Meyer Sound Self-Powered Loudspeaker HM-1 User manual

Patents Pending
Operating Instructions
HM-1
Copyright © 1997
Meyer Sound Laboratories, Inc.
All rights reserved
Part # 05.039.003.01 Rev A2
Self-Powered
Reference Monitor

2
Introduction ......................................................... 3
Power Requirements........................................... 3
Cable Requirements ............................................ 5
Audio Input .......................................................... 5
Interfacing Options.............................................. 5
Cooling and Fan Installation............................... 6
Protection and Limiting ...................................... 6
Safety Summary.................................................. 7
Mounting Specifications ..................................... 8
Dimensions .......................................................... 8
Contents
!
Pour indiquer les risques
résultant de tensions
dangereuses
Zu die gefahren von
gefährliche spanning
zeigen
Important operating
instructions
Pour indequer important
instructions
Zu wichtige betriebs-
anweisung und unter-
haltsanweisung zeigen
Frame or chassis
Masse, châssis
Rahmen oder chassis
Protective earth ground
Terre de protection
Die schutzerde
Para indicar azares
provengo de peligroso
voltajes
Para indicar importante
funcionar y mantenimiento
instrucciones
Armadura o chassis Tierra proteccionista
These symbols indicate important safety or operating features in this booklet and on the chassis.
Made by Meyer Sound, Berkeley, CA, USA
European Office:
Meyer Sound Germany
GmbH
Carl Zeiss Strasse 13
56751 Polch, Germany
UULL
®
LISTED
3K59
COMMERCIAL
AUDIO SYSTEM
Dangerous voltages:
risk of electric shock
Symbols Used
According to ISO/IEC Guide and EN 45014
Declaration of Conformity
The product herewith complies with the requirements
of the Low Voltage Directive 73/23/EEC and the
EMC Directive 89/336/EEC.
Office of Quality Manager
Berkeley, California USA
April 1, 1997
declares that the product:The Manufacturer:
Product Name:HM-1
Product Options:All
Name:Meyer Sound Laboratories
Address:2832 San Pablo Avenue
Berkeley, California 94702-2204, USA
conforms to the following Product Specifications:
Safety:EN 60065: 1994
EMC: EN 55022: 1987 - Class A
IEC 801-2: 1984 - 8 kV
IEC 801-3: 1984 - 3 V/m
IEC 801-4: 1984 - 0.5 kV Signal Lines,
1.0 kV Power Lines
Shock: 30 g 11 msec half-sine
on each of 6 sides
Vibration: 10 – 55 Hz (0.010 m
peak-to-peak excursion)
Operating temperature:0°C to +45°C
Nonoperating temp: < –40°C or > +75°C
Humidity: to 95% at 35°C
Operating altitude: to 4600 m (15,000 ft)
Nonoperating altitude: to 6300 m (25,000 ft)
Environmental Specifications for
Meyer Sound Electronics Products

3
Introduction
The Meyer Sound HM-1 is a very compact, full-range
self-poweredloudspeakersystemdesignedtoserveina
wide variety of installed sound reinforcement and re-
production applications. The HM-1 incorporates sig-
nificantdesigninnovationsthatcombineunprecedented
performance with several practical advantages. In
contrast to conventional small speaker systems, the
vented cabinet is tuned at 40 Hz to provide flat, full-
range response with half-space loading. The concentric
tweeter mounting structure is optimized to minimize
both back-wave interference and IM distortion. A
constant-directivityhigh-frequencyhornaffordsa100°
beamwidth,andsophisticatedphase-correctioncircuitry
assures true point-source performance without the off-
axis cancellation effects that normally plague dual-
concentric designs.
By implementing distributed amplification, the HM-1
affords substantial advantages in reliability and ease of
installationwhencomparedwithconstant-voltage(70V)
distributedsystems.TheHM-1 acceptsaunipolar48VDC
powersource,whichreducesinducednoisesignificantly.
The 48 VDC power may be supplied using twisted-pair
wiring jacketed with the signal source conductors,
eliminating the need for wiring conduits. Its amplifier
and signal-processing circuits are designed to tolerate
supply voltage drops of up to 25%, accommodating
light-gauge cables and long cable runs. Internal energy
storage circuits minimize the system's peak-to-average
supply current demands, allowing efficient use of
switched-mode regulated supplies.
