I know, I know... I'm a tough guy to please. That or I don't know what I'm doing. Either way, this being the third installment of the design I was starting to think it would never end. I think with the final changes I've made I am a happy camper.

I love the sound and look of the HiVi D5G woofers but they do lack sensitivity. I've been eyeballing the Aurum Cantus AC120/50CK since before we even started carrying them in stock. The specs were fabulous and I liked the idea of a very light and rigid cone. I got lucky since they fit in the same recessed openings as the HiVi's (+/- 1/16" or so) and I decided to give them a shot. This has to be the beefiest 5" mid-bass I have ever come across. HUGE magnet, cast frame with 8 mounting holes, 2" voice coil and very smooth response. The measured specs proved to be quite a bit different than publish but I expected this after measuring so many AC drivers in the past. The higher measured Q actually worked out in my favor since these were going in a fairly large sealed chamber, although I wouldn't need them to play any lower than about 80-100 Hz.

Here are my measured specs from the WT3:

Re: 7.48 ohms
Fs: 55.85
Qts: .508
Qes: .55
Qms: 6.616
Le (1kHz): .196 mH
Mms: 6.883 g
Vas: .3388 cubic feet
SPL using added mass method: 86.72 dB
Effective piston diameter: 3.875"

I purchased the drivers and brought them home for a quick in box measurement. The AC woofers were smooth as silk and had no sign of the slight rise at the top end as their IB measurements show. The Ushers, well...they're Ushers. The upper end drops pretty quick after about 12kHz but this is due to measuring conditions. After a bit of modeling I settled on a very low component design, a first order electrical, second order LR acoustic low pass on the woofer and second order Bessel on the tweeter with a simple L-Pad to bring the level down a few dB. Crossover point is ~2,880 Hz. Here is the result.





I waited 6 months to get my HiVi D8.8+ woofers on a special order after receiving one defective. They were like any other HiVi, great solid build quality, measured specs very close to published and reasonable box size requirements. When the original Apaches didn't pan out I really didn't want to get rid of these woofers. In the ~1 cubic foot sealed "stand" they were mounted in they had a projected F3 of about 66 Hz which would be fine for most music. They did well, punchy, clean and solid down to about 35 Hz. Once I decided to upgrade the D5G's I opted to upgrade these as well. I knew from past experience that the Dayton RSS210HF-4 worked very well in the volume I had and would be a better match to the 4 ohm stable SA100 amplifiers. I had to build adapter plates for mounting but this was no big deal. Right from the start the 210's modeled F3 was about 20 Hz lower than the HiVi. I immediately thought to myself, "Why didn't I do this before?"

The (sub)stitution of the subs was an immediate improvement. I expected a drop in overall sensitivity but it was actually the opposite. They played deeper, cleaner, easier, had more headroom and all this added up to a sound stage as big as my wall. I listened this way for a few months until I added a sub EQ to my home theater subwoofers...that's when I realized I needed to get a second EQ. With the Behringer FBQ1000 I was able to EQ these bad boys flat in room from 18-100Hz to blend perfectly with the full range cabs. These Dayton subs are incredible and will make you think they are at least 10's. As soon as I think they are being driven hard, I look at the cones and they are hardly moving. The headroom on this updated system is crazy and I must have gained about 3 dB of sensitivity overall. I used to listen to recordings for flaws, now I actually get lost while listening. Localization is impossible. Dynamics are incredible and defy the size of the speakers, especially the bass. If you happen to have a music only system and you have no EQ on your subs, you have NO idea what your missing. I've been looking for a system I could keep and call my own and this is it.

The only thing I plan on upgrading in the future is the source and power. I currently use a ~15 year old Denon AVR-5700 which has no system setup due to the OSD not working. My source is a $30 Sony DVD player I purchased about 5 years ago. It works although the display is glitchy. My plan is to eventually have an Emotiva USP-1 and UPA-200 with a SACD player. This system is for two channel listening but includes a subwoofer out and adjustable high and low pass filters for each pre out which is perfect for my application.













Footnote:
I was never one to buy into high priced caps or crossover components. Although I never tried much beyond a Dayton 1% precision cap, I decided to try some Jantzen Superior-Z caps this time around (go big or go home right?). I had plenty of listening time on the previous Dayton's and I was pretty skeptical regarding hearing any difference. I must say the sound stage is now beyond what I thought speakers were capable of. I can't give full credit to the caps since I changed the whole crossover topology although I am hearing new hidden effects in recordings I've critically listened to for years. One that stands out is a "ticking" sound that caught my attention enough to turn my head coming from the corner of the room on the floor...behind me. It was only until the track ended that I realized it was in the recording. That pretty well blew my mind. I do enjoy the sound of the super caps although I would not pay full retail for them.