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alidawani's picture
Last seen: 6 months 3 weeks ago
Joined: Jul 28 2019 - 1:48am
help need good amp

I just got my new focal 906 aria bookshelf speakers
i need strong amp for my hungry speakers
any recommended amp ?

JRT's picture
Last seen: 1 day 19 hours ago
Joined: Jul 12 2007 - 12:36pm
Third party measurements of your Focal 906 Aria...

Third party measurements of Focal 906 Aria show voltage sensitivity of 86.8_dB at 2.83_Vrms at 1_meter (averaged 300_Hz-3_kHz), and a minimum impedance of a little over 4_Ohms in the vicinity of 200_Hz. Combine those at worst case and you have 86.8_dB at 1.0_m at 2.0_W into 4.0_Ohm.

The factory specification sheet suggests a listening distance of 2.5_m.

For more explanation, see the thread at the following link.

For the shorter version:

Going with Dolby Lab's recommendation on max Lref of 82_dBA at -20_dBFS signal level from each separately at the listening position (turn it down on louder more highly compressed material), for crest level SPL of 102_dBA at 0_dBFS from each separately at the listening position. Also using Focal's suggested 2.5_m propagation distance, and headroom of +3_dB above 0_dBFS to accommodate maximimum crests in the top octave unclipped.

102_dBA + 20*log(2.5_m) dB propagation
= 110_dBA at 1_m at 0_dBFS

2_W * 10^((110.0_dB-86.8_dB)/10)
= 418_W into 4_Ohms at 0_dBFS
(brief crests, below clipping)

Impedance is higher than 12_Ohms in the top octave, but you won't likely find ratings at unusual load impedance. The underlying consideration is voltage, and you need (2^0.5)x increase in voltage for +3_dB. Essentially you need an amplifier that can deliver the same power in doubled impedance, relative to the lower frequency requirement into 4_Ohms. So...

= 418_W into 8_Ohms at +3dB above 0_dBFS
(very brief crests in top octave, below clipping)

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