USB vs. WiFi

[jdmccall]

Maybe it's just my imagination, but I'd swear that I have 320Kbps mp3 files that sound better straight from a USB flash drive plugged into my NAD CD player than the same files sound streamed via WiFi from a NAS to my Denon network music player. Of course the DAC and analog output stages are different and the wifi streaming is less direct, so that may explain the differences. What do ya think? Am I imagining things or could the sound straight from the usb flash drive really be better?

 

[trhee]

It's just a matter of you preferring the NAD to the Denon.

 

[titanstats]

Am I imagining things or could the sound straight from the usb flash drive really be better?

I don't think that you necessarily imagining things. Wifi isn't magic, it can be flakey and temperamental like any radio signal. I would prefer any physical connection over any wireless signal, any time. It's convenient, though.

 

[aidynphoenix]

Like Trhee said you must be hearing the differences between two different pieces of gear. both have to convert the mp3 file from digital into analog, the NAD must do it better.
There should be no differences between the data file on your flash drive, and the data file which the denon downloads from your wireless connection.

when there is a error in reading the wireless information sent. it must be re-sent. the receiver knows if the information is good or not because it knows what the total size of the data file needs to be.
it is very rare for there to be a error which still adds up to the correct file size. and even if there was a error in the file, it would sound like a pop, or a click sound, it would not be noticed as reduced audio quality.

it being digital information it is immune to the losses that analog signals are subject to.
its kind of like comparing a $200. hdmi cable to a $10. hdmi cable. because the information is digital, it is immune to signal quality problems, and the video and audio produced by the cable is identical.
and if some of the information being sent through the cable was not coming out correctly there would be huge problems which would easily be noticed. such as the screen being entirely green, or a loud buzzing sound, and the user would know the cable was defective.
i have read reviews where the reviewer claimed that the image looked better with the expensive hdmi cables. or a actors skin looked clearer with a certain cable. if you understand the way that the digital information is sent and used it makes the reviewer look like a buffoon. in order to change the color of a specific pixel to a different color the digital information must be so dramatically different that it is simply not possible. when colors are sent in a digital format it is sent by code, its a series of on and off signals referred to as one's and zero's. the strength of the on and off signal does not change the computers interpretation of the data, this is why cable quality does not matter. a series of ones and zeros turn into letters or numbers and those numbers and letters can be used to represent colors. in order for it to get a color wrong the amount of data which would have to be read incorrectly is absurd.

and the way that wireless data is sent over a network is no different.
now whatever the denon does with the data after it receives it, is different.. but you can be sure that just because the file was sent wirelessly doesn't have anything to do with the difference in sound.
sorry... about the rant..

 

[jdmccall]

I agree: It must be differences in the DAC's and/or analog output stages of the Denon and the NAD. Although I can't help but wonder if the more you manipulate and move a digital file around, the more possiblity of errors or jitter or something that could degrade it to the point it might become audible in some way. I suppose not, in theory anyway. Of course, I'd also swear my stereo sounds better late at night and early in the morning than it ever does in the afternoon and early evening. So I may still be crazy. :screwy:

 

[House de Kris]

When trying to compare things, it is usually a good idea to eliminate as many variables as possible. You've already identified the differences in DACs and analog circuits as a strong possibility of the difference. Next step is to eliminate these differences and do the comparison again. One method to do that would be to make an SPDIF connection between the NAD CD player and a your amplifier and an SPDIF connection from the Denon network player and your amplifier. That way, the DAC and subsequent analog stages are the same.

If these two sources playing the same file still sound different, further investigation is warrented before declare one method of file delivery superior to the other. First thing I would check in that case is if the WIFI server program is doing any transcoding on the fly. I had a video server that dumbed-down everything before serving. Once discovered, it was fodder for the landfill. Perhaps your NAS server program transcodes everything to 128kbps. Probably not, but it may be useful to determine if the 320k file is being recieved by the Denon as truly a 320k file.

If you get to the point where you know the 320k file is not being molested by the server, and you know the same DAC and analog circuits are in use, and it still sounds different, there may still be other reasons for the different sound. Just as all MP3 encoders are not created equal, not all MP3 decoders are created equal. IOW, some MP3 decoders just sound better than others. There's no way I know of to force the same MP3 decoder for daily use, but there are complicated methods to prove if there are indeed differences in the decoder. Probably unnecessary to describe here.


But, if you were able to prove that the two MP3 decoders were equivalent, the files are delivered the same, the DACs and analog circuits are the same, it may still sound different. Perhaps one of the devices has an optical SPDIF output, while the other has a coax SPDIF output. Unless they have the same types of outputs, it would be hard to do a head-to-head comparison. Even if they had the same output type (either both coax or both optical), they could sound different due to due to differences in quality of the digital signal on the output.

OR, if your amp doesn't have SPDIF inputs (and/or your playing devices don't have SPDIF outputs) you could just throw your hands up in the air and say USB is better than WIFI.

