SM Pro Audio PM8 User manual

2Safety Instructions
SAFETY INSTRUCTIONS
CAUTION: To reduce the risk of electrical shock, do not remove the cover or rear panel of this unit.
Do not expose this appliance to rain or moisture. No user serviceable parts inside.
Please refer servicing to qualified personnel only.
Retain Instructions:
Please retain all safety and operating instructions for future reference.
Ventilation:
Do not impede the flow of air through the ventilation openings. Take care when selecting appropri-
ate installation locations so obstacles do not obscure proper ventilation.
Heat:
This product should be situated away from other heat sources such as fire, high heat emitting
devices, heaters, etc.
Power Source:
Make sure the product is set to the correct voltage for the location in which it is being used.
Grounding and Polarization:
Never defeat the products power grounding means.
Power-Cord Protection:
Power supply cords should be connected or placed in a fashion that could allow possible exposure
to damage. Take care to avoid wear and tear, rubbing, squashing, etc.
Cleaning:
The product should be cleaned only with a soft cloth. Do not use any corrosive products on the unit.
Inactivity:
The power cord of the product should be unplugged from the outlet when left unused for a long
period of time.
Service requirement:
Service by qualified service personnel when:
- The power supply cable has been damaged in any way
- Liquid has been spilled onto or into the product
- The product has been exposed to rain
- The product exhibits faults or obvious performance degradation
- The product has been damaged in a way that exposes components
The user should not attempt to service this product beyond what is described in this operating
manual. All other servicing should be referred to qualified service personnel.

3Foreword - Features
FOREWORD
Dear Customer,
Firstly, we would like to thank you for purchasing our PM8 multi-channel passive summing mixer. With
much thought and effort, our engineers have developed a product we know you will be satisfied with.
The digital recording age has brought with it some great tools for tracking, editing, mastering, and
more. But will all these benefits comes the reality that it can sometimes seem to let us down sonical-
ly. Many recording professionals believe that audio summed digitally seems to compromise the sonic
integrity of their mixes.
Summing is the process whereby multiple audio tracks are mixed together to a common audio output
or outputs. Typically, most multi-track sessions are mixed down to a stereo two-track output. Whilst
digital workstations digitally sum audio signals via computer software, analog summing has tradition-
ally been performed by large format outboard mixing consoles.
Many recording professionals regard analog summing as superior to digital summing and believe it
provides sonic benefits in regard to clarity, punch, better resolution, the ability to record tracks at high-
er sample rates without having to dither down at final mix-down, improved imaging, greater headroom
during mixing, and much more.
The PM8 is a stand-alone unit designed to passively sum up to 8 audio channel outputs from a dig-
ital workstation to a stereo mix. A +24dB internal make up gain stage is provided for two of the three
independent stereo outputs, with a pure passive output also available for users wishing to provide
their own make-up gain device. With pan, mute, and variable volume attenuation controls, mixing
through the PM8 not only delivers that sought after classic analog console sound, but also helps min-
imize the effects of digital summing. Simply the best of both worlds!
Please read this manual thoroughly to best understand the safety and operational procedures
of the PM8.
We hope you enjoy your new PM8 but please don’t blame us if you feel you have to go back through
your body of work and remix everything over again!
Regards,
SM ProAudio
PM8 Main Features
The PM8 is a professional multi-channel passive summing mixer featuring:
Pristine 8 x channel passive mix bus
8 x combo TRS/XLR inputs
1 x 25 pin DSUB input
8 x rotary channel volume attenuator controls
8 x mute switches
8 x rotary pan controls
2 x stereo mix volume attenuator controls
2 x stereo output pairs with +24dB internal make-up gain
1 x stereo passive output (no make-up gain, pure passive)
1 x ground pin connector
110v-230v internal power supply
* It should be pointed out, that extreme output volumes may damage your ears and/or your head-
phone units. Turn down the LEVEL controls before you switch on the unit.

