QSOURCES Qohm2 Installation instructions
INFRA-QSOURCES
User Instruction
Qohm2 Monopole sound source
Updated: 181115 – batch A
By: LMB, JGL, Qsources BVBA
Content:
1. Intended application
2. lacing the source on a stand or tripod
3. Connections and powering
4. Warranty and liability
5. revent damage
6. Specifications and conformity declaration
7. Questions and Answers
8. Shipment instruction
Please always use ear protection when working with this product.
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1. Intended application
The 2-driver sound sources are optimized for low to medium
frequency measurement applications with better than +- 2 dB
omnidircetionality in 3D up to 5600 Hz. The Qohm2 source
easily satisfies the ISO140 and ISO 3382, ISO 16283-1 and 354
requirements.
The intended frequency range for high noise levels is from the
50 Hz third octave band till the 16 kHz third octave band. It is
possible to use the source at lower frequencies, with reduced
level. Wide band signals like white noise, pink noise, chirps etc.
can be used as well as sine signals.
The source is intended for use indoors, or in any moderate
moisture and moderate temperature environment. If exposure
to splash water or severe humidity is unavoidable, the source
can be wrapped in a thin plasic bag. However, this will resitrict
cooling and therefore the level and/or duration of operation
should be reduced. If used for music reproduction, it is advised
to keep the Qohm2 sources clear of walls, floor by at least 1
meter for a natural effect.
2. Placing the source on a tripod or other stand
Qohm2 is provided with a specifically adjusted light weight tripod for secure mounting of the
sound source.
Two sockets with M8 thread are available. These will fit to any M8 bolt or thread-end like the
provided tread-ends. Same for the tripod. Tightening of the M8 should be done by hand,
preferably. But a number 13 mm tool can also be used with care. Do not apply a torque higher
than 4 Nm.
A support or tripod can only support the source if the underground is stable and horizontal,
the spread of the legs is wide enough to allow the height, if the cables are protected against
tugging. And, any tripod can malfunction or slip. Make sure the set-up is secure.
The sources can also be placed on the circular handle, using it as a short support, but it should
only be done with the cable secured to the underground and only on a completely stable
underground.
3. Connections and powering
The sources as a standard have a neurik 2 pole socket.
To remove, turn the plug a few degrees and pull it out.
The plug should be easy to extract, when rotated at the right angle
The Qohm2 has a thermal protection and a overcurrent protection. When a
protection activates the maximum output level decreases to a level which
is much lower than the normal maximum level. Some lower level signal is
still allowed to go to the source. This lower level indicates that the source
is still working, but needs a cool down. So the level needs to be turned
down to allow it to recover and for the protection to reset.
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4. Pre ent damage
We have implemented protections. These protection will allow normal use of the sources for
their intended measurement application or for music replay at moderate levels. However, the
protection is not absolute, because that could restrict normal use.
Although highly exceptional, a special environment, special signals/ loud music signals or a fault
in the amplifier can cause damage. It is expected that the user remains vigilant and the user
retains responsibility to prevent damage.
A. rotect the source from impact loads in use and in shipment:
–
Secure the tripod and cable, when near moving persons
–
The provided soft-bag and felt pouches are intended for personal handling
in/out of a car or train etc.
–
The softbag is not intended for shipment by air, truck, or any commercial shipment.
B. If the sound from the source changes suddenly;
–
there is more than 3 dB loss of low frequency output,
–
the sound becomes clearly distorted,
–
a sharp or rattling noise occurs,
–
or some speaker parts come loose and visibly move
it probably indicates a beginning damage. In any of these cases further use should be suspen-
ded immediately, and it is advised to contact our support and/or send the source in for dia-
gnosis. Continued use when a beginning damage occurred will likely cause secondary damages
to all speakers and can cause out of warranty damages.
C. Do not expose the sources to:
–
water or other fluids
–
shocks in excess of a drop of 10cm height or equivalent
–
temperatures above 50 degrees Celsius
–
temperatures below -20 degrees Celsius
–
direct sunlight over longer duration.(It will reduce the life span)
If exposure to rain/splash-water/severe humidity/overnight condensation/severe dust or
powder/etc. or garbage bag) is unavoidable, then the source can be used inside a thin plasic
bag. (Like a disposable shopping bag) at own risk. A thin plastic bag should never allow sub-
merging the source in water or excessive dust or powder. The lack of cooling in the bag will
reduce the maximum allowable sound power level substantially.