The HM-1 is a two-way system comprising a 7” graphite
cone low-frequency driver, and a concentrically-
mounted 1” soft-dome high frequency driver with
constant-directivityhorn,ina vented cabinet; the drivers
are magnetically shielded. The enclosure contains two
200 Watt amplifiers, an active crossover, driver protection
voltage limiters, and frequency and phase response
alignment circuitry. A laser-trimmed differential input
stage affords superior common-mode rejection to ac-
commodate simple twisted-pair signal distribution.
Front-panel LEDs indicate power, signal limit, and
thermal overload; arear-panelcircuit breakerprovides
overall DC power protection.
The HM-1 enclosure is coated with a textured black or
white finish, and a variety of factory-installed mounting
configurations may be ordered. Optional accessories
include a remote switched-mode power supply, a
variable-speed cooling fan assembly controlled from a
rear-panel drive output, and an auxiliary subwoofer,
powered by the HM-1 low-frequency amplifier, that
extends the frequency response to 42 Hz in free field.
Power Requirements
The HM-1 requires a 48 VDC external power supply,
which provides these benefits:
• Low voltage wiring simplifies installation.
• Utilizes telecom 48 V supply and bus standard.
• Eliminates50/60HzAC noisecouplingin wiring.
TheHM-1canbepoweredbytheMeyerPS-1ACadapter
or a supply that conforms to the 48 VDC specifications
detailed in this section.
Meyer PS-1 AC Adapter
Using the Meyer PS-1AC adapter is the simplest way to
power a pair of HM-1s, or a single HM-1 with a sub-
woofer.TheACadaptercanbepurchasedthroughMeyer
Sound and comes with two 10 ft power cables. The AC
adapterhas two output connectors thatarewiredtogether
inside the supply, allowing either one connector to
drive two speakers at the end of a single cable, or one
connector and cable per speaker.
Do not connect the outputs of multiple PS-1 AC
adapters together!
For installations up to 10 HM-1s, using multiple PS-1
AC adapters is often the simplest and most cost-effective
solution. Since the limited output power for each supply
acts as circuit protection for light gauge cables, it is not
necessary to install circuit breaker distribution panels.
Usingthe PS-1does,however,limit each48V linetotwo
speakers.ThedimensionsoftheACadapterare10”x5”x3”.
Contact Meyer Sound for further information on the
PS-1 AC Adapter.
!
Do not use a ground-lifting adapter or cut the AC
cable ground pin.
Power Supplies for Large Systems
Ifan installation includes alargenumber ofspeakers, or
requires many speakers to operate from a single 48 V
line, a single high output power supply should be
considered. The following sections provide current and
voltagespecificationsfortheHM-1’spowerrequirements.

4
Current Ratings
Thewidedynamicrangeofaudiosignalsnormallycauses
a high peak-to-RMS ratio in an amplifier’s DC supply
currents.TheHM-1hasinternalstoragecircuitstominimize
the peak-to-average ratio, which
• reduces the peak power rating required by the
supply;
• allows efficient use of switched-mode power
supplieswhich have similar peak andcontinuous
ratings.
The following table lists the current and power draw for
a singleHM-1atlight,moderate, andmaximumoperating
levels.
1-MH1rofwarDrewoPdnatnerruC
leveLgnitarepO SMR tnerruC kaeP tnerruC SMR rewoP kaeP rewoP
thgiL
)gnitimilon(
A5.1
SMR
A0.2
KAEP
W27
SMR
W69
KAEP
etaredoM
)gnitimillanoisacco(
A0.2
SMR
A5.3
KAEP
W69
SMR
W861
KAEP
mumixaM
)gnitimilsuounitnoc(
A0.3
SMR
A0.5
KAEP
W441
SMR
W042
KAEP
Each HM-1 draws 0.4 ADC, 20 W in a quiescent state.
The RMS current is measured over a 500 ms integration
time.Thepeakcurrentis measuredovera10msintegration
time.
