This is a review and detailed measurements of Sony RSX-G9 high-end Car Media Receiver. It is on kind loan from a member. It retails for USD $1,499 so at the top of class when it comes to the category. In case you have not kept up, "Media Receiver" indicates the unit has no CD drive. So all media playback is through bluetooth and unusually so here, a host computer or phone using the RSX-G9 as a USB DAC.
Sony has done its part to make the unit look higher-end although there is so much you can do in a DIN configuration:
I am not a fan of the stiff volume control with no detents. The switches feel fine.
Sony's Media Controller works really well in managing the RSX-G9 remotely. Bluetooth pairing is made trivial by use of NFC which auto-pairs the unit. In the case of my Samsung S9 though I had to find the NFC spot to make this work. A down side of this pairing is that you need to do it every time the unit is powered on. At least this was the case with my last Sony head unit I tested.
Even though the RSX-G9 does not have any built-in amplification although oddly comes with the standard wiring harness with speaker leads.
The owner had re-wired the front panel USB socket to a USB-A lead coming out the back which made connection to PC and testing more tidy.
I remember seeing this unit at CES a couple of years ago and got a briefing from the Japanese Sony employee there. He emphasized DSD playback as the reason for the high cost. While I can't test DSD, let's see how she does with PCM.
Measurements
Since the unit can act like a USB DAC, I started my testing that way with the volume initially set to 2 volt output:
SINAD of 89 dB would place the RSX-GS9 in the fourth tier of our desktop DACs, so nothing to write home about. Indeed performance is inadequate for transparent playback of 16 bit CD music. In car environment though with high noise floor this is probably fine but it is disappointing to see Sony not target/deliver higher performance.
The owner wanted to know the maximum volume prior to clipping so I tested for that and the new is very good there:
We can go up to 4 volts without any penalty. This tells me the DAC is the limiting factor and not the pre-amp. Since higher output in car environment is very useful in reducing impact of noise and potentially long runs of RCA to power amplifier, this is "good news." As long as the power amp can handle it, I see no reason to not use full 4 volt output.
The owner wanted to know if the USB flash drive input does better so here is that results:
Performance remains the same. Slight improvement is due to truncation to 16 bits that is occurring due to use of ASIO over the Windows driver in USB mode. "Fortunately" DAC performance is so limiting that it makes almost no difference.
Dynamic range follows the same story:
So nothing to write home about but again, in the context of where the unit is used, this is fine.
IMD results show the much higher noise floor than desktop DACs:
Green represents max volume and hence shows the clipping toward the end. Setting the level to 48 avoids that. Not shown is the level at 44 which produced identical results to level = 48.
Jitter spectrum is high in USB DAC mode due to revealing the 250 Hz pulses in J-test signal used here (should be invisible normally):
USB thumb drive playing the same file shows total absence of jitter (likely masked by higher noise floor than desktop products).
The unit has Toslink digital optical output but oddly only allows you to select 48 and 96 kHz sample rates? Why on earth are these the two choices when vast majority of content is at 44.1 kHz??? Playing J-test signal and measuring jitter over TOSLINK shows pretty high levels of jitter:
Usually these measurements are in picoseconds, not nanoseconds. The culprit is that one peak around 100 kHz. A bit of instrumentation and circuit modifications would have eliminated that and result in much better performance. The second peak at 12 kHz is related to the main tone in J-test signal used for measurement. Changing that to a pure sine tone at 44.1 kHz makes it go away.
For grins, I connected a Topping D50 to the Toslink output and ran the dashboard measurement again:
Performance shoots up nearly 20 dB showing that the DAC inside the RSX-GS9 is the bottleneck to performance.
Conclusions
Sony aspires to build a high-end head unit here but sadly fails in performance department. Better attention to detail could have easily garnered better performance. For its intended application of being used in a car environment, higher performance would likely be lost when it comes to audibility. Still, if one is paying so much, one deserves better measured performance.
-------------
As always, questions, comments, recommendations, etc. are welcome.
