An apparatus includes a base, a first clamp, a second clamp, a first post, a first slot, a second post, a second slot, a rod, a catch and a channel. The first clamp may be attached to a first end of the base and configured to secure a first chord. The second clamp may be attached to a second end the base and configured to secure a second chord. The first post may be attached to the first end of the base. The first slot may reside in the first post opposite the base. The second post may be attached to the second end of the base. The second slot may reside in the second post opposite the base. The rod may be rigidly attached to the first post. The catch may be attached to the rod opposite the first post. The channel may reside in the catch.