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New rules/categories for Ohio Speaker Design Competition / MWAF?
Received an email from Jill at Parts Express this morning,
Hello speaker designers and loyal participants!
Parts Express is excited to announce the continuation of our annual Ohio Speaker Design Competition in 2025, coming this August 1st and 2nd!
Registration is not yet open but will be in the coming weeks, so stay tuned! https://www.parts-express.com/speaker-design-competition
The event location is just two minutes from Parts Express:
Grace Point Fellowship
1455 E W 2nd St.
Franklin, OH 45005
Please note, there are some significant changes to the categories this year. Be sure to review the details for each category carefully before submitting your project:
Open Unlimited
Open Unlimited includes Speaker Projects that include active electronics (amplification, active crossovers, DSP, etc.) or cannot be categorized in the other 4 areas. If the speaker design has been entered in the Open Unlimited category, the same design without active components cannot be entered into any other category.
Over $300 Large
Projects with an external volume greater than 2,000 cubic inches and costs more than $300 per pair to build ($ limit for drivers only). The volume is measured externally at the speaker’s extreme height, width and depth. This includes any external ports or horns. This excludes handles, terminals, outriggers, feet, built-in stands or bases, and externally mounted crossovers. Speaker project can include any brand drivers.
Over $300 Small
Projects with an external volume smaller than 2,000 cubic inches and costs more than $300 per pair to build ($ limit for drivers only). The volume is measured externally at the speaker’s extreme height, width and depth. This includes any external ports or horns. This excludes handles, terminals, outriggers, feet, built-in stands or bases, and externally mounted crossovers. Speaker project can include any brand drivers.
Under $300 Large
Projects with an external volume greater than 2,000 cubic inches and costs less than $300 per pair to build ($ limit for drivers only). The volume is measured externally at the speaker’s extreme height, width and depth. This includes any external ports or horns. This excludes handles, terminals, outriggers, feet, built-in stands or bases, and externally mounted crossovers. Speaker project can include any brand drivers.
Under $300 Small
Projects with an external volume smaller than 2,000 cubic inches and costs less than $300 per pair to build ($ limit for drivers only). The volume is measured externally at the speaker’s extreme height, width and depth. This includes any external ports or horns. This excludes handles, terminals, outriggers, feet, built-in stands or bases, and externally mounted crossovers. Speaker project can include any brand drivers.
Event schedule (tentative):
Friday, August 1st
5:00PM–6:30PM:
Meet-N-Greet & Registration
The Meet-N-Greet is a great opportunity to get to know your fellow speaker design enthusiasts and judges! Make sure to have all project information with you at the time of registration including project name, cost, components, etc. There will be a pizza party that evening so you don’t want to miss this!
6:30PM–9:00PM:
Speaker Design Competition Part 1 — Open Unlimited
Saturday, August 2nd
7:30AM–8:30AM:
Registration
8:30AM–4:00PM:
Speaker Design Competition Part 2 — Over $300 Large, Over $300 Small, Under $300 Large, Under $300 Small
4:30PM:
Winners Announced
The competition will begin promptly at 8:30am with a tentative hour lunch break. We will be working hard to stay on schedule! The announcement of winners and presentation of awards is scheduled for 4:30pm.
We’re excited for another year filled with amazing designs and great sound competition, and look forward to seeing you there!
Looks like there is no Dayton only drivers category any more!
The 2000 cubic inches OD size seems really really small to me.
Math was never my strong point, can someone double check my math?
assuming a perfect cube, one side = Cube root 2000 = 12.599
12.599 - 1.5 (assuming 0.75" material per side) = 11.099 internal per side
11.099^3 = 1367 cubic inches internal
1367 / 1728 (cubic inches in cubic foot) = 0.791 cubic feet or 22.4 liters internal volume.
Seems really really small.
Perhaps we should petition for a larger size for "small"?
Thank you,
David.
P.S. Don't make your box EXACTLY 2000 cubic inches externally, there is no category for you! 
Comments
Wouldn't the typical 6+1 and smaller bookshelfs fall into small? Maybe a slim 8" 2 way or a 7" 3 way might fit. Any bigger, which would be most floor standers and larger ones would be large.
How large would you suggest for small? The Indy challenge all speakers woul fit in the small since it specifies gross and incldues ports and stuff - whereas in MWAF you can keep your 0.5 cuft port external
I think this is about right. Usually, larger as 1.5ft^3 boxes get close to floor standers. I would have likely said larger than 1.2ft^3 for the partition.
BTW, 2000/1728 = 1.15ft^3. This is closer to 30 ltrs.
Both my Hancocks and Pangolins fit under the mark.
InDIYana Event Website
Whatever they want, it's their show
I like the new rules, mostly because my Cabrini the Last falls into the large under $300 category and it would be interesting to see how it stacks up against designs costing 4 times as much.
Like that not forced to find a dayton tweeter to use for that vanquished category and like others, wish had 35L cutoff for size, though also see how greater than 28L speaker approaching big boy. Think the under 300 large could get interesting - though becomes nuisance to set large speaker aside for the rotation of speakers that diy'ers accumulate.