4Table of Contents
TABLE OF CONTENTS
SAFETY INSTRUCTIONS 2
PM8 Main Features and Foreword 3
1. INTRODUCTION 5
2. THE DESIGN 5
2.1 High quality components and design
2.2 Inputs and outputs
3. INSTALLATION 5
3.1 What’s included in the box 5
3.2 Rack-mount installation 5
3.3 Mains Voltage & front panel power switch 6
Mains Voltage 6
Power on/off switch & LED power indicator 6
3.4 Audio Connections 7
Analog Inputs – Combo, Input Link 25pin D-sub 7
Analog outputs – Passive Output, Master 1, Master 2 7
4. FRONT PANEL CONTROLS & INDICATORS 8
4.1 Independent (8x) rotary volume attenuation controls 8
4.2 Independent (8x) LED enabled mute switches 8
4.3 Independent (8x) rotary pan controls 8
4.4 Master 1 & 2 volume attenuator controls 8
5. APPLICATION 8
5.1 General use of the PM8 8
6. SPECIFICATIONS 10
Inputs 10
Outputs 10
Power 10
7. WARRANTY 11
7.1 Warranty card and/or website registration 11
7.2 Warranty 11
7.3 How to request a return authorization number 11
7.4 Warranty regulations 12
7.5 Transferability 12
7.6 Damage claims 12
7.7 Other warranty rights 12

5Introduction - Design - Installation
1. INTRODUCTION
In purchasing the new PM8, you have acquired a multi-channel passive summing mixer of high
class that meets the demands of the home and professional studio. This sturdy 2RU allows for
up to 8 channels of audio to be passively mixed down to a stereo output pair. Each input chan-
nel features its own pan, mute, and rotary volume attenuator control. Eight professional combo
connector inputs (XLR & ¼” TS) and three balanced XLR stereo output pairs can be found on
the rear panel. A 25pin D-SUB connector is also available for direct connection from compati-
ble Tascam and Digidesign systems.
2. THE DESIGN
2.1 High quality components and design
The philosophy behind SM Pro Audio products guarantees a no-compromise circuit design and
fault-tolerant component selection. All SM Pro Audio products go through a rigorous planning and
production procedure from start to finish.
2.2 Inputs and outputs
All inputs and outputs are secured firmly to the exterior chassis housing thus ensuring robust qual-
ity and confidence under all conditions.
3. INSTALLATION
Your SM Pro Audio PM8 was carefully packed in the factory and the packaging was designed to
protect the unit from rough handling. Nevertheless, we recommend that you carefully examine the
packaging and its contents for any signs of physical damage, which may have occurred in transit.
* If you happen to receive a damaged unit, please notify your dealer and the shipping company
immediately.
3.1 What’s included in the box
You should have the following included inside your shipping box:
- 1 x PM8 Multi-channel passive summing mixer
- 1 x Power cable
- 1 x Operational user guide (the one you are reading!)
3.2 Rack-mount installation
The SM Pro Audio PM8 can be used stand alone on your desktop, however it is best installed into
“two” standard 19” compatible audio rack-mount unit spaces.
Please remove all cables (including power) before installing the PM8 into your audio rack.
Sturdy rack mounting ears are present on each side of the PM8’s front panel. Simply mount the
PM8 into an available 2 rack-space position and secure with rack-mount bolts/screws.
* Note: Please take into consideration ventilation of your equipment. A well-ventilated equip-
ment rack will ensure optimum operation and longevity of your equipment. It’s often a good idea
to leave 1 free rack-bay position between your equipment to allow.

6Installation
3.3 Mains Voltage & front panel power switch
Mains Voltage
Important - Before you connect your PM8 to the mains power supply, please make sure that your
local voltage matches the voltage required by the unit!
The PM8 has a professional internal power supply suitable for operation between AC 110/115v –
AC 220/230/240v. A voltage configuration switch on the left hand side of the rear panel should be
set to match the appropriate voltage of your mains power supply. Simply slide the selector switch
with your finger or a small flat-blade screwdriver to either the 115v or 230v position to configure the
unit accordingly.
To connect the PM8 to your mains power source simply connect the included standard
IEC mains power cable to the PM8’s three (3) pin power connector socket.
* If you are utilizing the ‘Passive Output’ pair mains power is NOT required. The
‘Passive Output’ delivers a pure passive attenuated signal. Typically this output would
be connected to a ‘make-up’ gain stage device such as a quality 2 channel outboard
microphone pre-amplifier. If you will be using the PM8’s built in ‘make up’ stage +24dB
outputs (Master 1 & 2 output pairs) then power will be required.
Power on/off switch & LED power indicator
The PM8’s power switch can be found on the right hand side of the front panel.
To enable power to the PM8 or ‘turn on’, simply place the power on/off switch into
the down position. The LED power indicator will illuminate to indicate the PM8’s
operational state as ‘on’ and ready for operation.
To power down or ‘turn off’ the PM8, simply place the power on/off switch into the
up position. The LED power indicator will NOT illuminate to indicate the PM8’s
operational state as ‘off’.
* It’s always good practice to protect your ears, and other audio equipment by taking appropriate
care when powering up any audio equipment. Being aware of your gain structure, and performing
a structured power up sequence with your equipment will help to avoid unexpected audio signals
bursts. It’s a good idea to power up devices in sequence from the start of the signal chain to the
end of the signal chain.
PM8 front panel

