Has anyone had any experience connecting a microphone to a CSI 2130 analyzer? I have been able to use a 625 voltage adapter plugged into the 25 pin connector at the top of the analyzer with a cable that has BNC (for the 625) on one end and a 1/4" plug for sound input. I had recorded various sounds with a laptop and the played these sounds back while having the 1/4" plug inserted into the headphone jack. It produces quite a nice waveform. I'm using the Advanced Analyze function of the 2130 with just a standard waveform collection in monitor mode. I changed the input from an accel to a microphone and piddled with the sensitivity. Notice that I said "piddled". That means I have no idea what I'm doing. Anyways, how can I connect a microphone to the analyzer to collect audible noise? Any takers??

Recently I used a microphone on a 2120. I guess connecting a mic to a 2120 will not differ much from connecting one to a 2130.

The mic I used needs at least a 15 V supply voltage. The ICP supply from the 2120 delivers that but it did not deliver enough power for this mic (the supply voltage dropped to 8V) so I decided to power the mic with an external (more powerful) ICP supply and to use the voltage input on the 2120.

It worked great. I prepared a measurement setup for sound measurements and I calibrated the setup with a Rion portable calibrator (which is very easy if you follow the steps in the 2120 manual). The A-weighted broad band values we collected were practically identical to the values we measured with a calibrated Rion sound pressure meter and of course all the usual analysis tools worked fine, even peakvue

This message has been edited. Last edited by: Ber van Loon,

Thanks. This is what I was thinking would be the case. I was hoping that the supply voltage from the analyzer would be enough to power the mic, but it seems that this is not so. Oh well.

How did you connect the mic to the 2120? Did you need a special adapter?

I believe B&K makes an ICP microphone preamp. Connect an ICP input to one side and screw an instrumentation microphone to the other for an easy set up. The down side of this approach is cost. Instrumentation microphones aren't cheap and I'm sure the adapter has a normal B&K price tag too.

For identifying characteristics and peaks in audible noise, any microphone will provide decent results. To conduct valid noise level surveys, the more costly method is probably needed to assure valid results.

Jon
Spintelligent Labs

Please note that the supply voltage of the 2120 is enough, it is the power of the ICP supply which was insufficient which caused the voltage to drop.
You may want to check your microphone specifications or post them here, perhaps your mic draws less current.

For only a few bucks I've built an ICP supply which delivers a higher current than the 2120 does and I used a voltage input adapter to connect the ICP plus mic to my 2120.

CSI sells an adapter with headphones that you can use to listen to bearings,gears, etc. It works really well and is not real bulky. I bought one and made a spliter so that I can record on a micro recorder as well.

The adapter is a Model 649 and cost about $1000 with head phones and the whole kit.

We have used several types of ancillary equipment on our 2110 in the past where we have tapped into the battery charging port and used the analyzer batteries for power. We have used microphones and tachs in this way.

If you know the sensativity, or can work it out in terms of volts/engineering unit(in this case dB I suppose) you can run a microphone in exactly the same manner as an accelerometer. If you are using an external power supply, remember to un-check the provide sensor power box in the point set-up, or the 21xx will try and read the data from the wrong pins on the multi-function plug. Microphones work pretty good, I once used one to detect cylinder bore scoring in IC engines. With PeakVue processing to detect the very short duration bursts of high frequency energy, it worked like a dream.