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What qualifies as a high efficency speaker?

24.72.171.222
Posted on July 21, 2017 at 17:47:16
Travis
Audiophile

Posts: 6170
Location: La Grange, Texas
Joined: November 25, 2001
 This must have been asked before but I'm a lazy butt.

Is it +90db @ 1 watt, +95db, 100db or more?

Thanks in advance.


"If people don't want to come, nothing will stop them" - Sol Hurok

 

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How long is a piece of string?, posted on July 21, 2017 at 19:20:00
Cpwill
Audiophile

Posts: 1096
Location: DC
Joined: December 22, 2003
Contributor
  Since: October 24, 2008
 Both depend on who you ask. A few will say 90 or 93, some will say 95 or 98, but others will insist over 100 or approaching 105. The correct question should be, "what is high enough efficiency for X?" with X being your preferred type of music, listening volume, amp typology and tube complement, listening room size, etc. And, don't forget out the impedance curve over frequency of the speakers as well.

Good luck on whatever your quest might be.


"Anyone who understands jazz knows that you can't understand it. It's too complicated. That's what's so simple about it." - Yogi Berra.

Cpwill

 

RE: What qualifies as a high efficency speaker?, posted on July 21, 2017 at 21:38:52
tube wrangler
Manufacturer

Posts: 2484
Location: USA
Joined: January 29, 2007
 It's really fairly simple:

What are your goals?

Do you want to have your speakers small in your room? That's NOT GOOD!
Are you subject to WAF? (wife acceptance factor).

OR would you like to have a decent facsimile of a real audio event appear
in your listening area?

Would you be satisfied with only correct tonality? (many are).

OR would you like to sample the intentions and attitudes of the musicians
on your recordings?

Do you value correct event timing and having the vertical components
of your speaker's output in the right place, or are you satisfied with slicing music into separate horizontal stripes, (caused by vertical stacking of drivers) thereby entirely destroying any possibility of reproducing a real musical event?

Do you wish to sample the powerful dynamics that are on all good
recordings, or are you satisfied with amplifiers that put out lots of power but won't give you the dynamic picture in real time?

The ultimate in all of these things, and more, is MINIMUM WATTS, and
MAXIMUM speaker efficiency from a POINT SOURCE ONLY. This, of course, demands speaker cables and interconnects that are extremely efficient
also.

A minimum watt amplifier must have a maximum power supply to
work. It must be clean, but much more importantly, it must charge
and recharge fast enough to complete one musical event before the next one comes. It must also sort-out many musical events all happening at
once in order to be truly convincing.

Only you can answer these questions: what do YOU want? How far will you go before you stop improving your setup?

-Dennis-

 

Most often, 96dB/w/m or greater, posted on July 21, 2017 at 22:33:57
Paul Joppa
Industry Professional

Posts: 7296
Location: Seattle, WA
Joined: April 23, 2001
 At least, that seems to crop up more often than other numbers.

For what it's worth, that's about 2.5% efficiency; it's also a good minimum for a 2A3 SET amp (good for a bit less than 4 watts).

 

RE: What qualifies as a high efficency speaker?, posted on July 21, 2017 at 23:30:05
RGA
Reviewer

Posts: 15177
Location: Hong Kong
Joined: August 8, 2001
 Efficiency is more than a sensitivity rating. A 95dB sensitive speaker that sits between 8 and 12ohms full frequency response is a FAR easier speaker to drive than a 100dB sesitive speaker that dips to 2ohm from 20hz to 120hz. Most SET amplifiers will wheeze and puff on the latter speaker and will have zero issues with the former.

The LS-3/5a is only 82dB sensitive but sits 11-16 ohms. So a SET has no problem with these speakers. And while you are limited by volume the speakers can only handle a max of 50watts so yoy are limited by volume regardless of the amp you choose.

The title of the forum should probably be called high sensitive not high efficiency and then there should probably be levels like high senstive 92dB-96dB and very high sensitive 97-102dB and ultra high sensitive 103dB+

 

RE: What qualifies as a high efficency speaker?, posted on July 22, 2017 at 06:34:30
tomservo
Manufacturer

Posts: 8210
Joined: July 4, 2002
 Well around 92dB 1w 1m is approximately 1% electro acoustic efficiency and 102 would be around 10%, 112 would be 100% (impossible). What makes this harder to gauge is that the above assumes a source with no directivity and directivity can raise the on axis sensitivity without rising the true efficiency.

