Usher D2 "clone" Project gone OPEN BAFFLE!!!
I was originally going to build an Usher Audio D2 clone, and build these OB's just as a temp thing to get the Usher 15HM drivers run in and out of my cramped bedroom. However, now that I've been listening to them since last night and all day today, I think I'm going to can the D2 clone idea and keep these open baffles. They sound that good!
I ran the idea across several people on various forums and they swore that running horns with open baffles would never work out. Some even said that the Altec 511B horns would not work in an MTM design. Well I have news for them.
Last night once I got them up and running playing fullrange and spent about 10 minutes doing some quick tweaking, a few things were quite apparent with these beasts (more of which I noticed today)...
1) For one, the imaging, soundstaging and depth are something in the order of very, very good, properly placed bookshelf speakers. The imaging in darn near pin-point, the soundstage is well beyond the walls of the room and the depth gets right up in your face and as far back as several meters behind the speakers and back wall. VERY 3-dimentional.
2) The uniformity of sound emitted from these speakers while standing, sitting, squatting and walking around the room is amazing. The tonallity doesn't change! As long as I'm as far back as the listening position (about 9' away) or further and I move all around, walking from the left wall to the right wall, sitting or standing, the sound remains the same. These speakers have a huge sweet spot! This also includes about 95% of imaging, soundstaging and depth and any of those locations.
3) Super sensitivity OB's! Theoretically, these OB's should be 98dB efficient at 1W/1M (wired parallel into 4 ohms each channel) or maybe slightly less due to being in OB's. I thought for sure the gains would remain the same between these and the Klipsch Cornwalls they replaced (also 98dB @ 1W/1M). I can honestly say that they are NOT. These things have to be somewhere around 101+dB, if not more. They are considerably more sensitive than the Cornwalls.
4) Power and dynamics are in abundance! From the quietest passages to the loudest, these things put it out without issue. There's just a huge wall of sound that slams into the room. Playing Telarc's "Trumpet Spectacular" with the large orchestra seems very real. The most real I have ever witnessed in my room. I felt like I was back in orchestra myself when I used to play 1st chair bass. BTW, the most power I saw going into these monsters was just under 4 watts with full pipe organ, orchestra and drum roll on the last chord of the last track. I would have to say it was right around the actual volume level as actually being there durring the live performance (not that I was there or anything, but I know how loud a recital can get).
5) A full, wide-range sound. These Usher 15HM drivers are not meant for OB use as their Qts is 0.30. Without any EQ at all, they roll off pretty sharp after 50Hz or so, but with a little EQ added into the mix, I'm getting strong, usable output down into the low to mid-30Hz range easily, maybe even touching into the high 20's. Bass is very clean, very tight and very "real" with these drivers in OB's. I'm loving this!
6) Lastly, if anyone on here knew anything about my dipole subwoofer project several years ago, I kept remarking on how difficult it was to see any kind of cone movement from the drivers with moderate to loud volumes with low frequencies. The same is true with these new OB's! Like I said, they're playing fullrange right now, so they're getting the entire range of sound and handling it all with great ease. The reason I think they move so little is because they use such little power, which is obvioulsy nothing to them. The simple explination is that they are hardly doing any work to produce lots of loud, clean sound into the room.
The absolute max wattage I've seen go into them now has been almost 10 watts, and that was near the point of being insanely too loud. The bass output at that kind of volume is just unreal for these OB's. You can definately feel and hear it, and you can also hear all the detail in that bass. That's the magical beauty of OB (dipole) bass!!!
Anyway, enough flapping of the gums. I know you all want to see some pictures, so here they are! Enjoy and please feel free to ask many questions.
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