Speaker efficiency - does it really matter ?

[Arjun4]

Hello Gentlemen,

I'm all set for upgrading my HT system and was doing some research before finalising the speakers. I happened to come across a forum which says the efficiency of speakers does matter while setting up a HT system.

Please let me know your thoughts.

The forum says "Review this post for more information on the impact of speaker efficiency.

http://www.avsforum.com/t/1334369/the-official-denon-avr-xx12-model-owners-thread/120#post_20456112

Bottom line is that going from speakers rated at 86db efficiency to 89db efficiency is like going from a 75W AVR to a 150W AVR so look for more efficient speakers rather than a higher powered AVR"

 

[Fantastic]

High efficiency speakers with moderate amps can give you a large dynamic range. Inefficient speakers need monstrous amps to drive them loud.
Generally speaking I like the 'sound' of efficient speakers even when played soft ! Not all large power amps sound good . A large range of medium power amps do sound quite good !
I do know some people who like sound at bleeding levels as it makes movies come alive ! It also kills your hearing after a while ! Sometimes it is not reversible ! Protect the ears of kids from such loud levels though they might appear to be excited ! You don't want them to loose part of their hearing before finishing school !
60 to 100 watt per channel power amps with 89dB/watt speakers can produce sound louder than is comfortable over a long period of time. A couple of db either way will not really make much of an audible difference.

 

[arj]

Hello Gentlemen,

I'm all set for upgrading my HT system and was doing some research before finalising the speakers. I happened to come across a forum which says the efficiency of speakers does matter while setting up a HT system.

Please let me know your thoughts.

The forum says "Review this post for more information on the impact of speaker efficiency.

http://www.avsforum.com/t/1334369/the-official-denon-avr-xx12-model-owners-thread/120#post_20456112

Bottom line is that going from speakers rated at 86db efficiency to 89db efficiency is like going from a 75W AVR to a 150W AVR so look for more efficient speakers rather than a higher powered AVR"

Technically speaking, what you are talking about above is sensitivity and not efficiency
I believe the usual efficiency of a speaker in converting power is 1-3 % and not more.
Sensitivity measures how much DBs 1 watt (or 2.8 V) will give at 1m

Sensitivity plays a very important role n speaker/amp matching but cannot be the only figure as the impedance/phase curves also play a very important role.

As you mentioned, every 3dB increase in sensitivity needs a doubling of power there is also the fact that that every 3 m you are further from a speaker, the there is a db decrease by around 2-3dB, hence the distance from the speaker also plays a very important role.

Ideally you choose your speaker in terms of your budget and presentation..and then choose the right amp for it. so suggest you first choose the speakers and then go for the amp which can drive them easily.(higher than the rated power) and that should be ok

 

[kapvin]

Efficiency does matter, for the reasons mentioned by other posters.

What complicates matters is that very few manufacturers follow standard practice of measuring at 1w at 1m pink noise in an anechoic chamber. (This means with a 2v signal for a nominally 4ohm system and a 2.83v for a nominally 8ohm system). Sometimes the figure is a bit optimistic, because the measuring conditions are tweaked.

In your place, I would not worry if the sensitivity is 1 or 2 or even 3 db apart (unless from the same manufacturer). More than that will definitely be a factor.

Finally this applies to hifi. If you are looking at HTiB or packaged speakers, mostly the follow the "pmpo" school of measurement

 

[spirovious]

Efficiency may be frequency response of a speaker which can be very important.Sensitivity helps to choose correct amp/power.

 

[arj]

Efficiency may be frequency response of a speaker which can be very important.Sensitivity helps to choose correct amp/power.

Both are very related and can be derived from each other but the measures are different.

The efficiency per se wont really tell you anything very important and needs to be converted to a Sensitivity along with the nominal frequency..Majority of speakers are betwen 2-3%

Sensitivity in dB = 112 + 10 log (efficiency

 

[Arjun4]

High efficiency speakers with moderate amps can give you a large dynamic range. Inefficient speakers need monstrous amps to drive them loud.
Generally speaking I like the 'sound' of efficient speakers even when played soft ! Not all large power amps sound good . A large range of medium power amps do sound quite good !
I do know some people who like sound at bleeding levels as it makes movies come alive ! It also kills your hearing after a while ! Sometimes it is not reversible ! Protect the ears of kids from such loud levels though they might appear to be excited ! You don't want them to loose part of their hearing before finishing school !
60 to 100 watt per channel power amps with 89dB/watt speakers can produce sound louder than is comfortable over a long period of time. A couple of db either way will not really make much of an audible difference.

My Polk TSi400 is 91dB . 8 ohm Speaker Denon 1612 is driving it which is 75W @ 8ohm

As per my upgrade plan - Marantz SR 6008 which is 110 W @ 8ohm

If i'm keeping the same speaker - (91db) - 35 W boost by AVR upgrade.

If speaker is also upgraded - (Dali Zensor 7 ) (90dB) loosing 1 dB there but Dali is 6 ohm speaker and @ 6 Ohm SR6008 will deliver 150 W

Bottom line is loosing 1 db but power is exactly doubled (75 -150)

Am i going in the right direction ?

 

[elangoas]

@Arjun4 - Don't worry abt speaker efficiency/Sensitivity....Audyssey will take care of equalizing the speakers in the initial setup....

These days most of the speakers are >=85 db <=~92 db...

 

[Sawyer]

Bottom line is that going from speakers rated at 86db efficiency to 89db efficiency is like going from a 75W AVR to a 150W AVR so look for more efficient speakers rather than a higher powered AVR"

Yes, but also consider this - one way to attain the speaker marketing people's objective of having higher sensitivity in the spec is by using heavier magnets, which can have the effect of damping bass delivery.
My criteria from a spec standpoint would be impedance drops at low frequencies, some speakers are terrible at this, dropping to 1-2 ohms, needing a lot more amp grunt than better designed ones that hold a steadier impedance.
My other criteria would speaker voicing - how good do the speakers sound to you, based on your preferences.
As suggested here, firm that up first, and then select an amp. Within limits, amplifier watts are cheap.