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Billet's InDIYana 2023 Theme Build
I'm starting a thread to show the progress of my InDIYana 2023 speaker design and build.
My first thoughts:
1. Find a wide range woofer that can play nicely in the midrange. I would like to cross over above the fundamental frequency of most music.
2. Utilize the largest cone area possible to minimize distortion and maximize efficiency.
3. Paper cone for natural tone.
I have been fascinated with guitar drivers lately, so I selected the Eminence GA-SC64. This driver is highly praised on many guitar forums for it's natural tone. It has a paper cone, surround, and voice coil former. Eminence describes the low end shape as tight/punchy and the midrange shape as warm.
I have purchased a set of drivers and listened to one long enough to make sure it is broken in properly. So far, I am very happy with the overall sound. Vocals sound natural and pianos sound like pianos. I hope it still sounds good in a box, that is always a challenge. It is difficult to hear the sound of the bass this way, but if I hold my ear close to the cone I can get some idea.
I have created a CAD drawing of a hardwood enclosure, it is planned to be very light for it's size. I will definitely try it sealed but I may experiment with a vent to reduce or eliminate the need for a baffle step filter when located away from a wall. I would like to be able to run the 12" driver full range.
I have a few tweeters on my "short list", but I am currently hoping to use the Beston ribbons that I picked up at the Meniscus get together in September. They may not be as efficient as I need, but I hope they will sound good with the low freq driver. Especially if I run some baffle step.
Next step, build a box and see how the 12" driver is really going to sound...
Comments
Maybe some more explanation is in order, this is obviously not a typical design. I am hoping for a very live sound with vocals, guitars, and drum kits having that "in the room" quality. Obviously low bass will be missing, but I will be pleased with good mid and upper bass.
I expect that off-axis response may suffer a little, but mostly in the midrange. I think that could actually be a bit of a positive. I'm not sure what to expect with the stereo image, but phase should be fairly linear and the forward focused midrange should have less room interactions. We shall see!
I had some unfinished boxes that a friend had given to me. They had Purpleheart veneer on the front and top. The 3" port hole was already in place. They are very well made.
I decided to mount the GA-SC64 12" guitar drivers in the boxes. I still need to finish the sides, I have a possible source for some Black Walnut that would look very nice. The port actually works pretty good as it is. I was thinking of adding a tweeter somewhere, but it doesn't seem to really need one.
I have been listening to these for quite a few weeks and they sound really excellent to me. And they keep getting better as they loosen up. The mid and upper bass is tight and full. The mids are very clean sounding. And the highs are better than expected, just a little rolled off. For my music, everything is there.
I am thinking I may finish these up as they are and try to come up with another plan for InDIYana.
Make a mount for the tweeter that sits on top and holds the XO? Doesn't necessarily need to be a permanent addition.
That is a very good idea. I'd probably put a couple of threaded inserts on the rear baffle and make a neat little tweeter bracket. I do like the idea of an interchangeable tweeter option.
I found a tweeter in my stash that sounds very nice with the GA-SC64 driver. After trying several traditional tweeters, including a Goldwood cone, I decided I really needed more sensitivity. The Eminence ASD-1001 is plenty sensitive and sounds nice.
I originally purchased some small Eminence horns for these tweeters months ago, but they are made of plastic and I don't really like plastic. I have always wondered if a HF horn driver could be used without a horn. The answer seems to be yes. I've been listening to these for about a week and they are a genuine improvement over the guitar driver alone.
My latest plan is to mount these in the port under the driver with a wooden adapter (not a horn). I will listen to the low freq driver sealed and see how I like it, so far I like this driver better ported but we shall see. I will probably end up with multiple small ports in the rear baffle.
Could use one of the thread adaptors as a faceplate. Unfortunately don't know what the OD is. Looks like it is probably around 4-4.125"
https://parts-express.com/Eminence-S2B-A-Aluminum-1-3-8-18-TPI-Screw-On-to-2-3-Bolt-H-290-561?quantity=1
Those adapters would probably work pretty well. I'd mount them on the inside for looks. Diffraction improves dispersion, right?
The two bolt circle pattern on the adapter is 3". The tweeter bore is also 3", I am pretty sure I could make it work with a few extra holes near the edge.
I've actually been listening with Goldwood cone tweeters for the past week or so. The horn drivers were working fine until THAT ONE SONG where they just about drove me out of the room. A higher order crossover might be a solution to that, I don't know yet. Still got time!
I upgraded to Audiocap film/foil caps this week and also added a litz wire inductor to create a second order filter. The Audiocaps measure almost identical to the metallized poly standard Z caps that I had in there, but the film/foils sound noticeably brighter. The ASD1001 HF drivers are back in and the shunt coil seems to have cleaned them up nicely.
Second order? Getting kinda sloppy with your crossover work...JK you know I love your stuff and can't wait to hear this. Please bring your own tracks for the demo so we can hear them in their natural element.