If this wasn't complicated enough, then one can add horns to the mix where it IS possible to get say 40 or 50 or more% true efficiency BUT only in a relatively narrow range and there simply aren't any compression drivers which are efficient up high. If one wants to end with flat response, it is the efficiency at either end of the spectrum that governs what you have in the middle.
Hope that helps
Tom

 

Anything that ca be driven by a 45 SET tube amp (nt), posted on July 22, 2017 at 08:15:06
seikosha
Audiophile

Posts: 42
Location: USA
Joined: March 21, 2013
 (nt)

 

RE: What qualifies as a high efficency speaker?, posted on July 22, 2017 at 08:52:09
lokie
Audiophile

Posts: 1989
Location: Georgia, USA
Joined: January 28, 2003
 I'll let the more knowledgeable inmates pontificate on this very complicated subject.

I'll go low tech and say that my personal experience is that at 100db (and at least a minimum of 8ohms) "things" start to get way more exciting: dynamics, inner detail, presence, amplification choices.

 

RE: How long is a piece of string?, posted on July 22, 2017 at 11:10:15
Travis
Audiophile

Posts: 6170
Location: La Grange, Texas
Joined: November 25, 2001
 No quest. Just thought I might get a consensus from this forum.

Now I see it was not a good question but thanks for your response.


"If people don't want to come, nothing will stop them" - Sol Hurok

 

RE: What qualifies as a high efficency speaker?, posted on July 22, 2017 at 11:18:33
Travis
Audiophile

Posts: 6170
Location: La Grange, Texas
Joined: November 25, 2001
 I guess it was a stupid question.

Thanks for your considered response and your ten questions.

I think I could never afford a system that you are suggesting and so it becomes a non-starter.






"If people don't want to come, nothing will stop them" - Sol Hurok

 

RE: What qualifies as a high efficency speaker?, posted on July 22, 2017 at 11:21:27
Travis
Audiophile

Posts: 6170
Location: La Grange, Texas
Joined: November 25, 2001
 Thanks, RGA.


"If people don't want to come, nothing will stop them" - Sol Hurok

 

RE: high efficency speaker? by William Cowan in AU, posted on July 22, 2017 at 11:25:37
claudej1@aol.com
Audiophile

Posts: 817
Location: Detroit
Joined: August 17, 2007
 Save your money and just get a Danley SH-50 and be done with upgrades. It easily meets all 10 of his criteria for high fidelity.

 

RE: What qualifies as a high efficency speaker?, posted on July 22, 2017 at 11:57:10
Travis
Audiophile

Posts: 6170
Location: La Grange, Texas
Joined: November 25, 2001
 Thanks, tomservo.


"If people don't want to come, nothing will stop them" - Sol Hurok

 

sounds about right, but -- , posted on July 22, 2017 at 12:08:37
mhardy6647
Audiophile

Posts: 16018
Location: New England
Joined: October 12, 1999
Contributor
  Since: October 23, 2016
 I wouldn't kick a 95 dB @ 1 meter @ 1 watt loudspeaker out for eating crackers in bed, you know?

:-)

I also wouldn't pre-judge the combination of an amplifier & loudspeaker without giving a listen first.

all the best,
mrh

 

:-) that's ca. 2 wpc (downhill, with a tail wind) -- , posted on July 22, 2017 at 12:11:43
mhardy6647
Audiophile

Posts: 16018
Location: New England
Joined: October 12, 1999
Contributor
  Since: October 23, 2016
 i.e., "pretty sensitive".

I' m thinkin' anything less than an honest 100 dB @ 1 meter @ 1 watt (and a benign impedance curve) need not apply ;-)

Anything's worth a try but SE 45 is gettin' down towards true fleapower.



all the best,
mrh

 

RE: sounds about right, but -- , posted on July 22, 2017 at 12:14:28
Travis
Audiophile

Posts: 6170
Location: La Grange, Texas
Joined: November 25, 2001
 "I wouldn't kick a 95 dB @ 1 meter @ 1 watt loudspeaker out for eating crackers in bed, you know?"

Precisely what I just acquired.

