Abbingdon Music Research LS-77 owner manual Appendix A - Adjustment of tonal balance

Appendix A - Adjustment of tonal balance

If you feel that the tonal balance in the upper midrange and lower treble frequencies of the LS-77 is not correct for you, you may wish to change the resistor combination fitted under the cover labelled “High Frequency Level Adjustment”. Some of the required adjustment may be due to the differences in listening distance while others may be a result of differences in taste and furnishings.

		LS-77 Professional Monitor
		Designed and Engineered in Great Britain
Sensitivity:	87dB
Impedance:	8Ohms	(dB)
Peak Prog. Handing:	600W	Output
Cont. Power Handing:	150W
Frequency Response:	27Hz-40kHz	High Frequency
		Level Adjustment	Frequency (Hz)

HF

Remove this cover after removing the machine screws that hold the cover in place using the 2mm metric hex key (Allen Key) which is provided with your speakers (or equivalent replacement if lost). Under the cover you will in stock condition find two resistors one marked 15Ù and one marked 47R. You will also find a pair of optional resistors included per speaker, one marked 100

15Ω	47Ω	and the other marked 220.
		Respectively the resistor marked 100 will be
		referred to below as 10R, the 15Ù as 15R and
		the one marked 220 as 22R. Using different
		combinations allows an adjustment of the upper
		midrange and lower treble frequencies by +/-3dB
		in steps of around 1.5dB.

LF

INOUT

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