A couple years back I went from a pair of passive dayton based bookshelves to a fully active system based on the daton PCX-12 coaxial. Details can be seen here: https://www.diyaudio.com/community/...s-the-box-less-important.392703/#post-7222109
These were a real learning experience from being my first go at active XO's, measurement, and PA gear. From the active XO side of things, I'm not looking back. The results that I have achieved (after investing the time) have exceed expectations that i dont think my patience could match rolling components in a passive xo.
Being PA coaxials with a small wave guide, the speakers have a very very narrow sweet spot for a residential sized room. I thought about experimenting with different waveguides but dont think I could sufficiently close the gap. One thing these do deliver though, is the party, and this was a design target for these. The super small sweet spot is 90% of my motivation to build a new set of speakers but solving this has many avenues that I could take. Some of my ideas are below, id be interested in hearing others suggestions.
1. Re-use the drivers but put the CD in a proper horn. Bonus, it only costs mdf and time. But again, the directivity may leave me lacking.
2. Go back to a traditional dome tweeter and build a set of 8" MTM's. This will help my LF xover to the sub and hopfully give me more even bass in the room/floor.
3. Make a 3-way 6.5" MTM with a 10 or 12" sub in each and leave the low lows to the UM-18.
4. .....Something else that wont break the bank
These were a real learning experience from being my first go at active XO's, measurement, and PA gear. From the active XO side of things, I'm not looking back. The results that I have achieved (after investing the time) have exceed expectations that i dont think my patience could match rolling components in a passive xo.
Being PA coaxials with a small wave guide, the speakers have a very very narrow sweet spot for a residential sized room. I thought about experimenting with different waveguides but dont think I could sufficiently close the gap. One thing these do deliver though, is the party, and this was a design target for these. The super small sweet spot is 90% of my motivation to build a new set of speakers but solving this has many avenues that I could take. Some of my ideas are below, id be interested in hearing others suggestions.
1. Re-use the drivers but put the CD in a proper horn. Bonus, it only costs mdf and time. But again, the directivity may leave me lacking.
2. Go back to a traditional dome tweeter and build a set of 8" MTM's. This will help my LF xover to the sub and hopfully give me more even bass in the room/floor.
3. Make a 3-way 6.5" MTM with a 10 or 12" sub in each and leave the low lows to the UM-18.
4. .....Something else that wont break the bank
Coaxial compression driver in horn mating with a woofer. I know people are building one now in my region with the B&C DCX354 in a RFC HF950 horn and crossing it to a pair of 12" Beyma woofers (don't remember the type) at 500Hz. The woofers go to subs at 90Hz. There are coax compression drivers that go lower, but they cost a lot more. But that is probally the best route for good dispertion on all axis. Or build a MEH going low enough (that is the new fashion, but it works well). Both will be better than MTM configs i think, and certainly better than a classic cone/CD coax.
@waxx I like that Idea, however I imagine that the coaxial horn is going to result in a large cabinet. I forgot to mention that I do have some space limitations in my current config. The lollypop style cabinets in my previous build were done to keep the cabinet as narrow as possible with the 12" drivers. Some cabinetry is getting shuffled around a bit which opens up my max cabinet width to ~14"
Adapting my current drivers to your suggestion: splitting the coax, putting the CD (SB Rosso 34CDN-PK) in a horn like the Dayton H110, cross over to the PCX12 to it at ~1kHz, then add a 12" (or dual to bring up eff?) woofer for the 150Hz-~60Hz where the UM-18 will take over below that? I am not sure what the optimal woofer crossover would be to the PCX12, but if high enough the PCX12 portion of the enclosure could be kept small.
One thing that is a slight limitation with the CD is how low it goes. Given that Ill never reach the SPL's its designed for I do have some excursion headroom currently crossing over lower than its recommended. Doing this again I would go to the larger size CD in the series with the 44mm diaphragm.
Adapting my current drivers to your suggestion: splitting the coax, putting the CD (SB Rosso 34CDN-PK) in a horn like the Dayton H110, cross over to the PCX12 to it at ~1kHz, then add a 12" (or dual to bring up eff?) woofer for the 150Hz-~60Hz where the UM-18 will take over below that? I am not sure what the optimal woofer crossover would be to the PCX12, but if high enough the PCX12 portion of the enclosure could be kept small.
One thing that is a slight limitation with the CD is how low it goes. Given that Ill never reach the SPL's its designed for I do have some excursion headroom currently crossing over lower than its recommended. Doing this again I would go to the larger size CD in the series with the 44mm diaphragm.
Part of me thinks that teh only way to get better constant directivity for around the room/floor listening is to stop asking so much from the 12" woofer. I might have a case for a 3 way (so i tell her).
The Dayton RST28F seems to tick most all my boxes for a tweeter: efficiency, power handling and off axis behavior. Its also in budget and available in Canada.
Now is there a comparable mid that I can cross from ~350-~2500? PA drivers like the Dayton MB620-8 seem inline for keeping power handling and efficiency up but getting close to beaming again. Perhaps dual RS100-4 for a MTMWW would be more suitable? But would a PA driver sound out of place being mixed in? Most home audio mids don't seem to have the power and efficiency.
Low reinforcement would then be brought from a: quad of 6 1/2, or a pair of 8's or 10's? I could even stretch to 12's if i could keep the box sealed and small.
The Dayton RST28F seems to tick most all my boxes for a tweeter: efficiency, power handling and off axis behavior. Its also in budget and available in Canada.
Now is there a comparable mid that I can cross from ~350-~2500? PA drivers like the Dayton MB620-8 seem inline for keeping power handling and efficiency up but getting close to beaming again. Perhaps dual RS100-4 for a MTMWW would be more suitable? But would a PA driver sound out of place being mixed in? Most home audio mids don't seem to have the power and efficiency.
Low reinforcement would then be brought from a: quad of 6 1/2, or a pair of 8's or 10's? I could even stretch to 12's if i could keep the box sealed and small.
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