Digital Trends

Infinity Alpha Series

July 7th, 2003 | by Doug MacLean

Features Continued...

Holding its place in center stage of your home theater is the Alpha 37c. This center speaker is a full frequency three way unit capable of reproducing not only the dialogue but every sound pushed into it. There are dual 6 ½” CMMD woofers, a 4” CMMD mid range and a 1” CMMD tweeter. Rated for 10 to 150 watts this speaker will handle most home theater systems. The audio frequency for this unit is a respectable 45 Hz to 22 kHz. Although the speaker weighs in at 32 pound it can be wall mounted.  With most configurations of your system you will find placing the speaker directly on top of or in front of your television set the best.

Now for the big gun of the system, the Alpha 1200s sub woofer. This 45 pound unit is as big as a typical end table. It contains a single 12” CMMD sub woofer speaker. What sets this sub woofer apart from so many of the others out there is the plethora of options available to customize the sound to the acoustics of your room and the particulars of your receiver and speaker setup. Even though ultra low audio frequencies are difficult to locate with your ear the instruction manual provides a little tutorial on how to properly place the sub woofer in relation to your other speakers. As with other Infinity manuals, ample diagrams are provided. Most of you are going to be impressed with the back of this sub woofer. While most sub woofers have a simple plug for the connection and a dial for the crossover frequency this model is packed with switches, dials and connection terminals. If you do not have a discrete six channel receiver you can connect the sub woofer in line with your front speakers. For this you use the set of eight binding posts. You run the wires from the front speaker outputs of your receiver to the sub woofer ‘IN' posts and then from the ‘OUT' posts to the respective speakers. This method permits the sub woofer to intercept the very low frequencies from the signals to the main speakers, based on the setting of the crossover, and process them with the sub woofer. This method of connection will mostly be used by those out there that are building their system and have not yet moved up to a full 5.1 sound system. For those systems with a LFE sub woofer channel you can run a cable terminated with an RCA jack to the two RCA connectors on the sub woofer. You will need a ‘Y' connector since most receivers only provide a single LFE sub woofer output. Now the fun begins for those of you that enjoy playing with switches and dials. There are three switches to contend with, a phase switch for 0 or 180 degrees, a low pass filter set to either On or Off and a power standby switch. There is also a main unit power switch. For systems using DTS the receiver will control the low pass range and the switch should be set to Off. You can also avoid the need for the ‘Y' connector with the RCA plugs for DTS systems and connect the single LFE cable to either the right or left input. The crossover frequency, the frequency where the sub woofer takes over processing, can be set from 50 to 100 Hz for most systems or between 120 — 150 Hz with systems using smaller rear speakers that do not contain a woofer. The gain control sets the volume for the sub woofer and the width control sets how wide a sound field is created. These are typically "Set once functions", but the initial set up should keep you entertained for a couple of hours.

Running them through the Gauntlet

Many reviewers like to use testing equipment to gauge how well a set of speakers perform. I prefer to trust the most sophisticated test equipment possible and the one most important to everyday use, the human ear. Rather than trusting graphs and wave forms I would rather judge a speaker by how it actually reproduces sound for me. To this end I have a set of DVDs, CDs and cable stations I use to test the performance of speakers. To test the crossover frequency of the sub woofer I chose a music video station. The pumping bass lines of much of modern music were well handled by the sub woofer as well as the woofers in the main speakers. When I tried the speakers out on some music CDs the response was crisp and clean. The highs were brilliant and the bass lines booming without over powering the rest of the audio spectrum. Another way I tested the full frequency of the main speakers independent of the sub woofer was with the first episode of the first season of the Sopranos. It opens with a full version of Frank Sinatra singing ‘It was a Very Good Year'. Since this song features a full string section and some woodwinds it was perfect to hear the whole spectrum. The bass was clear; I could hear the individual strings. The violins where not muddied by the lower frequency, they remained distinct. With all tests I put the front speakers through, they performed better than the usual three way JBLs I have in my home system. They delivered true highs, a strong mid range and a steady bass line. Each sound reproduced was done so without any noticeable coloration. It did seem that the ceramic design made a notable difference. Each range of audio was audible and remained individual  

The center speaker was among the best I have ever tested. The dialogue appeared to naturally come from the characters on the screen. The addition of a set of woofers and a tweeter provided a more natural timbre to the voices. I did have to dial down the volume to the center speaker during calibration with Ultimate DVD Platinum (a DVD used to make sure your home theater is performing at its best). Without careful calibration the center speaker had the tendency to be a bit overpowering, resulting in too much coming from the center rather than giving the feeling of a smooth, integrated part of the sound stage. To test this I tried several films where there was a lot of dialogue over a background of a good deal of action. The Lethal Weapons flicks were great for this. When properly set the dialogue was clean over the background action.