Wondering if I could be a member of the "club."

Thanks.


"If people don't want to come, nothing will stop them" - Sol Hurok

 

compression drivers that are 'efficient up high', posted on July 22, 2017 at 12:17:37
mhardy6647
Audiophile

Posts: 16018
Location: New England
Joined: October 12, 1999
Contributor
  Since: October 23, 2016

What about the Fostex "supertweeters" (T90A, T900A, etc.)?
On paper at least, they seem to be sensitive & to have reasonable output "up high"?

Or are you specifically referring to broad bandwidth treble horns & drivers to support them, Tom?

Also, I do recognize that mfgr. specs are sometimes, shall we say, optimistic. :)

all the best,
mrh

 

RE: high efficency speaker? by William Cowan in AU, posted on July 22, 2017 at 12:17:50
Travis
Audiophile

Posts: 6170
Location: La Grange, Texas
Joined: November 25, 2001
 Thanks!

Love the handholds.

Pro Audio.

Wonder how much. Sure isn't that big, physically.




"If people don't want to come, nothing will stop them" - Sol Hurok

 

I'd let you in, but you'll have to ask Dr. Joppa ;-) (nt), posted on July 22, 2017 at 12:19:26
mhardy6647
Audiophile

Posts: 16018
Location: New England
Joined: October 12, 1999
Contributor
  Since: October 23, 2016
 nt
all the best,
mrh

 

That seems like a convoluted, unsimple answer (to a fairly straight forward question)..., posted on July 22, 2017 at 13:24:36
musetap
Audiophile

Posts: 31879
Location: San Francisco
Joined: July 8, 2003
Contributor
  Since: January 28, 2004
 that would be appropriate for almost any audio board in these parts.

Plus there's no real answer to his question.




"Once this was all Black Plasma and Imagination"-Michael McClure



 

Don't worry, I won't judge you (nt), posted on July 22, 2017 at 21:29:10
Paul Joppa
Industry Professional

Posts: 7296
Location: Seattle, WA
Joined: April 23, 2001
 :^)

 

RE: :-) that's ca. 2 wpc (downhill, with a tail wind) -- , posted on July 22, 2017 at 21:53:19
ahendler
Audiophile

Posts: 5151
Location: San Antonio, Texas
Joined: January 24, 2003
 Maybe a 300B set amp
Alan

 

You ARE one of the good ones, sir!, posted on July 23, 2017 at 05:23:35
mhardy6647
Audiophile

Posts: 16018
Location: New England
Joined: October 12, 1999
Contributor
  Since: October 23, 2016
 And my hifi (and my outlook on hifi) has benefitted greatly from your contributions.

This seemed like -- not a bad time -- to say thanks.

DSC_8376 (2)
all the best,
mrh

 

RE: "speakers that can rock with just one watt"..., posted on July 23, 2017 at 09:20:06
Ivan303
Audiophile

Posts: 48887
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
 OK, maybe 5 watts.

I'm thinking 96dB or better but would have to include single driver speakers without x-over and an easy load (8+ ohms?) would qualify even in the low 90's dB-wise.

But then I ran Goodmans of England drivers (95dB maybe on a good day?) in open baffles with flea-powered amps (3 Watts or less) and they were perfectly happy.








First they came for the dumb-asses
And I did not speak out
Because I was not a dumb-ass

 

Seems to me, most of the post boils down to this, posted on July 23, 2017 at 09:37:33
Frihed89
Audiophile

Posts: 15703
Location: Copenhagen
Joined: March 21, 2005
 "A minimum watt amplifier must have a maximum power supply to
work. It must be clean, but much more importantly, it must charge
and recharge fast enough to complete one musical event before the next one comes. It must also sort-out many musical events all happening at
once in order to be truly convincing".

This is not simplistic or convoluted.

 

Another complication, posted on July 23, 2017 at 10:43:59
M3 lover
Audiophile

Posts: 6604
Location: SW Mich
Joined: May 29, 2005
Contributor
  Since: July 4, 2007
 I think some manufacturers suggest efficiency based upon ratings for the drivers utilized rather than testing the assembled whole. I had a pair of speakers rated at 90 dB but found that a minimum of 200 watts was needed in a medium sized room with playback levels averaging in the low 80s.

