New Desktop 3-way build: The Thumpers

In about a month I will have a new, much larger, office. I currently use a two way on my desk and I think the new office dictates some new 3-ways. This is my justification anyways....

Intended Budget: under $300

I'm calling these the thumpers because I want the to hit low. If I use silicone pads I can keep most of the vibrations from shaking my mouse when I do CAD work.

To use this Dayton woofer they will need to be 0.4-0.5 cubic feet. I think that is feasible on my desk which is a giant slab of wood.

Anyways, let me know your thoughts on my driver selection. This will be the first time using a dome midrange. I'm pretty excited about that. Its not the best one in the world but I think its worth trying out. PE has minimum order of 1000 but digikey has them for $22

All data is just traced data so I can see if everything "should" work together. I'll take all the measurements and redo the crossover when the actually drivers get here.
 

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When you reverse the midrange you should get reasonably sharp nulls like in the attached image.

Edit: I should add you can manipulate the phase by fiddling with the crossover - no need to time align your drivers or anything like that.
 

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The Peerless dome looks good to me. Personally, I trust the data (no offense wolf). Plus, who knows when the epique dome will come out, what it will cost or what it looks like on paper.

If this was my project, I would try to get it working with first order crossovers because the drive units are so close in size. This will pretty much guarantee good directivity without making more sophisticated measurements. Back in the day I used to think why would anyone use lower order crossovers? Now I know better.

Peerless_GBS-85N25PR03-04_(Frequency_response_+_Impedance).png
 
The Peerless dome looks good to me. Personally, I trust the data (no offense wolf). Plus, who knows when the epique dome will come out, what it will cost or what it looks like on paper.

If this was my project, I would try to get it working with first order crossovers because the drive units are so close in size. This will pretty much guarantee good directivity without making more sophisticated measurements. Back in the day I used to think why would anyone use lower order crossovers? Now I know better.

View attachment 1349671
I would use first orders but there is a nasty cone breakup on that Dayton sub. I won't match odd and even order crossovers. This leaves me with 2nd orders for the low end of the FR.
Pic of the horrendous breakup around and after 1k
 

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It looks like a little bulge around 225 Hz. I wonder if you pushed the wf / mid cross up a bit if you could make it go away? But it may all change with drivers in the box.

Yeah sure. It doesn't look good.

Fine for a "will it work" first effort, but when you re-do with your own measurements try to get a good reverse null, sez I. I was working with a DSP setup (easy to listen to different XOs and A/B) that had poor addition / reverse-null. When I noticed it and changed things around the whole things sounded much more in-focus.
 
The Peerless dome looks good to me. Personally, I trust the data (no offense wolf). Plus, who knows when the epique dome will come out, what it will cost or what it looks like on paper.

If this was my project, I would try to get it working with first order crossovers because the drive units are so close in size. This will pretty much guarantee good directivity without making more sophisticated measurements. Back in the day I used to think why would anyone use lower order crossovers? Now I know better.

View attachment 1349671
This is a near field speaker…..directivity shouldn’t be a design parameter. On axis behavior along with low distortion and phase quadrature rule the day…..a very analytic performance for monitoring. IME, not a lot of fun after half an hour or so as it reveals so many flaws in your favorite music.
 
It looks like a little bulge around 225 Hz. I wonder if you pushed the wf / mid cross up a bit if you could make it go away? But it may all change with drivers in the box.



Fine for a "will it work" first effort, but when you re-do with your own measurements try to get a good reverse null, sez I. I was working with a DSP setup (easy to listen to different XOs and A/B) that had poor addition / reverse-null. When I noticed it and changed things around the whole things sounded much more in-focus.
The bulge is due to the sensitivity difference. The woofer is actually more sensitive than the mid. I don't want to mess around padding down a woofer and dissapating that amount of wattage.
 
This is a near field speaker…..directivity shouldn’t be a design parameter. On axis behavior along with low distortion and phase quadrature rule the day…..a very analytic performance for monitoring. IME, not a lot of fun after half an hour or so as it reveals so many flaws in your favorite music.
This is something I have begun to notice with my other builds. You can tell if its a bad recording with a really good build.
 
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STV,

I see. Easiest way I see of doing this is just to take 3 pieces of scrap rebar and weld them to the magnet housing of the drivers. I see people are trying to use bracing that won't actually work.

This might make them difficult to implement with current DIY testing methods. Getting the full FR without the reflections screwing it up seems like the biggest challenge of this design feature