High End Quality Retailers in the Chicago, Il Area

Brian Walsh, owner of Essential Audio in Barrington just outside of Chicago. Brian is one of the good guys in this business.
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Music direct is located in Chicago. I have done plenty of business with musicdirect.com and according to the "about us" tab they have all stock on hand at their retail location. Visit the web site then go have a look.

You should point him to this website for education, and to save money. Have him read, if he truely has an interest he can learn many valuable things...and the savings is both in buying used and buying the right gear the first time.
The trouble with pointing a newbee in the direction of a dealer is the potential attitude that rub many novice's the wrong way and the high prices, if any of these 2 issues happen to bother your nephew you may never get a second chance to have him explore this hobby.

There is http://davincimedia.com/ just north in Milwaukee. Not far if he lives in the north burbs. http://www.saturdayaudio.com/ in Chicago itself. The is also http://www.abtelectronics.com/ in Morton Grove, they have some entry level stuff and do superb custom mobile audio. Dennis Rodman had one of his autos done there as well as a few other big guys. Thats just a few. And there was my house but I don't live around Chicago anymore.

The best place to go for fun and a solid education is Quintessenceaudio in Morton Grove. Not far from downtown.
Give Mick Surrvance a call.
847-966-4434
I think after speaking with him you will see why I recommend him.
Your nephew will have a blast and learn the what, why and how in developing
his own personal tastes. You are a really cool uncle by the way. Nice job man.
This is where I send relatives and friends. The first part of Chandliz's post is quite solid. Reading is a good thing, hearing and seeing are equally important.
Creating relationships and learning from different council, good or bad, is part of life.
The choices we make are what defines us as adults