Project System Frequency Response Charts

A full bandwidth pink noise signal was used on all three charts.

1st — Speaker position at 82cm from the front and side wall—measurement taken with the PX30. There is significant room gain in the low bass and a dip in the 100 Hz band. These problems would be much worse except the Project is equalized to help compensate.

2nd — Note that positioning the speaker in the center of the room minimizes the proximity effects seen in the first measurement. This more closely shows the Project's actual response—bass is flatter, 100 Hz dip is gone.

3rd — This chart shows the SP18M alone, without the PX30 subwoofer. Taken room center at 0.5 meter to further reduce room reflections from the measurement.

These charts don't look impressive. In-room measurements never do. What these charts do reveal is the range and spectral balance of the Project despite the ragged effects caused by room reflections.*

Project System w/PX30 — in-room HT position — 1 meter

Project System w/PX30 — room center — 1 meter

Project Base [SP18M] — room center — 0.5 meter

*Why aren't the room's effect completely corrected? Simple. Two critical reasons. 1) If you correct for the room's anomalies, you can only do it for one single point in the room. But even then, though it seems logical, this intuition is greatly flawed. 2) If you correct for the room's response, then the direct sound emitted from the speakers will be very, very wrong. Despite the fact that we hear the composite, most prominently heard is the first arrival direct sound (via the precedence effect) even when it's only a fraction of the total sound pressure level. If the direct sound is off, everything is off.

Which brings up another question. Then why correct for the bass? The longer wavelengths of the of low frequencies blend together more in time. This makes it nearly impossible to distinguish the first arrival direct sound in rooms with dimensions less than a wavelength. (Lowest two octaves, 80 to 20 Hz, are 4.3 to 17.2 meter or 14 to 56 feet.) In this case, we do not distinguish the direct from the composite and room correction is beneficial.

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