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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
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almarg
9,670 posts
 
I was just about to post a similar comment to Stan's, when I saw his post. I don't think that 90db speakers are sensitive enough for use with 300B or other low powered amplifiers, unless you are in a small room, listen from no more than around 8 feet away, listen to music that has narrow dynamic range, and don't listen at high volume levels.

To realize the same peak volume levels with 15 watts that the Grand Veena's can provide at their rated 200 watts, you would need speakers with 101 db sensitivity.

I do agree with the others that for best compatibility with a tube amp you should give preference to speakers with the highest possible minimum impedance.

Regards,
-- Al
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almarg
9,670 posts
 
Also, the Grand Veena's are actually about 1 db MORE sensitive than the Focal's, assuming the specifications are accurate. Their 90db rating at 1 watt at 1 meter, coupled with their 5 ohm impedance, means that they would reach 90 db at 2.24 volts into the 5 ohms. That corresponds to 92 db for the 2.83 volt input that the sensitivity of the Focal's is spec'd at.

The reason that many speakers have their efficiency spec'd at an input of 2.83 volts is that 2.83 volts into an 8 ohm impedance corresponds to 1 watt. However, if the spec is based on input power, not voltage, the impedance of the speakers being compared has to be factored in, to make the comparison meaningful.

Regards,
-- Al
herman
2,253 posts
 
The specs are too close to tell you anything meaningful. Speakers with very close specs can still sound very different from one another. While you can make a short list by using specs to weed out non-contenders these specs are close enough that you need to actually hear them to determine your preference.

What amp do you have? 15 watts is a lot of power from 300B amps unless it uses more than one tube per channel. Are you sure it is 15 watts?

If your budget is up to $6K I would get some horns like Avantgardes or good lowther based speakers like the Beauhorns. You want to be in the +100dB range for efficiency to work with 15 watts, not 90dB.
gregm
3,405 posts
 
Almarg sez:
I don't think that 90db speakers are sensitive enough for use with 300B
May I paraphrase? "90dB speaker ARE NOT sensitive enough for use with a 300B (you sure about the 15W?; Isn't more like 12W?)

Look in the direction of horns. Eliminate everything under 95-96dB. Regards
magfan
1,583 posts
 
Phase angle is Key. Too large a phase angle results in a lower power factor.
With some speakers having huge phase angles, you can easily turn a 100 watt amp into 30 or less. Tube amps don't like heavily reactive loads, (capacitive or inductive, don't 'member!)
That is the REAL indicator of 'easy to drive'.
If you can see the impedance and phase angle data that would help, at least from a purely technical viewpoint.
Of course, what will happen is the speaker which sounds better will also have the worst numbers. Don't buy Specs.
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