Frequency range, what does it mean?

Nelis87

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Looking at Acoustic Energy's website, model ae100: 45Hz -35kHz and the new Q acoustic 3020i: 64 Hz – 30 kHz. Just a random example.

I always see it as the lower the Hz the deeper the bass will go. In cases like this I am pretty sure the bass of the Q's will go deeper. Bigger driver, more cabinet volume, etc. Other example: the new Q 3020i is 25% bigger than the standard 3020, and with tweaked engineering and crossover it should result in deeper bass, yet they state the same 64Hz as the original.

What do these numbers mean?
 

AEJim

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Hi Nelis,

The devil is in the detail - the usual use of "Frequency Response" is the (relatively) flat +/-3dB output of the speaker, whereas "Frequency Range" generally covers the ends of the spectrum the speaker is capable of at +/-6dB. So repsonse is essentially a more tightly constrained figure vs the wider range one.

Physics always apply to box volume and driver size with regard to bass frequency coverage, though there are quite a few variables that can affect that; port tuning, sensitivity, magnet size/strength and driver throw amongst many others - even then it doesn't really tell you much about how the speaker will sound. For example; some very large PA speakers with very large drivers are limited to 50Hz bottom end to enable high power output, they will sound far stronger at 55Hz than a bookshelf Hi-Fi speaker that can technically reach 45Hz.
 

Strictly Stereo

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AEJim said:
Hi Nelis,

The devil is in the detail - the usual use of "Frequency Response" is the (relatively) flat +/-3dB output of the speaker, whereas "Frequency Range" generally covers the ends of the spectrum the speaker is capable of at +/-6dB. So repsonse is essentially a more tightly constrained figure vs the wider range one.

I do not think that there is any agreement between manufacturers as to the difference between frequency response and frequency range. In my experience, they use these terms interchangeably. The +/- dB qualifier is certainly important, because that provides a little more insight into how flat the response is across the speaker's range. However, even that does not tell the whole story, as manufacturers may apply different degrees of smoothing to their measurements before publishing their figures.
 

lindsayt

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Some manufacturers quote a -12db "in-room" (speaker on the floor right in the corner) response figure.

Others -3db anechoic.

A frequency range figure without the -xdb figure and anechoic or in-room means nothing.

Furthermore, even when the manufacturer specifies these, too often independent testing, eg by Stereophile, reveals that the manufacturer "exaggerated".

Added onto that, if the speaker is pulling port stunts to extend the range, the sound quality on bass transients, eg bass drums and bass guitars will be bad.

All in all, DO NOT USE THE MANUFACTURER'S STATED FREQUENCY RANGE AS A FACTOR IN MAKING ANY PURCHASING DECISIONS.
 
I think you can use the stated frequency range to compare models within a range, by the same manufacturer. It will tell you what a different sized box, or different drive unit will achieve. Beyond that, I agree with Lindsay that they are useless in comparing different manufacturers.

A number of manufacturers will use the limits Jim mentions, and they are probably the most common. But others will be less scrupulous, and output at the frequency extremes may be a fraction of the mid-band level. A bit like ‘music power’ quoted from ghetto blasters - remember them? - or car radios, it bears little resemblance to Hi-Fi standards. For example, power might be quoted peak with 10% distortionboth channels added together, whereas a decent Hi-Fi standard might be continuous at 0.1% distortion, one channel only!
 

Alantiggger

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IF...... now IF, you are blessed WITH Bat-Like Hearing...... Human Beings are not blessed with this as it'd be futile....... then the HIGHER THAT NUMBER, the better it'll sound to you..... except it won't as You are Human. (no bat-like-hearing)
 

lindsayt

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Andrewjvt said:
Not all

Manufacturers are cheats.
No, but as I said, too often they are.

"Frequency range: 36Hz–60kHz"

https://www.stereophile.com/content/tad-micro-evolution-one-loudspeaker-measurements

218TADfig5.jpg


"Frequency response: 20Hz–25kHz, ±0.5dB"

https://www.stereophile.com/content/kii-audio-three-loudspeaker-measurements

917Kii3fig3.jpg
 

Andrewjvt

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lindsayt said:
Andrewjvt said:
Not all

Manufacturers are cheats.
No, but as I said, too often they are.

