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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => SR Forum Archives => Installed Sound/Contracting FUD Forum Archive => Topic started by: Jim Crews on March 01, 2007, 06:27:50 am

Title: Impedence bridge for laptop???
Post by: Jim Crews on March 01, 2007, 06:27:50 am
Hello all. Does anyone know of an attachement/software for a laptop (usb/232, etc.) for testing 25/70/100v systems? Would be nice to have different tones, fixed and sweeps. We currently use several Goldline ZM-1's but they are expensive and seeing how most of the tech's carry laptop's now also, seems like a no-brainer. Would be nice if it would display like the ZM-1. SIMPLE. Calculated watts/impedence etc..

Jim
Title: Re: Impedence bridge for laptop???
Post by: Tom Young on March 01, 2007, 08:04:53 am
No.

When you look at the small number of stand alone devices that have been available over the decades (Goldline, Sennheiser, TOA), I think the market for this is too small for someone to develope one for PC. Time will tell.

The AudioToolbox (now available from Sencore) does pretty slick impedance over frequency measurements. But it is an expensive multi-measurement system. Plus it is limited to 4900 ohms (I think I got that number right) due to current limits of battery power supply. I think that 70V systems can exceed this value ?

One can construct a voltage divider impedance interface to use with Smaart, etc measurement systems. Smaart has Tech Notes about this.

And finally; LinearX makes the VI box, which allows either voltage or current based impedance measurements with Smaart and other measurement systems.

Title: Re: Impedence bridge for laptop???
Post by: Jim Crews on March 01, 2007, 05:38:12 pm
Guess I should read up on them a little more as I have both, Audio Toolbox (silver one) and Smaart, (Live & Acoustic Tools)
Title: Re: Impedence bridge for laptop???
Post by: Tom Young on March 02, 2007, 10:09:40 am
Yeah, I guess so Wink

The ATB is a very nice way to measure impedance and you are able to send the stored files to another Terralink user via email, which may or may not prove to be handy for you. Doing impedance measurements w the ATB is quicker/simpler than with Smaart. The only drawback to the ATB is the dang current limit (which they do not tell you about unless you ask). But then again, I have only run into this brick wall 2-3 times and only with 70V systems.

There is no such (current) restriction with Smaart impedance measurements.