I had these for the day to enjoy listening to (was mainly auditioning WA Duettes but asked dealer to bring these along as was curious due to reviews of the DSI200 that had really strange measurements) and was interesting in comparing to other products I have heard.
To clarify I spent a lot of time listening to the ARC gear on my own speakers to get a reference for their characteristic.
One thing that struck me is that I noticed the sound reached its optimum it seems after being on for about 1.5 hours, much more than other gear I have listened to.
Now not sure if it was the LS27 (more likely I assume) or the DS450, but definitely more than some doing serious auditioning may be able to give (would hope if listened to at dealer they would give a lengthy warmup).
Does this fit in with other's perception of the Audio Research and is it the pre or DS450 or both?
Anyway thought I would share the experience.