Thank you for the responses. The two decoders that I'm comparing are equipped with the same speakers and enclosures. I considered installing a second speaker, but I think I'll just send the decoder back and let them check it out.
......Paul
Speaker and speaker enclosure are critical in getting good volume out of Digitrax. The last Digitrax I installed had good volume on the horn and bell and somewhat disappointing for motor sound with a different speaker and enclosure. I feel the motor sound is not as loud as a Digitrax from a couple of years ago. With the sound volume you can get from Loksound and Soundtraxx, I'm spending the extra money to get the volume.
Lee
At least in theory you could install a small amplifier to boost the effective loudness and provide at least the possibility of volume-control 'trim'.
This might also, in theory, allow the right dynamic range between whistle, bell, and other sounds, which is one of the critical things separating prototypical from toy-train sound.
I installed a Digitrax SDH166D in one of my HO Proto 2000 SD7 and was happy with the results. Although the sound isn't as good as another SD7 with a TSU decoder, it is completely acceptable. I then purchased a SDXH166D (their Premium 16 bit decoder) to install another identical engine. The sounds are the same, but the volume isn't as loud as the SDH decoder. The prime mover is a hard to hear. So on to my question, Has anyone else experienced this and what did you do about? I contacted Digitrax and they said to return the decoder for repair or replacement. The reason that I'm asking the question is that I've found a couple posts around the internet that this a known problem. If it is, I don't want to send it back only to be told that there is nothing that can be done. Thanks
...........Paul