Mattes, those look absolutely amazing! I can just imagine how great they sound. I love the look of the small flower floating over the larger flower and you picked excellent drivers. Kudos on this design!
The picture and design makes it looks smaller than it is, but wow that is an 18" woofer in an almost 1meter diameter flower and I guess an 8" fullrange. My version will be a 3" fullrange and 10" RSS265HF-4 sub-woofer and even that doesn't feel small to me.
Don't worry about rushing your thread, just enjoy your speakers and all the hard work you have put into these.
I'll try to do some more baffle experiments later this week to share with the group.
Cheers
Jeshi
The picture and design makes it looks smaller than it is, but wow that is an 18" woofer in an almost 1meter diameter flower and I guess an 8" fullrange. My version will be a 3" fullrange and 10" RSS265HF-4 sub-woofer and even that doesn't feel small to me.
Don't worry about rushing your thread, just enjoy your speakers and all the hard work you have put into these.
I'll try to do some more baffle experiments later this week to share with the group.
Cheers
Jeshi
Hi Jeshi,
many thanks for your kind words! Yes it´s an 18-inch in OB, it goes down to 25 Hz and is able to produce an absolutely realistic illusion of an upright bass in original level, that was where I wanted to go, and it was a long way.
It´s not that difficult to buy an 18 inch driver, but I made several attempts before I realised that I had to get rid of ANY negative influences of boxes, wooden baffles or else. Obviously, that could have been achieved with the naked driver dipole approach, I tried it of course, but found it too much compromised with regards to efficiency. So I aimed at a baffle which gives the desired lift to the driver, maintains something like 88 dB efficiency and 25 Hz lower limit, but in the same time remains acoustically invisible, err, inaudible.
Now, for the first time, I realise the full beauty of Gary Peacocks performance (A closer view, with Ralph Towner) with an upright bass, powerful, ton´s of details, precisely located in my room, tone, colour, rhythm... I am very happy and can´t wait to continue...
You´ll have to realise that however, OB looses a lot of power. Your 10 inch driver will, as I assume you´ll make some type of enclosure, also be able to reproduce quite loud and deep.
All the best
Mattes
many thanks for your kind words! Yes it´s an 18-inch in OB, it goes down to 25 Hz and is able to produce an absolutely realistic illusion of an upright bass in original level, that was where I wanted to go, and it was a long way.
It´s not that difficult to buy an 18 inch driver, but I made several attempts before I realised that I had to get rid of ANY negative influences of boxes, wooden baffles or else. Obviously, that could have been achieved with the naked driver dipole approach, I tried it of course, but found it too much compromised with regards to efficiency. So I aimed at a baffle which gives the desired lift to the driver, maintains something like 88 dB efficiency and 25 Hz lower limit, but in the same time remains acoustically invisible, err, inaudible.
Now, for the first time, I realise the full beauty of Gary Peacocks performance (A closer view, with Ralph Towner) with an upright bass, powerful, ton´s of details, precisely located in my room, tone, colour, rhythm... I am very happy and can´t wait to continue...
You´ll have to realise that however, OB looses a lot of power. Your 10 inch driver will, as I assume you´ll make some type of enclosure, also be able to reproduce quite loud and deep.
All the best
Mattes
Mattes,
Beautiful work on the 18in flower baffle. I wonder if pink XPS home insulation foam can work here - rounded and sanded down. Painted of course. The 18in driver is quite impressive. Perhaps a double 18in flower?
Btw, I am walking around in Darmstadt at the moment and went into a HiFi store. Nice collection of B&O and B&W stuff. Germany takes HiFi more seriously I think. You don’t have to go far to find a good store.
Beautiful work on the 18in flower baffle. I wonder if pink XPS home insulation foam can work here - rounded and sanded down. Painted of course. The 18in driver is quite impressive. Perhaps a double 18in flower?
Btw, I am walking around in Darmstadt at the moment and went into a HiFi store. Nice collection of B&O and B&W stuff. Germany takes HiFi more seriously I think. You don’t have to go far to find a good store.
Attachments
Last edited:
Mattes, I do understand that a 10" will not produce as much bass as an 18" driver or go as low. But I live in a small Japanese apartment and my room has some acoustic problems, mainly a room node around 40-43hz that sucks energy and no matter what I do for treatments or positioning has worked to resolve it. Here are some graphs of measurements around my apartment (using my yamaha SW10 subwoofer to energize the room) showing one of the better spots and one of the worse spots. It really has to do with the geometry of my room and the limited positions I can place the speakers and sit for listening.
