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I ask because we often see speaker specs that show the frequency response and in the case below the "low frequency point".
For example, if the manufacturer doesn't specify the +/- 3dB for the speakers frequency range as shown below, do we assume he means +/- 3dB or is he possibly hiding something?
Same for the low frequency point shown below. Here it is spec'd as 32Hz -6dB. I assume this to mean the speaker will output to 32Hz but it will be 6dB down in signal strength from the overall frequency range. Is this an attempt by the manufacture to show that his speaker goes down to 32Hz albeit with 6dB less output?
Thanks.
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I just happened to see these specs for a pair of Focal Aria 936 K2 Limited Edition speakers:
Three-way Floorstanding Loudspeaker
The Aria 936 is a three-way loudspeaker featuring an elegant design and a small footprint. Very linear and with impressive dynamics, thanks to three woofers, it is naturally intended for listening in stereo for monitoring-type activities. This loudspeaker is also ideal for setting up a spectacular Home Cinema system.
The intention of the original Aria was a return to the very essence of acoustics for those who are passionate about music, and this delivers that message with even greater impact.
Specifications
Type: Three-way bass-reflex floorstanding loudspeaker
Speaker drivers: 3 x 6.5" K2 woofer, 6.5" K2 Power midrange, 1" Al/Mg TNF inverted dome tweeter
Frequency response (+/- 3dB): 39 Hz - 28 kHz
Low frequency point (-6 dB): - 6 dB 32 Hz
Sensitivity: 92 dB
Nominal impedance: 8 ohm
Minimum impedance: 2.8 ohm
Crossover frequency: 260 Hz, 3100 Hz
Dimensions (HWD): 45-1/4x11-9/16x14-5/8" (1150x294x371 mm)
Weight: 64 lb
Follow Ups:
"Frequency response (+/- 3dB): 39 Hz - 28 kHz
Low frequency point (-6 dB): - 6 dB 32 Hz"
I can tell right away it is a ported system. In 7Hz it drops from -3dB to -6dB which is a dead giveaway.
Speaker frequency response last I recall was 2/3rd octave pink noise. Also if you put 40Hz into a speaker and 120Hz comes out that is measured as valid output.
To make things even worse, they add a close miked response of the woofer to one of the port. They add these together but in reality they subtract.
All this came in the late 1970s and early 1980s. This is when they stopped overbuilding amps and they could not handle sealed cabinets, which technically should have no lower impedance than ported but does. They also took the low bass out of the bass controls to make it easier on the amp. I think they sound like shit. They turned the bass control into a mud control.
Also for a ported system the woofer has to be bottomproof. This means the suspension keeps it from bottoming. As a result when you get it cranked up it gets odd order distortion.
If you ever find a pair of speakers that actually rates THD you might have something there. The reason is that on most speakers the rating would be embarrassing. Why buy an amp with 0.005% THD when the speaker has 2% ? And many sound good at that. Good, but not excellent.
No matter what the numbers say, it tells us very little about what to expect from a performance point of view.
It gives us some idea about what kind of amp we need to use with sensitivity and (minimum) load numbers. But recommended wattage requirements/power handling are/is often a waste of time.
I have heard many a capable 30 watter (Naim Nait and Sugden A21SE to give two good examples) do wonderful things to speakers whose recommended power rating is 50-*** watts per channel.
And as for frequency response - that's an area of wild optimism from the manufacturer. The amount of speakers whose specs claim they go down to below 45 Hz (+/-6db) compared with those which actually do is a vast shift. Although 6 dB is a lot, and therefore suggesting there's a good chance you won't hear what you're expecting to hear.
Then there's the biggest reasons spec's can give us little idea about their sonic capabilities; how a speaker reacts in any given room, and how it is positioned. Looking at audio forums online, it's very apparent the masses who post pictures of their systems are not allowed to, or do not know how to position their speakers to get the very best out of them.
and you will quickly realize that there are a complete set of standards and measurements that will fully describe how a speaker will sound and interact in a room. The problem is that many manufacturers dont publish this data nor do audiophile rags properly review speakers with proper measurements. I would put ASR in 3rd place behind Soundstage and Stereophile for accuracy of reviews with Soundstage being far above the other two for accuracy.
Those focal specs are ok but are far from complete. For one thing, they are missing off axes measurements which are key in describing how a loudspeaker behaves. Very few companies publish this.
Those are very complete standard specs for the Aria. And at best they only tell you it's probably a decent speaker. Frequency response is secondary to sounding live:move a seat in a concert hall and the frequency response changes. Dispersion and how it changes with frequency matters. Linear dynamic changes matter, not just how loud a system goes but does it go up and down in loudness accurately at low medium and high levels. What is the bass quality, not just how low does it go. Is there significant ringing. How does a speaker handle transients at any frequency? Do they stop quickly with the signal. This often has to do with the affect of a crossover on a driver. Poor crossovers matter.
This is already a lengthy list of measurements that matter and rarely exist for us to check. And I'll bet there are many others to use and also to be discovered. For now we use the specs there are and we learn to listen both to the product and to ourselves. Each of us needs to understand what performance values matter the most to us and those that we can not tolerate in order to choose the speaker we can live with and enjoy.
