Relationship between Cartridge Alignment and Channel Separation

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Chart#1 shows the azimuth adjustment process of a cartridge mounted with stylus at about 2mm off the optimal alignment position. Chart#2 is with precise alignment to the Loefgren B IEC formula. One can see the overall channel separation resulting in more than 3dB of differential.

有知名音響網紅曾說裝唱頭時，因為可用的切線很多種，隨便裝也沒關係。這裡的實驗顯示，調整精確與否，明顯影響到唱頭的分離度。圖1是針尖與最佳狀態的點差了約2mm時，調整azimuth的過程。圖2是精確地對準Loefgren B IEC 的點且針桿平行於線。可以看到整體分離度有3dB以上的差別。

AC noise from elevator

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AC noise generated from the building's elevator moving, is quite visible from Chart#2 compared to the baseline Chart#1. The so called "EMI Meter" from Green Wave also reports up to 1000mV of noise compared to the baseline's 46mv. Unfortunately, no AC filter including the one from Green Wave, or even an ISO transformer can block such noise.

建物裡的電梯動作時產生的電源污染，可以從比較兩個附圖裡看出。那個號稱測EMI的錶，也顯示超過數百甚至上1000的數值，比平靜時46高出很多。而且所有的濾波裝置，甚至隔離變壓器，對這種頻段的雜訊似乎都沒什麼效果。

Tracking Ability of an Old Decca Cartridge

（中文在後）The Decca family of cartridges are often said to have poor tracking ability. In fact, with proper anti-skate force, at least in standard tests they track better than many MC cartridges. But when they mis-track, the distortions are more offensive to ears. Here in the first spectrum chart taken when running a typical tracking test, the old SC4E shows the typical Decca-family behavior of having higher 3rd harmonic distortion which is less pleasant than the 2nd. This is just the opposite of most other cartridges. In the second chart, the SC4E is put through the maximum signal strength of +18dB and it still manages to play through the whole track with manageable distortion levels, better than many MC cartridges.

許多人說 Decca系列唱頭循軌不好。其實如果抗滑設定對，至少在標準循軌測試，會比許多MC唱頭的循軌表現好。主要問題是，它們的三次諧波失真比二次高，這與大多數唱頭相反。耳朵會比較容易聽到奇次失真，所以容易察覺它微小的循軌問題。第1個頻譜圖是正常強度的測試，顯示這典型Decca唱頭的失真行為。第2個圖是用最強的+18dB訊號測試，顯示這個老唱頭還可以相當穩定的唱完，而且整體失真還不差，不像一些MC唱頭會出現很不堪的波型。

AC Noise from Home Lighting

（中文在後）Among various lighting options for the listening room, LED bulbs (right) are probably better than the compact fluorescent type (left). As shown in the first AC spectrum chart, the fluorescent bulb creates visible noise spikes in the near 50kHz region as well as higher order harmonics. The 2nd chart is the baseline with no light turned on, and there's no visible difference when the LED type is used.

如果聆聽室的照明燈光有選擇的話，LED燈泡（右）應該會比小型日光燈泡（左）好。頻譜圖1顯示日光燈泡會產生50kHz附近的雜訊，而且還有更高的諧波。圖2是未開燈的數據，與用LED燈泡時幾乎無差異。

One reason why Decca-family cartridges are difficult

（中文在後）One reason why the Decca-family cartridges are difficult to tune optimally is the sizable gap between the lateral and vertical compliance numbers (Fig. 1). With most tonearms, the lateral resonance tend to be lower than the 8--12Hz ideal range (Fig. 2) while the vertical too high (Fig. 3). Adding/subtracting mass will aggravate the situation in either of the directions.

Decca系列唱頭很難調整好的其中一個原因是橫向與縱向的順服度差異大，如圖1。在多數唱臂，會造成橫向的共振頻率低於8到12Hz的理想值，而縱向會太高。而加/減質量都會造成其中一個方向惡化。

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

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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。

Measurements at an Audio Showroom Lacking Low-Frequency Energy

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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。

A tonearm that can do "Signals Reproduction 100%"?

This tonearm's flyer (from years ago) showed some interesting data and pretty tall claims, such as "Signals Reproduction 100%", "Dynamic Improvement 5dB" and "fluid damping...eliminates all vibrations including rumble during playing".

Another case of cartridge spec not agreeing with actual product

（中文在後）Another case where the spec does not agree with the actual product. When the top of the cartridge is near level, the cantilever is close to 30 degrees, quite far from 23. Though given the angle between the contact line and cantilever is close to 120 rather than the more common 110 degrees, the SRA still ends up just slightly higher than 90.

又一個規格與實際不符的情況。當唱頭上緣接近水平時，針桿角度約30度，遠高於23。但還好它的線／桿夾角在120度左右，所以此時SRA只比90度高一些。

Turning off sub-sonic filter when measuring cartridge-arm resonance

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Some USB sound boxes/cards, preamps, and phono stages have subsonic filters to suppress ultra low frequency noise from playing record warps, etc. When measuring the natural resonance of a cartridge-tonearm combo, be sure to turn the feature off, otherwise one may get incorrect readings. Figure 1 is with the filter turned ON in the ART USB Phono Plus while Figure 2 is OFF and shows better results.

有些USB音效盒，前級與唱放有超低頻衰減功能，播放不平的唱片時可保護喇叭或其它器材。但在測量低頻共振點時（Adjust+ 裡的 f res功能），要將這功能關閉，才不會影響結果。圖1是ART音效盒的濾波ON，圖2是OFF。後者明顯得到比較符合預期的結果。

Why high-tech vibration isolation/cancellation devices?

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Why is it necessary to use high-tech vibration isolation/cancellation devices? Unperceived by human senses, there's plenty low-frequency background vibration present in any living environment. Figure 1 demonstrates the spectrum reported by the Kurashiki Mini-560F, with its active cancellation function OFF, and nothing is turned on in my system. We can clearly see the energy presence of sub-20Hz vibrations in my listening room. Figure 2 shows the active function ON, and the vibrations now get below the -60dB mark. Removing these unwanted vibrations greatly improves the overall sound reproduction, obviously.

為何需要高科技減震器材？圖1是用倉敷化工 Mini-560F 主動平台的頻譜功能，將主動減震功能關閉時，可以看到，即使音響系統完全關閉，聆聽室有明顯的20Hz以下，人類的感官無法察覺的震動。這是所有環境幾乎都無法避免的問題。圖2是將主動功能開啟，這些震動立刻降至-60dB 以下。將這些背景震動移除，對黑膠播放或其它器材的音質，必然會有立竿見影的改進。順便提到，這已經是在號稱避震極佳的音響架上，所得到的數據。

Is anti-skating still necessary when using the swing headshell?

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Is anti-skating still necessary when using the swing headshell? The answer is apparently YES. In the first chart, the anti-skating is OFF, and the right channel shows much higher distortion. Adding anti-skating force to the maximum on the SL-1200G, then the distortion levels of both channels now become more even. Unfortunately, there's no known way to increase anti-skating even further on this arm.

使用搖擺唱頭蓋，顯然還是需要抗滑力。第一個數據圖是將抗滑關掉，右聲道的失真高很多。加了抗滑，就比較平衡了。