Love this questions, since this is something we have been tackling in my current company and several other very rapidly growing startups I have been part of where we love the open design (but not the noise)
Solution has to be systematic. If you have the money - hire professional office interior designer, but be prepared to spend about $2K per seat.
If VC money is not flowing into your account, your options are mostly limited to DIY.
Low profile acoustical screens will have almost no impact. Those are more visual. Solution has to be systematic. In order for a screen to have any significant impact, it has to be at least 4 feet above the desk.
So what do you do?
- I hope your space is carpeted and not hardwood/concrete/laminate floor. If not carpeted, get some area rugs everywhere. You need those to reduce surfaces it bounces off.
- Get acoustic panels (pre-made or DIY materials). Just google it and you will see plenty of online places that sell them. You will need to place them above the noisy areas (like hang them from ceiling with wires) and also place them between desks. We are building for ourselves these large round acoustic panels with red cloth stretched over them. It will serve dual purpose for us, since our logo has a large red circle.
- Depending on how many desks you have, get several of these white noise generators (link to Amazon page for SleepMate Electro-Mechanical White Noise Machine). Key is to add them to noisy areas one at a time. If you put up 5 of those on day one, people will become aware of them and it will not help with their perception of the noise, it will just increase it. This is something a sound designer taught me - the less you are aware there is a white noise generator, the more effective it is.
- Artwork is great for reducing/changing sound reflection surfaces. It is a great investment in something that serves tripple purpose (nice to look at, noise absorption, and culture setting)
Hope this helps a bit. I have been doing heck of a lot of reading on this subject and talking to pros, since half of my team are "quiet people" (tech, ops, production, etc.) and half are "loud people" (sales and marketing) - environment ripe for tension due to noise levels.