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Large Format Usher Audio/Altec MTM Open Baffles...
Hello all, this is my first post here and just wanted to say hi... HI! :B
Anyway, I heard from another member here (chasw98 ) that there's a few members here that are into OB's, so I figured I'd join in on the fun and share my little project with everyone here.
So the original plan was to build an Usher Audio D2 clone using the exact same Usher 15HM drivers (4 of them, 2 per channel) and Altec 511B horns with Altec 902-8B drivers. The D2's use TAD horns and drivers, much better than what I can afford, and I already have the Altecs anyway and like them, so hey, why not?! :P
That was the original plan. I decided to build some quick and simple OB's to just get the Usher drivers up and running so they would be broken in when I finally got around to building the clones. Well, one thing led to another, and once I heard how things were shaping up with the OB's, I decided to scrap the D2 clone idea altogether and keep the OB's. So that's where I'm at now.
And when I say "large format", I mean it. These OB's have turned out to be 82"H x 24"W x 4.75"D. They stand nearly 7' tall and the base skids are a total of 31" long, 7" of which are stuck out front so they won't topple over on their face. The baffles are made out of 0.75" MDF and all the bracing and such are made out of standard 2x4's. The Altecs have small mounting ears on the backs of them so they could be angled up and down on Altec cabinets. In order to mount them to my baffles, I cut small "V" notches in the baffles so the ears would not get in the way and have maximum surface contact with the baffles for a secure fit. These OB's certainly aren't the prettiest things out there, but their sound more than makes up for it.
So how do they sound? Well, in a word... GREAT!
These OB's turned out much better than I had thought. My main concern was the integration between the 511B's and the OB's. For starters, a few people were telling me that the 511's would not work in an MTM configuration due to their dispersion characteristics, no matter what kind of enclosure used. They also said the same would be true because of the combination of a horn and a dipole. Well, I hate to rain on their parade, but they couldn't be further from the truth! Not only do the 511's blend in nicely with the MTM configuration, but they also integrate very well with the OB dispersion.
When I fired the OB's up for the first time, I had the xover freq set at 600Hz. Over a period of a few days of tweaking the woofer time delay and overall EQ, I have managed to get the xover freq up to 1kHz is excellent results. The 15HM drivers are very happy playing up to 1kHz and do so with mucho detail and liveliness. Of course, I am still tweaking the EQ a little bit nearly every day I listen.
The latest tweaks that I just did a few minutes ago include plugging the outer sectoral sections of the horns nearest to the side walls with a couple of folded up towels, and adding some boost on the EQ between 50Hz to 125Hz. I've also done a little more EQ work around the xover freq. I think I might have hit the nail on the head this time with these tweaks. These have by far been the largest and best improvements.
Right now, I have Norah Jones in my room giving me a personal performance. at least, that's how it sounds! When I shut my eyes, it gets downright spooky because you could swear that you are right there with the performers. It actually gets a little unnerving at times. I'm in another room at the moment writing this and the "live" sound is still very convincing. Like I've said on other forums about these OB's, they have a very "real" sound to them. I really don't know how else to describe it.
As for imaging, soundstaging and depth, think of some really good bookshelf speakers set up properly in a room. That's exactly how these sound except they also include scale and dynamics into the mix. They also portray size and height very well. Again, very convincing.
BTW, these OB's replaced a pair of '78 Klipsch Cornwalls that were modded. The Klipsch woofers were only being used and I had the Altecs on top taking care of everything from 600Hz up.
Anyway, enough talking for now. I want you all to see these things and give you a chance to ask questions and/or make comments. I'll post a fwe pics here but you can see all of them on my website... http://charlest.zenfolio.com/
Anyway, I heard from another member here (chasw98 ) that there's a few members here that are into OB's, so I figured I'd join in on the fun and share my little project with everyone here.
So the original plan was to build an Usher Audio D2 clone using the exact same Usher 15HM drivers (4 of them, 2 per channel) and Altec 511B horns with Altec 902-8B drivers. The D2's use TAD horns and drivers, much better than what I can afford, and I already have the Altecs anyway and like them, so hey, why not?! :P
That was the original plan. I decided to build some quick and simple OB's to just get the Usher drivers up and running so they would be broken in when I finally got around to building the clones. Well, one thing led to another, and once I heard how things were shaping up with the OB's, I decided to scrap the D2 clone idea altogether and keep the OB's. So that's where I'm at now.
And when I say "large format", I mean it. These OB's have turned out to be 82"H x 24"W x 4.75"D. They stand nearly 7' tall and the base skids are a total of 31" long, 7" of which are stuck out front so they won't topple over on their face. The baffles are made out of 0.75" MDF and all the bracing and such are made out of standard 2x4's. The Altecs have small mounting ears on the backs of them so they could be angled up and down on Altec cabinets. In order to mount them to my baffles, I cut small "V" notches in the baffles so the ears would not get in the way and have maximum surface contact with the baffles for a secure fit. These OB's certainly aren't the prettiest things out there, but their sound more than makes up for it.
So how do they sound? Well, in a word... GREAT!
These OB's turned out much better than I had thought. My main concern was the integration between the 511B's and the OB's. For starters, a few people were telling me that the 511's would not work in an MTM configuration due to their dispersion characteristics, no matter what kind of enclosure used. They also said the same would be true because of the combination of a horn and a dipole. Well, I hate to rain on their parade, but they couldn't be further from the truth! Not only do the 511's blend in nicely with the MTM configuration, but they also integrate very well with the OB dispersion.
When I fired the OB's up for the first time, I had the xover freq set at 600Hz. Over a period of a few days of tweaking the woofer time delay and overall EQ, I have managed to get the xover freq up to 1kHz is excellent results. The 15HM drivers are very happy playing up to 1kHz and do so with mucho detail and liveliness. Of course, I am still tweaking the EQ a little bit nearly every day I listen.
The latest tweaks that I just did a few minutes ago include plugging the outer sectoral sections of the horns nearest to the side walls with a couple of folded up towels, and adding some boost on the EQ between 50Hz to 125Hz. I've also done a little more EQ work around the xover freq. I think I might have hit the nail on the head this time with these tweaks. These have by far been the largest and best improvements.
Right now, I have Norah Jones in my room giving me a personal performance. at least, that's how it sounds! When I shut my eyes, it gets downright spooky because you could swear that you are right there with the performers. It actually gets a little unnerving at times. I'm in another room at the moment writing this and the "live" sound is still very convincing. Like I've said on other forums about these OB's, they have a very "real" sound to them. I really don't know how else to describe it.
As for imaging, soundstaging and depth, think of some really good bookshelf speakers set up properly in a room. That's exactly how these sound except they also include scale and dynamics into the mix. They also portray size and height very well. Again, very convincing.
BTW, these OB's replaced a pair of '78 Klipsch Cornwalls that were modded. The Klipsch woofers were only being used and I had the Altecs on top taking care of everything from 600Hz up.
Anyway, enough talking for now. I want you all to see these things and give you a chance to ask questions and/or make comments. I'll post a fwe pics here but you can see all of them on my website... http://charlest.zenfolio.com/
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