Each HM-1 can drive a slaved Meyer subwoofer from a
connectionontheamplifierpanel.Addingthesubwoofer
increasestheamplifier’soutputcurrent,whichincreases
the power supply current. The current and power ratings
for an HM-1 and a subwoofer are listed in the following
tableatlight, moderate, and maximum operating levels.
refoowbuShtiw1-MH1rofwarDrewoPdnatnerruC
leveLgnitarepO SMR tnerruC kaeP tnerruC SMR rewoP kaeP rewoP
thgiL
)gnitimilon(
A0.2
SMR
A5.2
KAEP
W69
SMR
W021
KAEP
etaredoM
)gnitimillanoisacco(
A5.2
SMR
A0.4
KAEP
W021
SMR
W291
KAEP
mumixaM
)gnitimilsuounitnoc(
A5.3
SMR
A0.6
KAEP
W861
SMR
W882
KAEP
An HM-1 with subwoofer draws 0.4 ADC, 20 W in a
quiescent state.
Voltage Ratings
The voltage operating range for the HM-1 is 48 VDC
nominal, 52 VDC absolute maximum, and 35 VDC
minimum without shutoff.
Allowing operation down to 35 VDC provides two
benefits. First, a moderate voltage drop (up to 8 V) for
long DC power cables has a minimal impact on audio
performance, enabling the use of light-gauge cables for
most installations.
Second, since some switched-mode power supplies
slowly foldback the voltage if they experience current-
limit,powersupplieswithlowerpower (current)ratings
can be used efficiently. Since supplies with lower power
ratingstypically experiencecurrent-limitwhenthe HM-1
is at continuous limiting, some voltage drop and loss of
headroom is acceptable provided the voltage does not
dropbelow35VDC.At35V,themaximumcurrentdraw
is 25% lower than the values stated in the preceding
tables.
NOTE: If the HM-1 will not be driven at continuous limiting,
a power supply that satisfies the moderate specifications
for voltage and current can be used safely without risk of
sonic degradation or interruption.
It is important to understand how the selected power
supply responds to current-limit, particularly for
switched-modesupplies.Somesuppliestripoffandmust
beresetmanually,while others remainoffforaperiodof
time and reset automatically. In both cases, the HM-1
suffers audio interruption. In the third, and preferable
case, supplies that feature voltage foldback allow brief
periods of current-limit without audio interruption; for
this reason, we recommend using such supplies.
The HM-1 does not require tight voltage regulation and
operates down to 35 V although peak SPL values are
reduced. This operating voltage flexibility allows for
wiring loss and voltage foldback without interruption
or degradation of the audio signal.
Many high power industrial supplies (1–5 kWatt) are
available for 19” EIA racks that are suitable for large
installations with equipment rooms. Distribution panels
with branch circuits can be used economically with up
to 8 HM-1s on a branch. Contact Meyer Sound for
information on tested and approved supplies.

5
Cable Requirements
EachHM-1drawsamaximumof3Armsand5Apkfrom
a 48 V power supply at peak SPL. The cabling between
the 48 V supply and the speaker adds resistance to the
circuit and produces a voltage drop at the speaker.
Decreasing the voltage at the speaker compromises the
peak SPL so cable resistance should be minimized.
Forbestsonicperformance,avoidvoltagedropsgreater
than 8 V at the speaker. Voltage drops greater than 15 V
maycausethe speaker to mute or distort.Themaximum
round-trip resistance for a cable attached to a single
HM-1 should be no higher than 1.6 Ω, which keeps the
voltage drop below 8 V during the maximum current
draw of 5 Apk.
Thefollowingtablehelpsselectcablegaugesforvarious
cable lengths.
pordV8<rofhtgneLelbaCmumixaM
tas1-MH#
elbacfodne
GWA81
)m(tf
GWA61
)m(tf
GWA41
)m(tf
1)0.83(521)0.16(002)6.001(033
2)2.91(36)5.03(001)3.05(561
3)8.21(24)4.02(76)5.33(011
4)8.9(23)2.51(05)1.02(66
5)6.7(52)2.21(04)2.91(36
Asingle HM-1 attached to a 100 ft 18AWG cable (1.27 Ω
total) produces a 6.4 VDC loss at the speaker (41.6 V)
duringmaximumaudiobursts (5A,0.5s).Thisresults in
a small loss in peak SPL.
