Hi Eric,
Many thanks for your reply it is very useful and we appreciate your contribution but I am still unclear.
I am about to invest in USB audio equipment, I frequently fly and travel so having minimal bits of kit is useful although I fully appreciate that the headphones wiring are the weak point - so Lyndsey's question is fab. Most calibration companies won't accept an audiometer without the headphones that are used with it and they say that calibration cert/results only apply to that 'set'. I understand all that you say but can you explain how the USB audios work?
There is one oscilla 300IB 'USB audiometer' and the Otosure (not advertising, just for clarification) where there is a small handheld unit into which the headphones and patient button plugs, with the unit then connecting to the laptop.
So, I am assuming the unit creates the tones and the laptop software is simply recording etc??
So should this be calibrated by sending to a company that has the Oscilla-Otosure kit for audios or is generic kit available - i.e. what questions do we need to ask the calibrating company to ensure they are doing what is required rather than visual inspection?
Can these unit's calibration be adjusted as you described in your previous email or if out of calibration is it generally possible to replace the chip or is the whole unit defunct?
Alternatively, for the Oscilla 310/330 audio machines where there is just a laptop and a set of headphones - apart from ensuring that software updates are installed, how can these be calibrated if you do not have the laptop whose audio card I am assuming is producing the tones?
Surely the quality of the laptop and components affects the quality/volume of the tones heard through the headset??
The manufacturers brochures do not specify any particular laptop/tablet specification.
Is the only option for the engineer to come to us to test or we go to them - we could not leave them unattended with the laptop due to the confidential nature of the information on the laptop......?
Rather than just using a subjective self-test should we be using a calibrated test head (audio equivalent to a 3l syringe, the only one I can find is the ER75 acoustic ear simulator - are there any others suitable for this role?) at frequent intervals. We need to demonstrate what we are doing is 'reasonable' based on the best available method in our setting for the screening equipment available.
(Lyndsey - re USB spiro - apparently, the calibration bit depends on the type of head - does it have a fan that spins or no moveable parts? I was told by a rep recently that the 'doesn't need calibration' means that there is nothing they can actually adjust, not that it doesn't need checking. I stayed with a rep once when he calibrated a spirometer - All he did is use a 3l syringe as well and records it on a certificate - which has to be calibrated of course ;0) - I think I'll pass on taking a 3l on an airplane imagine trying to get that through security!!)
Thanks Eric and all, crikey, I need coffee (hey, just realised it is snowing here!)
Catherine
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