
@Michael,
at the risk of becoming annoying, do you think it would be ok to start a new thread and discuss a bit about the materials you used?
Probably many of us are not that familiarised with different fibeglass/plaster materials and techniques. Not to mention alien concrete . I mean, the brands you are using and so on.
I guess that starting a new thread or continuing the one about your speakers posted several months ago would be better, in order to preserve Angelo's subject.
Oh, and by the way, you have mentioned listening to the radian driver in the same horn. How do you compare it with the coaxial one?
Thank you!
at the risk of becoming annoying, do you think it would be ok to start a new thread and discuss a bit about the materials you used?
Probably many of us are not that familiarised with different fibeglass/plaster materials and techniques. Not to mention alien concrete
. I mean, the brands you are using and so on.I guess that starting a new thread or continuing the one about your speakers posted several months ago would be better, in order to preserve Angelo's subject.
Oh, and by the way, you have mentioned listening to the radian driver in the same horn. How do you compare it with the coaxial one?
Thank you!
Hi SunRa.
Some words about the radian:
On the german "Frickelfest" there was a setup running my horns with the Radian and a DIY 300B (barossis speaker, shown above), and another setup with my horns and the BMS4590 connected to Peter Daniel LM3875 premium kit (my personal system).
In this special case I came to the following very personal impression:
The Radian has a lot of magic in the mids. Very lovely with female voices etc. Very relaxed and smooth with the 300B SET. In comparison to the BMS+LM3875 the radian+300B did this better.
For my ears the Radian cannot be used without a tweeter, there is missing quite a lot in the very high frequency range.
For my very personal taste in comparison to the BMS the Radian lacks a little bit of attac/punch, when it comes to very dynamic/fast/punchy music, specially at very high listening levels.
Now I have a 2A3 SET Triode connected to my BMS, and there it is, the sweet midrange and the smoothness. From the retrospection I would say as good as the Radian with 300B.
With the chipamp (which I will use alternately to the 2A3) you get mor details, attac and more "truth". But sometimes the truth hurts, if you know what I mean.
So, for me the two drivers are very close, but integrating an extra supertweeter when using the radian keeps me staying with my 4590.
Cheers, Michael
Good suggestion I think.
Some words about the radian:
On the german "Frickelfest" there was a setup running my horns with the Radian and a DIY 300B (barossis speaker, shown above), and another setup with my horns and the BMS4590 connected to Peter Daniel LM3875 premium kit (my personal system).
In this special case I came to the following very personal impression:
The Radian has a lot of magic in the mids. Very lovely with female voices etc. Very relaxed and smooth with the 300B SET. In comparison to the BMS+LM3875 the radian+300B did this better.
For my ears the Radian cannot be used without a tweeter, there is missing quite a lot in the very high frequency range.
For my very personal taste in comparison to the BMS the Radian lacks a little bit of attac/punch, when it comes to very dynamic/fast/punchy music, specially at very high listening levels.
Now I have a 2A3 SET Triode connected to my BMS, and there it is, the sweet midrange and the smoothness. From the retrospection I would say as good as the Radian with 300B.
With the chipamp (which I will use alternately to the 2A3) you get mor details, attac and more "truth". But sometimes the truth hurts, if you know what I mean.
So, for me the two drivers are very close, but integrating an extra supertweeter when using the radian keeps me staying with my 4590.
Cheers, Michael
Hi SunRa.
I´ll answer here, till it all togehter will be moved, ok. ?
Do you mean the mold or the prototye ?
Mold: appr. 5-6 layers of 300gr/m²
Prototype:
As far as I can remember, I used 4 layers for the inner mold: 180gr/m²+2x400gr/m²+180gr/m² .
On the inner mold I glued a lot of "reference points" of 25mm thickness, then I put compound plastic-concrete filler on this till I reached the thickness-marks. On top of that 3 or 4 layers of 180gr/m² glasfibre and the finish with car-spackle and fine filler.
This gives a thickness of 30mm+ for the horns lateron, as can be seen on this cut through a horn:
Perhaps because it isn´t mine, too and sometimes I don´t know if the technical terms really mean the things I want to describe.
If I write things that do not make sense, please give me a hint.
Cheers, Michael
I´ll answer here, till it all togehter will be moved, ok. ?
Do you mean the mold or the prototye ?
Mold: appr. 5-6 layers of 300gr/m²
Prototype:
As far as I can remember, I used 4 layers for the inner mold: 180gr/m²+2x400gr/m²+180gr/m² .
On the inner mold I glued a lot of "reference points" of 25mm thickness, then I put compound plastic-concrete filler on this till I reached the thickness-marks. On top of that 3 or 4 layers of 180gr/m² glasfibre and the finish with car-spackle and fine filler.
This gives a thickness of 30mm+ for the horns lateron, as can be seen on this cut through a horn:
An externally hosted image should be here but it was not working when we last tested it.
Perhaps because it isn´t mine, too and sometimes I don´t know if the technical terms really mean the things I want to describe.
If I write things that do not make sense, please give me a hint.
Cheers, Michael
Hi Lynn.
Thank you for the flowers.
I´m sorry I do not know, what MTM-system means.
And I´m a bit confused about the dipol-comment (because I´ve tried Dipols as subbbass, but none of them is shown on the pics)
(I´d better not be sleeping all the english lessons in school.)
I´ll write about the used bassdrivers. Just tell me, if that´s not, what you were asking for....
My first system (with the curved bass-enclosures) had a Beyma 15LX60 in a 120L vented encllosure, running from appr. 40Hz-400Hz.
My current system uses two 12" drivers, from 70Hz up to 400Hz, each in 55l cb.