Audio Input
The input impedance of an HM-1 is 10 kΩ. Pins 2 and 3
carry the input as a differential signal. Pin 1 and the case
are connected to the HM-1 chassis. The power cable can
be jacketed in the same sheath as the signal cable with-
out adding noise to the input signal.
For best EMI immunity, it is desirable to use a twisted
pair shielded cable with the twisted pair connected to
pins 2 and 3, and the shield to pin 1. However, an
unshielded twisted pair cable can be used effectively,
even if it is jacketed with the power cable.
The input is RF and ESD protected, capacitive coupled,
±50 V common mode to ground, +4 dBu nominal, +21
dBu max. Clipping occurs at the input at 12 Vpk. The
Common Mode Rejection Ratio (CMRR) is greater than
80 dB.
The HM-1 is available with either an XLR or a terminal
strip input connector.
Interfacing Options
Two types of interface panel are available for the HM-1.
One uses an XLR connector for the audio input, and a
four-pin terminal connector for the power supply input
and subwoofer output. The other interface panel type
uses a seven-pin terminal connector for the audio input,
powersupplyinput,andsubwooferoutput.Bothversions
use a two-pin terminal connector for the fan power
output.
The wiring for the terminal connectors is inserted into a
keyed plug that fits only into the correct terminal
connector. This section discusses both interface panel
types.
XLR Connector
The XLR connector is standard for most audio devices.
Pins 2 and 3 carry the input as a differential signal (pin 2
is hot) and pin 1 is connected to the chassis. The power
supplyinput and subwooferoutputconnectionsareeach
made with a two-pin plug.Each plug is keyedsuch that it
canbeinsertedonlyintothecorrectlocation. Forexample,
the power supply plug does not fit into the subwoofer
output.
Rear panel with XLR connector

6
Terminal Connector
The terminal connector combines the audio input, power
supply input, and subwoofer output connections into a
single seven-pin connector. The audio input uses two
pins for the differential input signal, and one for ground;
the subwoofer output and power supply input each use
two pins. A seven-pin plug accepts the wiring and can
be inserted into the terminal connector in the correct
orientation only.
Rear panel with pluggable terminal strip input
and fan connectors
The HM-1 Subwoofer
The low frequency response of an HM-1 can be extended
down to 42 Hz if used with the HM-1 Subwoofer or
placed next to a wall or ceiling (half-space loading). Each
HM-1 can power a subwoofer from the male 3-pin EN3
Sub output connector on the rear panel. However, de-
pendingontheloadingconditions,amplelowfrequency
energy may be obtained by driving a single subwoofer
fromtwo HM-1s, resulting in a correctly-summedmono
signal. Cables for connecting one HM-1 to a subwoofer
and two HM-1s to a single subwoofer are shipped with
each HM-1.
The addition of one subwoofer increases the maximum
SPL of a single HM-1 by 4 dB (without sub: 116 dB SPL;
with sub: 120 dB SPL). The HM-1 Subwoofer has the
following specifications:
Transducer 10” low frequency cone driver
Enclosure/Finish Medium Density Fiberboard (MDF) /
Oak Veneer (natural or black)
Weight 33 lb (11.0 kg)
Dimensions Height:17.5”; Width: 12.3”; Depth: 9.3
A 3-pin terminal block connector is used to apply the
amplifier signal from the HM-1 to the subwoofer.
Cooling and Fan Installation
The HM-1 depends on natural convection to cool the
heatsinksthatabsorbheatfromtheamplifiersandradiate
the heat into the surrounding air space. Natural convec-
tion requires free air in back of, and underneath the HM-
1 to allow air to flow up over the heatsinks. The HM-1
reaches an equilibrium temperature in approximately
15 minutes at a steady operating level.
In free air, at a typical room temperature of 25°C, the
HM-1 reaches an equilibrium temperature of
•40°C in a quiescent state (no audio signal);
•60°C at a moderate operating level (occasional
limiting);
•75°C at the maximum operating level (continuous
limiting), or at a moderate level with a subwoofer.
If the temperature reaches 85°C, the thermal limiters
activate(see Protection and Limiting )topreventhigh
source levels from further increasing the temperature
and damaging the drivers and electronics. The thermal
limiters provide 30 dB of muting until the temperature
decreases to 75°C.