D. Do not place the sound sources on soiled surfaces.
Especially not on surfaces with metal scraps, -chips or
-powder. Still, If metal objects have accumulated on the mag-
net, they should be removed as soon as possible. This can be
done with adhesive tape or putty/clay as shown in the
photo.
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5. Technical specification*
Frequency range: 50-16000 Hz
Omni-directionality: +-2 dB from 50-5600 Hz
Sound power level: 108 dB S L, 2 minutes** | 116 dB S L, 15 minutes**
Output level stability: better than 0.5dB during 10 minutes at 101dB**
Mounting thread: M8
Dimension, weight: 107mm diameter (285mm Height), 1.3 Kg (+-0,1 Kg)
ower requirement: 200 Watt RMS to 4 Ohm***
*These specifications may be adapted if necessary to improve the quality of the product.
**When driven with Qam generated low crest-factor pink noise at 22 Celsius ambient temperature or lower.
*** For maximum performance a dedicated power amplifier type Qam or Qca is available from Infra-Qsources.
The source output spectrum for white and pink noise in free field condition are shown below.
The sliding 30 degrees averaged directionality is given in the graphs below for 1/3 octave and
octave bands.
6. Warranty and Liability
Qsources stands highly on product quality and provides two years full warranty on all supplied
materials, workmanship and early failure in normal use, from date of delivery, with the
following conditions:
Mechanical damages due to non-careful handling, transportation, excessive
environmental conditions, etc. are excluded from warranty.
Electric overload due to excessive voltage, overheating, are excluded from warranty
In case of a need of service under warrantee or other, the user is responsible for
shipment to and from Qsources in Belgium,
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ISO
Declaration of conformity
roduct:
Infra Qsources omni-directional mid frequency sound source
Model:
Qohm2
Hereby is certified that the above mentioned product complies with the following
standards:
ISO 3382
ISO 140-3
ISO 140-4
ISO 16283-1
Responsible for this declaration is the producer
Qsources BVBA
Ketelwinning 38
3290 Diest Belgium
Declared by
. J. G. van der Linden
Diest, October 2018
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Ketelwinning 38 B-3290 Diest Belgium
Copyright Qsources BVBA
7. Questions and Answers
How long does it take for the source to cool down?
If the source is used at the absolute maximum levels, such as 108 dB sound power level pink
noise, then it will typically run for 2 minutes before protection occurs. But this time could be
longer or shorter depending on ambient temperature and the type of signal. The protection
will typically take 12 minutes to recover for a new test.
It is wise to turn the source on only for short periods during range selection and during tests;
Most of the users typically need only a measurement of 1/2 minute at maximum power, in
most cases. Then reposition microphone or source and again 1/2 minute test, reposition, 1/2
minute test, etc. In that way the temperature will not easily become critical.
How to notice the temperature protection?
When the temperature protection becomes active some lower level signal is still allowed to
go to the source. In that case the noise level is far below the normal maximum level, and even
more restricted when the power of the amp goes up. This lower level indicates that the
source is still working. But it needs a cool down. So the level needs to be turned down to al-
low it to recover and for the protection to reset.
What can I do when a longer continuous measurement duration is desired?
Do not try to cool the source with water nor with a ventilator pointed directly at the source.
These will cause permanent damage. However, adding external cooling of the source with
multiple fans is an option. It is required to create a very even spread of the flow around the
source fans. This could extend the active time up to 20%.
The effective measurement duration depends on the setting and the type of signal that is be-
ing used:
•very slow sine sweeps (slower than doubling the frequency every 10 seconds, or +- 1
minute for the full frequency range) are not advised because it may cause damage.
•Although uncommon to use, a slow sine sweep downwards in frequency is not advised
to use at all, because it can induce damage.
•as white noise has the shortest active time at full power, we did some more tests on
this setting. It shows that a 2 dB lower sound power level can triple the possible mea-
surement time.
•when using your own external signals, it is worthwhile to try best level-time combina-
tion before going on-site for tests
Can we use the source in a dirty environment?
Usage in dirty environment should always be done with extreme care and at own risk. We
here by provide some suggestions:
•Bring some foil or paper to place under the tripod and cables. And bring a plastic foil
or cloth to place over the equipment.
