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Frequiently Asked Questions(FAQ’s)
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1. Why do I need a test cell? There are several reasons:
2. Should I use a modular test cell or build it myself? It depends on your specific needs. Please refer to “The Advantages” section on our web site, then give us a call at 847.362.7440 or 800.472.5952.
3. Should I care about Noise at my property line? Yes…most municipalities and states have noise ordinances that stipulate how much noise can pass over your property line. You must comply with these laws or face fines and/or operating restrictions. Our modular test cells ensure you meet or exceed any noise ordinance.
4. I have an existing test cell but it is too noisy…what can I do? Sound will leak through the path of least resistance. If you constructed a test cell of concrete block and did not use a sound rated door or a sound rated window, the sound is probably leaking through these openings. Hard (non-absorptive) walls and ceilings cause reverberation. This can cause noise levels inside and outside your test cell to increase by up to 10dBA. This sounds twice as loud. You will need to add absorptive panels to the walls or ceiling of your test cell. Please refer to the “Components” section on our web site. If you used all hard surfaced ceilings and walls (such as masonry or drywall) you will need to add absorption to your walls. If you did not use silencers for your intake and exhaust air the noise is escaping out through your ventilation system. Please refer to the “Components” section on our web site… “Sound Control Doors and Windows”, “Absorption Products” and “Silenced Ventilation Systems.” Then give us a call at 847.362.7440 or 800.472.5952.
5. I have other shop noise…what can I do? If your shop has mostly hard surfaced walls and ceilings (masonry or drywall, metal buildings, etc.) you will need to add absorption to your walls. Refer to the “Components” section on our web site… “Absorption Products”. Then give us a call at 847.362.7440 or 800.472.5952.
6. Do I need to use mufflers in my test cell? Our standard Dyno Test Cells include a silenced ventilation with 60” long silencers. If you want to run without mufflers you may need to select our option of providing 120” long silencers. In the end, it depends upon your specific needs. Please give us a call at 847.362.7440 or 800.472.5952 and we can help you with a solution customized to meet your needs.
7. My existing test cell has ventilation problems…what can I do? If you did not use silencers for your intake and exhaust air the noise is leaking out through your ventilation system. Refer to the “Components” section on our website… “Silenced Ventilation Systems”. Then give us a call at 847.362.7440 or 800.472.5952.
8. What is “dBA”? Sound pressure is measured in decibels (dB). The dBA is a weighted measurement that more accurately reflects the way the human ear hears sound. Humans are less sensitive to low frequencies than high frequencies, so the dBA measurement places a higher importance on high frequencies by “weighing” out low frequencies.
9. What is NRC? NRC, or Noise Reduction Coefficient, is the average sound absorption of the four speech interference frequencies (250 Hertz, 500 Hertz, 1000 Hertz, And 2,000 Hertz). A material with an NRC of 0.95 absorbs approximately 95% of the noise that strikes it. That is, it prevents sound from reflecting off it.
10. What is STC? STC, or Sound Transmission Class, is a single number rating of a material’s ability to stop sound from going through it. It is used to rate doors, windows, walls, ceilings, or any other partition between spaces. Generally speaking, the higher the STC rating the greater the sound reduction.
11. What is noise? Noise is unwanted sound. It does not have to be loud, just unwanted. It can be disturbing, it may interfere with communications or it can be hazardous to your health.
12. How loud is my engine or motorcycle?
13. What does a 40 dBA decrease sound like? Every decrease of 10 dBA sounds like the noise is ½ as loud as before. A 40 dBA decrease sounds like the noise has been cut in half four times!
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