The HM-1 can be cooled by two fans, available as an
accessory kit. The fans should be used if:
• the HM-1 is enclosed in a soffit or ceiling mount
without adequate space for natural convection;
• the HM-1 is used in hot ambient temperatures or
direct sunlight;
• the user wishes to avoid accidental contact with
the heatsinks if the rear of the HM-1 is exposed.

7
R
E
-
C
I
R
K
-
I
T
P
U
S
H
Installed fans blow air over the heatsinks
The fans attach easily to the two bottom rear corners of
theHM-1.Usea5/32”Allenwrenchtoremovethebottom
screws and install the left and right fans according to the
diagram below. The fans are shipped with a correctly
wired terminal plug keyed for insertion into the fan
connector in the proper orientation only.
The fan speed is temperature controlled. At a heatsink
temperatureof 25°C, the fans turn on at half speed and
increase speed linearly until reaching full speed at
75°C.
Protection and Limiting
The front of the HM-1 has two LEDs that indicate power
and limiter activity. The right LED is green when power is
applied. This LED turns red if thermal limiting occurs
(described in the section Cooling and Fan Installation )
until the temperature decreases to 75°C.
The left LED indicates driver limiter activity with a
variable intensity red color; full illumination occurs at
thermal limiting.

8
• To reduce the risk of electric shock, disconnect the loud-
speakerfromtheACadapterbeforeinstallingaudiocable.
Reconnect the adapter only after making all signal
connections.
• ConnecttheACadaptertoatwo-pole,threewiregrounding
mains receptacle. The receptacle must be connected to a
fuse or circuit breaker. Connection to any other type of
receptacle poses a shock hazard and may violate local
electrical codes.
• Donotinstalltheloudspeakerinwetorhumidlocations.
• Do not allow water or any foreign object to get inside the
loudspeaker. Do not put objects containing liquid on, or
near, the unit.
• To reduce the risk of overheating the loudspeaker, avoid
exposing it to direct sunlight. Do not install the unit near
heat emitting appliances, such as a room heater or stove.
• Thisloudspeakercontainspotentiallyhazardousvoltages.
Do not attempt to disassemble the unit. The unit contains
no user serviceable parts. Repairs should be performed
only by factory trained service personnel.
English Français
Deutsch Español
• UmdieGefahreineselektrischenSchlagesaufeinMinimum
zureduzieren,denLautsprechervomStromnetztrennen,
bevor ggf. ein Audio-Schnittstellensignalkabel
angeschlossenwird.DasNetzkabelerstnachHerstellung
aller Signalverbindungen wieder einstecken.
• Der Lautsprecher an eine geerdete zweipolige
Dreiphasen-Netzsteckdose anschließen. Die Steckdose
muß mit einem geeigneten Abzweigschutz (Sicherung
oder Leistungsschalter) verbunden sein. Der Anschluß
der unterbrechungsfreien Stromversorgung an einen
anderen Steckdosentyp kann zu Stromschlägen führen
und gegen die örtlichen Vorschriften verstoßen.
• Der Lautsprecher nicht an einem Ort aufstellen, an dem
siemitWasseroderübermäßighoher Luftfeuchtigkeit in
Berührung kommen könnte.
• Darauf achten, daß weder Wasser noch Fremdkörper in
das Innere den Lautsprecher eindringen. Keine Objekte,
die Flüssigkeit enthalten, auf oder neben die
unterbrechungsfreie Stromversorgung stellen.
• Um ein Überhitzen dem Lautsprecher zu verhindern,
das Gerät vor direkter Sonneneinstrahlung fernhalten
und nicht in der Nähe von wärmeabstrahlenden
Haushaltsgeräten (z.B. Heizgerät oder Herd) aufstellen.
• Im Inneren diesem Lautsprecher herrschen potentiell
gefährliche Spannungen. Nicht versuchen, das Gerät zu
öffnen.EsenthältkeinevomBenutzerreparierbarenTeile.
Reparaturen dürfen nur von ausgebildetem
Kundenienstpersonal durchgeführt werden.
• Para reducir el riesgo de descarga eléctrica, desconecte
de la red el altoparlante antes de instalar el cable de
señalización de interfaz de la segnale. Vuelva a conectar
el conductor flexible de alimentación solamente una vez
efectuadas todas las interconexiones de señalizatción.