7Installation
3.4 Audio Connections
Analog Inputs – Combo, Input Link 25pin D-sub
The PM8 features 8 x combo (XLR & TS) connectors and 1 x 25pin (Input Link) 8-channel D-sub
connector as channel input connectivity options. Typically you would connect the outputs of your
digital audio workstation to your preferred input type.
Combo connectors
The combo connectors accept either XLR or ¼” TRS connector types.
25pin D-Sub ‘Input Link’ connector
The 25pin D-sub connector is wired in a standard Tascam/Digidesign pin con-
figuration. It allows for 8 channels of audio to be connected directly. This is
extremely handy for users who have compatible hardware and can take advan-
tage of the convenience of a single cable connection delivering 8 channels of
audio. Perfect for simple connection and for keeping the studio neat and tidy!
* The D-sub ‘Input Link’signal path is in-line with the Combo input connectors. Both inputs will actu-
ally function simultaneously. Take care with your mixing if you have active signal passing to both
connectors.
Analog outputs – Passive Output, Master 1, Master 2
3 x XLR stereo pair outputs are provided. These outputs deliver the 2 channel summed audio material.
Passive Output
The ‘Passive Output’ is provided
for pure passive transparent mix-
ing without any discernable audio
coloration that electronic circuits
can sometimes exhibit. Typically users will want to connect this output pair to a high quality 2-channel
microphone preamplifier to help compensate for the inherent 20-30dB of signal strength lost during the
passive attenuation and summing process.
Master 1
The Master 1 output pair is a stereo balanced XLR pair delivering the summed signal of the 8 con-
nected input signals.An internal electronic +24dB ‘make-up’gain stage is provided to help compensate
for the inherent loss of signal strength during the passive attenuation and summing process. Volume
attenuation is provided for these outputs via rotating the ‘Master 1’volume attenuator on the front panel.
Master 2
The Master 2 output pair is a stereo balanced XLR pair delivering the summed signal of the 8 con-
nected input signals.An internal electronic +24dB ‘make-up’gain stage is provided to help compensate
for the inherent loss of signal strength during the passive attenuation and summing process. Volume
attenuation is provided for these outputs via rotating the ‘Master 2’volume attenuator on the front panel.
PM8 rear panel

8 Front Panel Controls - Application
4. FRONT PANEL CONTROLS & INDICATORS
4.1 Independent (8x) rotary volume attenuation controls
8 x rotary volume attenuator knobs are provided for independent volume attenuation
of the corresponding channel input signal. They allow precise level adjustments within
1dB from 0 to -40dB.
4.2 Independent (8x) led enabled mute switches
8 x led enabled mute switches are provided for independent channel muting of the cor-
responding channel input signal. When depressed, the switch will illuminate to indicate
channel mute status as ‘on/muted’. This is handy for the simple visual recognition of
the PM8’s channel mute status.
* If using the PM8 without mains power connected (ie, you are using the ‘Passive Outputs’ only –
without the +24dB ‘make-up’ gain stage ouputs), the led enabled mute switched will continue to
function but will NOT illuminate when enabled.
4.3 Independent (8x) rotary pan controls
8 x rotary pan control knobs are provided for stereo positioning of the audio during the summing pro-
cess. Simply rotate the knob to the left or right position while monitoring the stereo outputs as desired.
4.4 Master 1 & 2 volume attenuator controls
Master 1 volume attenuator control
The Master 1 volume attenuator provided volume attenuation to the stereo
summed signal appearing at both the Master 1 and Passive outputs. It
offers precise level adjustments within 1dB from 0 to -40dB.
Master 2 volume attenuator control
The Master 2 volume attenuator provided volume attenuation to the stereo
summed signal appearing at the Master 2 output. It offers precise level
adjustments within 1dB from 0 to -40dB.
5. APPLICATION
5.1 General use of the PM8
Make the necessary input connections
The PM8 is designed to mix the outputs of up to eight channels of audio signal from your DAW
(digital audio workstation). Two choices of inputs are available on the PM8. You can either use
XLR or TRS standard cables to connect each channel individually to the PM8’s combo inputs,
or if you have a compatible Tascam or Digidesign configured multi-pin output device you can
connect eight (8) source signals directly to the ‘Input Link’ 25 pin D-sub connector.
Make the necessary output connections
- Master 1 - We recommend connecting the ‘Master 1’ output pair to your preferred 2-track mix-
down device (DAT machine, back into 2 channels of your DAW, analog recorder, external con-
verters, etc). The Master 1 output pairs is perfect for this function as it features an internal +24dB
make-up gain stage to compensate for the dB loss during the attenuation and summing process.
- Master 2 - We recommend connecting the ‘Master 2’ output pair to your analog monitoring device
(mixer, active monitors, etc). The Master 2 output pairs is perfect for this function as it features an

