McIntosh ml-1 (1970)

Name: McIntosh ml-1
Brand: McIntosh

Loudspeaker system designed to extend bass response to 20Hz when paired with a McIntosh equalizer

Overview

The McIntosh ML-1C is a loudspeaker system introduced in 1970 by McIntosh Laboratories, marking the company's first "mass" produced speaker model. Designed by Roger Russell, the system consists of the ML-1C speaker and the optional MQ101 environmental equalizer, which together maintain flat frequency response down to 20Hz within 1dB. The speakers were engineered to be used with a McIntosh equalizer—either the MQ101 or the lower-cost MQ102—as the full bass performance is only realized with equalization. Without it, the system lacks the deep bass response it was designed to deliver.

Specifications

Frequency response (with MQ-101)	20 Hz - 20,000 Hz ±1 dB
Frequency response (standalone)	30 Hz - 20,000 Hz
Power handling	100 watts
Sensitivity	92 dB
Impedance	8 ohms
Woofer	12" McIntosh with barium ferrite magnet
Lower mid-range	8" McIntosh
Upper mid-range	1-1/2" soft dome
Tweeter	2-1/4" cone with 1/2" super radiator
Crossover frequencies	500 Hz and 1500 Hz
Cabinet type	Acoustic Suspension
Finish	Walnut veneer
Grille	Black cloth
Dimensions	24" H x 14" W x 12" D
Weight	45 lbs
Original price (pair)	$624
MQ101 equalizer price	$250
MQ102 equalizer price	$74.50

Design

The ML-1C design is protected under U.S. Patent 3,715,501 and features an acoustic suspension cabinet with a driver complement of one 12" woofer and one 8" midbass per cabinet. The 12" woofer uses a barium ferrite magnet, an aluminum voice coil form, and has 1" of total travel with a 15-pound magnet structure. It is intentionally overdamped, rolling off starting at 150 Hz. The crossover network avoids electrolytic capacitors and includes a 1.6 mH iron core inductor (L1) and a 2-ohm series resistor (R1) in its supplementary design for modern driver replacements. Original drivers are no longer available, and restoration typically involves using Morel MDT40 and MDM 55 drivers as substitutes.

Context

The ML-1C was marketed on its ability to reproduce 20Hz bass, a claimed industry first at the time. Despite the system’s design requiring the MQ101 or MQ102 equalizer for full performance, only about one in three buyers purchased one. The equalizers were sold separately, and McIntosh advised against using them with non-McIntosh speakers. A planned ML-1D version with indicator lights for clipping and blown fuses was scrapped, though some cabinets were made with light cutouts later covered by metal plates.

Market

Common failures include deteriorated foam surrounds on the woofer and midrange drivers, requiring refoaming or full replacement. After approximately 50 years, tweeters and upper midrange drivers often have little or no life left. Direct replacement drivers are not available, making restoration dependent on modern substitutes and custom crossover work.