• Conecte el altoparlante a un tomacorriente bipolar y
trifilar con neutro de puesta a tierra. El tomacorriente
debe estar conectado a la protección de derivación
apropiada(yaseaunfusibleoundisyuntor).Laconexión
a cualquier otro tipo de tomacorriente puede constituir
peligrodedescargaeléctricayviolarloscódigoseléctricos
locales.
• No instale el altoparlante en lugares donde haya agua o
humedad excesiva.
• Nodejequeenelaltoparlanteentreaguaniningúnobjeto
extraño. No ponga objetos con líquidos encima de la
unidad ni cerca de ella.
• Parareducirelriesgodesobrecalentamiento,noexponga
la unidad a los rayos directos del sol ni la instale cerca de
artefactos que emiten calor, como estufas o cocinas.
• Este altoparlante contiene niveles de voltaje peligrosos
en potencia. No intente desarmar la unidad, pues no
contiene piezas que puedan ser repardas por el usuario.
Las reparaciones deben efectuarse únicamente por parte
del personal de mantenimiento capacitado en la fábrica.
• Pourréduirelerisqued’électrocution,débranchezlaprise
principale de l’haut-parleur, avant d’installer le câble
d’interface allant à l’audio. Ne rebranchez le bloc
d’alimentationqu’après avoir effectuétoutes lesconnections.
• Branchez l’haut-parleur dans une prise de courant à 3
dérivations (deux pôles et la terre). Cette prise doit être
munie d’une protection adéquate (fusible ou coupe-circuit).
Le branchement dans tout autre genre de prise pourrait
entraîner un risque d’électrocution et peut constituer
une infraction à la réglementation locale concernant les
installations électriques.
• Ne pas installer l’haut-parleur dans un endroit où il y a
de l’eau ou une humidité excessive.
• Nepas laisser del’eau ou tout objet pénétrerdans l’haut-
parleur. Ne pas placer de r´cipients contenant un liquide
sur cet appareil, ni à proximité de celui-ci.
• Pour éviter une surchauffe de l’haut-parleur, conservez-
laàl’abridusoleil.Nepasinstalleràproximitéd’appareils
dégageant de la chaleur tels que radiateurs ou appareils
de chauffage.
• Ce haut-parleur contient des circuits haute tension
présentant un danger. Ne jamais essayer de le démonter.
Il n’y a aucun composant qui puisse être réparé par
l’utilisateur.Touteslesréparationsdoiventêtreeffectuées
par du personnel qualifié et agréé par le constructeur.
Safety Summary
!

9
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, California 94702
Telephone: 510 - 486 - 1166
FAX: 510 - 486 - 8356
E-mail: [email protected]
http://www.meyersound.com
Mounting Specifications
Dimensions
All units in inches
2.25"
2.0"
Permissible to drill to a depth of 1.5"
Permissible to drill in the light grey area
to a depth of 0.75" due to the venting ducts.
The same depth applies to the areas on
the other side of, and underneath the cabinet.
Do not drill in this area
due to the electronics!
The HM-1 does not ship with mounting hardware, but
its 9-ply birch wood construction easily accommodates
a variety of user-installed mounting hardware using
wood screws. Drilling areas and depths are indicated in
the diagram at left. The weight of a single HM-1 is
11.0 lb (5.0 kg).
Do not to drill in the dark grey area due to the presence of
sensitiveamplifierandelectroniccircuitry.Thelightgrey
area indicates the location of the venting ducts that are
essential to the tuning and performance of the enclosure.
The same areas exist on the other side of, and under-
neath the cabinet. It is permissible to drill in these areas
to a depth of 0.75”. It is permissible to drill in the white
area to a depth of 1.5”.
NOTE: All Meyer Sound products must be used in accor-
dance with local, state, federal, and industry regulations.
It is the owner’s and/or user’s responsibility to evaluate
the reliability of any mounting method for their application.
Mounting should be done only by experienced professionals.
HM-1 weighs 11.0 lb (5.0 kg)
11.0
8.4
6.8
8.4
0.6 0.7
8.4
8.4
1.5
12.3
17.5
9.3
Meyer Sound Germany Gmbh
Carl Zeiss Strasse 13
56751 Polch, Germany
Telephone: [phone]
FAX: [phone]