[RPGWiZaRD]

Can any RMAA experts please guide me through how to set this RMAA up correctly, I know Realtek HD onboard isn't ideal here but I'm only looking to measure frequency response of the ZO2.1 amp (well its bass contour levels) and at least I'd like to know how to set up this correctly.
 
I'm wondering how to connect stuff, like should I connect from line-out (green jack in this case) to the line-in jack (obviously the amp in-between)? What should the volume levels be set like etc. I'm not comfortable trying to figure it out on my own in case I'd be breaking this Realtek HD chip by feeding too strong signal in a way it wasn't meant to etc. Also the "plugged-in device" in the Realtek software, should that still be set headphones/speakers or "line-in" when plugged in like that.

 

[xnor]

Yeah just connect line-out to the amp and the amp to line-in. You can also connect a Y-splitter to the amp and connect one end to the line-in and the other one to a dummy load.

Turn the volume all the way down. Open the playback/recording window and increase the volume until the levels are right. Make sure you've configured DirectSound to use the same format as you're going to test or just generate the test files, play them with your player of choice (fb2k ) and record it again with your tool of choice. You can then analyze the recorded files in rmaa.

 

[RPGWiZaRD]

Well I already did it but I didn't use any "dummy load", ie. headphones as they probably would have played quite loud. I only used the built-in FR test in RMAA but I got what I was looking for.

 

[xnor]

Well you probably don't need to turn it all the way up with headphones as load. But it would show you how the amp handles the load, e.g. in terms of bass roll-off etc. Measuring with line-in as "load" (10 k ohms) will most of the time result in a flat FR (ignoring deviations by the soundcard's line-out/in).

 

[RPGWiZaRD]

Quote:

Well you probably don't need to turn it all the way up with headphones as load. But it would show you how the amp handles the load, e.g. in terms of bass roll-off etc. Measuring with line-in as "load" (10 k ohms) will most of the time result in a flat FR (ignoring deviations by the soundcard's line-out/in).

 
I was just interested in measuring the bass contour levels how they were configured/shaped though on this 32-lvl bass boost amp, and this was perfectly illustrated without the load.
 


 
That's some mad bass boost right there. xD

 

[xnor]

Ah, I see. Yup, that's quite some boost there.

 

[svyr]

regarding dummy load (or rather a real one with disposable-ish headphones), do we just make a connector to put the hp in series and measure after (uuum before?) them? (and the cable going into line in)

 

[stv014]

Quote:

regarding dummy load (or rather a real one with disposable-ish headphones), do we just make a connector to put the hp in series and measure after (uuum before?) them? (and the cable going into line in)

No, the headphones need to be connected parallel with the line input.
 

 

[mikeaj]

Well if you want to test with headphones, it's not like you have to wear them while testing.  

 
I don't think the Realtek output is too powerful; even if the output is powerful, you needn't turn the volume up 100%.  Most headphones can probably handle like 1V just fine, some much more than that.  Check the manufacturer's max power spec to be sure, or just infer from how much power it needs to be loud.  If you're outputting at a level that doesn't even make the headphones go to 110 dB or so, it's probably not going to fry them.  You can check the output level of a device by outputting a 0 dBFS 60 Hz sine wave or so and measuring with a cheap multimeter (use a M/M TRS cable and measure like tip to sleeve or ring to sleeve), which should give you a good enough idea of what you're working with.

 

[xnor]

svyr, in series would cause a total load of ~10 k ohms (line-in) plus the impedance of the headphones. In parallel you get (10000 * R)/(10000 + R) where R is the impedance of your headphones/dummy load.