¿Cuál es la respuesta ideal en frecuencia de un altavoz? la plana

Now take a look at the graph in Figure B. That's the frequency response of the Erehwon Model 10, with drivers and tweeters made of pure Unobtainium ("Half the carbs, all the sound!"). The flat line on the graph indicates that the speaker is "flat"; it reproduces all the musically relevant tones at the same volume. That doesn't mean that a "flat" speaker will play all recorded sounds at the same volume — bear with me here — it means that it will treat all sounds equally; it won't impose its will on the music but will allow you to hear the music as it was recorded. Flat is good. Flat response means that the speaker reproduces sound accurately.



Too bad that the Erehwon Model 10 doesn't really exist, and neither does Unobtainium. Today's technologies allow speaker designers to get closer to the "flat" ideal than ever before, but they still fall far short of "perfection." So if a frequency range spec is not adequate, what is?

Frequency Response In Context

A big improvement would be a frequency response number that also includes the amplitude tolerance, expressed as "XHz-YkHz +/- 3dB." This tells you that the amplitude of the speaker's response relative to frequency does not deviate more than 3 Decibels from the center line. The "plus or minus 3dB" spec is regarded as a standard of sorts. The theory is that 3dB differences are "just perceptible," so a speaker whose response curve lies within that tolerance window is a reasonably accurate speaker. Let's see if that idea holds water...

Now look at the response of the speaker in Figure E. This speaker exhibits a smooth response curve with low amplitude variations so you'd expect a fairly natural sound; however, the bandwidth of these errors is very broad, and experience has shown us that even low volume variations are audible if they cover a broad range of frequencies.

In this case, Speaker E would have rich bass, prominent treble and be somewhat recessed or "laid back" in the midrange. Audiophiles call this "The Smile Curve." It's not the desirable trait it sounds like but it's a very "sellable" trait to naive buyers...

Flat is Beautiful

In engineering terms, a loudspeaker is a transducer, converting electrical and mechanical energy into acoustical energy. If the intensity of the acoustic signal exactly tracks that of the electrical input with frequency, the conversion is deemed to be perfect. This is exactly what a flat frequency response implies. In other words, flat is perfect. Cleavage is not a desirable feature in a loudspeaker response curve. But we’ve yet to see a speaker design grace this planet that is without some curvature or other irregularities in its response curve. The audio gods have made it hard to scale mount Olympus. Not a problem, at least if the manufacturer only has meet the basic response spec. After all, the speaker is allowed to swing a total of 6 dB - a factor of four in intensity - measured between the response minimum and maximum. Let’s take a look at some of the response possibilities embraced by such a specification...

Harmonic Distortion: A Final Caveat

Amplifiers of all shapes and sizes are typically decorated with a total harmonic distortion (THD) specification. Solid-state amps usually do really well here, sporting THD figures of 0.1% or less. Tube amps are sometimes belittled by techno heads for living dangerously at a THD of 1% or more. It is curious, however, that THD is rarely quoted for loudspeakers. You certainly won’t find that sort of measurement in Stereophile Magazine. The reason is that the figures are pretty bad.

There are many speakers out there that routinely exceed 5% THD or even 10% when pushed hard. That’s one of the reasons I’m drawn to horn-loaded designs. They at least don’t sound grainy, rough, or harsh when going from soft to very loud. Lack of distortion, relaxed musical textures, and purity of tone count for a lot in my book. That sort of information, unfortunately, is lacking in frequency response measurements. The speaker may measure pretty flat, but sound like crap. This is really the best reason for using one’s ears to evaluate a loudspeaker. Not all harmonic distortions are born equal. Some are consonant and others (in much lesser percentages) may be very dissonant. Hence, only the auditory system can reliably determine what is or is not objectionable...

This graph shows the quasi-anechoic (employing close-miking of all woofers) frequency response of the Beethoven Baby Grand L/R (purple trace)...

maty escribió:villegas63

-> http://www.google.es/search?q=VA+Haydn+Grand+review

Se va a la página de las imágenes y se buscan gráficas.

-> http://www.hometheater.com/content/vienna-acoustics-beethoven-baby-grand-speaker-system-ht-labs-measures

This graph shows the quasi-anechoic (employing close-miking of all woofers) frequency response of the Beethoven Baby Grand L/R (purple trace)...

Las desviaciones superan los 5dB, así que de planas no tienen nada.

Salvamus escribió:Villegas, la tuya es la linea roj de la grafica, se obtiene un sonido mas plano cambiando las conexiones del tweeter.

In this case, Speaker E would have rich bass, prominent treble and be somewhat recessed or "laid back" in the midrange. Audiophiles call this "The Smile Curve." It's not the desirable trait it sounds like but it's a very "sellable" trait to naive buyers...

Frequency response curves are often used to indicate the accuracy of electronic components or systems.[1] When a system or component reproduces all desired input signals with no emphasis or attenuation of a particular frequency band, the system or component is said to be "flat", or to have a flat frequency response curve.[1]

maty escribió:
Es más práctico y lógico intentar que aquello que podamos controlar reproduzca lo más fielmente posible. Si el sonido no nos convence o fatiga, ecualizar para obtenerlo.

Salvamus escribió:Para mi lo ideal es ir a un concierto, "todo lo demás es luz de gas", dijo una vez un director de orquesta...

slippery escribió:Revo Strauss... no conozco esa marca...