Here's the place for purifi woofer discussion, #lrisbo contributing himself too
https://www.diyaudio.com/community/threads/exploring-purifi-woofer-speaker-builds.352063/
https://www.diyaudio.com/community/threads/exploring-purifi-woofer-speaker-builds.352063/
Should we discuss it here; https://www.diyaudio.com/community/...-x-for-mid-ranges.376164/page-10#post-7709648
Since that is actually about all the technical aspects, instead of a generic topic?
Risbo is contributing there as well.
Since that is actually about all the technical aspects, instead of a generic topic?
Risbo is contributing there as well.
There may be only so much that the Purifi guys can share. It is very likely that there are trade secrets involved that go beyond the patents. I know in my professional career that we had far more intellectual property covered by trade secret/proprietary IP rules rather than patents. We (engineering) would consult with the company's legal department to decide if the idea/device/process was patentable. Often times we would decide to just keep it a trade secret. Sometimes an idea would have two parts, the patented part (to prevent competitors from utilizing the idea), and the trade secret part (which was the information that might allow a competitor to circumvent the patent without violating the patent).
I can understand the Sd(x) phenomenon by simply examining the drivers I have on hand. Clearly the radiating surface shrinks as the cone+surround moves out, and increases as the cone+surround moves in. And of course, a small driver with large Xmax is much more affected by this than a large driver with a similar Xmax. With a 6" driver, the proportion of Sd that comes from the surround is a lot higher than a 12" driver.
I can understand the Sd(x) phenomenon by simply examining the drivers I have on hand. Clearly the radiating surface shrinks as the cone+surround moves out, and increases as the cone+surround moves in. And of course, a small driver with large Xmax is much more affected by this than a large driver with a similar Xmax. With a 6" driver, the proportion of Sd that comes from the surround is a lot higher than a 12" driver.
@b_force - thanks for your thoughts on active filter/amp options.
The difference between a custom made active filter and a custom made passive filter, from a DIY perspective, is that most of us are comfortable and experienced designing and building a passive filter.
Perhaps you can make one for $20 in parts. Most DIY speaker designers/builders (me included) do not have the skill/knowledge.
The difference between a custom made active filter and a custom made passive filter, from a DIY perspective, is that most of us are comfortable and experienced designing and building a passive filter.
Extremely dangerous position to be in.
That only works when certain "secrets" are not visually and technically obvious.
Or when the procedure is very specific and complicated.
Otherwise it's a simple matter of a competitor reverse engineering your product (which is 100% legal) and you have zero rights to defend yourself.
Most definitely not the best position to be in as one of your main technical claims and advantages.
Well since this is a diy community, there are plenty of people to step in?
I absolutely hate to plug my ideas, but maybe you understand the reason for this idea;
https://www.diyaudio.com/community/...active-loudspeaker-filter-board-evalf.405002/
Soldering some through hole electronics isn't much more difficult compared to passive filters parts.
Since we already have one stereo amplifier to begin with, we only need one additional one and we are done 😎
You would not make that statement with such authority if you understood my industry, and the nature of the trade secret we were protecting. This strategy was very effective, for several decades, until the original process/feature became obsolete.
I have no idea what the situation is with Purifi's patents and trade secrets, other than they are producing drivers which are unique in their extreme low distortion signature. I was simply speculating that there may be intellectual property reasons why they do not disclose more information than they already have.
That is a really cool thread. I missed it the first time around, because I rarely look beyond the "Multi-Way" forum.
For prototyping I use a couple of Crown Com-Tech or a Crown CTS 4800 amplifiers and a Rane AC23S or AC22S line level analog active crossovers plus a Rane line level equalizer.
You can dial the crossovers and equalize most any way you want.
You can dial the crossovers and equalize most any way you want.
I started cutting plywood about a week ago.
In the process of doing this, I decided to upgrade my router circle jig. I have been using a Jasper circle cutting jig for many years, and it served the purpose well. But I had a few complaints about it, namely, the 1/8" diameter steel center pin that fit into the jig and also into the wood workpiece. The pin requires a tight friction fit in both the wood and the plastic Jasper jig, and there was always the risk that the pin would drop down into the workpiece and come out of the jig, leaving the router unconstrained (i.e. cutting a scribble rather than a circle). This only happened once to me, but it was a constant worry. Some of the pin holes on the Jasper jig get used a lot, and they would become loose, adding to the worry.