I have full range electrostatic speakers (acoustat 1+1) that can do down to about 25hz and I am still very happy with them as my main room speakers even with the room-node at 40hz. My diy speakers are for my near-field computer/music applications so I sit 1meter from the speakers. I choose the 10" driver for my next speaker build looking to see if they will work in this application and give me nice extension to about 45hz in an OB application. For a living room application I absolutely agree with you and would also be aiming at an 18" OB woofer. Let's see how my 10" experiments go from here.
XRK, I suspect that the XPS foam would work up to a point, but it is more rigid, resonant and reflective than EVA. EVA can be compressed and bounce back while XPS will permanently deform (push your finger into XPS and you get a hole). Although I don't have XPS to test, I suspect it is more sound reflective than EVA (sound will bounce off it) based on my memory of being in a construction with exposed XPS and the terrible acoustics of that space. The EVA foam is a good sound absorber (not best or perfect, but pretty good).
I think some of the benefits I hear (and I assume Mattes too) with the EVA baffles is that it acts to absorb reflected sounds, so even on the edges of a baffle the EVA is adding additional absorption. Also the EVA is vibration dampening so for something like a big 18" driver pumping out bass, an EVA baffle will not rattle and resonate, but I suspect that an XPS baffle of the same design would create a rattle and have a resonant frequency/buzz which would add color back into the sound. I suspect that Mattes previous experiments with wood baffles was showing a resonant rattle color. So yes it would be an interesting experiment but I don't think it would work well and given the effort needed to create an XPS baffle of this design, I don't think I would try it.
Awesome looking audio shop. Enjoy your time in Germany and enjoy the local food and beers
I have full range electrostatic speakers (acoustat 1+1) that can do down to about 25hz and I am still very happy with them as my main room speakers even with the room-node at 40hz. My diy speakers are for my near-field computer/music applications so I sit 1meter from the speakers. I choose the 10" driver for my next speaker build looking to see if they will work in this application and give me nice extension to about 45hz in an OB application. For a living room application I absolutely agree with you and would also be aiming at an 18" OB woofer. Let's see how my 10" experiments go from here.
XRK, I suspect that the XPS foam would work up to a point, but it is more rigid, resonant and reflective than EVA. EVA can be compressed and bounce back while XPS will permanently deform (push your finger into XPS and you get a hole). Although I don't have XPS to test, I suspect it is more sound reflective than EVA (sound will bounce off it) based on my memory of being in a construction with exposed XPS and the terrible acoustics of that space. The EVA foam is a good sound absorber (not best or perfect, but pretty good).
I think some of the benefits I hear (and I assume Mattes too) with the EVA baffles is that it acts to absorb reflected sounds, so even on the edges of a baffle the EVA is adding additional absorption. Also the EVA is vibration dampening so for something like a big 18" driver pumping out bass, an EVA baffle will not rattle and resonate, but I suspect that an XPS baffle of the same design would create a rattle and have a resonant frequency/buzz which would add color back into the sound. I suspect that Mattes previous experiments with wood baffles was showing a resonant rattle color. So yes it would be an interesting experiment but I don't think it would work well and given the effort needed to create an XPS baffle of this design, I don't think I would try it.
Awesome looking audio shop. Enjoy your time in Germany and enjoy the local food and beers
Attachments
Last edited:
At 41.5Hz we're talking an 8.19 meter wavelength. Your acoustic treatments would have to be quite large and cover a decent surface area to begin affecting that. That's why nothing has worked. Even tuned treatment like a limp membrane or Fraunhofer metal panel absorber would have to be large. We're talking 15.24+ cm thick and 2.4meter by 1.2 meter, and preferably multiple of them. What you can though, is attack it from multiple angles, aka distributed subs. I haven't seen that approach on this forum as much but several subs distributed around the room can blast those modes away, but still end up with the same overall SPL levels. Distributing like that you can also get away with many smaller subs that add up to same Sd as a larger one. I can post more on this if people are interested.
On the topic of foam, I tried to make an enclosure for my Tang Band W3-2141 drivers, did not work at all :/ It doesn't help that 1) I was enjoying a bottle of wine 2) I only had a retractable box cutter and 3) I had only 2" XPS lying around.
I should maybe just bite the bullet and order some EVA and a jeweler saw from smile.amazon.
I think you are right about the resonance Jeshi. XPS is actually the ideal material for DML’s since it is rigid and re-radiates sound. But perhaps a laminate of two pieces to give 2in thick with gooey viscoelastic material in between may work? I was thinking of the sticky mass loaded butyl rubber they use for car doors, and add a thinner layer of EVA craft sheets on the front surface. I am trying to find a lower cost version as these big sheets are quite pricey.