•If there is dust floating in the test space or light moisture, there is no problem. This
should also not require any cleaning after a few hours of tests.
•If you have trouble keeping you own clothes clean and dry because of dust, or water,
then you will need to protect the source with a enclosing thin plastic bag. (This is a
fairly normal procedure) This will take away 1 or 2 dB and it limits the measurement
time before thermam protcetion activates to 1/3 of normal.
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•If you forget the source in a dust environment:gently blow the dust from the speakers.
Do not use a nozzle from a compressor. Do not use a vacuum cleaner tube near the
moving diafragm of the speakers, because it can easily damage the source.
•If you forget the source outside in the rain until it is soaked then let is dry at room
temperature. Do not place it against a heating. Drying will takemultiple days. If the
amount of water was limited and clean, then the source may work well again. Check
this with a microphone near each individual speaker and compare the 3rd octave band
or narrow band curves. lace the source on a soft surface with one speaker upwards,
and place the microphone against the center. Run the source at a relatively low level.
Measure spectrum at a fixed amplifier setting with pink or white noise. Repeat this for
all speakers and compare the differences to the allowable spread within the ISO stan-
dard. The spread should be well below the standard. In case of doubtful results, clear
deformation of the moving parts it is best to send the source back for verification.
What to do when one of the two speakers, or the housing, is damaged?
To prevent damage amplification, it is necessary to stop using the source immediately when a
strange sound or loss of power occurs. Never use the source a high output level if you suspect
damage.
In doubt, to verify, place the source on a soft surface with one speaker upwards, and place the
microphone at the magnet. Run the source at a relatively low level. Measure spectrum at a
fixed amplifier setting with pink or white noise. Repeat this for all speakers and compare the
differences to the allowable spread within the ISO standard. The spread should be well below
the standard.
Never continue to use the source if in broken condition. It will aggravate the damage and in-
crease the repair costs significantly, and can cause exclusion from warranty.
When using an external input signal, could I damage the Qohm2 source or the Qam/Qca am-
plifier?
The Qam/Qca amplifier input will withstand any type of normal signal coming from any
measurement device or computer on the headphone outlet. The output of the Qam/Qca
amplifier will just try to follow the input signal up to ss 0.35V.
However if mains power is somehow in contact with the input, or if the power output of the
amplifier, or of another amplifier is in contact with the input BNC, then this will damage the
amplfier.
The Qohm2 sound source will also withstand normal test signal at a reasonable level in combi-
nation with a Qam/Qca amplifier. Some signals could be applied at maximum level of a
Qam/Qca amplifier until the source internal protection activates. But manynormal signals do
not allow a maximum level setting on the amplifier.
For example, not exhaustive, the following signals could lead to damage when applied with
maximum level, before the source internal protection activates:
–pulsed low frequency random or sine below 500 Hz, over-stroke
–sine signals below 300 Hz, over-stroke
–random noise or sine signals above 20000 Hz, local overheating
Over stroke; cone displacements above 8 mm peak-to-peak are audible as a sharp clicking
sound.
When using another type of amplifier, damage is possible if the peak voltage exceeds 70 V
ssph, even with normal test signals like sine, chirps, random.
The user should be careful not to exceed the short term power and prevent overstroke.
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Could we use any power amplifier and signal source to drive a Qohm2 sound source?
In principle, any audio or public address or measurement amplifier for loads between 2 and 8
Ohm impedance can be used. And in principle any type of signal; random, music, sines, chirps
etc can be used.
But, there are some risks or limitations when not using a Qam/Qca amplifier;
•Sine signals from external sources, can quickly heat up the Qohm2 and trigger the
internal protection.
•Clicks or short impulsive signals could potentially lead to mechanical damage of the
drivers. But these are uncommon to use for measurements.
Some amplifiers, proposed by other measurement equipment manufactorers for dodecahe-
dron sources, actually connect two or more channels to the dodecahedron. The Qohm2 uses
one high power channel. So, in such a case only one channel should be connected to the input
speakon socket of the Qohm2, and only the output power on this one channel will contribute.
Leaving the other channels unused (open) will not harm a normal amplifier.
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INFRA-QSOURCES
Shipment protection instruction
Infra-Qsources sound sources & equipment
Date: 140619
By: JGL
Carrier personnel does not have the luxury,
nor attitude, to be careful even if boxes are
clearly marked “fragile”
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Shipment in carton boxes:
Make sure that the equipment is inside the supplied cloth bag or in a soft clean plastic bag,
before adding any other protection. This will protect the equipment from intrusion of
wrapping materials and scratches etc.
