Matching the factory DCC sound unit for Spectrum K-4

[cacole]

Sound-equipped Bachmann Spectrum locomotives use a SoundTraxx Tsunami decoder, so that is the brand you need to use.

When you get the decoder, it will not have an NMRA 8-pin plug on it, but by carefully cutting away some of the shrink wrap you can remove the solder-in wiring harness and substitute a JST to NMRA short harness.  By doing this, the only soldering necessary will be the two speaker terminals.

[locoi1sa]

  A tsunnami medium steam will be close enough for you. The K4 Bachmann sound decoder is made by the same company that makes the Tsunnami.

[21st Century Limited]

I own a factory sound equipped Bachmann Spectrum K-4 and their DCC ready K-4.  I'd like to install a DCC sound unit that will match the sound of the factory equipped unit since they will be double headed in normal operation.  Any idea on what will be a match?  Thanks in advance.