FM Radio Stations Magically Sounding Better?!

[DarkStar]

On my commute to work today, I turned off a podcast and turned on the FM radio and flipped around a bit. I got to a station I haven't listened to in a while and noted how good it sounded, not just sorta better, but like the switch from crap to awesome was flipped. When I arrived at work, I had to email the broadcast engineer to find out what they changed on the audio processor.

The response: "I haven't touched that thing in 6 years."

Well, on my commute home I flipped around to a bunch of stations I listen to on a regular basis and noticed that the bass was a lot more crisp and the treble was more pronounced on all my stations. I had noticed that previously stations were a bit muddy and I figured it was probably an issue with the de-emphasis in the radio, like it was set for the European/Asian standard of 50µs instead of the North American standard of 75µs.

So, I called Nissan and learned that XM will send down necessary radio software updates including those related to Bluetooth and radio performance. They weren't aware of anything recently and suggested that I ask XM, however I'm not an XM customer so I couldn't get any info.

Here's the version numbers from my System Diagnostic screen, hopefully something will jump out at us:

Boot Ware (NK1): 108
Application (NK2): 108
Audio Unit Software: 067
CAN uCOM Software: 018
Front Display Software: 030
BOLERO Software: 00.05
Bluetooth Firmware: C230
Voice Recognition Engine: 925-123-000
Voice Synthesis Engine: 5.0.0.3-PS-P2
Voice Recognition Grammar Version: 00001080
Voice Synthesis Data Version: 00003000
Record Data Version: 00001026
Part Number: 3NA0B
XM Satellite Radio Software: 012
Switch Software: 030000
TCU Software: 3NA0000627
Map Version: 10/08/12/01

 

[Ingineer]

I haven't seen any evidence to support this. The XM module firmware may be flashable by XM, but the rest of the head unit definitely isn't. The only way the head unit can be reflashed is via SD card sourced from Clarion (the OEM).

I think XM sounds like crap, compared to any decent FM station, so if you listen to XM and then switch to FM, it will have this effect.

I've seen a few Leafs with a failed antenna amplifier have poor FM performance resulting in poor frequency reproduction and low dynamic range. Maybe yours is intermittent, and healed itself?

I'd like to suggest another possibility; Your podcast was poor sounding, so after listening for awhile anything will sound much better!

Audio quality is highly subjective. It's been proven over and over that humans are poor at comparing benchmark performance in the high-end audio world.

One of the first upgrades to my Leaf was new speakers and LF anti-resonance treatment around them. My system sounds great, and I'm very happy with the sound quality when sourced from high bit-rate MP3's or other decent sources. However, The UI in the heat unit is horrible.

-Phil

 

[RonDawg]

I think XM sounds like crap, compared to any decent FM station, so if you listen to XM and then switch to FM, it will have this effect.

I agree. I've listened to XM and Sirius receivers, both OEM and aftermarket, in various cars that I've owned/rented/borrowed/just ridden in, and while Sirius isn't all that great sounding, XM for some reason sounds consistently worse. That's the biggest reason why I didn't renew it when my 3 month trial expired. I just use the Bluetooth streaming off my iPhone.

 

[DarkStar]

Well something definitely changed, it was so dramatic that I had to bump the treble down one notch. XM has always sounded like horrible bitrate reduced junk and I told them that whenever they've called to sell it to me.

My podcasts to vary in quality, however most of them are stereo at 128 kbps. But all of my MP3 music is at 320 kbps, ripped from CD. The dynamic range reproduction of the songs on the radio much more closely match the CD versions.

The antenna amplifier is an interesting one. If this is the case, mine has been broken since the day we picked up the car and it just decided to fix itself!

Is there a good way to check the amplifier?

 

[oxo]

Loss of earwax? :lol:

 

[apvbguy]

Loss of earwax? :lol:

:lol: :lol: :lol:
I wanted to post the same question but my ability to converse here is somewhat limited

 

[DarkStar]

Loss of earwax? :lol:

No kidding! Well, I'll dig around the service manual a bit to see if there is a way to easily temporarily disable the antenna amplifier and see what happens. It could also be that with the excellent atmospheric conditions we're having right now, the car is just picking up a better signal.

Personally, I just wish I could swap out the Clarion with an HD radio and be done with it though...

 

[Ingineer]

Is there a good way to check the amplifier?

Attempt to tune a known DX station and compare it to the performance of another decent receiver.

I believe the amplifier is located in the base (#1 in the diagram).

-Phil