@dbphd asked, " What’s quasi-anechoic mean?"
Usually the term refers to loudspeaker frequency response measurements taken with a "gated" measurement system. This is a system which turns on the microphone long enough to capture the output from the speaker and then turns the microphone off before the first reflection arrives. This way the reflections are effectively excluded from the measurements without the room actually being anechoic, hence "quasi-anechoic".
The technique is only good down to the frequency where a whole wavelength can be captured before the first reflection arrives. So a different technique has to be used to get good data at longer wavelengths. John Atkinson of Stereophile close-mics the woofer(s) and port(s) at these longer wavelengths and then splices the curves together, and this is the most common technique.
Duke
Usually the term refers to loudspeaker frequency response measurements taken with a "gated" measurement system. This is a system which turns on the microphone long enough to capture the output from the speaker and then turns the microphone off before the first reflection arrives. This way the reflections are effectively excluded from the measurements without the room actually being anechoic, hence "quasi-anechoic".
The technique is only good down to the frequency where a whole wavelength can be captured before the first reflection arrives. So a different technique has to be used to get good data at longer wavelengths. John Atkinson of Stereophile close-mics the woofer(s) and port(s) at these longer wavelengths and then splices the curves together, and this is the most common technique.
Duke