I would like to take a little time to provide more information and address a few questions and comments.
First of all, many thanks to Amir for the review. I put him through a lot for this review. I freely admit that most of the speakers I build can best be thought of as prototypes. Drivers are frequently connected with removable connectors as opposed to solder. I've had a last minute defective driver replacement at a DIY event/competition and it's a lot easier than bringing a soldering iron... Crossover boards are often mounted in such a way to be removable for future tweaking. All of these issue came home to roost for this review as Amir's first comment was that something was rattling inside the cabinet, which turned out to be the crossover board that came loose during shipping. When Amir reattached that and ran his tests, it was apparent that the tweeter had no output, so he had to open them back up, reattach the tweeter wires, and remeasure. I wouldn't have blamed him at all for sliding these down on the Panther scale, but he did the opposite. If I send anything in the future, I will at least make sure the assembly methods are fit for commercial ground transportation.
HiVi deserves all the credit the cabinet design and tuning that protects the woofer and the midrange, enabling distortion to stay under control at high output. They picked a good set of drivers for this kit, which is what initially interested me, as I had previously heard all of the drivers (and worked with the midrange on another project).
I always thought it was odd that they chose to design a crossover with such a rising response. This is straight from the swanspeakers website.
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I saw an assembled pair for sale on our local craigslist and decided that it would be fun to see if they sounded like the manufacturer's response curve indicated and see what it would take to flatten the response curve. I step through the process on the Midwest Audio Club forum
MAC/DIY HiVi DIY 3.1 Post
I summarized the results on my Sehlin Sound Solutions page. The speakers reviewed include the option 4 "perfectionist option" crossover.
This is certainly true. There are a number of reasons for that, but the name is perhaps a bit misleading. I set out to see if simply tweaking resistors could fix the crossover, but that wound up not to be the case. Although I could bring the mids and highs in balance with the bass, the response was very uneven as shown in options 1-3. For option 4, I constrained myself in a couple of ways:
1. Add no complexity to the assembly process versus the original kit
2. Keep the cost low
These considerations meant that whatever I did would allow use of the circuit board that comes with the kit and would not touch the most expensive components (larger inductors and capacitors). The resulting mod only adds about $25 in parts to the $299 kit.
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I was very relieved that the on axis response and impedance (actual driver measurements with a simulated crossover applied) closely matches the on axis response from the Klippel NFS.
It is possible to tweak the crossover to bring the level down a dB or two where it is elevated. The changes I would recommend include
1. Increase C5 (in the woofer circuit) from 47 uF to 68 uF.
2. Increase R2 from 2 ohms to 3 ohms in the midrange circuit
3. Increase R1 from 5.6 ohms to 6.8 ohms (7 ohms would be fine depending on which is available) in the tweeter circuit.
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I'm not sure if that will sound better in all rooms as part of the reason I set the mid and tweeter level where I did was to avoid the upper bass region from standing out and sounding too "tubby"
I have long been a fan of dome and other unusual mids. Here is a recent picture of my listening rotation.
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The 3 way's with the dome mid are an unpublished design because the 3" Tang Band dome mid is no longer available to DIY'ers.
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This is the Indium 7 design which was one of my Parts Express Design Team projects and still can be built. It uses the same mid as the HiVi DIY 3.1A (except for a slightly different flange).