 

[titanstats]

it being digital information it is immune to the losses that analog signals are subject to.
if you understand the way that the digital information is sent and used it makes the reviewer look like a buffoon. in order to change the color of a specific pixel to a different color the digital information must be so dramatically different that it is simply not possible.

and the way that wireless data is sent over a network is no different.

Kidding, right? Wifi is merely another radio wave. It does experience data drops, it does fall out, wax, and wane. As with any other radio signal they are subject to many, many different types of interference; broad spectrum disturbances are common from a ton of household devices, and especially in the city (where I live) there are hundreds of 802.11 networks to interfere as well. I doubt many homeowners do an RF sweep before they place their router...

You ever try to reach a sub-optimal OTA digital TV signal, btw? Artifacting, misplaced colours, pixelation, smearing, you name it (all the stuff you said was impossible), but the picture plays on. It simply is possible.

Ever seen a mission critical, or ANY enterprise device running wifi as a data source? Ever? Like I said, streaming data via a small radio transmitter in your house is handy, but a hard connection is better every single time. I'd use wifi if I had to, but I don't have to, so I don't.

 

[Gang-Twanger]

As much as I don't like the idea of music through WiFi, I have to think that DAC differences would have a bigger effect on SOUND-quality preferences. The DAC used in the circuit is like the heart of the digital signal, and the analog output section in that DAC is integral. That's why I like the idea of going with separates (music-server/player, DAC) for the digital side of my system. PC-based music-servers have a huge learning curve though, so it's tough. I will eventually need an outboard player that can connect to an external DAC. Still learning the tremendous PITA that is digital playback. But hey, analog is no easier.

 

[chicks]

streaming data via a small radio transmitter in your house is handy, but a hard connection is better every single time. I'd use wifi if I had to, but I don't have to, so I don't.

I stream music every day throughout the house, using a proprietary, very well-designed peer-to-peer mesh Wi-Fi network. Every node in the network is also a repeater. Buffering is utilized to ensure recovery of any packets lost due to noise and interference. It's as robust as wired.

Most music streaming systems don't go to these lengths, and will suffer dropouts, but will not alter the "sound", since any missing packets will be resent.

 

[aidynphoenix]

Kidding, right? Wifi is merely another radio wave. It does experience data drops, it does fall out, wax, and wane. As with any other radio signal they are subject to many, many different types of interference; broad spectrum disturbances are common from a ton of household devices, and especially in the city (where I live) there are hundreds of 802.11 networks to interfere as well. I doubt many homeowners do an RF sweep before they place their router...

You ever try to reach a sub-optimal OTA digital TV signal, btw? Artifacting, misplaced colours, pixelation, smearing, you name it (all the stuff you said was impossible), but the picture plays on. It simply is possible.

Ever seen a mission critical, or ANY enterprise device running wifi as a data source? Ever? Like I said, streaming data via a small radio transmitter in your house is handy, but a hard connection is better every single time. I'd use wifi if I had to, but I don't have to, so I don't.

television broadcasts and radio signals don't get a chance to be resent incase of a error. the televisions and radios have to just use the information they captured. but our wireless computers check the information and send it again if they need to.
i have copied thousands of files over my wireless home network and never once found a corrupted file.

 

[jdmccall]

Very interesting replies, all.

If my pitifully limited understanding of digital audio is correct, the perceived difference I hear can't be in the bits. Both are from the same rip of the same CD. The original destination folder was on the USB flash drive. That was then copied to a NAS in another room, from which it was then streamed via wifi to my network audio player. The usb drive was plugged directly into my NAD CD player in the same system. My preamp is all analogue. I have no stand-alone DAC, but my Denon network player does have a usb input. I will try playing the usb through that to see if I still hear any difference with both usb and NAS using the Denon's DAC.

 

[titanstats]

I stream music every day throughout the house, using a proprietary, very well-designed peer-to-peer mesh Wi-Fi network. Every node in the network is also a repeater. Buffering is utilized to ensure recovery of any packets lost due to noise and interference. It's as robust as wired.

You, my friend, have done it right. Almost nobody else does, though.

Wired is always better for many reasons, wifi is convenient; there's room for both in the world. I am lucky in that I am able to hard wire all of my systems in my network. Streaming/sharing is a breeze, particularly HD content. Then again, I am hardware obsessive about my "system", and will do stupid things like restore and modify old IBM M keyboards, etc., when I find them., so... :-/

Do I really care that much how other folks deliver their music in their house? No, not really, was just tired and bitchy.

 

[E-Stat]

Wired is always better for many reasons, wifi is convenient; there's room for both in the world.

Agreed. The main system upstairs is hardwired using CAT6. For the Touch player in the garage system, I placed an access point nearby operating as a wireless bridge. From the player's standpoint, it is hardwired. For the bedroom system, I placed another access point in the room as a repeater using an iPad as streaming player. And for streaming Netflix on the TV.

I find that 24/96 challenges 802.11G throughput. With 802.11N access points, however, I find no buffering issues.