Understanding speaker specs and efficiency

W

woodyf

Audiophyte
I have Athena F2.2. They supposed to be rated at:

20w min
250w max
@ 8 ohms
93 db efficiency

So what does this mean exactly?
Does it mean to reach an SPL level of 93 db, I need to drive 250w?

How reliable are the numbers presented by Manufacturers, are they fudged as much as amps.

I bought a HK235 (50w x7)(65w x2) witch is supposed to be so called "high current". The Hk did not do justice to my speakers. They did not play Loud at all, no bass..... After I installed a Ashly amp at 300w @8ohms, they played "loud", more dynamic, more bass, big improvement in all aspects in mids to highs.

So what was it, a weak amp, or fudged numbers. 20w being a bare min....
 
Z

zumbo

Audioholic Spartan
woodyf said:
I have Athena F2.2. They supposed to be rated at:

20w min
250w max
@ 8 ohms
93 db efficiency

So what does this mean exactly?
Does it mean to reach an SPL level of 93 db, I need to drive 250w?

How reliable are the numbers presented by Manufacturers, are they fudged as much as amps.

I bought a HK235 (50w x7)(65w x2) witch is supposed to be so called "high current". The Hk did not do justice to my speakers. They did not play Loud at all, no bass..... After I installed a Ashly amp at 300w @8ohms, they played "loud", more dynamic, more bass, big improvement in all aspects in mids to highs.

So what was it, a weak amp, or fudged numbers. 20w being a bare min....
Weak receiver amp. Very weak. Although, HK is known to be more honest than others. So 50 watts is pretty much 50 watts.

93db is how efficient your speakers are with 1watt @ 1meter. 93 is very good.
20 watts is the bare minimum recommended for your speakers.
250 watts is the maximum recommended for your speakers.
So, 300 watts is great. You shouldn't have a problem with clipping at all, but don't push it too hard. You can pretty much tell when your speakers are at their limit. Just know when to say no.

From Audioholics Audio Terms.
1)Efficiency rating - the loudspeaker parameter that shows the level of sound output when measured at a prescribed distance with a standard level of electrical energy fed into the speaker (usually recorded as XdB @ 2.83V input signal from 1 meter of distance. However, a driver with a high efficiency rating needs a larger box to play a lower frequency than a driver with a lower efficiency rating.
2)Sensitivity - The sound pressure level directly in front of the speaker (on axis) at a given distance (usually 1 meter) produced by a given amount of power (usually 1 watt).
3)Clipping - a form of distortion caused by cutting off the peaks of audio signals. Clipping usually occurs in the amplifier when it's input signal is too large or when the voltage rails of the power supply cannot deliver the necessary voltage to the power amp.

http://www.audioholics.com/FAQs/wattsvsdBs.php
 
Last edited:
mtrycrafts

mtrycrafts

Seriously, I have no life.
woodyf said:
I have Athena F2.2. They supposed to be rated at:

20w min
250w max
@ 8 ohms
93 db efficiency

So what does this mean exactly?
Does it mean to reach an SPL level of 93 db, I need to drive 250w?

How reliable are the numbers presented by Manufacturers, are they fudged as much as amps.

I bought a HK235 (50w x7)(65w x2) witch is supposed to be so called "high current". The Hk did not do justice to my speakers. They did not play Loud at all, no bass..... After I installed a Ashly amp at 300w @8ohms, they played "loud", more dynamic, more bass, big improvement in all aspects in mids to highs.

So what was it, a weak amp, or fudged numbers. 20w being a bare min....

Sensitivity is 93, pretty good. But this is in an anechoic chamber. You also have room gain from that same 1 watt of power in a room, maybe about 3-4dB spl. But all this is at 1 meter distance from the speaker. When you double the distance to 2 meter, you loose 6 dB spl and when you double again to 4 meters, you loose 12 dB spl.

HK uses the high current rather loosely;) with no real meaning behind it, unless they combine all their channel current into one without telling you this. Kind of deceitful.
 
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