Tweet
This all started with my 'Convergence' project on a quest for a great bandpass design using a PR as the exit. Initially it was a TB W8-1445A (one-off production sample from the Tent Sale, and also this next item too) and an Eminence 12" PR. I wrote up the project here:
http://techtalk.parts-express.com/fo...ze-convergence
I had enough output with the 200W, but the extension on the bottom was lacking. It was made known to me of a commercial company, James Loudspeaker, that sells this kind of design commercially. This only fueled the desire to make this a viable little monster. It was well liked at InDIYana 2017.
Then I went to dig deeper...
I got a UM8-22 and RSS315PR, removed about a 0.25" for the mounting hole, coined the project 'Overdrive' in the same box, and got a little more extension, but the output then suffered. It seemed like where the amp was peaking out was where the design finally hit enough output on the 200W amp. I had a thermal driver failure in this setup, but ultimately do not know what the initialization of that traumatic event was. It could have been amp clipping, or just an inability to expel the heat being the kind of design this is, but I don't feel it was due to wrong box, or overexcursion. I had a replacement in it after that, and never had a problem up to removing it last weekend to make the retrofit explained herein happen for the finale of this 3-year design process. The models did not predict any issue to be concerned about before commencing down this previous path, and I've had several people review them just as reassurance.
I feel if you have a smaller living room or bedroom and require a subwoofer that either of these above would likely be sufficient, and the box isn't big at all. This was definitely a case for Hoffman's iron Law in terms of output vs Xmax.
And now the finale...
About 6 months ago, I started looking for another upgrade path to improve this design and make it what I want from it. On a whim, I modeled the UM10-22 in the same box, and to my surprise I might add, it basically gave me the same result the Um8-22 yielded in terms of response. The improvements were mainly in Sd, Xmax, power handling capacity, and nominal sensitivity. So- same response, but more and better of the 4 specs just stated. I'd call that a win!
I waffled over whether to take the plunge for a good bit of time, because not everyone is happy with this line of subwoofers. It wasn't until there was a sale on the Yung amplifiers in June that I had to make up my mind quickly. Rory was in town around that time, and we had a discussion about this project and the possible options, and he felt my aim was true. I had a lengthy exchange with MattP at PE via PM about the possible reliability concerns of both the amp and the woofers because he has had them himself, and likely not been totally congenial with them. I'm sure he put them to task. He said the 10 was a worthy step-up, and take boosted low end very well. He also said they have not had recent issues with the Yung amps. Since it came from the horse's mouth, I was reassured and bought the Yung SD500-6 amp right before the sale ended. I then picked up the UM10-22 at the Tent Sale a month later for a reduced price.
Now with supplies in hand, I had to modify the box. Most of the time when retrofitting, you just get out the jig-saw and cut a larger hole. Being this is a bandpass, I could not just do that. So after old-units removal, I had to slice off the front chamber of the box. Then I used the former 8" mounting holes as bridge mounts for the false-center. I marked the center using the corners of the box since it's a square x-section, and routed a new rebate, followed by a new through-hole. I marked and drilled mounting holes, and then I biscuit and glued the front back on. Of note- the driver does fit through the PR hole, but barely! I'm glad I had both sides of the driver accessible to position the driver appropriately, or this would have been extremely difficult.
Then I had to cut the new amp through-square, and I'm only lacking about 0.75" in dimension from taking up the entire rear panel. I had to remove the 4 braces I had glued in for the last iteration, and then glued in 2 new braces per side of the box for strength and resonance control.
I used a 4-pole terminal block for connection of amp to driver. There is a bridge connecting the center 2 connectors so that the DVC is connected in series. As for wiring, I wanted something really solid. The UM series takes banana plugs, and I had a set of "polycarbonate locking bananas" and some 2/16 Belden Brilliance wire handy. I used both wires for a net-13AWG assembly per terminal, and CRANKED on them in the jack with a pair of pliers to make them tight. Then I heat-shrunk the banana to jack connection for ultimate durability and keep them from coming apart. I wasn't going to use them for speaker cables, as the locking types tend to break with repeated use, and IMO are kind of a pain to undo and reconnect. I deemed this an acceptable use for them since they would only be attached once.
