JVC is modulated at around 38Khz and Sony is modulated at around 40Khz. A composite signal can have only one modulation frequency. For most such combos people have just gotten lucky and the frequencies were the same. You weren't that lucky.
Many devices are very tollerant of wrong frequency. Maybe JVC will work at 40Khz. Maybe Sony will work at 38. Maybe both will work at 39. That last is the most likely and worth trying first. If it doesn't work you need to experiment individually with frequency to see what works.
The crude way to combine such signals is:
1) Pick a middle value between the two wavelength values (6e and 67) and just use that value without worrying about the secondary timing distortion created by changing the wavelength without changing the durations numbers.
2) Make sure at least one of the one-time counts (3'rd number of each: 0001 and 0000) is zero. Otherwise more complication is required.
3) Add together the two repeat counts (the 4'th number of each sample: 0011 and 000d).
So far that gives us a combined header of 0000 006b 0001 001e
4) Follow the header with the body of the two signals (everything after the first four values) one following the other. If one of them had a non zero one-time part (as the JVC did) it must come first. So for vol+ we get
Try that and see how it works. If it basically works but is too slow or jumpy, it might be correctable by reducing the two values (0362 and 0422) that were the ends of the two original strings.
A less crude approach is to combine info from the two MakeHex .irp files to achieve the desired frequency shifts without the undesired duration shifts. Maybe I'll have time to post that later.
The first try might work, or the various frequency, duration and overall speed issues may need experimenting and tweaking, or the experimenting might reveal a problem you can't work around. We don't know how your devices will respond until you try.
