McIntosh XR27 owner manual Introduction

Figure 3

Introduction

McIntosh Acoustic Engineers have refined the Loud- speaker System concept to provide superior sound quality in a versatile enclosure with five different installation methods.

The Low Frequency Section of the System consists of four 8 inch Woofers. They have a large magnet assembly and long cone excursions with very low levels of harmonic distortion and frequency response down to 80Hz. Refer to figure 1. The Woofer also incorporates McIntosh’s Pat-

Figure 1

ented LD/HP1 Magnetic Circuit Design with shielding to

greatly reduce any external magnetic field. Extensive in-
vestigating and testing re-
sulted in a new design con-	LD/HP
cept which utilizes a pair of	Conventional
aluminum shorting sleeves
in the magnetic circuit. Re-
fer to figure 2. The sleeves
virtually eliminate the nega-
tive influence of the fluctu-
ating voice coil field on the
permanent magnet field.

The 6-1/2 inch Midrange Driver also incorporates McIntosh’s Patented LD/HP1 Magnetic Circuit Design with shielding to greatly reduce any external magnetic field. Refer to figures 1, 2 and 3. The low distortion of this Midrange Driver results in the incredible smoothness and clarity in the reproduction of the human voice. The five 1 inch soft dome Tweeters are inline and connected to pro- duce a Bessel Function Array. Refer to figure 4. The indi-

Figure 4

vidual tweeter amplitudes and phase relationships are ad- justed so the array acts as a high frequency point source. One advantage of such an arrangement is a very smooth and even acoustic polar response. This allows the listener to move off axis without suffering a change in high fre- quency output. The use of multiple tweeters, combined with a heat sink, also provides greatly increased power handling at high frequencies.

The Crossover Networks used in the XR27 Loud- speaker System are designed to ensure an even frequency response over the entire audible range. The Low Fre-

This results in lower distor-

Figure 2

quency Crossover Network is a Third Order design utiliz-

tion due to more linear magnetic flux in the voice coil gap. Refer to figure 3. Additional benefits are less volume com- pression due to improved heat

transfer through the sleeves and a

cooler operating voice coil. Both measurements, as

well as critical listening, reveal ten times less dis- tortion than previ-

ous designs.

1LD/HP Pat. No. 5,151,943

ing Capacitors and Inductors with high current capacity. Refer to figure 5. Low Loss (DCR) Inductors in the Low

Figure 5

Frequency Network, are chosen not to exhibit any core saturation even at high power levels. This prevents the ad-

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