internal +24dB make-up gain stage to compensate for the dB loss during the attenuation and sum-
ming process.
- Passive Output -As all make-up gain devices do have their own unique sound characteristic, the PM8
also features a ‘Passive Output’ pair for those users wishing to make their own make-up gain device
selection instead of ours. Users can choose their preamplifier of choice to make any necessary dB
compensation adjustment prior to connection to their destination device. Typically users would connect
to a high quality 2-channel microphone preamplifier and then to their 2-track mixing device (DAT
machine, back into 2 channels of your DAW, analog recorder, external converters, etc).
* Note: It is important to note that the ‘Master 1’ volume attenuator control on the front panel
attenuates the summed stereo mix to both the ‘Master 1’ and ‘Passive Output’ output pairs.
Configure your channel settings as desired
Channel control could not be any simpler. Each channel offers a volume level attenuator, pan
control knob, and a mute switch. When monitoring the summed stereo signal, simply adjust each
channels level and pan setting to attain the desired result. Mute switches are provided so as to
disable individual channel signal as required.
A simple mix-down process idea/example
Let’s assume you have a digital recording system comprising of a PC, Cubase software, and a
good quality audio interface featuring 8 individual analog D/A outputs. Your current recording
session comprises of 16 tracks of drums, bass, guitars, keyboards, and vocals.
During mix-down of your previous sessions you may have simply mixed down within Cubase to
two additional internal tracks, or even sent the final stereo mix out the 1&2 individual outputs
(or digital output) to your mix-down recording device (DAT, 2-track analog master recorder, etc).
This method relies on your software summing internally to create the final stereo mix. By group-
ing your audio tracks and connecting your audio interfaces analog outputs to the PM8, you can
passively sum your mix externally.
Suggested output routing of your recording session:
- Output 1&2 - Drums
- Output 3&4 - Keyboards
- Output 5&6 - Guitars
- Output 7&8 – Vocals, Bass
All drum tracks should be panned internally within Cubase to the stereo output pair 1&2. Channels
1&2 on the PM8 should be panned hard left and hard right to retain the stereo separation of the
stereo drum track settings of Cubase.
All Keyboard tracks should be panned internally within Cubase to the stereo output pair 3&4.
Channels 3&4 on the PM8 should be panned hard left and hard right to retain the stereo separa-
tion of the stereo keyboard track settings of Cubase.
All guitar tracks should be panned internally within Cubase to the stereo output pair 5&6. Channels
5&6 on the PM8 should be panned hard left and hard right to retain the stereo separation of the
stereo guitar track settings of Cubase.
As vocals and bass are usually mono recordings, they could be panned hard left and right within
Cubase to the 7&8 output pair. This makes them available separately in the PM8 for stereo posi-
tioning via the respective rotary pan control knobs.
9Application

