Cable length will not affect volume level. I don't know just how Toshiba is handling TrueHD decoding or how TrueHD encoding is being done, but it's worth remembering that DVD's are intentionally mastered a lower volume level than CD and VHS (to name two examples) because it allows for more dynamic range. It's also worth noting that DTS is usually mastered at a level about 4dB higher than Dolby Digital.