As the best recording studio design company from the equipment to the acoustics to the conduit infrastructure and cabling costs... As a client, a customer, and a friend people always want to know, bottom line, what is this idea going to cost... The reason it's always tough to give people a flat cost is because money is a very personal thing to a lot of people and there are a lot design factors that can add up to a lot of different costs.
As a solutions provider I know, once I say a price, they are going to emotionally make a connection to that number and hold me to it regardless of the fact that we haven't discussed any of the technical details.
So there are several analogies I can use. It doesn't particularly matter whether we are discussing building a house, a car, a yacht, a plane, writing a symphony, or anything else... The most costly portion of the project is always the labor of people's time. To do the best service for clients, we need to minimize the most expensive portion of the project otherwise we would be doing a dis-service to our clients. The way to do that is to spend some time organizing all of the details like an architect building a house drawing up the plans or a symphony conductor writing the symphony down on paper, The concept is still the same. To organize a large group of people and have them operate together as a coordinated team to minimize the cost and timeline... it requires the details to be put down on paper so everyone can agree the scope of what is going to happen. Likewise a bill of materials can be rendered and we can make sure that all the things the people are going to need are on site prior to starting so there aren't any logistical delays. Once you have the design, a project management plan, you can also use the drawings or putting it on paper to portion out things that may not fall under your specialty trade and it allows you to better coordinate with other trades to help you finish your project.
So the open ended question of how much does it cost with no design engineering is like saying, How much does the car cost? well... we can buy a used toyota corolla for 3,000 and we can buy a bugati for 2 million. The difference is in the technical specifications that you want for your recording studio.