Benchmark HPA4 - Page 35

Instruction Manual for HPA4 with 1.0.X Firmware – REV B Page 35
Graph 4 - THD vs. Output Frequency - Headphone Amplifier - 20 Hz to 20 kHz Sweep
This frequency sweep shows that the THD remains extremely low when the frequency increases.
The THX-888 headphone amplifier delivered this performance while driving a 16-Ohm load.
Notes:
• The scale on the left is dB THD relative to the output level.
• The output level is 1 Watt into 16-Ohms (4 Vrms, 14.3 dBu).
• The THD measurement bandwidth is 48 kHz.
• The test tone is swept from 20 Hz to 20 kHz.
• Balanced inputs to headphone outputs, volume control set at 0 dB.
Audio Precision
07/16/18 12:27:53
THDvsFreq_BAL_IN_HPA_Out_16_Ohms_1Watt.at27
ColorSweep
Trace Line Style Thick
Data
Axis Comment
Source 2 Cursor1 Cursor2
1 2
Green Solid 4
Distortion.Ch.1 Harm Sum1 Ratio Left
L dB : 7.00000 =Swr.Ch. A Input -126.430 dB -120.588 dB
1 3
Green Solid 4 Distortion.Ch.1 Harm Sum1 Ratio
Right L % : 7.00000 =Swr.Ch. A Input
0.00005 % 0.00009 %
2 2 Red Solid
4 Distortion.Ch.1 Harm Sum1 Ratio Left
R dB : 8.00000 =Swr.Ch. A Input -125.405 dB -121.412 dB
2
3 Red
Solid 4
Distortion.Ch.1 Harm Sum1 Ratio Right
R % : 8.00000 =Swr.Ch. A Input
*0.00005 % *0.00008 %
0.00004
0.001
0.00005
0.00006
0.00007
0.00008
0.00009
0.0001
0.0002
0.0003
0.0004
0.0005
0.0006
0.0007
0.0008
0.0009
0.00005
0.00008
%
-130
-100
-128
-126
-124
-122
-120
-118
-116
-114
-112
-110
-108
-106
-104
-102
d
B
2k
20k 4k 6k 8k
10k
12k 14k
16k
18k
1.019k
10.01k
Hz
TTTT
dx=8.99100 kHz
dy=0.00003 %