Openning a hi fi shop

First off, I would allow drunk people to rent out the showroom on weekends. I would also run a "hardware as a service" model where the customer doesn't actually own any of the gear but for a monthly subscription price they can swap out gear upon request. I do all installations and networking. Customers are charged for each service call. Different subscription tiers give you access to higher-end gear. Lowest tier is $100/mo., highest is $500. At the highest tier, for $6,000, you can enjoy a six-figure system in your house for an entire year, and then change it out next year if you want. You never have to pay for repairs and you're not tied into any piece of gear. You get to listen to everything hi-fi has to offer in your own home for as long as you want. Any gear I own that's more than 5 years old gets auctioned off. I would need about 50 customers at different service levels to make a decent living. But I'd be busy af.  

Been there, done that.

First, you need $250,000 (MINIMUM!!!) in cash or credit plus another $50,000 CASH in first-year running costs (advertising, online presence, etc.).

Get that, and then start planning WHERE you will go.  High-end audio does not sell in Gulfport, MI or Clarksburg, WV.  Nice towns, but people there do not buy many $100,000 systems.  

Once you have a place, make sure there are not other stores around as the better manufacturers do not sell to several stores within the same general area.

Once you have all that and a good business plan, you have to build out the location.  Visit other high-end stores that have been around a while and you will see how to build out your space--2500 sq ft MINIMUM is required in a high-traffic area.  You can be a "destination" store in Austin, but not in every town, so heavy traffic is needed.

If you go into a "center" you have to pay rent, overage (check with a business person to understand that little "gotcha" and maintenance, which goes up every year.  PLUS, centers are not as popular as they used to be.  Free-standing is nice, but expensive.

Finally, and there are a million steps in between the last one and this one, you need to find a local repair shop or one that is actually reliable.  It ALL breaks eventually, and high-end customers are NOT patient when their $20,000 amp breaks and they want it fixed NOW!  Loaners are often required, which means more up-front capital.

Tough business--make sure you know what you are doing before you do it, but good luck!  I loved my shop and learned SO MUCH.  One nice thing is that you have time to LISTEN to all the stuff and figure out what is REALLY the best and what is just hype...

Cheers!

The question you are asking really needs to be turned around and looked at from the perspective of what type of customers are you trying to serve. If you are starting a store in Redmond and catering to Microsoft millionaires you might want to focus on ultra high end gear. If you have a store in a college town you would want products that students could afford.

It would be a fun exercise to research this. Every month I hear of a new brand of speakers or electronics that are being introduced into the US market and all of these companies are looking for distributors and dealers.

An example of an interesting line that is not well represented here is Tsakiridis from Greece. I saw this stuff at the 2018 AXPONA and was really impressed by the sound and workmanship. The prices were very reasonable.

The store I deal with in Gig Harbor took on Line Magnetic gear which was a surprise to me because I had considered it the type of thing you ordered from China. However, this gear is stunning to look at and seeing it in person was a revelation. I'm sure that there are a lot of people who would never consider that brand unless they saw and heard it in person.

Curating the gear for a particular store would be a complex challenge.

I started a Hifi Shop back in 1986, as a Student with £10K, my business partner had £10K and off we went - highly specialised niche market to begin with £300 system, and a £1000 system. Aimed at non-audiophiles, and we installed everything for free in their homes. We lost money for the first year, but gained a great reputation. The shop was memorably named "The Cornflake Shop" and it's still going strong...though moved from hifi to Custom install and Home Cinema. 
Above all else what you need is customers, and you have to work out what you can do that special in your area that is going to connect you to these people.
Start specialist - really be ultra specialist rather than generalist, then you establish a very clear brand, and following for your individual talents. Its a people thing. 
But to sell Hifi means comparisons, and you do need some money to have the right stock. Hard work for years, but such good years ! Good luck ! (It is a bit of a religion I have to say I liked erik's idea..)

Retail and dealing with the public is a hard business. As per what was mentioned above it requires a ton of planning and a lot of money. There is a lot of risk too. I look a all business adventures in terms of what is my annual rate of return going to be and what risks do I encounter in trying to achieve that return. Then, (this is important), how does this rate of return and risk compare to other things that I can do with my money. There are always alternatives. Maybe you can make a better return with similar or less risk doing something else with your money and your time than opening a hifi shop. Plus here is a great quote from one of my former business managers: “Business would be great, if it weren’t for the people”. Please be careful.