That's good to know, shows the amp can last! Hopefully someone else can take advantage of a big saving off the cost.
I know it’s been a while since this thread was updated but the design is intriguing to me. Any thoughts as to if the UMII10-22 would be a drop in replacement for the design as the UM10-22 is no longer available or will some remodeling be in order?
It has longer Xmax, but if the Qts and Vas are close, it should be okay. I could model it and find out how it handles the sealed box.
The Qts dropped a bit from .72 to .57. Vas is a little higher. Looks like the driver would have a different response unfortunately.
Okay, the best I can come up with is just a little different. The output potential for the UMII10-22 is +2dB over the former UM10-22 with these shifted parameters at the same power input. The +6dB boost at 30Hz is still plausible, but the response increases a bit with decreasing frequency to where it could just meet and match room gain and sound fine without it.
The PR needs to be tuned a touch higher at 52Hz. This yields a bandwidth of 32-64Hz, which is very close to the former. However, the chambers need slightly adjusted. The former UM1 was 18/8 ltr arrangement, whereas the UMII looks good in a 17/10 ltr arrangement. Xmax in check at 200W for 107dB peak output. The Q change of the new driver involves this shift to flatten the response a bit. However, this difference changes the 0.8dB gain in the former to the 0.6dB loss in the latter. I could not get a better alignment with less loss as the response was too peaked.
The amplifier being 500W is still capable of blowing the woofer, so be careful. Be advised that it may change distance dimensions internally and change clearance from amp to driver. UMII has 155mm behind mounting of the basket. The former is only 145mm deep. With the shift of the internal driver baffle to the rear to make 17 ltrs, mounting the woofer atop both inner baffles instead of in the middle will move it forward. The PR is also in a larger chamber, so the proximity to the active driver should also be fine.
Take this for what it's worth...
The PR needs to be tuned a touch higher at 52Hz. This yields a bandwidth of 32-64Hz, which is very close to the former. However, the chambers need slightly adjusted. The former UM1 was 18/8 ltr arrangement, whereas the UMII looks good in a 17/10 ltr arrangement. Xmax in check at 200W for 107dB peak output. The Q change of the new driver involves this shift to flatten the response a bit. However, this difference changes the 0.8dB gain in the former to the 0.6dB loss in the latter. I could not get a better alignment with less loss as the response was too peaked.
The amplifier being 500W is still capable of blowing the woofer, so be careful. Be advised that it may change distance dimensions internally and change clearance from amp to driver. UMII has 155mm behind mounting of the basket. The former is only 145mm deep. With the shift of the internal driver baffle to the rear to make 17 ltrs, mounting the woofer atop both inner baffles instead of in the middle will move it forward. The PR is also in a larger chamber, so the proximity to the active driver should also be fine.
Take this for what it's worth...
Thanks for putting this together wolf! This still strikes me as having good potential for clean output in a small package. I’ll update the thread with progress if I move forward with the build.
One more thing, the height and width for best relative component positioning should remain at the same dimension(s). Just reposition the doubled inner baffle to reflect the new volumes, and lengthen the depth of the enclosure to allow the extra liter of front chamber volume.
Upon further review, the rear chamber can be the same dimensions and likely not perform any different or worse. It's maybe 3-4 Hz difference on both ends. The boost would make up for the loss. The front PR chamber should be 5" deep instead of the former 4". This means the woofer can still be mounted to the front instead of the middle of the partition like intended. It stays within the 1dB loss bracket, so I find that acceptable. If the components still fit, anything from 7.75" to 7" deep in the rear chamber should be just fine. There is ample power and ample xmax on tap to not tax the driver or PR in anything within these dimensions.
Upon further review, the rear chamber can be the same dimensions and likely not perform any different or worse. It's maybe 3-4 Hz difference on both ends. The boost would make up for the loss. The front PR chamber should be 5" deep instead of the former 4". This means the woofer can still be mounted to the front instead of the middle of the partition like intended. It stays within the 1dB loss bracket, so I find that acceptable. If the components still fit, anything from 7.75" to 7" deep in the rear chamber should be just fine. There is ample power and ample xmax on tap to not tax the driver or PR in anything within these dimensions.
I was actually drawing this out this afternoon - I was keeping the same height and width and arrived at 5” for the front chamber but am missing something on the rear as to how you were getting 18L from the original arrangement before scaling it to 17. Without the amp or driver Vd factored in the volume I’m getting is 16L (11.25x11.25x7.75) x .0164 conversion factor. I’m probably missing something obvious though and will just go with 7.75” depth. I did get the drivers on order (but they are backordered until May).
Funny you mentioned that, as my math was doing the same thing. I figured out I gained a liter in the amp cutout, but that was still only 17 ltrs. Either way, math right or wrong, the design worked initially, so I wouldn't sweat the volume of the sealed chamber too much. Anything from 16 to 18 is likely going to work, but the newer woofer has less loss at the 17 ltr volume as I figured from the original depth. Room gain and the bass boost obviously swamp the difference.
I don't know how many times I did the math originally, but I am surprised I still got it wrong after it was all said and done. Oh well, live and learn.
I don't know how many times I did the math originally, but I am surprised I still got it wrong after it was all said and done. Oh well, live and learn.
