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InDIYana 20/20 theme build redux
This is a replacement project for my 20/20 InDIYana theme build.
Don't have a lot to say about it just yet, but here are a few pictures of the MTM top portion. Made from a cheap poplar board I had laying around. I really like the tone and clarity of the Peerless 630656 drivers and the DA25BG tweeters are quite nice. The woofer portion may stay the same with a single MCM 55-5670 in a ported bass bin per side. Or hopefully two Peerless 830668 10'" woofers per side in a shallow OB H-frame (I haven't built those yet). I tried to keep the MTM baffles as minimal as possible without going the "naked" driver approach. The mids will easily cover the two octave dipole rule requirement. Probably 400 to 1600 Hz. These are just rough cut with no sanding or finish on them yet.
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What is the "two octave dipole rule requirement"?
One of the Hindsight requirements for the theme in 2020, now 2021.
InDIYana Event Website
Ah, ok the ob driver(s) need to cover two octaves. I assumed it was some unwritten Dipole gospel that I wasn't aware of... Though there's isn't much about Dipole/on I know about!
The bevels on the baffles are classy looking. Nice attention to details Craigory .
I used the 830667's in an H frame. They do alright at moderate levels, but can easily get into trouble. The 10's will probably get you a bit more output, but due to xlim will probably experience the same issues. Used wisely you should be happy.
Yeah they will probably struggle in Indy, but at home I plan to use my MiniDSP to high pass them and run large sealed subs. We'll just have to see. I might have to use the ported 8" bass bins with them for Indy.
Yay it hit a high today of 11 degrees. So I put on my Carhardt's and used the short time before the snow started to cut and router my Indy OB project 2x 10" bass modules.
Should have typed "H frames".
11 degrees would feel balmy here. We're up to -6 right now. I think it was -17 when I let the dog out at 5am!
Hope his legs were tall enough to keep his balls from freezing to the ground.
-13 here this morning. Hit a high of 1 above around 2 pm. Glad I got all my cutting and routering done yesterday. The H frames are now assembled. Time for measurements!
I'm happy that you are planning to use open baffle woofers. Have you built any OB woofers before this?
They have a different sound, less overall bass energy but more natural sounding IMO. It is probably best to give them some listening time before you make any conclusions.
Built these a long time ago. Billet definitely nailed how OB bass sounds.
No, this will be my first open baffle woofer project. I've done several OB midranges and tweeters with monopole woofers.
Those are one of my faves of yours, Eric! Classy looks....
InDIYana Event Website
Looking good! You must have braved the cold to cut some wood. I'm not that crazy....I mean dedicated.
Thanks! Yes, it was 8 degrees and dropping fast last night after work (flush trimming the butt joints with my router). I was bundled up pretty well but my face was still exposed
Man, that is some determination.
Man, that's dedication.
Bet your router bits will last longer being cryo-treated and all.
TomZ
**ZARBO AUDIO ** https://www.youtube.com/channel/UCEZUyvobRaFQSTl6NdOwgxQ
Yeah I'm crazy like that!
Actually it wasn't that bad. Way back in high school and college we use to go skiing all day (10am to 10pm) when the temps never even reached zero
I was only out there making saw dust for about 45 minutes. I might be getting old but that's not going to make me a sissy
It is supposed to be really cold this weekend and my wife and kids will be out of town, so I'm glad these are to the point where I can take measurements, measurements, and even more measurements...
As I know nothing about crossover design, I'm curious to know how a crossover for an open baffle speaker differs from that for a 'normal' cabinet: in this case, if you had a conventional MTM box with the same Peerless drivers, compared to your open baffle design?
Very much enjoying your TMs with these drivers!
Thank you
Geoff
Hi Geoff,
Glad you like my TM crossover design. Several of my friends have listened to them and love them. Awesome sound for such a low cost.
The biggest difference in xo design for OB vs monpole is what and how you measure the drivers. The power responses are very different, so measurements with short gate times are very inaccurate for OB designs.
That and there's usually a notch filter to tame the dipole peak.
Learning opportunity here.
Never working with open baffles before, what is the reason for having the woofers mounted opposite of each other?
Is it to cancel out distortion or just to look cool?
Yes and yes.
What about a samich configuration of the woofers, like the Hurricane?
Was that Dan's project with a bunch of GRS 8" woofers? If so that is called a Ripole.