Room or speaker resonance???


I received an interesting test CD with Audio Magazine. It has test tones to determine ideal/optimal distance from wall. My measurements are:
50 Hz - -1 dB; 70 Hz - -10 dB; 100 Hz - -6 dB; 140 Hz - -10 dB; 200 Hz - 0 dB; 280 Hz - 0 dB

Is this normal? Seems as huge dip to me?
Is this speaker (say a bad speaker element or bad crossover part) or room or both? How can I tell?
How would I go about to correct?
Thanks
dcaudio

Showing 1 response by dcstep

That's normal. Placement of the speakers within the room is super critical in the bass region. Since you've got the meter out, move the speakers a foot closer to the wall and note how different the response is.

There a nodes that cause the bass to peak at certain frequencies. Reduce the peaks via placement and you'll flatten the overall response. Trying to set the speakers using a meter is tough work, if you can get professional help, do. Many people merely pull the speakers way out into the room to null most of the nodes. (That's what I used to do). However, the best approach is to optimize bass performance by using the nodes, but it's much easier said than done.

Hopefully there'll be a DVD ready later this year to help you do this.

Dave