Yes this is a much better approach. In fact my plan for a Mattes flower is to use a thin layer (2mm or 5mm) of EVA surface over a spar and strut formed structure like an old WWI biplane wing. The EVA can be thermo-formed (heat gun) into shapes and I think this would be a great application for thermo-forming an EVA baffle. I will use EVA for my spars and struts though
For what it is worth I use an exacto knife for most of my EVA cutting and shaping followed by lots of wet sanding. But a jewlers saw is a great tool to have around.
about my room. you have to realize that this is a small Japanese rented apartment where my living/kitchen/music room is about 8m x 4m and that holds my sofa, main stereo, kitchen, computer space, diy speakers, 88key piano keyboard, dj rig, harp, bicycle, cat tree, litter box, record & cd collection, book shelves, storage boxes, every wall has something covering it, and there is a little bit of free floor space to walk around and set up a yoga mat. All the treatments you suggest would probably take up 33% of the space in my living room and I honestly don't know if it would actually fit (maybe if I take the stereo out lol). I don't want to loose that much of my precious space to try to fix this room node.
So I am happy to just live with it and hopefully when I can afford to buy a house I can find a place with better room acoustics. I am happy to have good extension to 45hz and then a surprise 30hz boom every now and then. I can live with it.
Last edited:
Mattes,
unique in every way, and gorgeous looking.
You have an good eye, and a good ear for these things!
I can only think you meant 800 hours on shaping the petals? Yikes! Ever thought about
going CNC?
It's funny because we just went to our local hardware store, and they sell EVA mats, 1m x 1m, 3cm thick for about $18. I thought of you guys.
unique in every way, and gorgeous looking.
You have an good eye, and a good ear for these things!
I can only think you meant 800 hours on shaping the petals? Yikes! Ever thought about
going CNC?
It's funny because we just went to our local hardware store, and they sell EVA mats, 1m x 1m, 3cm thick for about $18. I thought of you guys.
Hi Jeshi,
you´re absolutely right, XPS is not the material of choice. I used it for some cheap prototype baffles, to explore the benefits and drawbacks of first circular, than petal baffles, and yes it will rattle, resonate and reflect... and yes, I had wooden (massive particle board) baffles as well. The Dipole 18 has only (for an 18-inch driver) 115 gr. of moving mass, but if there is something in the vicinity of the working driver which might resonate, it will resonate.
My way out of this dilemma was the free-swinging approach (big thanks to Michael in Austria) and the 16 cm thick, massive EVA baffle.
Jeshi, somehow I wasn´t aware of you planning OB as well, sorry. Hope it works out well. In simulations, I have checked a lot of bass drivers for OB, in 10 inch I found the Peerless/Tymphany 830668 to be near perfect for OB, and cheap as well, should be decent up to a few hundred Hz, maybe together with your 10F ?
Hope your aircraft plane building method will work, I for myself would be afraid of the hollow structure... but good luck!
Hi XRK, enjoy your time in Germany!
Hi Perceval, no, it wasn´t 800 hours, but 800 metres to route. Hours I can only estimate, maybe something around 200 or 250 hours so far. Probably next time I´ll think about CNC, for sure, but in the moment I´m glad that I didn´t need to do that again anytime soon. Still have to get rid of enormous masses of ugly black dirt and dust in my garage...
Your EVA mats seem incredibly cheap, but which density is it? The density is crucial... however, I paid more than 5 times your price for my material...
All the best
Mattes
you´re absolutely right, XPS is not the material of choice. I used it for some cheap prototype baffles, to explore the benefits and drawbacks of first circular, than petal baffles, and yes it will rattle, resonate and reflect... and yes, I had wooden (massive particle board) baffles as well. The Dipole 18 has only (for an 18-inch driver) 115 gr. of moving mass, but if there is something in the vicinity of the working driver which might resonate, it will resonate.
My way out of this dilemma was the free-swinging approach (big thanks to Michael in Austria) and the 16 cm thick, massive EVA baffle.
Jeshi, somehow I wasn´t aware of you planning OB as well, sorry. Hope it works out well. In simulations, I have checked a lot of bass drivers for OB, in 10 inch I found the Peerless/Tymphany 830668 to be near perfect for OB, and cheap as well, should be decent up to a few hundred Hz, maybe together with your 10F ?
Hope your aircraft plane building method will work, I for myself would be afraid of the hollow structure... but good luck!
Hi XRK, enjoy your time in Germany!