So- there is the process of this build. Now for the grit in numbers and graphs, as well as some assembly photos of the adaptation.....
More in the next post,
Wolf
http://techtalk.parts-express.com/fo...ze-convergence
I had enough output with the 200W, but the extension on the bottom was lacking. It was made known to me of a commercial company, James Loudspeaker, that sells this kind of design commercially. This only fueled the desire to make this a viable little monster. It was well liked at InDIYana 2017.
Then I went to dig deeper...
I got a UM8-22 and RSS315PR, removed about a 0.25" for the mounting hole, coined the project 'Overdrive' in the same box, and got a little more extension, but the output then suffered. It seemed like where the amp was peaking out was where the design finally hit enough output on the 200W amp. I had a thermal driver failure in this setup, but ultimately do not know what the initialization of that traumatic event was. It could have been amp clipping, or just an inability to expel the heat being the kind of design this is, but I don't feel it was due to wrong box, or overexcursion. I had a replacement in it after that, and never had a problem up to removing it last weekend to make the retrofit explained herein happen for the finale of this 3-year design process. The models did not predict any issue to be concerned about before commencing down this previous path, and I've had several people review them just as reassurance.
I feel if you have a smaller living room or bedroom and require a subwoofer that either of these above would likely be sufficient, and the box isn't big at all. This was definitely a case for Hoffman's iron Law in terms of output vs Xmax.
And now the finale...
About 6 months ago, I started looking for another upgrade path to improve this design and make it what I want from it. On a whim, I modeled the UM10-22 in the same box, and to my surprise I might add, it basically gave me the same result the Um8-22 yielded in terms of response. The improvements were mainly in Sd, Xmax, power handling capacity, and nominal sensitivity. So- same response, but more and better of the 4 specs just stated. I'd call that a win!
I waffled over whether to take the plunge for a good bit of time, because not everyone is happy with this line of subwoofers. It wasn't until there was a sale on the Yung amplifiers in June that I had to make up my mind quickly. Rory was in town around that time, and we had a discussion about this project and the possible options, and he felt my aim was true. I had a lengthy exchange with MattP at PE via PM about the possible reliability concerns of both the amp and the woofers because he has had them himself, and likely not been totally congenial with them. I'm sure he put them to task. He said the 10 was a worthy step-up, and take boosted low end very well. He also said they have not had recent issues with the Yung amps. Since it came from the horse's mouth, I was reassured and bought the Yung SD500-6 amp right before the sale ended. I then picked up the UM10-22 at the Tent Sale a month later for a reduced price.
Now with supplies in hand, I had to modify the box. Most of the time when retrofitting, you just get out the jig-saw and cut a larger hole. Being this is a bandpass, I could not just do that. So after old-units removal, I had to slice off the front chamber of the box. Then I used the former 8" mounting holes as bridge mounts for the false-center. I marked the center using the corners of the box since it's a square x-section, and routed a new rebate, followed by a new through-hole. I marked and drilled mounting holes, and then I biscuit and glued the front back on. Of note- the driver does fit through the PR hole, but barely! I'm glad I had both sides of the driver accessible to position the driver appropriately, or this would have been extremely difficult.
Then I had to cut the new amp through-square, and I'm only lacking about 0.75" in dimension from taking up the entire rear panel. I had to remove the 4 braces I had glued in for the last iteration, and then glued in 2 new braces per side of the box for strength and resonance control.
I used a 4-pole terminal block for connection of amp to driver. There is a bridge connecting the center 2 connectors so that the DVC is connected in series. As for wiring, I wanted something really solid. The UM series takes banana plugs, and I had a set of "polycarbonate locking bananas" and some 2/16 Belden Brilliance wire handy. I used both wires for a net-13AWG assembly per terminal, and CRANKED on them in the jack with a pair of pliers to make them tight. Then I heat-shrunk the banana to jack connection for ultimate durability and keep them from coming apart. I wasn't going to use them for speaker cables, as the locking types tend to break with repeated use, and IMO are kind of a pain to undo and reconnect. I deemed this an acceptable use for them since they would only be attached once.
So- there is the process of this build. Now for the grit in numbers and graphs, as well as some assembly photos of the adaptation.....
More in the next post,
Wolf
Comment