Buy the Tool instead of paying a shop?

[colin748916]

I used one half of my Koss PortaPro headphones as a microphone. They pick up at 100Hz and well below and the one half is easily placed in a close position to the belt.

[Armor]

How do you know the cheap computer microphone or headphones are giving you accurate readings?

[BK_856er]

How do you know the cheap computer microphone or headphones are giving you accurate readings?

Easy...record and analyze a test tone.  I did this just to satisfy my curiosity and as a reality check of my methods.

BK

[scott_araujo]

Y'all are gettin' way too tech geek.  Get an old school 2 valve and just use an allen key like the rest of us poor slobs.

On a serious note, best thread I've see on this stuff so far.

Scott

[mitt]

I read the belt tension of my DS using my Peterson Strobosoft 2.0 instrument tuning software.

How much and where do you get it.

this thread might be sticky worth with low cost frequency tools.

mitt

[colin748916]

How much and where do you get it.

mitt

This is the software I used. It is what I am familiar with from my profession and it is already in my computer. I am sure there are other options.

http://www.petersontuners.com/index.cfm?category=143&sub=378

[mitt]

This is the software I used. It is what I am familiar with from my profession and it is already in my computer. I am sure there are other options.

http://www.petersontuners.com/index.cfm?category=143&sub=378

thanks - $50 isn't bad for a good software.

mitt

[mitt]

anyone use pitch perfect?

http://www.nch.com.au/tuner/index.html#103

or

aptuner

http://www.aptuner.com/cgi-bin/aptuner/apmain.html

they are free, but I am not sure if they have enough features.

mitt

[mitt]

I realize its free, but IMO Audacity is very clumsy to use for this application.  Maybe I just haven't spent enough time using it, but it seems that you can't get a real-time result.  You need to capture the waveform, then convert it to the frequency domain using the Analysis tool, or compute the frequency directly from the time domain plot.

A real-time spectrum analyzer gives you an instantaneous read-out of the primary frequency as soon as you pluck the belt, along with a plot that shows you how strong the primary frequency is relative to the surrounding noise.  There is also a trigger level control, which causes the instrument to only register a signal that is higher than a chosen level.  You can also save a record of the data on your PC.  I can set the belt tension in < 1 minute this way.  I've been using Virtins Multi Instrument.  Its free for a few weeks, but is $50 to buy it if it works out for you.

I've no vested interest in anyone buying this software, but I do think it works great for this application:
http://www.virtins.com/

This is what the output looks like, saved from setting the tension on my 2V engine.  You can see that the frequency is reported to be 108Hz, right above the frequency domain plot:

Ivan - what do you use to input the sound?  I see they sell sound card kits with a probe, but is that required or optional?

mitt