Tekton Design Ulfberht Speaker Sensitivity Rating
After hearing or rather being told that Tekton Design inflates its sensitivity rating I decided to test for myself. The article published and written by Stereophile is usually quoted no matter which Tekton speakers are the topic of discussion.
One of the first things to understand is that Tekton like many other companies rates its speaker's sensitivity at 2.83 volts. It's important to note:
"For an 8 ohm speaker, 1 watt of power from the amplifier is the same as 2.83 volts from the amplifier. As shown in the side box, if an amplifier outputs 2.83 volts into an 8 ohm speaker, then it produces 1 watt of power.However the same is not true for a 4 ohm speaker. If 2.83 volts from the amplifier drives a 4 ohm speaker, it produces 2 watts of power. So for a 4 ohm speaker, 2.83v/1m equals 2w/1m." Source: Speaker Sensitivity
Tekton Design's Ulfberhts are rated 99db @ 2.83 volts. That is for a 4 ohm tower.
Before testing the rating I first encountered some varying recommendations. Some suggest that a 1000hz tone ought be used as the standard reference. That, however, makes no sense to me because such a tone is going to isolate only the speakers in a 21 speaker tower which play at that tone. So I used Noise which is spread throughout a wide spectrum. If you're interested in the Test tones I used then the CD may be located here: Precision Test Tones. The track is number 83 on the disc.
Second, I used a digital volt meter to measure the audio signal's voltage to the back of the tower. Since the sensitivity rating is @2.83 volts I increased volume until 2.83 volts was achieved:
Then with my Decibel meter I measured the SPL in front of an Ulfberht tower from 1 meter away. Note, no other towers, subs, etc were connected at this time. This is the sensitivity as measured [in room] for a single Ulfberht. If you're interested in the Decibel meter it may be purchased here: Professional Decibel Meter
Note, the rear ports of my Ulfberhts are plugged as the towers are not pulled away from the wall far enough. As a result without the plugs I found the bass rather "boomy". I suspect the sensitivity might be higher with the plugs removed and the towers take advantage of being corner loaded etc. However, I'll sacrifice some of the room gain achieved by speaker placement near a corner or wall for detail.
99db @ 2.83 volts for a 4 ohm speaker. Just as Tekton Design publishes.