So I stumbled over the script that handles the detection of secret objects and remembered how I'd seen people complain about the sound that gets played if the PC has a voiceset. I don't know how warranted this is, but I thought it might be an idea to change the x0_o2_sec_* scripts (excluding x0_o2_sec_reset). Unless animal companions/familiars/empathized animals are considered henchmen when it comes to detecting these it looks like commenting out line 36 (AssignCommand(oEntered, PlayVoiceChat(VOICE_CHAT_LOOKHERE));) should do the trick.

It was argued that it was at times a good thing with the voice, since you'd then be alarmed about hving found a secret object, but there is indeed the risk of revealing oneself to other PCs, which I gather is rather annoying. SendMessageToPC(oEntered, "[Insert informative message regarding the successfully locating of a secret object here]" could be used to counter this.

Oh yeah, and there are 25 of these scripts. >.>

You're right, there are both positives and negatives for this. Sometimes, I wouldn't have realised that my character had stumbled across something, were not for the delightfully annoying NWN voice-set firing off.

Of course, some of the non-standard monster and NPC voicesets don't have such a problem.