Toilet that howls

Help. When we flush one of our toilets, we hear a howl (about 4 seconds after the toilet flushes). The howl lasts probably 3 seconds. What is wrong? I tried turning on the sink water and that doesnt seem to stop the sound.

Also, our second toilet has sound like a quiet trickle of water is somewhere. It's not silent when just sitting....what could that be?

One episode I had which sounded similiar was from an evapourated seal in the shower stall next to the toilet - the shower didn't get used very often and when the toilet was flushed the sound howled and echoed through the shower trap. Turning on the water in the shower stall fixed that problem, but if it doesn't sound like it could be your issue, then I'm sure the guys on this site have experienced a lot more and could give other advice...

The trickle in your other toilet is coming from one of the many parts of the assembly in your tank. Could be the overflow tube, could be the flapper, could be the float... replacing the entire tank assembly is cheap and easy for any DIY'er, you can buy the parts from HD in one kit and the instructions are super straightforward...

I've been quite happy with the Moen flush valves, but I mostly see Fluidmaster's out there.

noise

The ballcock is the first that comes to mind.

Thank you

Thanks for your replies. The ballcock for the second toilet or the howling one?

2nd toilet

Could be ballcock and or could be flush valve.
Is the high water line below the top of the overflow pipe? The b/c may not shut off totally. Or the flapper may be rotted or worped.
Check the condition of the flush ball or flapper.
I would repair both toilets. You can do each for $10 to $15.........