might be a stress relief issue. these were built by IRO (read: Velocity) in march (or april?) and the pinging has persisted since about a week after they arrived on my Angus.
The front wheel arrived slightly out-of-true (shipping?), so I did a couple minor corrections on it. I guess the noise started shortly thereafter...
Is there a visible difference to the spokes (bend angle?) after they've been stress relieved?