Wallin jig, sound card and connection problem

[JacquesK]

Hi im very new to all this sound stuff so bear with me...

I build the wallin jig with the 4 switches but it doesnt seem to work at first i had led protection on it but i read some where this causes problems so i took them out.

I have realy tried everything i have been going through the waliin circuit for about 2 hours now and it seems alrigt.

My problem is when i connect the jig to my sound card "onboard" i use rca to miniplug connectors, the sw displays nothing its as if nothing is going trough my jig or my sound card is not capable of working with the program. I have done the sc test in the sw program and i can do all the duplex things and it says my card is fine i mean its a brand new computer 3 months old cost me 20k for goodness sake. Im stuck i have been going through the forums all day but cant find any solutions.

I went to the claudio negros home page follow his volume setup step by step but where he get nice looking sine waves for R and L i get a flat line with a bit of noise so i removed the jig from the computer and the results were the same its like it never even new the jig was there.

[Dave Bullet]

Have you done the tests Eric lists for testing the jig itself? (independent of SW and the sound card connection). If you have a multi-meter - test the resistance levels on the various switch settings as published for the jig.

Make sure your reference resistor checks (I can't recall the jig switch settings) are constant (ie. 4 and 16 ohms respectively). Some switches have variable contact resistance which will render the jig useless.

If the above checks out ok - make sure you are connecting the jig to the line in and not the preamplified mic line in on the soundcard.

The very first test you should be able to do is a loop back (sound card) check in SW. This should produce a nice sine wave.

Have you goit Jay Buttermans unofficial SW manual? The calibration steps using the jig are listed there.

If all else fails - wire up a Claudio Negro cable only jig. At least that will prove your soundcard / use of SW independently of some hidden component issue within the jig.

One more thing to do when verifying jig connections (or any electric circuit for that matter) is work backwards (opposite to the way you soldered / constructed). This stops the mind from "remembering" a mistake in the construction process tricking you into thinking you got it right.

David.

[JacquesK]

Thanks david so far so good i got all those manuals you discribed and checked and rechecked. I got as far as i am getting the signal through the jig and into my sound card but the thing that set me back was eric mentioned in his guide that you must set the X axis of your signal to 10 that caused me to loose the whole signal because it was delayed for some reason by about 25ms so all i saw was noise and a line...

So i played around with the latency and got it to 25ms so now i can actualy see my wave.

Next step for me was to calabrate the jig MAYOR hassle because every time when i measure the ref resistor and series one sw recaulculates it to be in te region of 500k and 500.1k for the jig its weird because those two values allways seems to stays very close together, so maybe i got some dodge solder joints i dont know but i doubt it. I have chect the continuety of the circuit numerous times and i also did the post build ref checks for cal1,cal2,loop and such. Do you recon i should rebuild my circuit and try again or what. Dont know what the fuss is about the jig it only has couple of resstors few switches and some connectors AND A LOT OF HASSLES jeez.

For above mention the calabration i read some where you need to play around with the interchannle delays and lower st sc impedance aswell as add a 1nf cap to the equation but yea dont know enough bout the program t start changing those things.

Just want to get it to work so that i can start designing my speaker thats due for next monday sigh!!!!!

Thanks In advance>>

[Dave Bullet]

Do you recon i should rebuild my circuit and try again or what. Dont know what the fuss is about the jig it only has couple of resstors few switches and some connectors AND A LOT OF HASSLES jeez.

I cannabalised my jig in the end. I ended up getting wild resistance readings for my reference resistors. The 4 ohm setting would read between 6 at best and upto 40 ohms. This was all due to the variable contact resistance of the dodgy switches I was used.

So... I ended up removing all 3 switches. I then crimped some circle lugs on the end of wires and the reference resistors and screw them down on the binding posts supplied with the jig. I can guarantee consistency and the internals are much simpler to use. It is more complicated but easier than the claudio cable jig since I only need my hands to change modes - not a screwdriver for a terminal strip. I'll post some photos tonight to show you what I mean.

Unfortunately you have to get the calibration steps right before you design speakers. Garbage in / out applies here. Otherwise, you'll find errors when you get into speaker modeling / measurement that you can't explain. Get the foundations working and predictable, and then your speaker measurement and xo simulation will be very close to actual measured response.

Yes - you will need to tune interchannel latency. This isn't too hard. Jay;s writeup is pretty good about this. You just need to keep zooming the graph in and tweaking. I think mine ended up being -14usec (that is micro secs).

I also found my card and impulse measurements are very consistent after the PC has warmed up for 10 minutes. So you should only need to occasionally calibrate.

I think you can skip the amplifier calibration. I skipped mine and the speakers I designed (played through another amplifier and measured) were spot on to my simulations using measurements from a different amp altogether. Most solid state amps have a pretty linear FR.

It sounds like to me you should go hard wired with the cable jig or a variant like mine, so you can bed down your SW setup. It's that much harder trying to get 2 new things workign well together when you don't know whether item 1 or 2 is causing the problems.

Keep us posted....

Cheers,
David.

[JacquesK]

I have just rebuilded my wallin jig and started with my calabrations i have done all the tests jay prescribed in his manual. My input signal is 500hz sine wave i attached a print screen copy of the software. The graphs are pretty self explanetory. My right wave has a larger amplitude than my left wave why can that be. Another thing is when i run the channle calibration my resultant wave dos not look like the on in the manual.

ANy help

[Dave Bullet]

I did not see a picture - are you sure you attached it?

My right wave has a larger amplitude than my left wave why can that be

Normally, the left channel will have greater amplitude than the right when going through resistance for the calibration setup. Are you sure you haven't reversed the left in / right in channels to the soundcard by mistake? Normally left is reference / loop (ie. line out direct to line in) - and right goes through the DUT, reference resistors etc....

Another thing is when i run the channle calibration my resultant wave dos not look like the on in the manual.

I can't remember what signal type is used for this (MLS or Sine wave). Can you post an image? If a sine wave, are you getting clipping? (indicating your soundcard playback / recording volumes in Windows are too high)

David.