The ‘Master 1’ output pair could be connected to your choice of 2-channel mix-down recording
device whilst the ‘Master 2’ output pair could be connected to your monitoring solution of choice.
* The individual master level attenuator controls on the front panel allow for independent levels to
be sent to both your 2-track master recording device and your monitoring solution. Of course this
is needed so you can monitor at a different level to what you send to your recording device!
If you choose to use your own make-up gain stage rather than the PM8’s internal +24 dB make-up
gain stage, simply use the ‘Passive Output’pair instead of the ‘Master 1’output pair. You would then
connect to your preferred 2-Channel microphone preamplifier of choice to compensate for dB level
loss during the attenuation and summing process prior to connection to your 2-track final recording
device of choice (DAT, 2-track analog master recorder, etc).
To complete your mix-down simply set your PM8’s channel level controls to achieve the desired
channel level balance required, and attenuate the ‘Master 1’ level attenuator to an acceptable level
for your desired 2-track recording device to accept.
---
By mixing this way through the PM8 you will have minimized some of the digital summing effects
of your Cubase workstation. Like many other audio professionals before you, we believe you too
will be astonished once you hear the difference!
6. SPECIFICATIONS
INPUTS Input channels: 8
Connector: COMBO (XLR / ¼” TRS) & 25pin D-sub
Type: Balanced/unbalanced
Input impedance: 25K
Max input level: +42dB
OUTPUTS Output channels: 6
Connector: XLR
Type: Balanced
Output impedance: 50 ohms balanced
Recommended load impedance: 1300 ohms
Max output level:+24dB
Frequency response: 20-100KHz within 0.5dB
Crosstalk @1kHz: -90dB
POWER Type: Internal 110v-230v
* Power is only required to operate the ‘Master 1’ or ‘Master 2’ output pairs internal ‘make up’ gain
electronics. If passive operation is preferred and you would like to use your own ‘make up’ gain
device, you should use the ‘Passive Output’ pair that does not require mains power connection.
SM Pro Audio is constantly striving to maintain the highest professional standards. Modifications
may be made over time to improve the performance and operation of this unit. As such, specifica-
tions and appearance may differ from those listed or shown.
10 Application - Specifications

11 Warranty
7. WARRANTY
7.1 WARRANTY CARD &/OR WEBSITE REGISTRATION
To be protected by this warranty the purchaser of the product must complete an SM ProAudio prod-
uct registration procedure.
Product registration is available via two methods:
- Complete and return the enclosed warranty card within 14 days of the date of purchase to SM Pro
Audio (see address below).
- Complete an online product registration form at the SM Pro Audio website. www.smproaudio.com
7.2 WARRANTY
- SM Pro Audio warrants the mechanical and electronic components of this product to be free of
defects in material and workmanship for a period of one (1) year from the original date of purchase.
SM Pro Audio will at its sole discretion either repair or replace the product if any defects occur that
are not caused by normal wear or inappropriate use within the warranty period.
- This warranty does not apply if the product has been damaged by negligence, non-authorized mod-
ifications, accident, abuse, misuse, misapplication, or as a result of unauthorized service other than
performed by that of SM Pro Audio’s service department.
- All freight charges incurred for transport of justified warranty claims are at the buyer's expense.
All other warranty claims other than those indicated above are excluded.
7.3 HOW TO REQUEST A RETURN AUTHORIZATION NUMBER
To obtain warranty service, the purchaser must call SM ProAudio during normal business hours
before returning the product (Tel.: [phone]). An SM Pro Audio representative will dis-
cuss any issues with you over the telephone and then issue a return authorization number if
deemed appropriate.
Please ship original shipping cartons along with your return authorization number to the following
address:
SM Pro Audio
Service Department
Warehouse 25
Roberna Business Park
26-28 Roberna St
Moorabbin 3189
Melbourne, Victoria
Australia

7.4 WARRANTY REGULATIONS
- Warranty can only be serviced when accompanying proof of purchase is provided. Dealers invoice
and date stamp required.
- SM Pro Audio will endeavor to repair or replace any product under the terms of this warranty with-
in 30 days of receipt of the product at SM Pro Audio.
- Modifications performed in order to comply with any applicable technical or safety standards in any
country which is not the country for which the product was originally developed and manufactured
shall not be considered a defect in materials or workmanship. SM Pro Audio shall not be held
responsible for any costs incurred or resulting from any such modification whether performed cor-
rectly or not.
- This warranty does not cover defects of parts caused by normal operational wear. These parts are
typically switches, knobs, and other similar components.
Product damage caused by the following conditions are not covered by this warranty:
- Operation of the unit in a way that does not comply with the safety regulations applicable in the
country where the product is used.
- Damages or defects caused by conditions beyond the control of SM Pro Audio.
7.5 WARRANTY TRANSFERABILITY
This warranty is non transferable and available exclusively to the original purchaser.
7.6 DAMAGE CLAIMS
Failure of SM Pro Audio to provide proper warranty service does not entitle the purchaser to
claim further damages. SM Pro Audio’s liability shall in no way exceed the invoiced value of the
product.
7.7 OTHER WARRANTY RIGHTS
This warranty does not exclude or limit any statutory rights provided by national law.
12 Warranty

The information contained in this manual is subject to change without notice.
ALL RIGHTS RESERVED © 2006 SM Pro Audio
SM Pro Audio
Service Department
Warehouse 25
Roberna Business Park
26-28 Roberna St
Moorabbin 3189
Melbourne, Victoria
Australia
PH- [phone]
FAX- [phone]
13 Legal Notice