For me the rule of thumb is to keep the Mid's/Highs the same brand, front to rear. As far as mix-matching subs and amp brands, no problem. We routinely get our customers into mid-level amplifiers with entry level subwoofers. It creates a repeat customer when they want to upgrade their bass system and all the have to do is bump up the subs. Plus it creates an image of respect for the shop when we do this kind of thing, instead of saving them money up front and then hit their wallets hard when they want to upgrade, we ease them into a killer sound system.
We have been mildly successful because we have the stigmata that we're the "High-end" shop in town, which has pushed away the far more popular entry level customer. However, we have been hitting the advertising hard for our entry level equipment to break that barrier and after 4 months we've seen an increase of traffic and sales of those "deck and pair" customers.
We sell for our entry to mid-level subs and speakers: Eclipse. For mid to high-end is the JL Audio lines. For decks we dabble in a few brands but are direct with Eclipse for the High-end customer. Eclipse has been great because they have the image of extremely high-end but their unit pricing is low enough to compete with the main-stream brands such as Pioneer and Alpine.
We have a very limited inventory of Dual single din CD players and Mobile vid's which we don't even display. We use those decks for the customer who is looking for the cheapest thing they can get their hands on, or our Car Dealership customers.
Like I said before, what I've seen in my 15 years in the industry is that those shops that have been successful, are the ones that offer about two or three brands of head-units, two or three brands of amps/speakers, and focus on the entry and mid-level customer. In reality we all like to say that we tailor to only the high-end customers what what works is a great selection of mid-line equipment with a limited selection of High-end equipment. A smaller line of High-end equipment lets your customers know you mean business and builds the mystique of the high-end audio systems. If you focus on added accessories such as bluetooth, iPod adaptors, etc., then you'll make up the margin on those entry and mid-line CD decks. On entry level decks, Kits and harnesses are essential to making any kind of profit for your business.
With Jensen you will retain the popular brand by servicing the entry level customers. You can use that brand as a stepping stone to the quality lines such as Pioneer, Alpine, Kenwood, JVC, Sony, etc. It all comes down to the quality of your sales staff and how effective they can step the customer up. Try top-down selling. Start at a fairly high-end peice and then come down a few models to give the customer the illusion that they are not paying top-dollar, but it's better and easier for your staff to sell a less expensive unit, than starting at the Jensen line and trying to work up.
For speaker and amplifier lines, we've tried in many different markets the less known brands, and unless you have a great sales staff, it is very difficult to sell an unknown brand. I've sold Memphis Audio in the Ft. Lauderdale market and killed, then tried that market up in the Northwest and it was a devastating dud. When it comes to choosing your lines it comes down to business. What brands are you partial to, and can you get them at a decent price? Are the reps in your area for the products returning phone calls or e-mails? For me, if it were my business I would start at the distributor level, pull in a few name brands like JBL, Infinity ( great group of products for entry-mid-high end products, and they are both from the same company), also decks from Kenwood, pioneer, Eclipse, Alpine, those are your four heavy hitters. You can try out the "boutique" type brands like MA Audio, Audison, Memphis, AudioBahn, and the like, but be fore warned that your sales staff needs to be keen on these products. Excitement for the product in your staff creates excitement in your customers. For mainstream brands that cater to all levels, you have Rockford Fosgate, MTX, and Kicker.
Our business direction has been to cater to the entry-mid level customer, and get the word out as much as we can. For High-end systems we don't advertise or focus on them, as they are truly a rareity in my market. I'll get maybe five complete systems in a month which makes me good money, but is a drop in the bucket compared to the vast sales of entry to mid-level product.