I never been happy with Touch pro 2 sound quality. It's definately not up to Ipod Video 5/5.5 gen standards (6 gen ipod known as classic is one of the worst sounding ipods so I won't use it as a reference, imho). The most noticeable difference is in the bass. So I decided to do some measurements and try to correct the bass using built-in equalizer (audio booster) to get the flattest possible frequency response.
BTW I have VZW touch pro 2 running latest Mighty WAR ROM. I used Right Mark Audio Analyzer (there is a free version available on their site if anyone cares) and performed the measurements using test wave file generated by RMAA.
I've tested with EQ off, optimum EQ settings found with and without 3.5mm adapter. Note that VZW TP2 has a dedicated 3.5mm plug, unlike t-mobile version of TP2. I haven't tested my wife's T-mobile TP2, but I will post my results if I find any difference.
Here are the overall results:
Here are the frequency response graphs:
The optimal EQ settings achieved by utilizing Audio Booster (available only when adapter or 3.5mm jack is utilized) with 32Hz band raised to 4dB.
You can use EQ builtin in other media players (i.e. Core Player), but it will affect only sounds played through this application. The advantage of Audio Booster is that it works with all aplications. So if you use Audio Booster don't adjust the EQ in media player (Core Player) otherwise you'll get double effect.
Note that you may get somewhat different results due to different loads presented by headdphones/external amp. I've used M-Audio Transit sound card to perform this measurement.