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InDIYana 2026 theme announcement....
"FourMidAble Intersections"
1.5 cubic feet internal gross maximum volume, everything but the outside walls. Allows svelte towers if the need be. Xover must be internal.
The object is to utilize a 4-octave spread midrange in a 3way from Fc to Fc, or split the 4 octaves to 2 octaves a piece between an upper and lower midrange in a 4way.
Widerange drivers are allowed, as they can throw their own issues into the mix.
I had to announce this before the SDC hit for sale prices if people want to purchase items this weekend, however, QnA will likely be limited as my time is as such before Friday.
We have not done 4ways before for the theme, nor are they commonplace projects in attendance. That said, I want to attempt one at some point, but some others may find it daunting. So the 3way option is for those that don't want to go that direction. It still stretches the midrange bandwidth for an inherently less easy blending.
Comments
Assuming MTM(W) kosher? Since the Ms will be covering all those octaves equally?
I like the Name of the event!
I like the thought but not a 3-way.
Oooooh! 4 ways . . . .
I’m confused. Is this to be a 3-way? Or a 4-way? I’m seeing both configurations mentioned.
I have no problem with an MTMW, Drew.
@tommytunes50 , you pick which one you want to do, just make the midrange 4 octaves in a 3way, or 2 octaves each in a 4way.
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Internal crossovers....ugh...my proto boards will never fit like that!!!!
😛
Both are options, If you split the mid you have to do a 4 way if you use one mid it will be a 3 way. Both options the midrange has to cover 4 ovtives, "FourMidAble".
Yeah probably plenty of 4" drivers could handle both the high xo and have enough excursion to do without the woofer in an MTM. But I guess Ben just wants us to spend a bunch of money on huge caps and coils
This correct for 4 octaves?
200-3200 : 200 x 2 x 2 x 2 x 2=3200
300-4800 : 300 x 2 x 2 x 2 x 2=4800
That's how I do the math, with those being the crossover points.
Yes. Other possiblities:
100-1600 (at this point, your woofer essentially becomes a sub-woofer)
400-6400
500-8000
600-9600 (at this point your tweeter essentially becomes a super-tweeter)
Also assuming with mention of 4 way, could be like LX521 with 2 different 'mids' ? Or almost like 3 way + sub.
I know you are busy getting ready for the Dayton thing but I have a couple quick/easy questions:
Only passive crossovers I assume?
Can off the shelf drivers be DIY modified?
Craig-
Yes and yes.
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Are you going to place restrictions on driver sizes for the MR to prevent someone from using a tweeter and supertweeter which would technically meet the qualifications for the 4-way?
I wasn't going to because that can really mess with the top octave in terms of lobing and integration. If using a 10k point, that is about 1.3 inches. Just trying to get them physically close enough is tough.
As long as Meredith doesn't bring his special tweeters we should be just fine. 😉
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Seems like a fun and keepable project theme this year. Yay to that! Thanks for your timely response to my questions Ben.
Just throwing this out there for a mental picture. 4ways don't have to be in a straight line for all drivers. The top 3 can be like my Bottleships or Purveyor, and place a larger woofer below. it makes for a more compact or squat solution, and moves drivers to where all acoustic centers are closer together within wavelength distances. The pictured below is likely too big in volume, but the layout idea is shown.
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Ha, its only been one day and I already forgot the criteria in post #1.
Come on, if you are encouraging 4-ways maybe we should scrap the volume limit? I wasn't going to participate but then thought about getting a quad of SIG270s at the PE sale this weekend for some 4.5cf four-ways.
That's part of the challenge!
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If a 3way can go in 8 ltrs, that leaves 34 ltrs for the woofer. Not bad of you ask me!
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That speaker/layout looks cool Ben.
Someone in Europe over on diyaudio built those. Great drivers too!
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I have my project all planned out and am getting ready to make sawdust. It will be a 1.5 cu ft 3 way with crossovers of 150 and 2500Hz (4 octaves).
bandpass for the 4th way?
You mean woofer? Sure, that is fine. Watch your impedance.
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I'm kicking around my mid choice to use ~ 250-500-1000-2000-4000 Hz. Current driver choice has an out of box cone breakup just above 6kHz. Maybe a little X-Acto surgery and repair can improve that. I have zero intent on purchasing any new drivers... just work with what's already parked on my shelves. Enclosures will be constructed of Menards cheapo shelf boards. Should be a fun project (for me).