Backenst Posted December 18, 2014 Report Share Posted December 18, 2014 Has anyone noticed that a song played via the SD card sounds superior to the same song played via the iphone (and direct connection)? I am considering transferring my entire library to the SD card, apple carplay notwithstanding, becasue of this. I have also noticed that if you periodically clear all your settings in the iPhone or do a full restore that it improves the sound quality. Has anyone else experienced this? Quote Link to post Share on other sites
rockthebeef Posted December 18, 2014 Report Share Posted December 18, 2014 It's really hard to say without testing your theory scientifically. I have an AppRadio 4 and it doesn't have an SD card slot, but it does have two USB ports. I think music from the USB plays louder than that from an iPhone. I think the difference in volume can definitely be perceived as having better sound quality. I'm not too sure I would buy the part about clearing the phone settings for better sound quality. Not saying right or wrong - just that it can't be proven without an appropriately designed experiment. All that considered, with the noise floor being so high in a moving vehicle, I'm not too concerned about audiophile quality in my car. I only say this because seeking perfection can be a long and tortuous journey and I'm perfectly happy with "good enough". BTW, I'm the type who usually sets EQ flat and turns off any DSP or boost functions. However I performed auto EQ on my AppRadio 4 and the results are very very nice. The soundstage was raised and the overall sound is much more airy and less muddy - like a nice home system. I'm pretty impressed with Auto EQ in my particular vehicle. Quote Link to post Share on other sites
Backenst Posted December 19, 2014 Author Report Share Posted December 19, 2014 Thank you for the input. I am convinced of the two theories outlined above however, and admittedly, I cannot find any discussion on audio sites on either of them. So I appreciate any discussion from audiophiles on this forum. There is plenty of discussion on the "quality of output" from different iPhones and direct connection vs wireless but I have not seen any comparisons of the SD Card connection vs iPhone USB connection. Nor have I seen any discussion of perceived degradation over time from an iPhone which can be corrected by resetting the iPhone. (Although restoring the iPhone is often listed as the answer for fixing other performance issues with the phone.) One thing I would add is that I do have a very advanced stereo system in my car; In fact, it is better than my home system. I am running an Alpine PDX-4.150 Amp into the JL Audio ZR Series speakers, along with a second Alpine amp dedicated to a small but high quality JL Audio 8' sub. The car has been sound proofed to deaden much of the noise. I believe I can hear the nuances between the different outputs but as I said I have not been able to verify any of this. So I am interested in hearing what others have experienced. Quote Link to post Share on other sites
epsilonkore Posted December 19, 2014 Report Share Posted December 19, 2014 I too have a sound deadened car with a mild system (OEM Audio+) oriented toward sound quality and reproduction (using my NEX8000). I have noticed playback from different sources are not only at different volumes (which can be fixed if you adjust your source gain settings per input) but also different qualities. For example, Nashville has WSIX over the air HD Radio channel, and so does SiriusXM (or it did until it was removed earlier this year). The SiriusXM quality never was as good as the HD Radio version. I would tweak the settings over and over, even did a gain meter calibration to make sure levels were the same, but SiriusXM is always "muddy" sounding compared to the built in HD Radio. I dont know if this is the SiriusXM tuners fault or if it is some sort of interface issue between it and the headunit, either way, it isnt as good. On my other car, that has SiriusXM and HD Radio (Toyota Prius) the SiriusXM is BETTER sounding, crisp, clear and accurate with channel WSIX vs HD Radio. SiriusXM has always had a decent bitrate so I cant imagine what the issue is other than some sort of interface or software issue between the NEX and the SiriusXM adapter. Bluetooth vs CarPlay vs SD MP3's is a bit trickier even still... I have noticed that my lossless ripped music from my iPhone sounds just as good over Bluetooth or CarPlay, once you configure the gains to be the same. CarPlay vs Bluetooth phone calls... thats another matter. SD music wont be a perfect comparison to iPhone for me as I rip all my music files in using iTunes AAC Lossless format. The same exact songs are on my SD card, but they have been transcoded to MP3 256kb format due to the SD Card size limitations. SD sounds good, though its volume levels were also way off from the other sources. I could never get it to measure the same using my db reader, as other sources. This, and the difficulty to update the music (iPhone sync is just too easy in comparison) I only use it as backup collection due to the SD card size limitations. Quote Link to post Share on other sites
Free Posted December 20, 2014 Report Share Posted December 20, 2014 I have a NEX 4000. I compared my Samsung S4 aux-in connection to the USB1 Input using a 256GB SS hard drive using FLAC (44khz, 16 bit). I played the exact same FLAC file on both my phone and NEX 4000 USB1 and I will never go back to the phone aux-in again. There is a significant sound quality improvement playing the FLAC files directly on the NEX unit. The bass is deeper and tighter and the mids/highs are well defined. The unit has a great DAC. I now realize that a phone is not an audiophile device! Quote Link to post Share on other sites
Backenst Posted December 22, 2014 Author Report Share Posted December 22, 2014 Thank you Free & Epsilonkore for your input. I did find another blog from several years ago, 2011, where a poster who indicated he was a sound engineer commented that the output from the iPhone is not as good as the SD card given that the 30pin connector needs to convert the digital signal to analog so that the Pioneer unit can receive it properly and then use its DACs to convert it back to digital, (or something like that). So even though the Pioneer has excellent DAC's, the transferring of the music causes a loss of integrity. This is a tough call because as I transfer music over to the SD card, I have various formats (apple lossless) that are not playing on the SD card, some album art is lost and I can't figure out how to add playlist functionality without renaming every file to a number format. So converting all these files to a supported format, renaming them and adding back in album art would require some dong. So there is a big convenience issue. I am upgrading to the iPhone 6 over Christmas and I wonder if the 6 output is superior to previous versions. Quote Link to post Share on other sites