I believe that was for two reasons. One, as RGA explained, was an impedance curve which dipped below 3 ohms at two different frequencies. The other was a very complex 1st order crossover designed for time/phase considerations. A friend brought over a 50 watt amp he'd built to test with those speakers and if fell flat on its face. Normally 50 watts should work with 90 dB I expect.

"The secret of life is honesty and fair dealing, if you can fake that you've got it made." Groucho

 

RE: What qualifies as a high efficency speaker?, posted on July 23, 2017 at 12:02:51
tube wrangler
Manufacturer

Posts: 2484
Location: USA
Joined: January 29, 2007
 Ah Hah! The TRUTH comes out on our forum!

Thanks for the accurate assessment, Lokie!

Hi-Eff does require some large and very good cabinetry.

There's more to this, however.

Really good Hi-Eff drivers are designed MUCH better, machined
MUCH better, and made from better materials, and are heavy weights.

Most medium or low-eff speakers-- many of them VERY expensive,
are using relatively CHEAP drivers.

These cheap drivers are CHEAP!

JUST LOOK at those CHEAP drivers in your Mega-Buck speaker!

-Dennis-



 

RE: Another complication, posted on July 24, 2017 at 10:27:40
RGA
Reviewer

Posts: 15177
Location: Hong Kong
Joined: August 8, 2001
 I have 90dB Audio Note AX Twos. 7 watts is recommended. I ran my OTO on AN Js for 13 years. The OTO measures 4.2 watts undistorted. I could play AC/DC or Black Sabbath or Nightwish etc without any problems or having the system puff or wheeze. The AN J is 92.5dB in corners and 89.5dB free standing.

I think people need to simply try the stuff out. AN is likely the biggest selling SET maker globally and their matched speakers are around 90-97dB. And most of their amps are under ten watts. So to me it's one thing to discuss specs and measurements but the ear test is the final and only test that counts.

Now it could be their amplifiers are simply way more robust than average too and I did compare the Kit One to a 300b Cary. The KIT one had vastly better deep bass control. So this is not all about the speaker itself.

 

RE: What qualifies as a high efficency speaker?, posted on July 24, 2017 at 13:44:20
Don Reid
Audiophile

Posts: 890
Location: Rural NW Georgia
Joined: February 2, 2001
Contributor
  Since: April 1, 2010
 I agree with you about 100dB/1w/8 ohms. Through many many different speakers over decades about 100dB seems to me to be the point where things come alive.
I dream of an America where a chicken can cross the road without having it's motives questioned.

 

Yup, two 90 dB examples with very different results,, posted on July 25, 2017 at 09:51:13
M3 lover
Audiophile

Posts: 6604
Location: SW Mich
Joined: May 29, 2005
Contributor
  Since: July 4, 2007
 so trials are absolutely called for.

"The secret of life is honesty and fair dealing, if you can fake that you've got it made." Groucho

 

RE: Another complication to the complication , posted on July 27, 2017 at 20:19:08
A.Wayne
Audiophile

Posts: 2527
Location: Front row center
Joined: November 30, 2011
 Well here's the real complication ... :)

A 96 db /m/8 ohm @2.83V Speaker is less efficient than a 96db/m/16ohm @2.83v speaker but they both have the same sensitivity ...

How's that for magic ...!!!

Regards


PS , those AN sensitivity numbers were already debunked and are fake news ...

 

RE: compression drivers that are 'efficient up high', posted on July 29, 2017 at 09:23:52
tomservo
Manufacturer

Posts: 8210
Joined: July 4, 2002
 Well lets say one wanted to use that driver as part of a broad band system.
IF you wanted "Flat response" on axis then you could get it between about 3K and 20 K with an on axis sensitivity of over 100dB.
Flat response is derived by attenuating the mid band down to the upper and lower limits of the desired bandwidth.

At the same time, without knowing the directivity, one cannot know the actual efficiency, the best one can get then is the on axis sensitivity.

Directivity makes the difference between a bare 75W bulb and a high beam headlight

 

Roger that. Thanks for the explanation, sir! (nt), posted on July 29, 2017 at 10:21:11
mhardy6647
Audiophile

Posts: 16018
Location: New England
Joined: October 12, 1999
Contributor
  Since: October 23, 2016
 nt
all the best,
mrh

 

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