Wavelength vs. Frequency

DonH50

Member Sponsor & WBF Technical Expert
Jun 23, 2010
3,867
231
500
Monument, CO
Nothing special in this one, just a simple plot. When discussing distances, whether related to room interaction, comb filter effects, room treatment or whatever, there is often the assumption that bass frequencies are "everywhere" while higher frequencies can be "directed" or are "more directional". The reason for this argument has to do with wavelength -- the length of the total sonic wave at a given frequency. Like waves in the ocean, there is a certain distance from peak to peak of audio signals, and that is their wavelength. It is related to frequency; higher frequencies have shorter wavelengths. The actual equation is w = vp / f where w is the wavelength (e.g. feet), vp the propagation velocity (about 1130 ft/s for sound in dry air at sea level), and f the frequency (Hz). Room modes or comb filter effects happen when sound waves bounce off walls or interact with other surfaces, or even arrive from two different sources (like, two speakers) at the same time. at the listening spot. The sound waves recombine, either adding (constructively) or canceling (destructively). This changes the frequency response.

There are many discussions about the effect of reflections and recombination of sound waves from various sources (speakers, walls, ceiling, tables, whatever) but all I am going to do here is show wavelengths for various frequencies. This will hopefully provide a little insight into what distances matter in your room. Note that room modes tend to happen around w/2*x (x = room dimension), and w/4 can lead to sound cancelling or doubling as well.

HTH - Don

wavelength..JPG
 

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. This is THE place where audiophiles and audio companies discuss vintage, contemporary and new audio products, music servers, music streamers, computer audio, digital-to-analog converters, turntables, phono stages, cartridges, reel-to-reel tape machines, speakers, headphones and tube and solid-state amplification. Founded in 2010 What’s Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals, we enjoy learning about new things and meeting new people, and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing