What's the greatest bargain in SET these days?

Like Tubegroover I don't want to rain on anyone's parade, but I thought I would point out what appear to be highly credible measurements of the Reference 3A MM de Capo BE, performed by the National Research Council of Canada. They indicate a measured sensitivity of 86.7 db/2.83 volts/1 meter. As can be seen in the first graph, the sensitivity is in the vicinity of 92 db at a few specific frequencies, but is considerably lower at a great majority of frequencies.

Also, the impedance curve shown near the bottom of that page indicates that their impedance is about 6 ohms throughout much of the mid-bass region, where lots of energy is often required. 2.83 volts into 6 ohms is 1.33 watts, which is 1.2 db greater than 1 watt. So on a per watt basis, the 86.7 db figure is arguably optimistic by 1.2 db, meaning that 85.5 db/1 watt/1 meter is probably all that can be counted on with a lot of music.

Something to consider, despite the comments by the esteemed designers mentioned above. Regards,

-- Al

Hi Al,
Your insight and technical perspective is always welcome. This is a fine example of very logical use of measurements (Al) vs actually listening to the pairing of amplifier and same speaker (Bill).It seems this combo can do quite a lot with the exception of orchestra music at really high volume. If this isn't a requirement for Rebbi there's the potential to be very happy with this match. Reviewer Tim Smith says the Dynamo was a good match with lower sensitivity Harbeths.
Charles,

Its gotta be. It goes against physics for a small box to be more efficient and have flat extended bass. Just cannot be. But might sound quite good still at low to moderate volume and soft clip increasingly as the volume goes up, limiting dynamics. Large scale dynamic works would suffer most. End results at higher volume might still be quite good, but can't be optimal in terms of dynamic headroom.

Smaller high efficiency speakers with low ends that roll off at higher frequencies, 50-60 hz or above say, like my "90db" Triangle Titus XL speakers for example would be less affected and probably a better match overall. Or larger more full range high efficiency designs.

Tubegroover,
I agree with you, this has been a very informative thread with many good contributions, this is what I look forward to on this site. I've become plain worn out with the battleground threads with the same predictable lines drawn in the sand. Tubegroover you should read Tim Smith's Dynamo review in 6 Moons. The work and effort he put into it is very apparent, in addition he writes well.
Charles,

I did read the review Charles. Very insightful and through as is the review of the ML 518i. I sensed much the same in Brownsfan's and Mikirob's impressions as well. It makes me want to purchase the amp just to HEAR it particularly at that price. It seems quite remarkable that a product obviously so well made and attractive to boot could be made in Canada, not China, at such a great price. It makes me more curious about Coincident's other offerings.