“Wim van Keulen is als deskundige op geluidsproblematiek wegdekken een uitermate scherpzinnige en deskundige consultant. Hij weet en de regelgeving en de meetmeetthoden op de juiste wijze uit te te leggen en meetresultaten kritisch op waarde te schatten. 
Bij innovatieve projecten en/of bij afwijkingen durft hij out of box oplossingen aan te dragen die voor opdrachtgever en -nemer in de wegenbouw tot tevredenheid leiden. 
Bij echte geluidsvraagstukken is deze deskundige een eerste aanspreekpunt.”

“Wim is an expert in the field of noise by existing and to developed pavements. He is accurate and fits the theoretical ideas into practical solutions. He is a tower of strength and I just can recommend him as a partner of your projects” 

“I am pleased to recommend Wim van Keulen, Wim is one of the view scientists who is able to translate theoretical knowledge into practical solutions! Another quality of Wim is his Psycho-acoustic view on acoustic problems, for example: he designed a pavement with a reduction of zero dB that sounds like a super-silent pavement! Besides his proven quality as acoustical engineer he’s a fine human being (with a great sense of humor), Wim is always interested in the person behind the ‘face’.”

“Wim is an uitstanding expert with no-nonsense approach.”

“Wim van Keulen is one of the most talented and knowledgeable professionals that I have had the privilege of working with in my over 32 years experience in the engineering field. In addition to being able to apply his vast knowledge and ability to explain the most demanding technically challenging engineering topics, it is his non-egotistical manner and sense of humor which makes him a super great person and joy to be around. It doesn't take long to want to consider him as a friend. It is truly a privilege to know him and to have been able to work by his side on the In Situ determination of Acoustic Absorption Noise Coefficient project.”

“With this short text I wish to recommend Wim van Keulen to any person who is facing issues related to noise or acoustics. I know Wim as a highly skilled person with high-end knowledge in the field of noise and acoustics. As a person I know Wim as a scientist, someone who pushes the envelope in his strive to get forward. As an engineer Wim will solve issues even when science does not give answers. Wim is a trustworthy person with whom it is a pleasure to work.”

“Wim is passionate, open and on the highest level an expert in his field. 
Next to that he is a warm human being with the right values in life. 
If you hire Wim, you know you get the best results and a fine human being who is trustworthy. I highly recommend Wim.”

“Wim is a top-scientist and also a nice guy to work with.”

“Wim was a pleasent colleague to work with: critical and good-humoured. I have fond memories of him.”

“Wim is a very knowledgeable person and is able to turn this knowledge into practical solutions. It is nice working with Wim.”

“Wim's insight into perceptual problems has been an inspiration in finding new solutions to binaural auditory processing problems”