I believe the "famous" measurements referenced by Geoff are from the paper linked below;
http://www.hifi-tuning.com/pdf/wlfr.eng.pdf
For an even more enthusiastic testimonial about audible improvements, refer to the Positive Feedback Issue 51 article by Myles B. Astor;
https://positive-feedback.com/Issue51/hifi_tuning.htm
Draw your own conclusions.
http://www.hifi-tuning.com/pdf/wlfr.eng.pdf
For an even more enthusiastic testimonial about audible improvements, refer to the Positive Feedback Issue 51 article by Myles B. Astor;
https://positive-feedback.com/Issue51/hifi_tuning.htm
Draw your own conclusions.