Photos and specs Headphones Koss PRO-4AA Titanium

I noticed immediately that these headphones is not for the weak ears: impressive weight and great effort of cushions can cause discomfort. Closed design and dense material also makes it difficult ventilation. But the headphones are Soundproofed and good sensitivity. However, a high resistance 250 Ohm) will make it difficult for quality reproduction for use with portable appliances. For their buildup need a powerful amplifier. Feature of the given model in the use of titanium coating for increased stiffness of the cone of the radiator. Twisted cords will not get in the way and will allow you to focus on the music.

Significant prevalence of bass and lower mid causes a shift of the tonal system down, and painting in this part of the range, which, however, does not extend upwards. Headphones weakly damping bass. High-frequency detail in the sound PRO-4AAT missing. When the model reproduces large write performing groups: orchestras and bigband), lost the depth of the image, line "bunch up". This model can be recommended to those who love to the sound was a lot of bass.

Side view.

Fig.1. Frequency Response

Fig.2. Nonlinear distortion factor

Fig.3. Module input impedance

Immediately catches the eye hump response in low frequencies (40 Hz - 1 kHz), with a height of 16 dB. It is noticeable shifts tonal balance in the direction of the bass. However, it should be noted that this is not accompanied by an increase in non-linear distortion and throughout the surge THD is at a very low level. Next, from 1 kHz to 10 kHz frequency response is characterized by a small imbalance and low inequality. Here CED increases slightly, but remains at quite reasonable. Above 10 kHz frequency response forms a ravine with a depth of 16 dB. Although the schedule is returned again to zero to 20 kHz, a deep failure creates a shortage of high-frequency components. At the bottom of the ravine (15 kHz) also noted a sharp increase in non-linear distortions. According to the schedule CED shows that distortion strongly depend on signal strength, and to high volume them least of all in the whole measuring range. Probably, it is connected with more severe and rigid cone with titanium coating.