Digital Trends

Infinity Alpha Series

July 7th, 2003 | by Doug MacLean

Introduction

Infinity Acoustics is part of A Harmon International and is known for both home and car audio. The Alpha series reviewed here occupies the middle part of their home audio product line and provides both an esthetically and acoustically pleasing array of home theater speakers. The design philosophy behind the Alpha series is to make sure their speakers are a neutral part of your home theater, neither adding to nor subtracting from the audio information contained in the source.

While many people, especially those new to home theater, will prefer the complete set of six speakers as one set, the advantage to buying the individual components is you can build up over time and still stay within a reasonable budget. The Infinity Alpha series may take a significant portion of your home theater budget but it is well worth it for the performance you will receive.

Design and General Features

The Alpha models I reviewed were all black veneer, they are also available in Beech or Cherry finishes. My first impression after getting them out of the six huge boxes that dominated my home was ‘they look great'. They are sleek and will satisfy those in your family who consider how well a piece of equipment fits into your room. I know this is very subjective but they had the heft of a good quality speaker, they just feel well made, they will last for a very long time in your home. You will most likely have to rearrange a lot of furniture to accommodate them but the effort will pay off when you fire up the amplifier and sit back to listen.

All Infinity Alpha speakers employ patented Ceramic Metal Matrix Diaphragms (CMMD™). This provides a clean, clear sound with almost no alterations from the audio source material. This is accomplished by minimizing the strong resonances found in some speakers that can adversely affect the timbre of the reproduced sound. The use of a ceramic cone instead of the industrial standard metal gives a stiffer material that better resists alteration of the sound and permits the individual speaker to reproduce only the sound in its targeted set of frequencies, high for the tweeters, mid range or low for the woofers. The sum affect of all this is the speakers provided a sound that never seemed muddy or overly bright. I noticed the difference immediately when I switched to the Alphas from my trusted set of JBL speakers. I've used JBLs for decades and have always considered them my preference, I guess I have to change that long held opinion after all this time. Of course, all the speakers in this series are magnetically shielded. While many will think this is only important for the center and front speakers that often come the closest to your television set, adding the shielding to the rear and subwoofer makes sure if you place them a little too close to your VHS collection (yes I know many of you have tapes of favorite films not out on DVDs) the tapes will not be degraded. This is just typical of the attention to details that Infinity incorporates into their designs.

The main front speakers, the Alpha 40 model, are configured as floor standing towers. Each contains a one inch dome tweeter, a 5 ¼” mid range and dual 6 ½” woofers. All four speakers employ the CMMD technology. The edges of the cabinet are curved providing a nice, modern look to the speakers. They are ported at the bottom of the cabinet. The first thing most of you will notice when setting up these speakers is they are configured for ‘bi-wire' or ‘bi-amp' connections. There are two sets of connection binding posts, one marked high frequency, and the other low. This permits you to use different connections for the upper and low frequency speakers or if you have them, different amplifiers for the low and upper ranges. In case you just want to use one set of wires to make the connection the gold plated posts come with a little flat metal connector to pass the signal to both sets of posts with one connection. The speakers are rated for 10-150 watts and provide 45 Hz up to 22 kHz.

The rear/surround speakers are the Alpha 25es. They are mountable on the wall or can easily fit in a bookshelf or stand. The first thing you will notice about them is they are angled; the four speakers contained in the cabinet are set at about a 45 degree angle for maximum dispersion of the sound. The lower frequencies are handed by two 5 ¼” CMMD drivers, one on each side of the angle, while the higher frequencies are processed by two 1” CMMD drivers. One nice little design touch is the speakers on the left side have the larger driver on top, the ones on the right have the larger driver on the bottom. Supposedly this is to help make sure all frequencies are equally mixed for the listeners. For optimum performance in any level home theater you can use these speakers in one of three modes: bipole, monopole or dipole. The provided recommendations are as follows. If you are mounting the speakers more than 14” from the listening position or they are mounted near a corner use the monopole setting. For those systems with THX certification and the THX surround mode is selected or with older Prologic only receivers, use the dipole mode. For most other installation situations the bipole mode is recommended.  Bipole is also recommended if you use these speakers for the rear center speakers in a Dolby EX or DTS ES system. These speakers can handle power from 10 to 125 watts from 60 Hz to 22 kHz.