Right on, right on. My homemade speakers probably wouldn't pass any tests but I enjoy them very much. I think, in fact, that they are the first speakers I've ever been totally happy with.
I remember J. Gordon Holt's appreciation of the Altec Voice Of The Theater. "If you can ignore its considerable frequency variations..."
Thanks for the memories. I was friends with Gordon when he was in Philadelphia and long distance after that. He was a great guy and a superb audio person.
He and John Crabbe were my two favorite audio reviewers.
Jeremy
companies use to spec them off measurements made in anechoic chambers. Then FFT was commonly used.
From Bing:
"Gated frequency response measurement. This means the signal picked up by the microphone is gated, so that after a certain time frame, all other received signals are ignored. The problem with gated measurement is that the shorter the gate time interval, the higher the cutoff frequency. This means that to get accurate data down to 20 Hz, you will still need no boundaries for at least 8.5 meters, which is pretty pointless indoors"
If a company doesn't spec how measurements were made then it's a guess, bad measurement, or wishful thinking.
I had the good fortune of a day with a classmate's Father (worked on the LED design) at Bell Labs in NJ where I had the chance to see cutting edge before the term was even used. They were making specialized IC's in a room with a laser and saw it in action (the computer we had in school used nixie tubes). The anechoic chamber they had was the size of a football field and 4 stories in height. They were running speaker specs and other weird experiments. The courts eventually dissolved ma bell.
'how do you like Socialism so far?...'
.
Same for the low frequency point shown below. Here it is spec'd as 32Hz -6dB. I assume this to mean the speaker will output to 32Hz but it will be 6dB down in signal strength from the overall frequency range. Is this an attempt by the manufacture to show that his speaker goes down to 32Hz albeit with 6dB less output?
As Dave_K said, the specs are largely meaning less compared to your room and how the best position those speakers.
In general, if a speaker is -6dd at 32Hz, it can't hit 40 or 50Hz, so you need a sub unless your have room reinforcement.
-Rod
There is no standard measurement technique behind those loudspeaker FR specs. Some manufacturers specify it at the -3 dB point, some at -6 dB, and many just don't say. And they all include some amount of boundary reinforcement, but the measurement conditions are never specified. So you can't compare numbers across manufacturers, and the opportunity is wide open for some to game the specs by assuming near wall or corner placement. And some just outright lie. Even when a manufacturer tries to give you a number that is representative of a typical room and placement (and I would say Focal tries), the results in your own room could vary a lot.
So the only information that I get out of them is a rough guess about whether they are going to excite my worst room modes and whether they can work with my subs.
That's a good question. Lots of years ago I unfortunately got myself into a marketing role, and one of the things I did was write data sheets for a tech product. Maybe there was a standard for speaker specs at one time, but if it is like my experience it is a marketing job so the guidelines were to use industry accepted specs, emphasizing the strong points of the product while downplaying weaknesses - standard marketing spin.
The specification look reasonable-
I would agree with others that the sensitivity spec should be accompanied with either the 1w/1M (1 watt @ 1 Meter) or the 2.83V @ 1M - see linky below....
But otherwise - the specs seem good....
Happy Listening
in terms of measurements and specifications.
At the risk of drawing fire ;) if you want to, you can go peruse stuff on speaker measurement and objective assessment over at everybody's favorite objective hifi website -- see link below.
Spoiler alert (FWIW). I am there, and (at this point) unapologetically so, even though my opinion of that gang was quite jaundiced for some time.
all the best,
mrh
I think ASR's speaker reviews are very valuable though Amir tends to test only less expensive speakers and/or monitors.His methodology is the most advanced and he evaluates speakers based on the standard Toole criteria including flat frequency response and even dispersion across the full range.
I like that he also measures distortion and a couple of different output levels. Distortion is often overlooked in speaker reviews that show FR only.
Unlike his reviews of electronics, Amir does offer subjective ( !! ) comments on the speaker's sound. He also make suggestions for electronic equalization of the speaker in question.
Dmitri Shostakovich
Edits: 03/03/21
I just bought a pair of ELAC Reference based on his measurements and his subective listening notes.
He is kind of inconsistent though is he not, in that he is willing to make subjective listening evaluation of speakers but not of electronics?
If art interprets our dreams, the computer executes them in the guise of programs!
These should in fact be down -3dB from broadband average at 39Hz and 28kHz.
-6dB at 32Hz is altogether respectable. There will still be output at that frequency, mostly from the reflex port, but subjectively much reduced in level. If you like a lot of organ and synth music, a subwoofer should be considered.
92dB sensitivity, PRESUMABLY at 1 meter with 2.83V input (they really SHOULD specify that) is optimistic, but not impossible with three woofers.
It's good to know that the actual minimum impedance is 2.8 Ohms. These should NOT be regarded as 8 Ohm "nominal" speakers, and SHOULD be used with a gutsy amp capable of sinking some current.
Back when they served the DIY/OEM market, raw Focal drivers were well regarded for both absolute quality and closeness to published spec.
Focal was one of the pioneers of Kevlar drivers, including both some very good woofers and a horrible concave tweeter that was soon discontinued after everyone hated it.
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