Optimal Audio SUB15-B Low Profile Sub Bass Loudspeaker User Guide
- June 4, 2024
- Optimal Audio
Table of Contents
USER GUIDE
SUB15-B Low Profile Sub Bass Loudspeaker
Sub
Loudspeaker
Congratulations on your choice of Optimal Audio for your latest sound system installation.
The Optimal Audio range of compatible audio zoners, amplifiers, and
loudspeakers are designed to work together simply and effectively. Our quick
start guides will take you through the simple connection and setup procedure.
Optimal Audio Sub loudspeakers are designed to extend the low-frequency
performance of cuboids.
When used in conjunction with the rest of the Optimal Audio eco-system Sub
will surprise you with its punchy performance and professional aesthetic. This
Quick Start Guide will help you get your Subs rigged, positioned and connected
correctly.
Sub 10 and Sub 15 are passive, low-frequency loudspeakers. Each model consists
of a single driver loaded into a compact bass-reflex cabinet.
The loudspeaker has no internal electronic cross-over network and requires the
use of a DSP preset to ensure the loudspeaker is fed with an appropriate
signal.
This can be achieved via external DSP processing or by using a dedicated
preset in SmartAmp 30 (Sub 10 only).
Sub loudspeakers are often mounted on the floor and for good reason. Sub 10 is
particularly suitable for placing discreetly under banquette seating. Floor
mounting increases low-frequency efficiency due to the acoustic energy being
reflected from the plane of the floor. The proximity of the cabinet to the
floor, and the fact that low-frequency sound waves are long, means that the
reflected energy couples with the direct output without cancellation, adding
the acoustic power back to the wavefronts rather than it dispersing or
reflecting back from more distant surfaces and causing cancellation.
Sub can be also mounted on a wall or suspended from a ceiling using the
dedicated Sub Brackets, or M8 eyebolts and steel wire rope. These are
available separately as Optimal Audio accessories. Be sure to connect up
before mounting against a wall!
It is critical that the structure to which Sub is to be mounted is suitable
for taking the weight of the loudspeaker/bracket assembly. It is highly
recommended that a secondary safety fixing be fitted. This can be achieved
using a suitable rated eyebolt and rated safety chain or steel wire rope fixed
to an M8 eyebolt screwed into one of the M8 fittings.
Sub Loudspeaker alignment
To get the best out of your Optimal Audio loudspeaker system, it’s well worth
considering how best to align Subs with your Cuboids, depending on the
relative placement of the sub-bass and higher frequency elements of the
system.
If you are able to deploy Sub and Cuboid in close proximity to each other,
this is the best possible option as they essentially work together as one
speaker – Sub extending the low-frequency response. Ensure the grilles are
perfectly aligned with each other to get the best coupling.
In many cases, Cuboid will be wall or ceiling mounted and Sub placed on the
floor. From the point of view of the ideal listening position, the two
cabinets are not the same distance away, which can lead to destructive
interference at crossover frequency at worst, and loss of transient detail and
low-frequency punch.
The system can be optimized by applying delay to the cabinet that is closer to
a given listening position, usually halfway into the coverage area. This will
always be a compromise everywhere else, but to a much smaller degree if good
alignment is in place.
In this example, the Cuboid has been wall-mounted, and Sub is on the floor.
Decide on a Recommended Listening Position (RLP), usually halfway through the
coverage area. Measure the distance to each speaker.
Here, Cuboid is 0.9m closer than Sub.
Using the formula distance/speed of sound (334m/s @ 20 degrees C), Cuboid
should be delayed by 0.9/334 = 2.6 milliseconds.
Connecting Up
All Sub loudspeakers are fitted with Euroblock connectors. These have two
pairs of terminals.
Sub uses only 1 and 2. Pins 3 & 4 are linked to pins 1 & 2 respectively and
provide an easy way of connecting to a further Sub. No more than two Subs
should be connected to a single amplifier channel.
For connection, we recommend using a flexible cable with a minimum cross-
sectional area of 2.5mm². When wiring loudspeaker cables are careful to
observe the correct polarity of the cable and connector at both ends.
Matching Speakers and Amplifiers
To get the best from your loudspeakers, it’s important to make sure the
amplifier you are using is up to the job. Several factors have to be
considered, and it’s worth clarifying what they mean and how they affect the
performance of a loudspeaker.
Loudspeakers tend to be quantified using Watts, but this is purely a measure
of the amount of power a loudspeaker can take at its input over time, and not
necessarily a measurement of how loud it might go.