I decided to try the "Milescraft" circle jig.
https://milescraft.com/product/circleguidekit/
It has two big advantages over the Jasper. The first is that the jig is fixed to the work piece with a small #6 screw which serves as the center pin. The screw allows the jig to rotate in a circle, but everything is firmly held together, no worries about a smooth pin slipping out of a hole. The second advantage is that the router is not permanently fastened to the jig. The router has a quick-detach mechanism, so it is possible to set up the jig and attach it to the workpiece, and then attach the router. Overall, the circle cutting process feels safer, with fewer opportunities for error.
In the process of doing this, I decided to upgrade my router circle jig. I have been using a Jasper circle cutting jig for many years, and it served the purpose well. But I had a few complaints about it, namely, the 1/8" diameter steel center pin that fit into the jig and also into the wood workpiece. The pin requires a tight friction fit in both the wood and the plastic Jasper jig, and there was always the risk that the pin would drop down into the workpiece and come out of the jig, leaving the router unconstrained (i.e. cutting a scribble rather than a circle). This only happened once to me, but it was a constant worry. Some of the pin holes on the Jasper jig get used a lot, and they would become loose, adding to the worry.
I decided to try the "Milescraft" circle jig.
https://milescraft.com/product/circleguidekit/
It has two big advantages over the Jasper. The first is that the jig is fixed to the work piece with a small #6 screw which serves as the center pin. The screw allows the jig to rotate in a circle, but everything is firmly held together, no worries about a smooth pin slipping out of a hole. The second advantage is that the router is not permanently fastened to the jig. The router has a quick-detach mechanism, so it is possible to set up the jig and attach it to the workpiece, and then attach the router. Overall, the circle cutting process feels safer, with fewer opportunities for error.
Thanks for the tip hifijim. I recently go the Jasper Jig Pro but I modified it for my DeWalt 20v max compact router - not having a cord twist up is great but it is off by a little less than 1/32-inch. It looks like the Milescraft works with my router and is more flexible.
So, thanks...for costing me $50 🤣
So, thanks...for costing me $50 🤣
I liked my Jasper jig and used it for many years, so your money was not wasted. Now that I am using this Milescraft unit, I realize that I could have used a small screw with the Jasper jig to replace the functionality of the 1/8" steel pin. I don't think a #6 screw would cleanly fit into the 1/8" holes in the jasper, but I bet a #4 pan-head screw would work fine. This would (for me) increase the usability of the jasper jig. Unfortunately, my router base coves the jig holes assigned to some very common diameters... nearly every tweeter requires a 4" recess and a 3" through-hole, so for those I would still be using that annoying pin.
Routing holes is the least enjoyable aspect of the speaker design/construction/testing process. This design has two full bulkhead braces above and below the woofer, and each brace has 6 holes. I don't do large-scale routing like this in my shop because of the vast amount of dust. I set up a work table outside. I notice some folks on this forum send their baffle designs to a CNC machine shop, and I wonder if that is the smarter move ... Someday I may reach that point. 🙁
j.
Routing holes is the least enjoyable aspect of the speaker design/construction/testing process. This design has two full bulkhead braces above and below the woofer, and each brace has 6 holes. I don't do large-scale routing like this in my shop because of the vast amount of dust. I set up a work table outside. I notice some folks on this forum send their baffle designs to a CNC machine shop, and I wonder if that is the smarter move ... Someday I may reach that point. 🙁
j.
Jim, if you create the proper sized hole in a piece of BB, you can then use this along with a template router bit with top bearing to create your through hole for the tweeter. Two way tape can hold this BB template in place to the baffle. For the recess, you can do the same, though you'd need to accurately set the depth.
Just make sure that the baffle and template does not move during routing.
Just make sure that the baffle and template does not move during routing.
(Disclaimer - for any of the cordless tools out there, assuming you have (or will have) more than one, you will pretty much be locked into that brand due to the cost of batteries.)
I love the cordless router in general - keeping the cord out of the way is wonderful. The only draw back (which I think is true of pretty much any compact/trim router) is the lack of a 1/2-inch collet. However, I understand for safety reasons why that is the case and am fine with it. It has a dust collection hood which works great, much better than my full-size corded DeWalt router (which is 70% dead).
Side note: With the near death of my old corded DeWalt router I bought a Triton 3HP router dedicated to my router table and absolutely love it. It has several features where I'm pretty impressed with the cleverness of the designers.
Since you mentioned dust earlier...I have bought the "Dust Right" click-connect accessories from Rockler. So I have an adapter attached to each of my compact router, table saw, miter saw and router table. I just un-click the hose from one tool and click it onto the next tool. In the last week I recessed 6 driver holes, made 6 trim rings and made rings and holes for ports with the compact router and Shop-Vac and had minor dust to vacuum up after words.
