Changing the attributes of multiple clips in Final Cut Pro

You can remove attributes, and you can set up one clip just the way you want, then Copy; select the other clips, and Paste Attributes.

Another possibility is to use an Adjustment Layer. This is just an empty title that you place above everything in the timeline, and apply the desired effects to it; these will affect everything underneath.

For some unknown reason, FCP does not ship with an Adjustment Layer, but you can either create your own (if you have Motion, it is trivial, just create a new Title, remove the text layer and Save); or there are several that you can download for free. I think that rippletraining offers one of those, but there are others.

Sorry I missed the part where you mentioned selecting several clips and adjusting some setting on all of them.

That is possible too. Just select them all, and in the Inspector change the settings and it will change it for all.

That error means you've selected a group of clips and are trying to change the noise gate effect on all of them, but one or more clips does not contain that effect.

To narrow down which one, do View>Timeline Index>Clips, then enter "gate" in the search term. It will show an entry for each clip having that effect.

In that result list in the Timeline Index, do CMD+A to select all of those. It will visually highlight the clips on the timeline having that effect. That should enable identification of the clips that don't have the effect.

For more info on audio mixing workflow in FCP, Google this: "Audio Finishing using Roles in FCP"

I think the expected behavior is you can do "ganged" audio effect adjustments on clip selections having the same audio channel config. E.g, 2+ stereo clips, or 2+ mono clips, or 2+ Sony MXF 8-channel clips. You cannot do ganged audio effect adjustments on clip selections with differing audio channel configs. The Inspector will either not show the controls for that effect, or it will warn, "Effects Not Available On Mixed Selection."

If you select several clips already having a specific audio effect such as Noise Gate or Channel EQ at varying settings, you can adjust the controls for each effect and all the selected clips should change to that new setting. This assumes they all have the same audio channel config.

The exception is that the volume effect can be adjusted on any number of selected clips, regardless of their audio channel config. Select the clips and do CTRL+ or CTRL- (Hold control key and press the plus or minus keys).

Audio level changes can be made quickly on a portion of a clip using the "range" tool: Press R, then drag a yellow range box over a portion of the clip. CTRL +/- will adjust the volume of only that range. A shortcut is to press and hold the R key when drawing the range. When the R key is released, it will automatically switch back to the select tool.

After doing multiple range adjustments within clips, you can select several entire clips containing those adjustments and adjust audio levels with CTRL +/- while maintaining the previous differential range adjustments

It is possible to apply an effect to one clip, adjust the effect controls, then select/copy/Edit>Paste Attributes to one or more target clips. It will apply the effect at the adjusted setting to all of those. If the target clips already have that effect, you can select those clips and remove that specific effect with Edit>Remove Attributes prior to applying the changed effect as above.

There is some intermittent anomaly whereby it will not properly make a ganged effect adjustment to several clips, even if they all have matching audio configs. In that mode it will only change one of them. That is apparently a "state" bug because if I re-launch FCP then re-do the test sequence, it then works.

The preferred approach is using organized audio roles, as shown in the video "Audio Finishing using Roles in FCP." That, when combined with compound clips, lets you apply effects on specific types of audio clips which are segregated by role and grouped in a compound clip.

If you want to selectively remove one attribute (ie effect) from several clips, select them and pick Edit>Remove Attributes, and select the item you want removed.