May June 2016 Page 37 May/June 2016

Note: 110 to 116 dB is very loud - I used ear plugs to protect my hearing for these test tone measurements. The SPL (loudness) tests Rec eiver power alone Test Model: Alpine UT E-52BT , #500UT E52BT $119. 99 Reading: 1,000 Hz t est t one at 21" - 1 0 dB SPL B SPL Notes: I played a 1K Hz t est t one through a reference speaker . I then turned up the volume of the UT E-52BT until the clear t one start ed buz ing. That revealed the clip ing point of the receiver: 22 on the dial. T urning it down t o 21 cleared the t one back t o a clean signal, making that the maximum clean volume for the receiver . 1 0 dB is gener al y enough t o overcome road noise. g p p k Adding a power pack Test Model: Alpine KTP-445A, #500KTP445A $129. 99 Reading: 1,000 Hz t est tone at 21" - 113 dB SPL Notes: The gain for the KTP-445A is preset for Alpine receivers, so the 21 setting of the receiver's volume again produced the t op clean output for the Power Pack, but with 3 dB more output . That may seem small, but it t akes twice the amount of power to raise the output 3 dB. In other words, the Power Pack doubled the output power of the receiver alone - hence the significantly louder output with bett er musical det ail. p y g p f Ap lying amplification Test Model: Alpine PDR -F50 #500PDRF50 $39 . 9 Reading: 1,0 0 Hz t est t one at 21" - 1 6 dB Not es: I set the gain of the PDR -F50 as I had the receiver - turned it up until it buz ed, then down until it didn 't. The 3 dB improvement shows we doubled the power again. This would explain the vast improvement I heard in the sound. Very clean, but thin Noticeably fuller Stunning 37

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