Which speakers are higher efficiency?


Hi, I am in the market to buy a high efficiency speakers to match my 300B with given 15W output. When I do some search online, I have 2 speakers in my mind:

Reference 3a Grand Veena Loudspeakers
Efficiency: 90 dB. 1Watt/meter.
Frequency response: 36Hz - 20 kHz (+/-) 3dB.
Up to 100 kHz high frequency extension.
Bass loading: F3@ 36Hz., tuned port,
quasi-second order, -15dB at 20Hz.
Impedance: 5 Ohm (+/-0.5 Ohm).
Power handling: 200 Watts RMS.
Phase: Almost constant at 10 degrees @94dB, wide band.

Focal 1037be
Type: 3-way bass-reflex floor standing speaker
Frequency response (+ or-3dB) 38hz-40hz
Sensitivity (2,83 V/1m) 91dB
Nominal impedance 8 Ohms
Minimum impedance 3,5Ohms
Crossover frequency 350Hz/2000Hz

Just look at the number, Focal 1037be is more efficiency, b/c it gives 91dB v.s. Reference 3a Grand Veena only give 90dB. Is that right? or am I missing something here?
Or can you guys suggest a 4~6k high efficiency speakers for me?
Thanks,
audiorichard
I don't know the Grand Veena, but used to own Ref 3a deCapo loudspeakers. The deCapos aren't hugely sensitive, but they present a very easy load. The minimalist x-over is said to contribute to this. Bottom line: they work very well with 300Bs (no obvious deviations in FR), but have limitations on dynamics and ultimate spl. If you can live with (and listen within) these limitations, Tvad's original comment is right on. If you can't, Johnk and Gregm offer good advice.

Marty
Gotta say I agree with Johnk and Gregm on this one. You need at least 95dB to make those 300Bs work really well, and I would almost say you need 98 (though it would depend on the impedance curve (and at that level, phase angle may come into play :^) but I'll defer to others on that)). Anything below or with a large impedance range with the low impedances in the bass and you will be risking serious disappointment (especially in the bass). I think the Coincident Total Eclipse are good high efficiency speakers in the 'box speaker' format, but my heart belongs to horns, which can come in all kinds of flavors. I'd think for $4-6k you could do yourself very well, either by buying something used off the 'gon or buying speakers custom-made for you direct from the manufacturer (disclosure: I've never purchased any speakers from any manufacturer who mentions himself on this thread (or is likely to going forward for that matter) but I've seen some of his creations in photos. Other builders are those who deal with BLH (back-loaded horn) designs. You can check Frugal Horn for some DIY designs, though there are some builders who will build a set for you, sometimes ones which are tweaked/improved beyond the original design. You might also dig around the archives here and over at AudioAsylum.com (the High Efficiency Speaker Asylum). There will be lots of ideas in both places.
Most 300b amps have 7 watts output or so. Is your amp an SET (and therefore class A2) or is it push-pull?

If an SET, it is essential that the speaker have higher efficiency. I am running a 30-watt amp on speakers that are 98 db, in an average size room (17x23') and that seems to be about the minimum amount of power to get by. With SETs in particular (my amp is an OTL) you don't want to be driving the amp hard if you really want to hear what it can do (which will be good low level detail/transparency). That will require a speaker that is 98 db at the minimum, 103 would be nearly unlimited headroom.

That is why you see so many SET users using horns.

Plan B- if you really are considering a choice between these two speakers (both are excellent- FWIW I prefer the Ref3a in this case), then you will want to get a more powerful amp- one that has at least 100 watts. The 10 db difference in efficiency of speakers (91 to 101 db) translates into a 10X power difference.
Agreed with JohnK, neither two speakers you are a good match for a SE tube amp. Sensitivity is only one factor you must look at; more importantly is a benign impedance curve.

You should consider one of Johns speakers (KCS), Cain and Cain or Carder sound (and many others)

Regards
Paul
Agree with the posters saying you need 98dB efficiency at a minimum for that type of amp, especially if it is single-ended, in which case you will want even more efficiency if you are in a large room. Horns match very well, as others have said. You certainly don't need to spend 4-6K, either, if you don't want to - I got a very nice pair of Klipsch Cornwalls on this site for only $600. You may need to spend a little more than that, but certainly not 4-6K. Anything in the Klipsch Heritage series would be good, or something similar.