I love the cordless router in general - keeping the cord out of the way is wonderful. The only draw back (which I think is true of pretty much any compact/trim router) is the lack of a 1/2-inch collet. However, I understand for safety reasons why that is the case and am fine with it. It has a dust collection hood which works great, much better than my full-size corded DeWalt router (which is 70% dead).
Side note: With the near death of my old corded DeWalt router I bought a Triton 3HP router dedicated to my router table and absolutely love it. It has several features where I'm pretty impressed with the cleverness of the designers.
Since you mentioned dust earlier...I have bought the "Dust Right" click-connect accessories from Rockler. So I have an adapter attached to each of my compact router, table saw, miter saw and router table. I just un-click the hose from one tool and click it onto the next tool. In the last week I recessed 6 driver holes, made 6 trim rings and made rings and holes for ports with the compact router and Shop-Vac and had minor dust to vacuum up after words.
That Triton is fine, fine machine. Someday I will need to do a complete upgrade to my router table, and may get a Triton.
I was prompted to switch to a new circle jig because I needed a new mid-size plunge router anyway, the old one died. I have a fixed base Bosch 1617 that is very nice, so I decided to get the plunge version of the 1617. It is nice to have two interchangeable router motors with a fixed base and plunge base. The 1617 is compatible with both Jasper and Milescraft jigs.
I have not been happy with any dust collection device attached to a hand-held router. I have a compulsive need to watch bits/blades as they cut through wood. I don't like anything blocking the view. This means dust collection of hand-held routers is problematic for me, so I do most router work outside. But I am always on the lookout for better dust collection methods, so I will see what Rockler has to offer.
j.
In other news, I have the panels for the inner carcass cut and machined, so I am ready to start gluing up. In the photo I have the inner baffle, rear, top/bottom, and the primary bulkhead bracing. Later I will cut the sides and outer baffle.
Hi Jim! / Hi All!
I would like your opinion.
I have a small BR box with SB26CDC / SB17NBAC speakers. With passive crossover. I would like to complete it with a closed(?) active SUB. I looked at the FaitalPRO 10FE330 for it. Do you think this idea could work. (I followed several threads here in read-only mode, this is similar to your low-budget LCCAM-10.3 project)
I would like your opinion.
I have a small BR box with SB26CDC / SB17NBAC speakers. With passive crossover. I would like to complete it with a closed(?) active SUB. I looked at the FaitalPRO 10FE330 for it. Do you think this idea could work. (I followed several threads here in read-only mode, this is similar to your low-budget LCCAM-10.3 project)
So the 2-way SB26CDC/SB17NBAC speaker already exists, and you are happy with the sound? yes?
An active sub would be a good addition to this speaker. For best results, you should plug the bass reflex port on the 2-way. Foam is a good choice for this.
I am not familiar with the FaitalPRO 10FE330... but a quick look at the T/S parameters indicates to me that it is not ideal for a sealed box sub. With the right active EQ, it could work, but there are other drivers that would be better. The Dayton RSS265HF for example.
An active sub would be a good addition to this speaker. For best results, you should plug the bass reflex port on the 2-way. Foam is a good choice for this.
I am not familiar with the FaitalPRO 10FE330... but a quick look at the T/S parameters indicates to me that it is not ideal for a sealed box sub. With the right active EQ, it could work, but there are other drivers that would be better. The Dayton RSS265HF for example.
Thank you @hifijim for your valuable thoughts.
I am satisfied with my two-way SB box, but I would like a little extra bass. The ideal would be an old-school 3-way system (like the Just-DIY-it Triade) but I don't want to spoil what has already been completed. That's why I thought of a separate box. The FaitalPRO 10FE330 has a very nice datasheet, it looks good, but yes, you're right, it's better for a BR box. The question is, if I were to upgrade my system to the MiniDSP 2x4HD or the Dayton DSP-408, would the BR woofer be more of an advantage or a disadvantage?
I am satisfied with my two-way SB box, but I would like a little extra bass. The ideal would be an old-school 3-way system (like the Just-DIY-it Triade) but I don't want to spoil what has already been completed. That's why I thought of a separate box. The FaitalPRO 10FE330 has a very nice datasheet, it looks good, but yes, you're right, it's better for a BR box. The question is, if I were to upgrade my system to the MiniDSP 2x4HD or the Dayton DSP-408, would the BR woofer be more of an advantage or a disadvantage?