jhren Posted December 22, 2014 Report Share Posted December 22, 2014 .... I did find another blog from several years ago, 2011, where a poster who indicated he was a sound engineer commented that the output from the iPhone is not as good as the SD card given that the 30pin connector needs to convert the digital signal to analog so that the Pioneer unit can receive it properly and then use its DACs to convert it back to digital, (or something like that). So even though the Pioneer has excellent DAC's, the transferring of the music causes a loss of integrity. ... IMO, never trust anyone claiming to be a sound engineer. Doesn't mean they aren't... but there more not so good ones than there are really good (being polite to maintain professional etiquette )... and his statement is a prime example. An iPhone/iPod 30-pin connector is capable of both analog and digital transmission. If it wasn't, I most certainly wouldn't be using an iPod Classic as my main audio source (all lossless)... and while I'm not an audio engineer, I am a former sound reinforcement professional, a licensed journeyman electrician (commercial/industrial), a licensed fire alarm & detection professional, mostly work as a nuclear-power EPRI-certified instrumentation & controls technician, and of course a self-proclaimed audiophile And FWIW, the unsponsored vehicle I entered at the time took third place overall in a U.S. Midwest Regionals audio competition a few years ago. Quote Link to post Share on other sites
Backenst Posted December 22, 2014 Author Report Share Posted December 22, 2014 Jhren -- please tell us more then. In your opinion, would there be a difference in sq from the same song coming through an SD card vs the USB connection via an iPhone/pod? Would the 30 pin differ from the lightning adaptor? Quote Link to post Share on other sites
Pjrm68 Posted December 22, 2014 Report Share Posted December 22, 2014 I think what it comes down to is the quality of the DAC used in the iPhone vs. the one used in the head unit, not the 30-pin connector or otherwise. But, I could be mistaken. Quote Link to post Share on other sites
Free Posted December 22, 2014 Report Share Posted December 22, 2014 Use the DAC in the head unit whenever possible. As I stated in my post above, the DAC in the 4000 sounds much better than my Samsung S4 phone, as I am sure it's the case in most/all phones. I used the same flac file in my comparison. Quote Link to post Share on other sites
Pjrm68 Posted December 22, 2014 Report Share Posted December 22, 2014 Use the DAC in the head unit whenever possible. As I stated in my post above, the DAC in the 4000 sounds much better than my Samsung S4 phone, as I am sure it's the case in most/all phones. I used the same flac file in my comparison. Does anyone know exactly what DAC is used in the NEX units? Not sure if that would be published anywhere. Quote Link to post Share on other sites
jhren Posted December 23, 2014 Report Share Posted December 23, 2014 Jhren -- please tell us more then. In your opinion, would there be a difference in sq from the same song coming through an SD card vs the USB connection via an iPhone/pod? Would the 30 pin differ from the lightning adaptor? There shouldn't be any difference (assuming you mean same file rather than same song)... but I can't guarantee that because I haven't got into the technical aspects of exactly how an iPod/Phone streams digital audio... or whether Pioneer units use streaming digital and not analog. All I can factually tell you is that the Apple 30-pin connector is capable of both (you can look up the pinout on the 'net)... and AFAIK the lighting connector is digital only (I haven't looked up the pinout). At this point I can't even give you an evaluation of performance on my 8000. Still working on custom in-door enclosures for my front mid-woofers; also yet to install a new set of sub amps (burnt up my last one). My rears components sets are connected but I have the amp fuse pulled until I get my fronts in. And with all that left to do, I seem to keep getting overriding higher priorities issues that are preventing me from getting it done. Fortunately, it is not my everyday vehicle Quote Link to post Share on other sites
jhren Posted December 23, 2014 Report Share Posted December 23, 2014 Another thing I can add, but is with respect to my other vehicle. It has a Kenwood DNN990HD head unit with my iPod connected via USB. I also have most of the same songs on SD card as backup... but in compressed AAC format (@ maximum bitrate) because the HU doesn't support any lossless format. I can without a doubt say that I realize the benefits of the lossless files on my iPod... Quote Link to post Share on other sites
donmontalvo Posted December 24, 2014 Report Share Posted December 24, 2014 I now realize that a phone is not an audiophile device! Apple Lossless (is supported by iOS) and FLAC (is not supported by iOS) should give you the same quality, but I guess I see what you guys mean, the connector might be causing problems. I wish I could open an Apple enterprise support request, to get straight answers. Unfortunately its not work related, and I don't want to get fired. Might be able to post to the Apple Developers site: https://developer.apple.com/devcenter/ios/index.action Quote Link to post Share on other sites
Free Posted December 24, 2014 Report Share Posted December 24, 2014 Just to be clear, I was referring to the Aux out of the phone where the phone is converting the music from digital to analog via the phone's DAC. (phone aux out, head unit aux in) I would agree that if you are using the phone's digital connector and the head unit is receiving the digial data and converting it to analog in the head unit, then the sound quality should be the same as using a USB hard drive directly plugged into the head unit. (using like for like as the digital source) Happy holidays. Quote Link to post Share on other sites
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