If you like this review, or even if you don't but wish for me to escape the rain in Seattle and go somewhere sunny, please consider donating using:
Patreon: https://www.patreon.com/audiosciencereview), or
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).
Sony has done its part to make the unit look higher-end although there is so much you can do in a DIN configuration:
I am not a fan of the stiff volume control with no detents. The switches feel fine.
Sony's Media Controller works really well in managing the RSX-G9 remotely. Bluetooth pairing is made trivial by use of NFC which auto-pairs the unit. In the case of my Samsung S9 though I had to find the NFC spot to make this work. A down side of this pairing is that you need to do it every time the unit is powered on. At least this was the case with my last Sony head unit I tested.
Even though the RSX-G9 does not have any built-in amplification although oddly comes with the standard wiring harness with speaker leads.
The owner had re-wired the front panel USB socket to a USB-A lead coming out the back which made connection to PC and testing more tidy.
I remember seeing this unit at CES a couple of years ago and got a briefing from the Japanese Sony employee there. He emphasized DSD playback as the reason for the high cost. While I can't test DSD, let's see how she does with PCM.
Measurements
Since the unit can act like a USB DAC, I started my testing that way with the volume initially set to 2 volt output:
SINAD of 89 dB would place the RSX-GS9 in the fourth tier of our desktop DACs, so nothing to write home about. Indeed performance is inadequate for transparent playback of 16 bit CD music. In car environment though with high noise floor this is probably fine but it is disappointing to see Sony not target/deliver higher performance.
The owner wanted to know the maximum volume prior to clipping so I tested for that and the new is very good there:
We can go up to 4 volts without any penalty. This tells me the DAC is the limiting factor and not the pre-amp. Since higher output in car environment is very useful in reducing impact of noise and potentially long runs of RCA to power amplifier, this is "good news." As long as the power amp can handle it, I see no reason to not use full 4 volt output.
The owner wanted to know if the USB flash drive input does better so here is that results:
Performance remains the same. Slight improvement is due to truncation to 16 bits that is occurring due to use of ASIO over the Windows driver in USB mode. "Fortunately" DAC performance is so limiting that it makes almost no difference.
Dynamic range follows the same story:
So nothing to write home about but again, in the context of where the unit is used, this is fine.
IMD results show the much higher noise floor than desktop DACs:
Green represents max volume and hence shows the clipping toward the end. Setting the level to 48 avoids that. Not shown is the level at 44 which produced identical results to level = 48.
Jitter spectrum is high in USB DAC mode due to revealing the 250 Hz pulses in J-test signal used here (should be invisible normally):
USB thumb drive playing the same file shows total absence of jitter (likely masked by higher noise floor than desktop products).
The unit has Toslink digital optical output but oddly only allows you to select 48 and 96 kHz sample rates? Why on earth are these the two choices when vast majority of content is at 44.1 kHz??? Playing J-test signal and measuring jitter over TOSLINK shows pretty high levels of jitter:
Usually these measurements are in picoseconds, not nanoseconds. The culprit is that one peak around 100 kHz. A bit of instrumentation and circuit modifications would have eliminated that and result in much better performance. The second peak at 12 kHz is related to the main tone in J-test signal used for measurement. Changing that to a pure sine tone at 44.1 kHz makes it go away.
For grins, I connected a Topping D50 to the Toslink output and ran the dashboard measurement again:
Performance shoots up nearly 20 dB showing that the DAC inside the RSX-GS9 is the bottleneck to performance.
Conclusions
Sony aspires to build a high-end head unit here but sadly fails in performance department. Better attention to detail could have easily garnered better performance. For its intended application of being used in a car environment, higher performance would likely be lost when it comes to audibility. Still, if one is paying so much, one deserves better measured performance.
-------------
As always, questions, comments, recommendations, etc. are welcome.
If you like this review, or even if you don't but wish for me to escape the rain in Seattle and go somewhere sunny, please consider donating using:
Patreon: https://www.patreon.com/audiosciencereview), or
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).