Project Ryu New Spider Concept Test スピーカースパイダーテスト

facebooktwittergoogle_plusredditpinterestlinkedinmailby feather

Hello, こんにちは,



Today i could do a first test of the new spider for my 12 inch field-coil loudspeaker. I attached the spider to a voice coil and to a frame. Without any added mass i applied variable DC voltage on the voice coil to determine how much it will move at a specific voltage.



First I had to create a variable DC Voltage generator.This can be done with op amp but since the voice coil has low resistance (Rdc = 5.1 ohms) the op amp will need to deliver high current. This is why i chose LA6520 which has a 500mA output current. In the picture below you can see the schematic. Please note that LA6520 has different pinout like in the next picture so keep it in mind when soldering. Also this circuit needs symmetric +/-15V power supply.

回路図では、LA6520 pinoutをご参照ください。

Small Voltage Generator Schematic 小さな電圧発生回路図   LA6520 pinout   The test setup includes a series resistor. We will measure the voltage drop on this resistor in order to calculate the current through the voice coil. It is advantageous to display excursion vs current as the force that pushes against the spider’s restoring force is defined by F=BL*i where BL is the motor strength factor and i is current through voice coil. The series resistor was formed from two 30W 3R3 resistors connected in parallel. This way temperature effects are negligible. Below you can see the setup. Spider test setup スピーカースパイダーのテスト·セットアップ

Spider’s behavior proved to be quite linear. Shown below is the results measured for the voice coil’s up direction. Above 3.5mm the voice coil is getting out of the magnetic gap so force becomes smaller. As can be seen though Project Ryu’s magnetic circuit is strong enough to use the fringe field to its advantage increasing this limit to about 5 mm.


Spider x vs i field-coil loudspeaker project ryu SPIDERフィールドコイルスピーカープロジェクトリュウ


Below are some images of the test:

フィールドコイルスピーカースパイダー  Field-coil speaker Spider フィールドコイルスピーカースパイダー  Field-coil speaker Spider フィールドコイルスピーカースパイダー  Field-coil speaker Spider Voltage generator 電圧源


And a small video on youtube:

Thank you for visiting,


Leave a Reply

Your email address will not be published. Required fields are marked *