Any Thoughts On These?

I've done serious seat-time with the ML Motion 60 XTi in two different shops with, obviously, different listening rooms & acoustics.  Both listening rooms, however, were somewhat similar in dimensions.  Here's my take and please remember this is all, of course, IMHO:

First shop used a 60 watt NAD integrated amp whose model number I can't remember.  Room dimensions were something like 17' X 20' with 7' ceiling.  Kinda like a conventional living room with carpeting, bookcases, sheetrock construction, etc.  I think the NAD might have been a Class D design.  The ML sounded very nice but I don't think that NAD had enough power for them and I don't think it was the right match for 6 ohm nominal load speakers like that, even though those ML are relatively sensitive.  The money chair or sweet spot in that room was about 9' away from the ML.  The ML were about 6' apart and the wall behind the sweet spot was about 3 or 4 feet away.  This would make for around 2 or 3 feet behind the ML front baffles and wall behind them.  IMO, speakers with AMT tweeters need more room behind the sweet spot or listening position.  A friend and I both got significant listening fatigue after about 30 minutes or so of concert level volume and a little less.

Second shop used a Simaudio Moon NEO 340IX.  This is one outrageously and hellaciously nice amp!  The ML in this shop only had, we were told, about 40 hours play time on them.  Probably not enough but they still sounded really, really nice.  In fact, my friend and I thought they sounded a hair better than a pair of GoldenEar Ttriton 2+ we A/B'd them with.  However, to be fair, we were told those GE only had about 20 hours play time on them.  Probably not nearly enough.  The listening room was a little larger than the first one but chock full of other speakers & components behind the speakers we listened to.  It, too, was like a conventional living room.  The money seat was about 9' from the speakers but had about 12 to 14 feet to a wall behind the sweet spot.  The ML and GE were separated by about 6'.  The wall behind their front baffles was about 6' away but, again, just chock full of other speakers and components.  Not the greatest set-up but I believe these ML definitely benefitted from the space behind the sweet spot.  No listening fatigue at all after about an hour & a half to two hours at concert level volumes.  I was impressed by both speakers but definitely gave the nod to the ML.

My advice:  if your listening room doesn't have at least 6' (preferably more) of empty space behind the sweet spot, you might like something else, like Revel Performa3 F206.  That's what I bought after auditioning somewhere around 18 different pairs of speakers and they sound even better in my living room set-up than they did in the shop I bought them from.  I also liked the PSB Imagine T2 and the Monitor Audio Silver 500 but the Revel were just jaw-droppers!

Because of my experience with AMT tweeters (not my first, BTW-I demoed the old ESS AMT back in the day) I've always wondered if Beryllium tweeters might need similar room placement (i.e. lots of empty space behind the sweet spot).  Anybody have any experience with this?

High-amp, just want to clarify a few things about the ML Motion 60XTi and speakers with AMT tweeters, in general.

With regard to room placement issues related to speakers with AMT tweeters, a few reviewers have noted they sound best when there is plenty of empty space behind the sweet spot or listening position. This was, indeed, my personal experience with the ML Motion 60XTi. If the sweet spot in your listening room is, for example, a couch with a wall directly behind it, I think this would quickly lead to listener fatigue. On the other hand, if your sweet spot has... say, 6’ or more empty space behind it, then I think that might be OK. I would factor this in to scheduled auditions of speakers like this.

With regard to other room placement issues (e.g. space between speakers and wall behind them; space between left & right channel; etc.), I would also factor that into scheduled auditions, as well. Basically, you want to replicate your listening environment as much as possible, including the equipment you’ll be using.

Is 12" from the back wall 12" from wall to back of speaker cabinet or wall to baffle, which I think is the more important measure. With that particular room placement constraint, you might want to concentrate on front or bottom ported speaker designs. One notable exception to this might be Monitor Audio. If I remember correctly, their Silver 500 and 300 are rear ported designs that do relatively well with that sort of room placement issue.

With regard to the power question, generally speaking, speakers of less than 8 ohm nominal load design, even efficient or sensitive ones, tend to perform best with amplifiers that can feed them adequate current. Watts of power and quality of current supply are different factors. The ML Motion 60XTi are, if I recall correctly, a 6 ohm nominal design and relatively sensitive. This will not be as much of a factor with them as with 4 ohm nominal load design speakers. If you are also in the market for amplification to go with these ML or, for that matter, any other speakers, you should also factor this into your auditions and research. For example: I recently auditioned a pair of Aerial Acoustics 6T speakers (4 ohm nominal load design) that just dropped my jaw! Fantastic speakers! I was ready to buy them on the spot after auditioning them with a 75 watts rated big MAC tube stack. However, after spending a little time listening to them with a 100 watts rated solid state MAC integrated (what I have) it only took a minute or two to hear that these gems really did best with a better power supply. They still sounded fantastic with the 100 watts rated MAC SS but you didn’t have to listen hard to tell they did best with a better power supply. Proper matching of the equipment chain is key.

High-amp, I haven't heard that particular Krell but have spent time listening to the older Krell amps in the past. I've always been SUPER, SUPER impressed! Based upon my reading of the k300i, I have no doubt it should be able to make those ML Motion 60 XTi sing and then some! Did you get one with the optional DAC? With an amp of that quality & power, you might want to set your sights on higher quality speakers if your budget allows.  Not that the ML Motion 60 XTi are slouches but that is one terrific amp! Maybe Aerial Acoustics 6T? 7T? Something in the Revel Performa 3 line? Just sayin'. 

Haven't heard the KEF R11s but did do about an hour of seat-time with the R7s. I've done a fair amount of seat-time with KEF, B&W and other British speakers, over the years.  The only British speakers I've ever spent serious seat-time with and liked, thus far, were Monitor Audio (i.e. Silver 300 and 500) but that's just me. As I'm sure you know, more than anything else in audiophile land, speakers are a very subjective choice. Different ears like different sound signatures and, of course, a lot depends upon your room dimensions, acoustics, component chain and musical preferences. Best is what sounds best to YOU! Your ears will tell you everything you need to know.

I currently have a McIntosh MA5200 in my main system and absolutely love it!  The only things I've heard around its price point in controlled auditions that could compete (IMHO) are the Simaudio Moon Neo 340 IX and a Luxman whose model number I can't remember. The Musical Fidelity M6si was very nice, too, but I heard that one in another shop with different speakers and different room acoustics. Not a fair shoot-out. Also did about 3 hours seat-time with a MAC MA5300 which is basically the same as the MA5200 but with the advantage of the option for an upgraded DAC. I heard the Simaudio Moon with the ML Motion 60XTi and that was REALLY nice!  If you can afford that combo I don't see how you'd be disappointed there. However, as with the Krell amp, you might want to shoot higher for speakers with that one. That Simaudio's current supply is outstanding! You might want to schedule some seat-time with Revel speakers for that one.

It's really fun helping other people spend their money!  LOL!  Good luck!

High-amp, the hunt never ceases. It just goes from vicarious to serious sometimes.

With regard to active speakers, have you spent any time with GoldenEar Tritons? The day I spent about 1.5 hours of seat-time with the ML Motion 60XTi, I actually A/B'd them with the GoldenEar Triton+2 and spent about the same amount of seat-time with them, as well. Unfortunately, the sound room I was in wasn't the greatest and the GE only had, I was told, around 20 hours play on them. The ML, I was told, had about 40 hours play. Power source was a Simaudio Moon 340 IX. You might want to give the GE Triton line a listen if you can find a shop with properly broken-in pairs and a proper sound room.