"Frequency range: 36Hz–60kHz"

https://www.stereophile.com/content/tad-micro-evolution-one-loudspeaker-measurements

 

"Frequency response: 20Hz–25kHz, ±0.5dB"

https://www.stereophile.com/content/kii-audio-three-loudspeaker-measurements

 

 

 

Most are
 

andyjm

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lindsayt said:
Andrewjvt said:
Not all

Manufacturers are cheats.
No, but as I said, too often they are.

"Frequency range: 36Hz–60kHz"

https://www.stereophile.com/content/tad-micro-evolution-one-loudspeaker-measurements

"Frequency response: 20Hz–25kHz, ±0.5dB"

https://www.stereophile.com/content/kii-audio-three-loudspeaker-measurements

A the risk of being pedantic, the second graph is ±5dB not ±0.5dB as you have written.
 
andyjm said:
lindsayt said:
Andrewjvt said:
Not all

Manufacturers are cheats.
No, but as I said, too often they are.

"Frequency range: 36Hz–60kHz"

https://www.stereophile.com/content/tad-micro-evolution-one-loudspeaker-measurements

"Frequency response: 20Hz–25kHz, ±0.5dB"

https://www.stereophile.com/content/kii-audio-three-loudspeaker-measurements

A the risk of being pedantic, the second graph is ±5dB not ±0.5dB as you have written.
I thought Lindsay’s quotes were what the manufacturers claimed, but the reality was the Stereophile graph. Maybe I misunderstood though? You’re correct that plus or minus 5 would be more accurate in the second case!
 

Strictly Stereo

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lindsayt said:
No, but as I said, too often they are.

"Frequency range: 36Hz–60kHz"

https://www.stereophile.com/content/tad-micro-evolution-one-loudspeaker-measurements

"Frequency response: 20Hz–25kHz, ±0.5dB"

https://www.stereophile.com/content/kii-audio-three-loudspeaker-measurements

With regard to the Kii Three measurements from Stereophile, this chart actually shows the average of several measurement positions, according to the caption which accompanies it in the review. This would explain why the reponse is tilted slightly. There is another review of the Kii Three in the January 2017 edition of AudioXpress, with measurements taken in Delft University's anechoic chamber. That shows a flat response from 20Hz-20kHz. 20kHz is as far as they measured.
 

Strictly Stereo

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davidf said:
That Kii measurement is presumably without its digital trickery?

In a true anechoic chamber the Kii Three cannot exploit boundary reinforcement in the same way it would in a real room. This means that the amplifiers have to work harder to maintain the same level. All of its other "trickery" can be employed though. Reading between the lines a little bit, it looks like Stereophile's anechoic measurements are actually "quasi-anechoic" measurements, made by gating measurements taken in a less exotic space to eliminate the effect of reflections. This is not quite the same thing as a true anechoic chamber though.
 

Strictly Stereo

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nopiano said:
I thought Lindsay’s quotes were what the manufacturers claimed, but the reality was the Stereophile graph. Maybe I misunderstood though? You’re correct that plus or minus 5 would be more accurate in the second case!

That was my understanding too. Kii actually claims 30Hz-25kHz +/-0.5dB (anechoic) for the Kii Three nowadays.

Some aspects of Stereophile‘s measurement methodology are a little opaque, but I do rate them very highly and I expect their measurements are much more consistent than those published by manufacturers, and therefore a much more valid way to compare products. I also really like how they combine subjective opinion with objective measurement.
 

davedotco

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I am not sure about the usefulness of such measurements, sure it gives a repeatable, consistent way of measuring speakers but I do not see how it translates to performance.

So many factors combine to produce an in room response, I have always considered power response to be the most important but even so I feel that practical matters are more important. Harman's 'house curve' of a gently falling response from low to highs, seems to correlate well with listeners preferences but as a fan of presentation that might be considered quite explicit, i do not find that it works all that well for me.

Weirdly I find that I rather like different speaker designs with wildely different characteristics, I love big dipoles for example, and, for totally different reasons, domesticated 'bin and horn' type speakers...*unknw*
 

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