Two Different Sound Cards and 2 Different Results

[Cut-Throat]

I have two Sound Cards (MobilePre and a Tascam US-366) and decided to compare them minutes apart with the exact same Sound System.
Any Speculation on why they are giving different results? Both Sweeps were done with Crossover set at 325 Hz between the Horn and Bass Bins - Blue Line is the Tascam US-366

 

[John Mulcahy]

You'd need to attach the mdat file for any meaningful comment. What do you mean by "Sweeps were done at 325 Hz"?

 

[perceval]

I agree that we need more info.
Need to know the routing used as well.
Was each sound card used for output to amp, and input via mic, or were the sound cards used for input only and output via another step?
Same parameters? etc...

 

[Cut-Throat]

I agree that we need more info.
Need to know the routing used as well.
Was each sound card used for output to amp, and input via mic, or were the sound cards used for input only and output via another step?
Same parameters? etc...

Each Sound Card was used for output to amp and input from the same Mic. Everything stayed in same place. Only the sound cards were swapped. The Sound Cards and their associated Calibration Files were the only Changes... The Cables to the Amps and Mic were the same and in the same place. As well as the Mic, and the Amps, the Room, the Speakers, The Preamp and their associated Cables.

 

[perceval]

so it seems there's some discrepancies within the calibration files.

 

[Cut-Throat]

Why not the Sound Cards themselves? The Calibration files look identical. They're flat.

 

[perceval]

of course, different A/D D/A chips and what not inside will have some impact, that's where calibration files are supposed to come in and smooth out the rough edges of a particular setup, to match things up across different products.
So, the calibration files are the culprit. Or in this case, the lack of customized cal files for the products.

 

[Cut-Throat]

Well, I did create 'Customized cal files' before I used them to measure. Each Sound Card creates its own Cal File. The Cal files did not create themselves.

 

[John Mulcahy]

It is difficult to be sure what was actually used when the measurements were made as you didn't make any device selections in the REW soundcard preferences, so you are relying on the Windows default device setting.

Input noise floor is very high in the first two measurements.

What is the soundcard output connected to? Soundcard output impedance, coupling capacitor size if AC coupled and the input impedance of whatever they are connected to may be factors.

Was the mic on a stand so identically placed for each measurement?

 

[Cut-Throat]

The Sound Cards were both connected to a Dan Sachs 6SN7 Pre-amp..... The Mic Stand was placed identically for both Sound Cards.......

But I have a solution at any rate, as a Friend of Mine Brought over his Sound Card and we did the same measuring as above against my Tascam Sound Card and they Matched. So, I am done 'with this problem', and will just use the Tascam.....

So, thanks for comments...... This thread is finished for me.