Being that the number 2020 also has other meanings, it's only appropriate for this to be themed what it should be. Please see below...
Another bit of info to take note of, is that I will be taking the following year 2021 off as host for InDIYana. I will coordinate with Chuck M. on some things that year and keep the website viable, but will likely not be involved in the majority of the plans. InDIYana will relocate to LaPorte, IN for 2021 only, and I will return as host for the following year. I've been hosting since 2009, so it's only justified that I can get a year off after doing 11 annual and consecutive events. It's been a labor of love, and I've enjoyed those events, people, and projects immensely. No worries, I will return.
Without further ado, I've listed below the requirements for the theme builds for the up and coming year. I wanted to post this prior to MWAF (one week from now), so those who would like to take advantage of the cost savings this event entails can do so.InDIYana 2020 theme: “Hindsight is 2020”
There will not be a poll for theme selection for this next year, as the year in question dictates that we should ‘think about what is behind’. Please forgive the skew on the original meaning, but it does ironically apply quite well.
So- this is the year of the rearward radiation pattern. As usual, special considerations and a few restraints/rules exist for those inclined to enter the challenge. I have had a sounding board with some suggestions and concerns to make up this list. Being what this theme entails, the details are not supposed to be too stringent to stifle creativity, but to influence and make one ponder what to try. If you do not wish to enter the theme, you do not have to for attendance, and can bring whatever build tickles your fancy.
While the board of inquiries is not opposed to cardioid designs being brought under this year’s mantra, they are too hard to define in criteria via multiple means of execution for them to be valid as a theme entry without being looked at as another form of design. However, as long as there is attempt for equal radiation to front and rear in the same driver bandwidth; omnipolar, bipolar, and dipolar designs will qualify. For example, this means you can’t have a rear mounted tweeter and a front-facing boxed wide-range mid and qualify. You would still need any of a dipolar, omnipolar, or bipolar woofer section to qualify because the other 2 driver bandwidths do not.
Your woofers, mids, or tweeters, or any multiple driver sections if you choose to go full 4pi radiation for full bandwidth have to have a rear emanation of sound alike its front-facing counterpart.
- 2-way or 3-way designs are allowed. You want to build something simpler via a 2-way, go for it.
- Xover must be passive as usual.
- Only one driver bandwidth is required to have the rearward radiation. More than one is encouraged. Multiple drivers of same bandwidth are allowed, but all drivers with same bandwidth should have matching emanation.
- Qualifying frequencies for this theme are 100Hz and above.
- For the entries to be seen as valid there should be at least a 2 octave range where the entry exhibits approximate equal front and rear radiation.
- If you choose a closed/vented-box (bipolar) woofer alignment, you are limited to 8” woofers and 2ft^3 maximum volume. Down-firing subwoofers do not qualify as a rearward radiation method due to limited bandwidth and normal 4pi radiation of low bass.
- Dipole bass is limited to 12” woofers. H/W/U/N frames as well as ripoles are allowed.
- All theme projects should conform to a full-project-frame not to exceed 4’ H x 15” W x 18” deep. This is mainly for space constraints in the venue, and this should be adequate. Stand mounts are also allowed.
- Cost limits; as normal, this is not expected of contestants, but a limit as some of these open-backed/bipolar projects can get expensive with larger drivers and multiples used. This is merely to somewhat level the playing field and allows a more fair approach to those that enter. Pricing for drivers, purchased waveguides, and PRs; should not exceed $550/pair. Again- you do not have to spend $550, and can enter with much less out of pocket expense if you desire.
- Cost part 2; Due to likely multiples being used in this case, the limits ‘per driver’ are associated with their relative bandwidths. For woofers, $200 or less per side/channel, without exceeding $100/woofer. For mids/tweeters, $100 or less per side/channel. Since entries are limited to $550/pair in drivers for the entered pair of speakers, obviously the $800 total of the above limits does not apply. You will have to pick what you want to spend more on and where to cut costs to remain under $550.
No buyouts, wide/full-ranges as tweeters, and no NLA unless they were available for purchase when you planned your project or the manufacturer has a newer model to use under the current price list. Retail pricing should be used. PRs, waveguides and drivers are included in cost, not xovers. All of these rules are the typical MO.
I hope this encourages you to try a design with a rearward response coefficient.
Thank you to those who have participated in past themes and/or attended InDIYana. Your presence and talent are appreciated.