Bright Sounding Speakers

jay27

When a component set has a "bright" sound, is this solely based on the tweeters or can the midrange contribute to a bright sound?

Face

Generally, no. But, the midrange can contribute to harshness.

MacLeod

Both midrange and/or tweeter could be the culprit. It really will depend more on the crossover points.

The "brightness" comes from the upper midrange from around 2500-5000 Hz. Both midrange and tweeters play these frequencies but it depends on your crossover points which driver plays them most prominently and it depends on exactly what frequencies are too hot and giving off the bright sound.

Jstas

Actually, when you are talking about drivers overlapping in range, it's not so much the crossover as it is the physical characteristics of the drivers. That's why things like Thiele/Small Parameters and the Klippel Distortion Analyzer that Polk Audio uses are so important.

With the various methods for measuring and categorizing driver performance, the actual physical behavior of the driver can be watched. By doing this, the engineer can see distortion patterns and other anomalys that would affect driver performance like cone resonances and thermal properties of the motor structure.

That tells the engineer alot about what the drivers are doing. The Carver Amazing loudspeaker has a 5 foot ribbon driver that can reach down to 25 Hz. But, the crossover is set to 100 Hz and the low frequencies are diverted to the woofer array for low-end duty. Why? Well, simple, just because the driver can play to 25 Hz doesn't mean it should. Impedance goes up as the frequency drops on the ribbon and output at those levels suffers to the point where it is almost inaudible in the presence of other programming at other frequencies. Therefore, the crossover is added as well as drivers more suited to that level of audio reproduction to compensate for a shortcoming in the full-range driver.

The same goes for tweeters and mid-range. The crossover keeps the speaker array from trying to produce sounds with a driver that might be hitting it's resonance frequency and causing distortion. Or maybe the motor structure gets heat soak on one side of the coil and causes a non-linear and asymmetrical movement of the driver cone that cause harshness due to distortion. A crossover can help eliminate that by keeping the driver that has issues with that frequency range from reproducing that information and redirects it to a speaker more suited and more capable in that range.

Once the crossover is set up to limit the frequency ranges, it is tuned to give as flat of a signal response as possible in the cabinet that the drivers are installed in. But everybody's ears are different so adjustable crossovers allow you to change certain aspects of the crossover network to intentionally create peaks and valleys in the response curve so that you get the sound your are looking for. Those adjustable parts of the crossover don't necessarily push the frequency ranges being delivered to each speaker that far out of design as much as they attenuate certain frequency ranges and/or boost others.

The problem is that every component in a loudspeaker system has a resonance as well so those resonances have to be compensated for in the crossover circuit as well. That includes inductors, capacitors and resistors.

But there are 3 kinds of crossovers. Active, passive and physical. Physical? How can it be physical? We've said it time and time again here in car audio. Installation is everything. Junk drivers installed well can out-perform good drivers installed poorly. But an example of a physical crossover is a band-pass sub-woofer. A sub with a range of say 20 Hz to 210 Hz, installed in a certain kind of enclosure, can physically be limited either by cancellation of sound or physical restraint through air pressure to play strongly between 50 and 80 Hz. That is an example of a physical crossover.

A ported sub tuned to say, 38 Hz, is another example because it boosts the output at a resonant frequency and uses the resonance to load the enclosure to emphasis a very small frequency range to obtain maximum performance.

A tweeter mounted on the dash, right next to the windshield gets an audible boost from the reflections off of the glass windshield. In a tweeter with good off-axis response, this can help the sound stage by providing a slightly out-of-phase sound that adds depth to the sound stage. Or it can cause an incredible amount of cross-talk and cancellation. That cancellation and crosstalk can make a tweeter sound "brighter" than it is because the high end of the response curve get emphasized and reinforced due to the reflections causing corner loading between the windshield and the dash. That all has to do with wavelengths and such and it'll make this post way longer than it already is.

That's why SR sets are so sensitive to placement. The ring radiator tweeter is very directional and susceptible to reflections, crosstalk and cancellation. It can make them seem very bright because certain things like unwanted resonances can be emphasized while the programming information is canceled out.

So it's not just crossovers that make a speaker seem bright.

AudiAudiohead

i have the polk mm5251 component series in my a4 and have had this problem with the speakers sounding to bright even with the crossover set -3 and my hpf set around 60-90.

And this is with my treble @ -8, mid @ -3, bass @ -8.

I have subwoofer too.

Popeye89

^ nice setup