Q. Where has all the bass gone?

By Hugh Robjohns

I recently moved house and, having now set up my equipment in a new room, I seem to have lost all of the bass end. My monitors are set up as they should be and my setup worked and sounded fine at the last house, but now for some reason the bass is only prominent at a point just behind my head in my normal sitting position. The closer I get to my computer monitor the less bass I get. Do you have any suggestions?


Steve Carter

Technical Editor Hugh Robjohns replies: This sounds like a classic room mode problem to me. The low frequencies are reflecting back and forth between the front and rear wall (and almost certainly the side walls and elsewhere as well), and are creating what is called a 'standing wave'. When the reflected waves meet, they will reinforce each other at certain points in the room and cancel each other out at others, causing the uneven bass response and 'dead spots' that you are experiencing. As you move forwards and backwards your ears effectively hear different parts of that standing wave. So when you get closer to the monitors you are hearing a quieter part of the wave, and as you move back you are getting closer to the wave's peak. The dimensions of your particular room will dictate which frequencies are most affected and how severely — the room's 'modes'.

The only real way to resolve this problem is to install some bass trapping. This will help to reduce the amount of low-frequency sound being reflected, and thus reduce the standing-wave problem. Switching to monitors with a less extended bass response will reduce the scale of the problem, but if you have to have deep bass, acoustic treatment is the only solution.

This is a topic that has been discussed in these pages many times before, as well as in several of the Studio SOS features. Paul White's five-part 'Room For Improvement' series on studio acoustics from 1998 and Mallory Nicholls' Studio Installation Workshop series from 2002-03 are both archived and available to read on the SOS web site, and are excellent places to start if you're new to the subject of studio acoustics. This subject is regularly debated in the SOS Forum (also accessible via www.soundonsound.com/forum), where I'm sure you'll find plenty of helpful advice and ideas.


Published August 2004