Hi Perceval, no, it wasn´t 800 hours, but 800 metres to route. Hours I can only estimate, maybe something around 200 or 250 hours so far. Probably next time I´ll think about CNC, for sure, but in the moment I´m glad that I didn´t need to do that again anytime soon. Still have to get rid of enormous masses of ugly black dirt and dust in my garage...
Your EVA mats seem incredibly cheap, but which density is it? The density is crucial... however, I paid more than 5 times your price for my material...
All the best
Mattes
I am seeing the beauty of EVA really is the material of choice for OB. I will look around for larger thick sheets. I must try this! I have some rather higher Qts Eminence Beta 12cx that Freddi gave me. They might work for a smaller room?
Mattes,
Yes, really enjoying Germany. Wonderful country and such nice polite helpful people! Having a splendid time and about to go out for dinner with friends. Amazing beer!
Mattes,
Yes, really enjoying Germany. Wonderful country and such nice polite helpful people! Having a splendid time and about to go out for dinner with friends. Amazing beer!
Last edited:
I chose the Dayton audio RSS265HF-04 which is the same driver Gainphile uses for his top end S19 OB speaker Gainphile: S19 4-Way Dipole Radiator
He uses a pair in an W-frame. I just picked up the driver and did a test this morning of the bare driver without any baffle (at 0.2m measure distance) and it was really good. It has 12mm of linear xmax and a massive motor. I think it will respond quite well to an OB like your flower, but if not, I will put it in a U-frame.
I have no idea if the hollow structure will work, but I want to try. I am planning quite a lot of ribs and spars so it won't be that hollow, but it will be a lot easier to construct. But I'm not a fast builder so it will take a fair amount of time. For my small driver (10f or TG9) I will do a solid construction.
cheers
Jeshi
Attachments
Last edited:
You can always start with the EVA mats you can find in almost any store. But something like these rubber top EVA mats might be really good. they don't have the ribs like all the cheap mats do.
Amazon.com : Velotas Rubber Topped Interlocking Foam Fitness Floor Mat, Multiple Colors Available : Sports & Outdoors
I forgot to mention that I have not bought these so I don't know the density (like Mattes mentioned). The cheap orange EVA floor mats I bought (you saw in my recent circle baffle pics) are very low density and don't work so good. That is why I am trying to use them up now with these prototype experiments.
Last edited:
Hi Mattes and everyone,
I forgot to say thank you for your last response, it was 2am when I wrote my last posts. The peerless 10" 830668 was very high on my list for a long time until I discovered the gainphile speaker build and the RSS265HF. I also considered the SBacoustics 10", the SEAS L26RO4Y that linkwitz uses in his LX521 speaker and a few others. I did some models for OB on these and in the end the RSS265HF looked the best for me. I was also expecting to need to do DSP EQ correction like linkwitz and my previous OB experiments with the SB Satori MW16P-4. In fact my current diy speakers are left-side a closed box and right side OB with a 2way Satori MW16p-4 and dayton RS28f tweeter which I love.
So you have really inspired me and I can't seem to stop experimenting. This morning before heading for work I decided to do a quick flower with my 20cm disc. Just worked with the small 2" peerless 830983 driver. It's a simple biohazard-like 4 petal flower by cutting out wedges and then using the bendable nature of EVA to roll over the petals.
pics and graphs. yes this works great! Rolled over flower petals gives a smoother response. Even with the same diameter the roll over petals even gives a bit more extension. This is very promising. And with small 2-4" drivers maybe all we need is to bend an EVA sheet since they don't vibrate so much. The yellow trace is the round 20cm disk and orange is this biohazard flower.
But of course I will continue my experiments. I think my next experiment will be with using ribs under the petals to hold them at a steeper angle, or try thermo-forming so they can hold a more extreme shape. I might also work on shaping the petals with more rounding like yours. This little 830983 is not a bad little driver.
cheers
Jeshi
I forgot to say thank you for your last response, it was 2am when I wrote my last posts. The peerless 10" 830668 was very high on my list for a long time until I discovered the gainphile speaker build and the RSS265HF. I also considered the SBacoustics 10", the SEAS L26RO4Y that linkwitz uses in his LX521 speaker and a few others. I did some models for OB on these and in the end the RSS265HF looked the best for me. I was also expecting to need to do DSP EQ correction like linkwitz and my previous OB experiments with the SB Satori MW16P-4. In fact my current diy speakers are left-side a closed box and right side OB with a 2way Satori MW16p-4 and dayton RS28f tweeter which I love.