•A layer of at least 6 cm of impact shock absorbent material is needed all around
the equipment, and at least 2 cm in-between equipment. Suitable materials in
combination with carton boxes are :
•Closed cell polythene foam
•Expanded poly-styrene foam
•Self expanding olyurethane foam in plastic wrap
•bubble plastic foil
•thicker layers of wrinkled paper or carton
Unsuitable materials are:
•extruded polystyrene foam
•polyether foam and other soft ply-able foams
Foam peanuts can be used as a secondary filling of voids, because filling the carton boxes
completely with material improves the protection.
Use two layers of carton boxes to improve the protection against intrusion of pointed objects.
The inner box must be sufficiently large to cover the equipment (including all protrusions) with
a layer of material of at least2- 3 cm thickness. The outer box must be sufficiently large for
another layer of at least 2 cm. And important, the overall thickness from equipment to outer
box must be more than 6 cm all around.
Carton boxes need tape at all slits, and all around all corners and edges to reach a sufficient
strength.
Even though it has a limited effect on the treatment by carrier personnel, it is necessary to
have clearly visible “fragile” markings on the outside of the box. The carrier must be informed
that they are handling sensitive equipment. lace a 25G (yellow) Shock-watch label on a paper
or plastic sheet against the equipment.
ictures help to support a claim and prevent costs, and the effort is very limited. Set the
camera so the date shows, and make sure that the date is correct. Take pictures of the equip-
ment when successively protecting from the visible equipment till the ready and marked box.
Make sure to have a picture of the shock watch label too.
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Copyright Qsources BVBA
Shipment in flight cases:
Make sure that the equipment is inside the supplied cloth bag or in a soft plastic bag, before
adding any other protection or placing it in a flight case. This will protect the equipment from
intrusion of wrapping materials and scratches etc.
To prevent high impact loads on equipment inside a strong flight case, a layer of at least 6 cm
of impact shock absorbent material is needed all around the equipment, and at least 6 cm in-
between equipment. Suitable materials are :
•Closed cell polythene foam
•Expanded poly-styrene foam
•Self expanding olyurethane foam in plastic wrap
Unsuitable materials are (unless these materials are used as a secondary filling of voids):
•extruded polystyrene foam
•paper or carton
•polyether foam and other soft ply-able foams
•foam peanuts
The shock absorbent foam material should also have some voids and should not fit too well
around the equipment too. It should allow some setting and deformation. (see the box-shaped
amplifier in the sketch below.
To prevent damage the locks and clamps and corner reinforcements need to be strong enough
to remain closed even if a part of the flight case is damaged. After each use check the
condition of the corner reinforcements and locks and clamps. Replace when damaged.
Even though it is has a limited effect on the treatment by carrier personal, it is necessary to
have clearly visible “fragile” markings on the outside of the flight case. The carrier must be
informed that they are handling sensitive equipment. lace a 25G (yellow) shock-watch label
on a paper or plastic sheet against the equipment.
ictures help to support a claim and prevent costs, and the effort is very limited. Set the
camera so the date shows, and make sure that the date is correct. Take pictures of the equip-
ment in the fight case when successively protecting from the visible equipment till the ready
and marked flight case Make sure to have a picture of the shock-watch label too.
It is actually more difficult to protect the equipement in a flight-case because the hard outer
shell can cause high peak accelaration levels on the equipment inside.
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Soft poly-ether foam and other soft foams are not suitable because they do not absorb energy.
Foam peanuts are not suitable on its own. But it can be used to fill voids between other
material.
Self forming polyurethane foam is suitable for carton box and flight cases. But the material
can wear.
Expanded poly-styrene foam is suitable for carton and flight cases, but it will wear off quickly
in flight cases. Extruded poly-styrene foam however is too hard, and too elastic, for equipment
purposes.
Closed cell polythene foams are suitable for flight cases and for carton box shipment. The
material is available in various colours and cell sizes.
Bubble foil is suitable for single or limited cycle use in combination with carton boxes.
Thank you for helping us protect the Infra-Qsources equipment.
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Ketelwinning 38 B-3290 Diest Belgium
Copyright Qsources BVBA
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