Re-Creating Film Experience May Be an Affordable Option : Though it is possible to spend from $10,000 to $100,000 for a deluxe version, it is also possible to assemble one that’s fairly impressive for only a few thousand dollars.

Home theater systems are expensive but, contrary to popular opinion, they are not so costly that only the rich can afford them.

Though it is possible to spend from $10,000 to $100,000 for a deluxe home theater, it is also possible to assemble one that’s fairly impressive for only a few thousand dollars.

A home theater is a room equipped with an audio-visual unit featuring, minimally, a big-screen TV and a surround sound system that includes an array of front and rear speakers set up to create three-dimensional sound.

Primarily used for watching movies, home theaters are outfitted with a big-screen TV and either a laserdisc player or a stereo VCR, or both. Most home theaters also include equipment for listening to music--such as a CD player, a tape deck and a tuner (radio).

Real surround sound, which is the essence of the home theater, requires three speakers for the front of the room--left, right and center--and two rear speakers. Other key elements are a subwoofer (a bass speaker for the low frequencies) and a decoder, which dissects information from tapes and laserdiscs, and sends certain portions of the soundtrack to certain speakers. In other words, the decoder--part of the audio/visual receiver or amplifiers that serve as the system’s power source--provides precise sound separation.

Optional side speakers, for the middle of a larger room, can further enhance the sound.

According to Robert Eitel, who heads Robert’s Home Audio and Video in West Los Angeles, the best surround sound is delivered by THX, the home-theater version of the LucasFilm sound system found in some movie houses. Introduced last summer to the consumer market, the THX system sells for $12,000.

At Eitel’s showroom, the THX system is featured in a $50,000 home-theater unit that boasts better sound than in many theaters. It also includes a front-projection TV.

Eitel mostly deals in units costing $10,000 and up. In the very expensive units--$20,000 to $40,000--part of the expense is for custom installation, such as putting speakers into walls and ceilings. But some of that cost is for enhancements and refinements that are mainly significant to audio/videophiles or the very rich.

For people with smaller houses, apartments and condos--and generally less money--the low-end home theaters don’t offer the same stunning, three-dimensional presence, but a system in the $3,000 to $5,000 range provides potent enough sound.

One option is the one-brand, package system. For example, the Ken Crane outlet in West Los Angeles offers two all-Mitsibushi systems, one for $4,200 and one for $6,200.

You can also put together a less expensive system one component at a time, if that’s all your budget allows. And you can cut corners. For instance, you can get by with a smaller screen, and although it’s ideal to have all high-quality speakers, you can get by with inexpensive rear speakers. Having good front speakers is more important.

In addition, the $1,000-plus power sources aren’t necessary for smaller systems. A good audio/ visual receiver, including a decoder, can be purchased for about $500.

Don’t hesitate to make use of what you have. If you already own a big-screen TV, build a surround-sound system around it. Or incorporate your current speakers into a surround-sound system. Companies such as AudioSource, located in Burlingame, Calif., sell a decoder and two speakers for just over $600; add two speakers you already have to such a package and you get instant surround sound.

Here are some things to remember when planning a low-end ($3,000 to $5,000) home theater:

* Screen size vs. room size. The bigger the TV screen, the bigger the home-theater room should be, because the bigger the screen, the farther away you have to sit to get the best image. With a 45-inch screen, you need to sit about 10 feet away.

* Purpose. If you don’t intend to watch movies often, a home theater is a waste. Using it for regular TV doesn’t make sense since the standard broadcast signal delivers picture and sound well below the capacity of a decent home theater.

* Noise. Apartment and condo dwellers should think twice before investing in home theaters. If the walls are thin, you may not be able to crank up the volume on your home theater, curtailing its effectiveness.

* Misleading advertising. Don’t be fooled by TVs that supposedly have built-in surround-sound. “What you get is a kind of wrap-around sound that’s a poor imitation of the real thing,” Eitel explained. “What the manufacturers have done is play around with electronics to give the image of real surround sound, but it’s just coming from two speakers in front.”

Also, some stores offer home-theater packages in the $4,000 to $6,000 range that include only two or three speakers. The rear speakers cost extra.

* Installation. Hiring someone to install your home theater may be necessary, even for a small system. You’ll probably need help with wiring or putting the equipment in cabinets or arranging it to get the best sound and picture.