My Alpair 12pw/7.3 MarKens have been sounding great for a few years now, but I got the itch for something new over the summer. I spent a lot of time at our cabin where I have a pair of Bozak Symphonies. They have a lushness that I craved at home, without losing the accuracy and dynamics of the Alpairs. After casting about for awhile I came to the conclusion that there was no reason to get rid of the Alpairs, just add more drivers!
Enter the big MTMs from Woden/Planet 10.
While not as complicated to build as the Onkens, they weren't simple monkey coffins either. I'm happy with how the cabinets turned out, but I can't report on their sound yet. Unfortunately, I realized mid-build that one of the 12pw arrived damaged so I had to order a replacement that is taking weeks to arrive. So frustrating!
I'll run these with the same PLLXO I used with the Onkens at first, but I plan to build the passive crossover design in the paid planset. This will give me the ability to more easily play with different amps.
Stay tuned for listening impressions and test results once the new drivers arrive and are broken in.
Enter the big MTMs from Woden/Planet 10.
While not as complicated to build as the Onkens, they weren't simple monkey coffins either. I'm happy with how the cabinets turned out, but I can't report on their sound yet. Unfortunately, I realized mid-build that one of the 12pw arrived damaged so I had to order a replacement that is taking weeks to arrive. So frustrating!
I'll run these with the same PLLXO I used with the Onkens at first, but I plan to build the passive crossover design in the paid planset. This will give me the ability to more easily play with different amps.
Stay tuned for listening impressions and test results once the new drivers arrive and are broken in.
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Gorgeous build; especially the grain matching on rear panels - something that on a pair of enclosures this size certainly affects your cut plan. How did the fronts turn out?
After fiddle futzing around with several band passing / active amp configurations- including a purpose built 4 channel class D amp with buffered selectable XO - I found I preferred the sound of the passive XO, and most definitely so when powered by Neurochrome Modulus686.
I don’t think you’ll be disappointed with the final results.
After fiddle futzing around with several band passing / active amp configurations- including a purpose built 4 channel class D amp with buffered selectable XO - I found I preferred the sound of the passive XO, and most definitely so when powered by Neurochrome Modulus686.
I don’t think you’ll be disappointed with the final results.
Thanks, Chris.
I matched the fronts as well, though I dont have a shot of them in the same frame yet.
I remember you saying that you liked the passive crossover the most of all the options you tried. I'm having trouble finding all the parts I need. Might reach out to you for some details on component sourcing and layout.
I matched the fronts as well, though I dont have a shot of them in the same frame yet.
I remember you saying that you liked the passive crossover the most of all the options you tried. I'm having trouble finding all the parts I need. Might reach out to you for some details on component sourcing and layout.
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As best as I can remember, the parts were sourced from Solen.ca or Partsexpress, and as things turned out the XOs were built in a pair of external plastic cases that allowed much more physical distancing of parts than often occurs than when trying to fit onto a board that can be shoehorned through a driver cut out. Also, my build was completely veneered in quarter cut Sapele and lacquered before the finalization of circuit design, and I didn’t feel like retrofitting the enclosures. If I was doing them now, I’d certainly incorporate a large enough removable 1/2” rear panel to accommodate.
Dave has them at his place, and maybe he could pop the cover off one of the boxes to snap a photo of the internals - something with which I got very lax the last couple of years of building. Or, maybe such a photo has already been posted?
Dave has them at his place, and maybe he could pop the cover off one of the boxes to snap a photo of the internals - something with which I got very lax the last couple of years of building. Or, maybe such a photo has already been posted?
Thanks, Chris
I plan to build mine in separate boxes, too, so no worries on size.
I can find the poly caps I need no problem, but I'm having trouble with which inductors to get. What gauge should I use? I figure probably the smallest gauge available that matches the desired value? Wirewound or foil? I can find the exact value for one of the specified units, but the other two I can only get within 0.1 mH. Is that close enough?
Thanks!
I plan to build mine in separate boxes, too, so no worries on size.
I can find the poly caps I need no problem, but I'm having trouble with which inductors to get. What gauge should I use? I figure probably the smallest gauge available that matches the desired value? Wirewound or foil? I can find the exact value for one of the specified units, but the other two I can only get within 0.1 mH. Is that close enough?
Thanks!
To be clear, I’m not an XO designer, and relied on the work of someone experienced with them (Aaron Drabitt) for my last several. Assuming that the schematic provided by Dave was that same circuit, I’d comment that Aaron’s approach is usually to use the lowest DCR inductors possible - which usually means at least #14 gauge aircore, but not necessarily as exotic as foil (Jensen, etc) or Hepta-Litz (Solen), budget priced polypropylene films (Solen, or Bennic, etc).
You might be able to model or measure the difference that a few percent variance in component value might make, but I suspect it’d be hard to hear.
You might be able to model or measure the difference that a few percent variance in component value might make, but I suspect it’d be hard to hear.
That is exceptionally helpful, Dave.
I have zero experience building crossovers, and only understand the most basic concepts. I didn't want to order a pile of parts, wire it all up, and post a picture only to have more knowledgeable people say "Oh, no. Not THOSE inductors!" or something similar.
Everything is now ordered. I'll let ya know how it goes.
Thanks again.
I have zero experience building crossovers, and only understand the most basic concepts. I didn't want to order a pile of parts, wire it all up, and post a picture only to have more knowledgeable people say "Oh, no. Not THOSE inductors!" or something similar.
Everything is now ordered. I'll let ya know how it goes.
Thanks again.
Finished, in place, and sounding good. Lighting is tough in my room, so please forgive the poor pics. I hope these are at least upright.
The new 12pw have around 125 hours on them. I'll run them in a bit longer before testing.
So far my impressions are of a significantly weightier low end. They go down lower, and the overall tone in the mid-bass on down is richer. Male voices have more texture, and electric bass notes are fatter and rounder. I'm getting more than just hints and harmonics on the lowest notes now.
One thing I didn't expect was a bit more of....something on the upper end. I had to turn the 7.3 down a bit. This is likely due to too much or too little dampening in the midTL. I'll play with it in coming weeks.
Also, Dave's prediction regarding room modes seems to have come true. Early impressions suggest that adding more sources of bass has reduced room resonances somewhat. The end of my couch nearest the room corner seems less boomy.
More to come as I get more time with them.
The new 12pw have around 125 hours on them. I'll run them in a bit longer before testing.
So far my impressions are of a significantly weightier low end. They go down lower, and the overall tone in the mid-bass on down is richer. Male voices have more texture, and electric bass notes are fatter and rounder. I'm getting more than just hints and harmonics on the lowest notes now.
One thing I didn't expect was a bit more of....something on the upper end. I had to turn the 7.3 down a bit. This is likely due to too much or too little dampening in the midTL. I'll play with it in coming weeks.
Also, Dave's prediction regarding room modes seems to have come true. Early impressions suggest that adding more sources of bass has reduced room resonances somewhat. The end of my couch nearest the room corner seems less boomy.
More to come as I get more time with them.
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The upper drivers have been in my Onkens for a few years, so they are much paler than the new ones which are noticeably more blue.
