"I've been looking into replacing my Maggie's (music 30%, HT 70%) for some time and have really struggled with my options. The Maggie's bring true high definition sound to the table, true Audio Nirvana as long as you sit in the Sweet Spot (which unfortunately is minuscule) and can handle the limited dynamics. Shift to one side of the couch or stand up and the difference is tremendous. Definitely not a speaker to be shared with friends and guests."
There are two things in that quotation that catch my eye.
IMO, if you're HT 70%, then you might as well consider yourself to be HT 100%. There's a great deal of controversy about whether you can have a system that can do both audiophile music and batcave HT, but I'm inclined to say you should aim your purchases at one and hope for the best about the other.
Second is the sweet-spot issue. To me, the phrase "wide sweet spot" refers to avoiding the soundstage-collapse-to-the-nearest-speaker phenomenon. This is important for HT if you have more than one person watching. This was one of the prime considerations in my purchases. An old trick in this regard is to severely toe in the speakers. SPL differential (especially with regard to the highest octave) is a prime pyscho-acoustical device used by the brain to indicate location, and toeing more or less maintains the SPL balance as one moves left or right because the more distant speaker becomes more on axis. Of course, this creates other issues related to off-axis frequency response. Now the Ohms are already built toed in at 45 degrees, so I figured that they had attempted to address all this. And it does work fairly well. With two Ohms you can move quite a bit between the speakers; the soundstage will shift but it doesn't collapse. You might ask Newform for a a psycho-acoustical explanation of their wide-sweet-spot description. Having said all this, another advantage of the center-channel speaker is that it helps prevent collapse, especially with dialogue.
"The 645's appear to have great dynamics and also offer the ribbon/planar sound, however, I was concerned with coherency with the 1Khz crossover between the woofers and the ribbons."
I also was concerned about the crossover issue, especially as most speakers cross right in the prime part of the vocal range. And, of course, Ohms have that high pass filter to the super tweeter at about 8KHz.
Mapman says several important things.
On the SPL issue, I only point out a fringe trend I am beginning to see on the forums about producing HT systems that can play at reference levels. Many people pursuing that seem to be going towards high-efficiency profesional-audio stuff. I agree with Mapman that such an endeavor may not be consistent with keeping your hearing, and I find that -10dB (which corresponds to 95 dB non-LFE peaks at the listening position) is as loud as I would want to go. IMO, the main argument in favor of reference level is that it is hard to get kick-in-the-chest bass without really high SPLs and merely raising the gain on your subwoofer will destroy the spectral balance of the entire presentation.
Finally, Mapman advises starting with what John suggested to you. This is my advice as well. Ohm's customer service is incredible, and John is interested in making sure that every customer gets what they want. For example, He made me a special center-channel version of the full-size 100S3s that fired straight ahead, and he sold it to me at one half the normal price of a pair. He allowed me a full credit when, after a year, I switched my surrounds from micro-Walsh short omnis to 100S3 short omnis. Other stories like this are well-known. To be fair to John in such matters, I would start with his recommendations.
There are two things in that quotation that catch my eye.
IMO, if you're HT 70%, then you might as well consider yourself to be HT 100%. There's a great deal of controversy about whether you can have a system that can do both audiophile music and batcave HT, but I'm inclined to say you should aim your purchases at one and hope for the best about the other.
Second is the sweet-spot issue. To me, the phrase "wide sweet spot" refers to avoiding the soundstage-collapse-to-the-nearest-speaker phenomenon. This is important for HT if you have more than one person watching. This was one of the prime considerations in my purchases. An old trick in this regard is to severely toe in the speakers. SPL differential (especially with regard to the highest octave) is a prime pyscho-acoustical device used by the brain to indicate location, and toeing more or less maintains the SPL balance as one moves left or right because the more distant speaker becomes more on axis. Of course, this creates other issues related to off-axis frequency response. Now the Ohms are already built toed in at 45 degrees, so I figured that they had attempted to address all this. And it does work fairly well. With two Ohms you can move quite a bit between the speakers; the soundstage will shift but it doesn't collapse. You might ask Newform for a a psycho-acoustical explanation of their wide-sweet-spot description. Having said all this, another advantage of the center-channel speaker is that it helps prevent collapse, especially with dialogue.
"The 645's appear to have great dynamics and also offer the ribbon/planar sound, however, I was concerned with coherency with the 1Khz crossover between the woofers and the ribbons."
I also was concerned about the crossover issue, especially as most speakers cross right in the prime part of the vocal range. And, of course, Ohms have that high pass filter to the super tweeter at about 8KHz.
Mapman says several important things.
On the SPL issue, I only point out a fringe trend I am beginning to see on the forums about producing HT systems that can play at reference levels. Many people pursuing that seem to be going towards high-efficiency profesional-audio stuff. I agree with Mapman that such an endeavor may not be consistent with keeping your hearing, and I find that -10dB (which corresponds to 95 dB non-LFE peaks at the listening position) is as loud as I would want to go. IMO, the main argument in favor of reference level is that it is hard to get kick-in-the-chest bass without really high SPLs and merely raising the gain on your subwoofer will destroy the spectral balance of the entire presentation.
Finally, Mapman advises starting with what John suggested to you. This is my advice as well. Ohm's customer service is incredible, and John is interested in making sure that every customer gets what they want. For example, He made me a special center-channel version of the full-size 100S3s that fired straight ahead, and he sold it to me at one half the normal price of a pair. He allowed me a full credit when, after a year, I switched my surrounds from micro-Walsh short omnis to 100S3 short omnis. Other stories like this are well-known. To be fair to John in such matters, I would start with his recommendations.