I agree with @erik_squires re GIK. I've gotten good products and good guidance from them.
Even if you ultimately hire a consultant, the first step is to understand the underlying principles of room acoustics, speaker and listening position placement, etc. Learning to use REW software to measure in room frequency responses, decay times, and identify early reflections was an eye opener and game changer for me. It does take time and effort, which not everyone can dedicate, in which case it may make sense to hire a consultant to to the heavy lifting if you have the money. But these services don't come cheap. I've spent under 3K to treat reasonably well my 20 x 15 x 8 dedicated listening room, and can probably finish it for less than 4K total. All of the companies that offer room treatment products have useful tutorials.
Even if you ultimately hire a consultant, the first step is to understand the underlying principles of room acoustics, speaker and listening position placement, etc. Learning to use REW software to measure in room frequency responses, decay times, and identify early reflections was an eye opener and game changer for me. It does take time and effort, which not everyone can dedicate, in which case it may make sense to hire a consultant to to the heavy lifting if you have the money. But these services don't come cheap. I've spent under 3K to treat reasonably well my 20 x 15 x 8 dedicated listening room, and can probably finish it for less than 4K total. All of the companies that offer room treatment products have useful tutorials.