I used A&D Audio R1230 and a kind of OEM version of this driver , which looks as an A&D and measures nearlythe same (I guess probably coming from the same factory).
It´s a chinese driver, which seems no longer be on the manufacturers homepage.
This is where we bought them:R1230 specs
For my tappedhorns (from 70Hz down) I use B&C 15PS100.
The setup of my buddy uses four 10" midbass-driver per side, each in 40l closed. It´s the A&D Audio R1030 -> R1030 specs
His subs are two tappedhorns. He used 18" SPH450TC
specs but now has the B&C 15LX60, because they are a bit "faster" and spl still is more than enough.
The chinese midbass-driver are very inexpensive and I´m usually not a guy who favours the "cheap-thrill".
But in my opinion, !only considering home-use!, they don´t have to hide from the Pro-Drivers I had in my hands. Till now I´ve bought 16 of the A&D 10" and 12" and with none of them I had to claim on grade of quality. By contrast, out of the box one of two Beyma 15LX60 had an objekt behind the dustcap, which was "tickering" and had to be replaced. One of four B&C15PS100 had a hardened glue-drop behind the surround which caused a tickering noise and therefor had to be replaced.
The A&D measure quite good and they sound very good to me.
For pro-use there are other things like power rating etc., but this don´t matters for my home use.
They actually survived a hard outdoor-session on the Frickelfest:
Hi agent 5.
The curved baffle (all walls are curved) is made of 8 curved layers of 10mm MDF reinforced with a lot of fibreglass and I also wasted a lot of filler. Pics from the process here:
link to my page
Hi Spasticteapot.
I´m willing to do that. But all I´ve done is just from the spec-sheets of the manufacturer. It´s all about two things:
1.)
How do I make a mold, which has the desired surface (here: glossy/fair) and which allows to get the thing out of it lateron.
Refer to the molds for fibreglass etc. There is shrinkage and you better have no undecuts, split the mold in parts, where it is necessery. Use a lot of waxing on the mold and arrange some air-pressure conections.
2.) Find your personal concrete-mix. This depends on what cement and what additives you can get an what kind of sand and other additives (pigments etc.) you use.
For first tries refer to the manufacturer datasheets, then start to vary. Our first few attempts were cr*p, but learning by doing is a good way to go. You have to get a feeling for the material first.
Cheers, Michael
Thank you for the flowers.
I´m sorry I do not know, what MTM-system means.
And I´m a bit confused about the dipol-comment (because I´ve tried Dipols as subbbass, but none of them is shown on the pics)
(I´d better not be sleeping all the english lessons in school.)
I´ll write about the used bassdrivers. Just tell me, if that´s not, what you were asking for....
My first system (with the curved bass-enclosures) had a Beyma 15LX60 in a 120L vented encllosure, running from appr. 40Hz-400Hz.
My current system uses two 12" drivers, from 70Hz up to 400Hz, each in 55l cb.
I used A&D Audio R1230 and a kind of OEM version of this driver , which looks as an A&D and measures nearlythe same (I guess probably coming from the same factory).
It´s a chinese driver
, which seems no longer be on the manufacturers homepage.This is where we bought them:R1230 specs
For my tappedhorns (from 70Hz down) I use B&C 15PS100.
The setup of my buddy uses four 10" midbass-driver per side, each in 40l closed. It´s the A&D Audio R1030 -> R1030 specs
His subs are two tappedhorns. He used 18" SPH450TC
specs but now has the B&C 15LX60, because they are a bit "faster" and spl still is more than enough.
The chinese midbass-driver are very inexpensive and I´m usually not a guy who favours the "cheap-thrill".
But in my opinion, !only considering home-use!, they don´t have to hide from the Pro-Drivers I had in my hands. Till now I´ve bought 16 of the A&D 10" and 12" and with none of them I had to claim on grade of quality. By contrast, out of the box one of two Beyma 15LX60 had an objekt behind the dustcap, which was "tickering" and had to be replaced. One of four B&C15PS100 had a hardened glue-drop behind the surround which caused a tickering noise and therefor had to be replaced.
The A&D measure quite good and they sound very good to me.
For pro-use there are other things like power rating etc., but this don´t matters for my home use.
They actually survived a hard outdoor-session on the Frickelfest:
Hi agent 5.
The curved baffle (all walls are curved) is made of 8 curved layers of 10mm MDF reinforced with a lot of fibreglass and I also wasted a lot of filler. Pics from the process here:
link to my page
Hi Spasticteapot.
I´m willing to do that. But all I´ve done is just from the spec-sheets of the manufacturer. It´s all about two things:
1.)
How do I make a mold, which has the desired surface (here: glossy/fair) and which allows to get the thing out of it lateron.
Refer to the molds for fibreglass etc. There is shrinkage and you better have no undecuts, split the mold in parts, where it is necessery. Use a lot of waxing on the mold and arrange some air-pressure conections.
2.) Find your personal concrete-mix. This depends on what cement and what additives you can get an what kind of sand and other additives (pigments etc.) you use.
For first tries refer to the manufacturer datasheets, then start to vary. Our first few attempts were cr*p, but learning by doing is a good way to go. You have to get a feeling for the material first.
Cheers, Michael
For general information on designing this from concrete you can google for "concrete furniture", "polisched concrete floors", "concrete countertops" etc.
I just found this video:
coloured concrete table
(I love concrete for all kind interior design. All the floors in my new house will be concrete, there will be concrete furniture and finally the horns, for sure.)
I just found this video:
coloured concrete table
(I love concrete for all kind interior design. All the floors in my new house will be concrete, there will be concrete furniture and finally the horns, for sure.)
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.