The way I read the rules they are specifying maximum external size outright. Subtract wall thickness from your 30liters and that is the internal volume you get to play with.
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For quick calculations I use the "Volume Calculator - Rectangular/Square Enclosures" here:
https://the12volt.com/caraudio/boxcalcs.asp
For internal volume specify your wall thickness (such as .75"). For total external dimension volume make the "Thickness" 0.
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I have mixed feelings about the Dayton category going away. I always wanted to try entering in the category, just hadn't happened yet. And of course now that I do finally have a build with all Dayton drivers they sunset the category
. Due to the more limited selection I got the feeling it inevitably would turn into the "RS" category.. or whatever was the latest best sounding hotness from the lineup to truely be competitive on the SQ side of things. But it always seemed like "normal" sized bookshelf speakers had an inherent disadvantage in all the categories. So I see it as a net positive in the end. IMO the deliniation seems very reasonable. Most normal people would consider a "bookshelf" speaker over 2000ci to be very awkward and likely opt for a slimmer tower instead. If yours is slightly larger.. well in all the previous years it would have been slugging it out with the biguns anyway.
As Nick stated, but am surprised on the no Dayton only class.
External.
Internal, unless my math is wrong, assuming 3/4" walls is 22.4 liters before drivers, port, braces, XO, etc.
Keep in mind, they are measuring extremes - so if you have outriggers it will be considered to be part of the gross volume.
I Think 2000 in. sq. would be a rather large stand mount speaker. Like a tetradactyl egg.
I bought heavy duty stands from Monoprice for exactly that reason. I build a lot of larger stand-mount designs.
It really doesn't take much to hit that 2000 cubic constraint. Given 3/4 wall construction it is barely over 1 cubic foot. A lot 7" MTM would exceed that threshold, and probably every 8" based designs as long as they are either ported or use high Q woofers.
I'm really curious to see how they measure something like one of your designs.
Yep, that was the biggest thing I noticed. Overall, I think the new categories are an improvement and removing the Dayton category is probably a good decision.
I appreciate that they do keep trying to tweak and improve the event each year, but a side effect is that sometimes the tweak doesn't work well. The individual judges room didn't go over well and didn't last past the first trial year.
EDIT: I get to go down in SDC history as winning the LAST Dayton Only category competition.
I don't think that is the case.
"This excludes handles, terminals, outriggers, feet, built-in stands or bases, and externally mounted crossovers"
So are you suggesting that they should have a curvy speaker category? I second that motion. I kinda doubt they will
strictly enforce that rule. They have gotten very laid back with this event. Probably honor system. Afterall we are an honorable bunch of fella's
Oops, 2000 in. cubed not sq. That would be impossible
Ah, I misread.
I'm still at I don't give a shit. I just go to hang out.
Yup and they'll probably learn from this and update it for next year. Unfortunately doesn't change that I won't have a project to even enter this year.... again....😒
Not that it matters at all to me but I think the new categories make pretty good sense really. Maybe the "2000" external cubic inch delineation isn't at the perfect spot for everybody (arguable of course), but it does break it up between towers and bookshelves.
So the way I look at it is someone using a pair of single Purify woofers, even the little ones, was automatically thrown into the "old over $300" class where any other entry might be using 8 Purify drivers, an ATC dome mid, and a RAAAAL ribbon. The enclosure size kind of levels the playing field in that respect.
Agreed. It did make it tougher for the littler project as it was before.
InDIYana Event Website
A little Purifi two way tied for first with my 2.5 way towers, so if it sounds good, judges don't apparently favor that aspect. Again, it's all light hearted, bring your project, have fun, hang with your peeps!
Yep, those were Brad's, and I tied for second with my small 3ways. What was interesting that year is you had one of rhe few floor standers.
InDIYana Event Website
Wait - what about oddball drivers like the OEM Infinity I used in Iaell? I think greater that 2000 inches, but paid less than $300 for all drivers.
Probably under 300 large.
InDIYana Event Website
I might clean house with this design if I wwre so inclined 🤔
You would likey have to go by the used price you paid, as they are not commercially available outside a completed commercial offering. Even if the drivers should cost more, you don't have another price to go by.
InDIYana Event Website
If you make your box EXACTLY 2000 cubic inches, then they will be forced to put you into the "Open Unlimited" category, which includes speakers that ". . .cannot be categorized in the other 4 areas. . ."
Probably worth reaching out to Jill. I am sure I am not the only one with this question.
Slightly disappointed in the no Dayton class as within the next year or two I was going to do an entry there. My guess is with adding the “large” and “small” categories, keeping the Dayton-only would’ve made too many categories as they would’ve needed to do a large and small there as well. And since they’re giving away $400/category it would’ve been too much of an added expense
Otherwise I do like separating the bookshelves and floor standers/large bookshelves
I've only accidentally made speakers with drivers that cost over $300