I agree with Fred about levels. If the pro equipment is expecting 0dBm into 600 Ohms, not all consumer equipment will appreciate this. Some of the older consumer equipment will barely reach 0.5V into a few thousand Ohms.

And I agree with Ernie too. Cooking up a valid A-B comparison is surprisingly difficult because fractional dB differences in level will tilt the comparison.

Early in my audio career I worked for a (now defunct) retail chain. On the first day of salesman training one was introduced to the level match system for A-B testing and shown how critical the level match was. On day two we were introduced to the idea that this could be used to sell the "right" speaker (the high margin speaker in stock). Commissions and bonuses were more likely for sales people who sold what was in stock.