So you have really inspired me and I can't seem to stop experimenting. This morning before heading for work I decided to do a quick flower with my 20cm disc. Just worked with the small 2" peerless 830983 driver. It's a simple biohazard-like 4 petal flower by cutting out wedges and then using the bendable nature of EVA to roll over the petals.
pics and graphs. yes this works great! Rolled over flower petals gives a smoother response. Even with the same diameter the roll over petals even gives a bit more extension. This is very promising. And with small 2-4" drivers maybe all we need is to bend an EVA sheet since they don't vibrate so much. The yellow trace is the round 20cm disk and orange is this biohazard flower.
But of course I will continue my experiments. I think my next experiment will be with using ribs under the petals to hold them at a steeper angle, or try thermo-forming so they can hold a more extreme shape. I might also work on shaping the petals with more rounding like yours. This little 830983 is not a bad little driver.
cheers
Jeshi
Attachments
Hi Jeshi,
thanks for posting the biohazard measurements! To be honest, I thought a lot about the impact this materials might have, and I fear that there´s nothing environmental-friendly in EVA... apart from the paint which is not needed. I thought about using cork for some time, but in the end abandoned the idea.
I will make a few simulations later today with the RSS265, TSP looking quite good for OB. Just be warned that with 120 gr. MMS (more than the Dipole 18 with 3 times the surface...) the driver will, once in action, move anything in it´s vicinity. I see you´ll be using DSP, and of course that´ll give you a lot more headroom than a passive approach.
I´m sure you´re aware of the AE Dipole 10
Acoustic Elegance Dipole10 woofer for Open Baffle Applications
which is purpose designed for OB, but is expensive, and will be more expensive once at your door outside the USA.
However, your Peerless 2 inch looks good, and I like the biohazard shape as well. I think in the end it doesn´t make a difference wether you have 3, 4 or more petals, the path difference and the roundover are the decisive factors in the design. The non-reflective and non-resonant properties of the EVA baffle come on top.
Yesterday evening, I pulled out my Trentemöller LPs (which I bought just to know how Reinout blew his Accuton drivers...) and set my amp just shortly before the switchdown limit, which gives several hundreds of watts into 4 Ohm, in order to reach the maximum excursion of the Dipol 18 (a few centimetres). Yes, it´s possible. OK, I´ve been there. I know now. Nothing´s damaged. I don´t do things like this very often, but sometimes I need it. I also love my Björn Meyer and Jonas Hellborg bass solo albums...
All the best
Mattes
thanks for posting the biohazard measurements! To be honest, I thought a lot about the impact this materials might have, and I fear that there´s nothing environmental-friendly in EVA... apart from the paint which is not needed. I thought about using cork for some time, but in the end abandoned the idea.
I will make a few simulations later today with the RSS265, TSP looking quite good for OB. Just be warned that with 120 gr. MMS (more than the Dipole 18 with 3 times the surface...) the driver will, once in action, move anything in it´s vicinity. I see you´ll be using DSP, and of course that´ll give you a lot more headroom than a passive approach.
I´m sure you´re aware of the AE Dipole 10
Acoustic Elegance Dipole10 woofer for Open Baffle Applications
which is purpose designed for OB, but is expensive, and will be more expensive once at your door outside the USA.
However, your Peerless 2 inch looks good, and I like the biohazard shape as well. I think in the end it doesn´t make a difference wether you have 3, 4 or more petals, the path difference and the roundover are the decisive factors in the design. The non-reflective and non-resonant properties of the EVA baffle come on top.
Yesterday evening, I pulled out my Trentemöller LPs (which I bought just to know how Reinout blew his Accuton drivers...) and set my amp just shortly before the switchdown limit, which gives several hundreds of watts into 4 Ohm, in order to reach the maximum excursion of the Dipol 18 (a few centimetres). Yes, it´s possible. OK, I´ve been there. I know now. Nothing´s damaged. I don´t do things like this very often, but sometimes I need it. I also love my Björn Meyer and Jonas Hellborg bass solo albums...
All the best
Mattes
I love where this is going!
Great rebirth of this thread. The combination of EVA and the shapes... great match!
Jeshi, great demonstration of the flower-power indeed!
BTW, how did you get a Dayton driver in Japan?
Mattes, this is the EVA mat I saw over here. They are not the flimsy kind, but not as hard as I remember the EVA mats we had in elementary school for PE activities. And I think they may have some black ones too!
Great rebirth of this thread. The combination of EVA and the shapes... great match!
Jeshi, great demonstration of the flower-power indeed!
BTW, how did you get a Dayton driver in Japan?
Mattes, this is the EVA mat I saw over here. They are not the flimsy kind, but not as hard as I remember the EVA mats we had in elementary school for PE activities. And I think they may have some black ones too!
Attachments
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.