CA: What do you see as potential ramifications for the future of car audio? With ever more powerful internal amplifiers being incorporated into in-dash receivers, will users have a greater chance of blowing their factory speakers, and consequently need to upgrade to higher quality car speakers?

Tripath: There are three major ramifications for aftermarket car audio.

1. The first is that high power head units will take a big hunk out of the need for stand-alone amplifiers. The Panasonic head unit offers more real power then many outboard amplifiers. Why pay for and install an amp, when you can get the same power from the head unit? This will mark a new level of performance for people who want to just replace their factory components. Refitting a high-power head unit and new speakers will offer a major performance upgrade without rewiring.
   
   

   Panasonic's MXE CQ-C9800U uses a 60W x 4-channel Class-T® amplifier that gives you power comparable to that from an external 4-channel amp.

   
   
2. The second big impact is the space and heat savings. With the extra space created by getting rid of the heat sinks, OEM's [Original Equipment Manufacturers, the companies that make factory stereos] can add better DSPs [Digital Signal Processors] and bigger LCD monitors.
3. The third big impact is that with Class-T® we can begin to cram more channels into the head unit. Why just 4 channels? Some OEMs are already looking at 6 channels for in-car-theater, but what about 8 or 12 channels? With the horsepower in the DSP, you can use active crossovers and then separately amplify each speaker driver. Best of all, you could still fit it a normal single-DIN package.

Overall these will definitely continue the trend to greater demand for speaker and wiring upgrades.

CA: What type of amplifiers do you expect to introduce next year?

Tripath: We're working on two parts specifically targeted at automotive head units. The first is a digital controller for Class-T®. This will make it easier to for OEMs to build-in Class-T® amplifiers to their head units, hopefully making it a bit more common and accessible.

The other part is a 4 x 100-Watt version of our current part. Imagine a head unit putting out that much power! Look for some units built around that part in a few months.

For the home theater market, we have just introduced a new family of amplifiers that will make Class-T® very competitive with traditional designs. We expect these parts to be a big hit for A/V units and "all-in-one" DVD players. The new parts are optimized for power output of between 50 and 150 watts. One of the neat aspects of the new family of amplifiers is that it allows the manufacturer to scale the power to fit the needs of the system.

The Alpine MRD-F752 5-channel amp uses Class-T® technology.

CA: Most car amplifiers have a peak power rating that is around twice as high as their RMS power rating. Yet the Panasonic MXE CQ-C9800U, which utilizes Class-T® amplifiers, is rated at 60 watts RMS, 70 watts peak power.

Tripath: The spec game is always an issue, as I'm sure you know. There are several issues that contribute to the apparent proximity of the two numbers. The shape of the THD curve that I discussed earlier contributes to this. Because Class-T® maintains good performance through its whole operating range, it can be rated with a higher RMS power rating at any given THD.

The main underlying issue is the power supply. Most head units use the car battery power for a supply (12 or 14.4 V). To get the most power from the Class-T® design, Panasonic has used an internal power supply to boost the operating voltage much higher than 12V. This is similar to how stand-alone amplifiers work. The peak power is limited by the power supply in this case.

It's important to keep in mind what the ultimate goal is: great sound. Sound quality comes from a variety of parameters like power, headroom, and damping factor. The peak output power is a bit of a meaningless number. Running any amplifier at the conditions given as its "peak" output is really unacceptable and is probably damaging to both the amp and your speakers. Many people think of peak power as headroom; however, the max supply voltage determines the true headroom, and almost every car stereo uses 12 or 14.4 volts. This is why specifications like the CEA-2006 are so critical. This will help consumers compare the real usable power rating of products.