This sounds like a problem with a vent pipe, not your sewer lines. If your pipe goes through the roof (and it should), make sure its not clogged and that birds havent built a nest on it. You may need a plumber to snake out that vent line. The gurgling sound is because what you are flushing, or draining, is using another sink, bathtub, toilet etc for venting.

Almost certainly a venting issue. If the sound is new then look for blockages, unfortunately many houses have really terrible venting with pipe paths that don't really work or that can fill with water from rain or condensate, and it may require getting into the walls to fix the issue. This is usually a result of the plumbing inspector being the brother in law of the plumber, or something like that.

Wherever the vents are visible, eg in the attic space, look for horizontal runs that might have sagged or been built with a low spot creating a place for water to gather.

Sulfuric acid won't fix your problem

Call a licensed plumber.

@Valinta Call a competent plumber, it was almost certainly installed by a licensed plumber. Licensure and competence are only marginally related.

Agree with what the others wrote about it being a venting issue.

In addition, in wintertime it can sometimes be a buildup of rime ice inside the vent pipe on the roof.

Might not be a blocked vent pipe, but I'd check out the pipe for an obstruction before anything else.

Your idea about sulfuric acid is a good way to create a new and much more expensive problem, without solving the original issue. Take the constructive advice offered above. And stay away from chemicals that are not only potentially dangerous to your plumbing, but to you as well.

I was not at all enthusiastic about using sulfuric acid so I am going to stay away from that option. Is this vent on the attic? Can it be accessed without going on the roof? What do I look for once I am on the attic? If I call a plumber what will he likely do? How much time do I have? There are no blockages or back ups right now only the loud sound.

https://www.ahs.com/home-matters/repair-maintenance/learn-about-plumbing-vents/

Watched this video which seems like an ingenious way to handle this issue. Please your thoughts?

Still I am hesitant to do something like this and don't know if this house has a similar vent near the hot water heater but I will check and post pictures.

https://youtu.be/THjHdmE_3rA

I bet it's a tub venting problem. Toilets, tubs and sinks need to be vented to the outside so that they can freely drain. Get a licensed plumber to look at it and vent it according to your local codes. You might not have to tie into the stack that goes through the roof if a mechanical vent is allowed.

Its most likely not a do it yourself project. You need a licensed plumber to take care of this problem. It sounds like this is a fairly new problem. How long have you lived there. Did you notice it at any time previously. If it is a new problem, and you have lived there for a while, then it is a stopped up vent, and it could be anywhere. A plumber has tools, to snake through all the vent lines, and the know how to fix the problem.

We have lived here for several years. The toilet splashing around when the upstairs toilet is flushed has been there for a longer time may be a couple of years or more. The noise from the Jacuzzi drain is more recent may be several months. I tried the vinegar/baking soda to clean the Jacuzzi drain a couple of times a few months ago and that seemed to help with the noise initially but then when it came back now it is louder.

It seems many think the vent is there for: "Toilets, tubs and sinks need to be vented to the outside so that they can freely drain." According to this video and demonstration this is NOT the case. The vent is there to protect the trap from emptying. Perhaps this is why we don't have any issues with drains being clogged up but a noise issue.

https://youtu.be/P8hA6Z1djqo

I thought this is a pretty important information and should be shared.

bijan-

I think most if not all of the commenters here already understand that vents are necessary to maintain the integrity of the traps. However, this does not mean vents do nothing else, or that this guy's video somehow invalidates the likelihood that there is a problem with your venting that is causing the noises. You seem to be looking for alternate explanations when several people have already suggested you need to look for problems with your venting. Until you do, I suspect the problem will continue.

Vents stop siphoning and also pressure differentials in the pipes that can form behind traps leading to gurgling and bouncing of water in toilets. You will have to "break some eggs" to solve your problem and to do it properly you need a good plumber who understands basic physics and local codes. My bet is your tub drain does not have a vent.

The consensus is obviously that there is a venting issue and I fully agree since other than the noise there seems to be no other problems like clogging or even slow drains. Yet it seems to unblock a vent is the same procedure as unblocking a drain and in fact it seems to be somewhat easier in many cases since there is easier access to vents in many cases. So I am puzzled why someone has commented: "Sulfuric acid won't fix your problem". I am asking this only for the sake of curiosity and not to actually wanting to use the sulfuric acid. If sulfuric acid is used to unclog drains why can't it be used to unclog vents? Thanks for your enlightening comments.

Also about finding a licensed plumber. I assume all plumbers are licensed if this is a requirement for their trade. So the question for me is to find the plumber that uses the most effective, least intrusive and most environmentally procedures and has the best value overall. Watching online videos there seems to be at least 2 popular ways to handle this type of issue snaking and jetting. There is also the chemical route which seems is most often used by the diy homeowners. My assumption is that jetting is likely the more expensive and used by the more upscale plumbers. Should I try to find a plumber that uses a specific method?

No, just find a plumber that knows how to do the job, and has a good reputation for being a good plumber. You dont use chemicals in a vent pipe.

A blocked vent may well be above the drain in quastion. Your sulfuric acid can't climb up the pipe. If the blockage is due to water in a low spot (more common than you would think) adding any sort of chemical will do nothing to relieve it, you need to change the slope of the pipe. You really need a plumber with diagnostic skills.