Thursday, July 25, 2019

Good example demonstrating relationship between cartridge's compliance and resonance frequency

(中文在後)
A good example demonstrating the relationship between the compliance of a cartridge and the resonance frequency of the arm/cartridge combo. Here the cartridge has a horizontal compliance at 15*10^-6 cm/dyne, and the measured lateral resonance is at 10Hz. Its vertical compliance is lower at 12*10^-6 cm/dyne, and the measured vertical resonance is at 12Hz. BTW, the arm is a uni-pivot design so the effective mass in each plane should be very similar.
唱頭的順服度與裝在唱臂上時的低頻共振頻率的關係,這是個好例子。它的水平向順服度是15*10^-6 cm/dyne,縱向是比較低的12*10^-6 cm/dyne。在單點軸承唱臂上,測得水平向10Hz,縱向12Hz。理論與實際數據算相當吻合。

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Monday, July 22, 2019

Measurements at an Audio Showroom Lacking Low-Frequency Energy

(中文在後)
Figures 1 and 2 are for the Left channel, 3 and 4 the right channel, frequency response and bass decay data. The green line in each frequency response curve shows the phase response. 

The bass region below 60Hz is indeed down 10 to 15 dB, unexpected of such sizable speakers. The differences between channels are also quite significant, likely due to the asymmetric room shape. 

圖1,2是左聲道,3與4是右,頻響及低頻殘響數據。綠色線是相位響應。喇叭算很大,而60Hz以下的確是凹下,伴隨較高頻率的凸出,屬於典型的房間與喇叭交互作用。左右聲道的低頻明顯差異,應該來自不對稱的喇叭後方牆角。左後方的牆角相當近,應該是主要問題來源之一。