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• Reference 200s, 1 or two channels. Continuous (RMS) power: 40 watts x 2 at 14 volts, 4 ohms, or 100 x 2 at 1 ohm. Manufacturers’ suggested retail: $329 / Average wholesale cost to dealer: $237 / Price: call.

• Reference 300, B, 1 or two channels. Continuous (RMS) power: 80 watts x 2 at 14 volts, 4 ohms, or 150 x 2 at 1 ohm. Manufacturers’ suggested retail: $399 / Average wholesale cost to dealer: $288 / Price: $ 179

• Reference 160, B, 1 or two channels. Continuous (RMS) power: 30 watts x 2 at 14 volts, 4 ohms, or 80 x 2 at 1 ohm. Manufacturers’ suggested retail: $269 / Average wholesale cost to dealer: $200 / Price: $ 95

• Reference 604 B, 2, 3, or 4 channels. Continuous (RMS) power: 120 watts x 4 at 14 volts, or 160 x 4 at 1 ohm, or 320 x 2 at 2 or 1 ohms. Manufacturers’ suggested retail: $749 / Average wholesale cost to dealer: $540 / Price: $ 249

• Reference 700, 1 or two channels. Continuous (RMS) power: 165 watts x 2 at 14 volts, 4 ohms, or 350 x 2 at 1 ohm. Manufacturers’ suggested retail: $599 / Average wholesale cost to dealer: $430 / Price: call.

• Reference 500, 1 or two channels. Continuous (RMS) power: 120 watts x 2 at 14 volts, 4 ohms, or 250 x 2 at 1 ohm. Manufacturers’ suggested retail: $479 / Average wholesale cost to dealer: $345 / Price: call.

• Reference 414s, 2, 3, or 4 channels. Continuous (RMS) power: 80 watts x 4 at 14 volts, or 100 x 4 at 1 ohm. Manufacturers’ suggested retail: $599 / Average wholesale cost to dealer: $430 / Price: $ 249

• Reference 705, 5 or 3 channels. Continuous (RMS) power: 80 watts x 4 + 200 x 1, at 14 volts, or 220 x 2 at 4 ohms + 400 x 1, 1 ohm. Manufacturers’ suggested retail: $1169 / Average wholesale cost to dealer: $840 / Price: $ 399

Soundstream designs and manufactures amplifiers, subwoofers, speakers, crossovers, and other car stereo accessories. Soundstream was highly regarded (still is) back in the 80’s as one of the top, high-end car amplifiers, along with the likes of Rockford Fosgate. When I worked for Speaker Warehouse and the owners of JL Audio, we sold a lot of them.

One of the unique features of the Reference series amps is something that Soundstream dubs “Coherent Stereo”. Most car amplifiers today are designed with one of the two channels purposely inverted. This allows the amp to be bridged simply by wiring it differently, rather than using a built-in switch on the amplifier. Not only that, but with an inverted channel amplifier, you can run two stereo speakers, and one, single voice-coil subwoofer, all off a two-channel amplifier! This came about back in the Model-T days of car audio, and was a quick and dirty way to throw together a subwoofer-satellite system. I think it was Rockford Fosgate that pioneered this. As a mater of fact, Rockford Fosgate had a popular, pre-packaged speaker system called “The 3-Way for the Free Way”. Now you know what made them famous. This trend still continues today, and more than 80% of all car amplifiers fall into this category. Most experts would agree, this is not the way to do it. Specifically, The inverted channel is slightly different from the other. So the question is this: I would not want a different amplifier for the right channel than I have for the left... so why would I buy an amplifier that does not have matching channels? The Reference amps have identical channels for quality, and can be bridged with a switch.

An interesting thing that can be done with this non-inverting topology is surround-sound... without a processor! How is that, you say? First, a brief background on surround sound is in order.

Originally, surround sound was a four-channel system. It’s distinguishable from the five-channel systems, called Dolby Pro-Logic and Dolby Digital, that are so prevalent in homes today. Surround sound utilized the standard stereo speakers in front of the listening area, with the addition of two speakers behind you. These rear speakers are fed a difference signal, which is exactly that - the difference between the left and right signal. These rear speakers give you the sound that is present only in either the right or left channel. The result is, that lead vocals, and things that are supposed to be at the front sound stage stay up front. Stereo sounds, background singers, and ambient sounds seem to come from the sides and all around... surround sound! Just like an inverted channel amplifier can be bridged, or summed to mono, a Reference amplifier can be wired to derive a difference signal for the rear speakers. As a mater of fact, several of their new Rubicon models, including the 805 and 555, incorporate a “rear-fill” switch and inboard filter to enable them to produce a Dolby surround signal, without any special wiring.

To wire a Reference amplifier for rear surround channels: The rear left and right speakers should be wired normally for stereo - to a stereo amplifier, or to the stereo pair of a multi-channel amplifier, except for one major difference: Do not connect the negative (-) amplifier terminals, and do not connect the negative(-) speaker terminals to the amplifier. Instead, connect the negative speaker terminals together; So, essentially, you have the positive speaker leads connected normally to the positive amplifier leads, the negative speaker terminals are connected to each other by a jumper wire, and the negative amplifier terminals are left unconnected. If you use 4 ohm speakers, the resultant ohm load the amplifier will see is 4 ohms. There may be other amplifiers you can do this with, but at present, I am only aware of the Reference line. If you try to wire an amplifier with inverted channels, or other designs, like dual mono amplifiers, you may have trouble, and you could damage the amplifier. If in doubt, always consult someone knowledgeable in the industry. Additionally, a couple of the highest power Reference amplifiers have separate gains for each channel. You may or may not be able to hook them up this way; If the amplifier has separate gains for each channel, call Soundstream to verify that you can do this. They can be reached at (916) 351-1288.

In the home, surround channels are filtered. The filter is a first-order (6db/octave) low-pass at 7khz. You could use an separate x-over for this. An alternative method is to use your rear midranges, or component speakers, minus the tweeters. The common size for rear car speakers is 5” - 6” or smaller, and high-frequency roll-off approaches 7000 Hz. They are perfect for this application.

In review, the Soundstream amplifiers are certainly top-of-the-line, and at these prices, they are a find. They will go down as one of the best car audio bargains this year. Even if you are not in the market for an amplifier today, if you know you will be, consider buying one now. These are most certainly limited in supply, and will probably sell out quickly. I bought two Reference 405s amplifiers for myself - I don’t know what higher recommendation I could give. Even though one of my vehicles is not ready for a system yet, the 405s can stay in the closet for awhile... it is just too good a deal to pass up.