Optimal Audio loudspeaker power handling is therefore quoted as Watts (AES)
and Watts (Peak), Peak delivering 6dB(SPL) acoustic output higher than AES
(AES2-2012 standard) and referring to the loudest transients a loudspeaker can
handle without distortion.
In Watts, this means that the peak power handling of a Sub 10 for example is
1000W, four times its continuous power handling of 250W.
So, give a Sub 10 250W of continuous power and you will get 121dB(SPL) out of
it if you are standing 1m away from it. It will however be able to deliver
transient peaks in the audio signal at 127dB(SPL(@1m, half space)) without
distortion or damage.
What this all means is that for the best performance from your loudspeaker,
make sure you have an amplifier that is capable of delivering more than a
loudspeaker’s rated AES power handling ability at the nominal impedance of the
loudspeaker – 8 Ohms in the case of all Sub speakers. A 250W amplifier will
deliver 121dB(SPL) from a Sub 10 and nothing more, but a more powerful
amplifier will have the headroom to deliver short musical transients at higher
levels, thereby ensuring that faithful reproduction of the program material is
maintained.
Specifications
| Sub 10| Sub 15
---|---|---
TYPE| Sub-bass loudspeaker :| Sub-bass loudspeaker
FREQUENCY RESPONSE (with preset)| 50Hz – 150Hz ± 3dB ,
-10dB @42Hz| 45Hz – 150Hz ± 3dB -10dB @40Hz
DRIVERS| LF: 10″ (250mm) ,| LF: 15″ (380mm)
RATED POWER| 250W (AES) 1000W (peak) .| 500W (AES) 2000W (peak)
NOMINAL IMPEDANCE| 8Ω| 8Ω
SENSITIVITY (1W/1m)| 97dB (half space) ‘| 102dB (half space)
MAXIMUM SPL| 121dB (cot), 127dB (peak) (half space) .| 129dB (cot). 135dB
(peak) (half space)
CROSSOVER| n/a| n/a
DISPERSION (-6dB)| n/a| n/a
ENCLOSURE| Plywood| Plywood
FINISH| Black textured paint.| Black textured paint
PROTECTIVE GRILLE| Perforated steel| Perforated steel
CONNECTORS| Euroblock type| Euroblock type
PIN CONNECTIONS (INPUT)| 1+ 1-| 1+ 1-
FITTINGS| 12 x M8, inset bolts| 12 x M8. inset bolts
DIMENSIONS| (W) 470mn»c (H) 297mm x (D) 353mm
(W) 18.50″ x (H) 11.7″ x (D) 13.9″| (W) 716mm x (H) 443mm x (0) 480mm (W)
28.19″ x (H) 17.4″ x (D) 18.9″
WEIGHT| 12.9kg (28.41b)| 34.3kg (75.61b)
ACCESSORIES (available separately)| Sub bracket (pair), M8 eye bolt| M8 eye
bolt
WARNING!
DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE
This symbol is intended to alert the user to the presence of important
operating and maintenance (servicing) instructions in the literature
accompanying the appliance.
CAUTION
THE RISK OF ELECTRIC SHOCK DOES NOT OPEN
This symbol is intended to alert the user to the presence of uninsulated
“dangerous voltage” within the product’s enclosure that may be of sufficient
magnitude to constitute a risk of electric shock to persons.
Important Safety Instructions
- Read these instructions.
- Keep these instructions.
- Heed all warnings.
- Follow all instructions.
- Do not use this apparatus near water.
- Clean only with a dry cloth.
- Do not block any ventilation opening. Install in accordance with the manufacturer’s instructions.
- Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
- Protect the loudspeaker cable from being walked on or pinched particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.
- Do not unplug the unit by pulling on the loudspeaker cable, use the plug.
- Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.
- The apparatus shall not be exposed to dripping or splashing and no objects filled with liquids, such as vases, shall be placed on the apparatus.
- Do not remove any covers, loosen any fixings or allow items to enter any aperture.
- Ensure the loudspeaker is mounted with appropriately sized fixings of suitable load-bearing capacity
- Always ensure a secondary safety fixing is used where loudspeakers are mounted overhead.
Relax, It’s Optimal Audio.
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Optimal Audio Group Ltd.
Century Point, Halifax Road,
Cressex Business Park,
High Wycombe,
Buckinghamshire,
HP12 3SL
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