Cogent Field Coil Compression Drivers
Cogent field coil bass compression driver. Baixar drivers avermedia avertv super 009 m733 m733a analog. To a direct radiator.' 'A 2-way all-horn system by Cogent True to Life Loudspeakers from California. A DS-1448 field-coil bass compression driver with, on top, a mid-high range DS-1428 driver. Instead of a direct radiator made by some factory in Germany with a different wrapper, I'm happy to say that.
Jul 15, 2018 It was a homage to the RCA 1428b field coils and are very similar to what is in the Cogent field coils. Wolf Von Langa who is a hot designer at the moment was making for a while a field coils rca 1428 as he called it that was actually this compression driver with a. Nov 17, 2009 Most compression drivers don't take too kindly to being used below LF cutoff on a horn and the conical's poor performance in this regard doesn't help. I'd been aware for quite a while about the old RCA field coil cinema drivers, the MI-1428b/MI-1443. Some people think they are the best drivers ever made, a couple of these folks being Steve.
The Heresy has always been a three-way closed-box design throughout its history, but it underwent two upgrades, first in 1985 when it was released as Version II and then in 2006, to coincide with the 60th anniversary of the K-Horn, when several Heritage models (Klipschorn, Heresy, LaScala, Cornwall) were updated. The responsible designer was and still is Roy Delgado, who worked directly with Paul Klipsch for many years. Version III features significant driver upgrades. First of all, a more powerful woofer was selected with smooth response (and proven reliability in Klipsch’s pro-cinema surround applications).
Both the tweeter and midrange compression drivers incorporate Kilpsch’s best- effort phasing plugs to maintain coherent wave fronts, and both have been updated to titanium diaphragms for extended response and lower distortion. Roy Delgado related the following: “One of things Paul taught me was to make sure that the drivers tell you where they want to be crossed over by taking into account several parameters. Minimum or no interference in the crossover band is the goal.” The speaker ships with a slanted riser base to tilt the cabinet backward for floor placement, which is how I used and evaluated the Heresy.
However, the riser is removable to allow for bookshelf (i.e., non-audiophile) installations. I deliberately referred to the Heresy as both high-efficiency and high-sensitivity. A high speaker sensitivity does not necessarily imply high speaker efficiency. For example, it is possible to combine several low-efficiency woofers to obtain a high-sensitivity rating. Efficiency is a figure of merit for the conversion of electrical into acoustical energy.
The efficiency of an 8-inch woofer radiating directly into half space is typically no better than 1%. That means that 99% of the electrical energy fed into the voice coil is dissipated as heat. No wonder heat is a voice coil’s number one enemy. Woofers do much better when radiating into tubes or pipes whereby the efficiency can increase by up to a factor of 50. However, the required mouth size for a bass horn becomes prohibitively large at low frequencies.
Another approach, exemplified by the Heresy, is to increase the intrinsic efficiency of the woofer. That can be done in three ways: increasing the woofer’s cone diameter, reducing the cone mass, and increasing the magnetic-field strength. Unfortunately, there is no free lunch. Reducing the cone mass raises the resonant frequency, while overdamping the woofer with a large magnet reduces the total Q; both of these parameters combine to reduce low-frequency extension. It should be noted that speaker sensitivity can be and often is a misleading specification.
A higher sensitivity does not necessarily imply a higher maximum SPL, as that depends on the woofer’s voice-coil excursion limit and power handling. Furthermore, the reported sensitivity is greatly influenced by the measurement protocol, which may not be disclosed by the speaker manufacturer. International standards specify using a broadband test signal such as band-limited pink noise. There have been cases where a pure sinewave has been used at a frequency corresponding to a peak in the frequency response in order to pad the stated sensitivity. Sensitivity is conventionally measured using a voltage that corresponds to one watt into the nominal impedance of the speaker. Hp samsung wave 533 theme. That would be 2.83V across an 8-ohm load and 2V across a 4-ohm load.
The problem is that a speaker’s impedance magnitude is far from being flat with frequency, and manufacturers do not rate their speakers consistently. The box resonance of the Heresy is at 64Hz and the minimum impedance is about 4.2 ohms at 150Hz. Klipsch confirmed that it uses a 2.83V pink-noise signal over the bandwidth of the speaker to determine sensitivity and that measurements are usually performed in half space.
However, according to the international standard, the nominal impedance is to be no greater than the minimum impedance times a factor of 1.25. Thus there’s an argument to be made that the Heresy should be rated as a nominal 5-ohm load instead of 8-ohm. Using a lower test signal voltage appropriate for a 5-ohm nominal load, would of course reduce the Heresy’s measured sensitivity. It turns out that Klipsch uses an integrated impedance approach to establishing the nominal impedance rating.