I have recently bought Asus RP-N14 Range Extender (http://www.asus.com/Networking/RPN14/) with intent to use it as wireless audio connection between computer and amp. I have managed to get it running using Foobar2000 and Airfoil (no luck with dlna) but output seems audibly distorted in high frequency range. Am I doing something wrong or Asus actually managed to produce terrible sounding device in 2014?
I have recently bought Asus RP-N14 Range Extender (http://www.asus.com/Networking/RPN14/) with intent to use it as wireless audio connection between computer and amp. I have managed to get it running using Foobar2000 and Airfoil (no luck with dlna) but output seems audibly distorted in high frequency range. Am I doing something wrong or Asus actually managed to produce terrible sounding device in 2014?
There is a good chance the board is just fine and your troubles are the result of a "ground loop" between the sound card output and the amplifier input. I have a low end Acer and the sound output was fine though headphones and terrible when piped to an external amplifier. I purchased a ground loop isolator (which is basically just a 1 to 1 transformer) off the internet and voila! Try listening to the output with headphones and if they sound O.K. then your problem is likely a ground loop.
Unless the range extender decodes and re-encodes your music or somehow incorporates D/A and A/D converters and does analog sound processing, the distortion cannot possibly come from a piece of networking equipment. Digital audio does not work that way.
I will certainly check it, but it doesn't sound as ground loop. Ground loop sounds like hum (at least in my experience) and this sounds like distortion.
That is quite possibly one of the most bizarre devices I've seen! A wireless extender that you can stream to and is also a night light!?!?!
KozmoNaut, you can actually stream to the device. It has a headphone socket so I assume it's probably just a really crummy headphone amp? Maybe?
papucar, it's a headphone socket rather than a line out so that could have some effect.
Unless the range extender decodes and re-encodes your music or somehow incorporates D/A and A/D converters and does analog sound processing, the distortion cannot possibly come from a piece of networking equipment. Digital audio does not work that way.
And I don't think trans-coding is an issue as I have tried various formats played from two different devices (Windows and Android) but distortion pattern remained very similar.
Unfortunately this extender doesn't have digital out, only analog line-out (3.5 mm), so I guess the culprit must be either bad DAC implementation or bad sound processing.
papucar, it's a headphone socket rather than a line out so that could have some effect.
Should I suspect impedance mismatch?
Should I suspect impedance mismatch?
No. The input impedance of your amp will be much higher than the output impedance of that unit, and that is fine. You don't want or need matched impedances for audio.
Have you tried Ed's suggestion of listening directly though headphones yet (no amplifier connected).
Should I suspect impedance mismatch?
No. The input impedance of your amp will be much higher than the output impedance of that unit, and that is fine. You don't want or need matched impedances for audio.
Have you tried Ed's suggestion of listening directly though headphones yet (no amplifier connected).
I am testing it at the moment but distortion seem even more pronounced while using headphones (Grado SR125). And there seems to be heavy low frequency roll off using headphones.
I am testing it at the moment but distortion seem even more pronounced while using headphones (Grado SR125).
Ok well that rules out the ground loop theory.
And there seems to be heavy low frequency roll off using headphones.
That means that it has an ac coupled output, with too lower capacitance value to drive phones. Disappointing, particularly as they show a "headphones icon" on that output. But it shouldn't effect the performance when driving an amplifier.
At this stage I'd try an RMAA test on it. You can play the RMAA produced waveforms through the network device and record it on a laptop or something, and then later feed those recorded waveforms back into RMAA to analyse. It's kind of the same as a loopback test but done in two separate recording and playback phases. An RMAA test should definitively point to exactly what type of distortion you are getting.
BTW. I notice that on the "specs page" for that device they show absolutely no audio performance specifications whatsoever.
http://www.asus.com/Networking/RPN14/specifications/ (http://www.asus.com/Networking/RPN14/specifications/)
That means that it has an ac coupled output, with too lower capacitance value to drive phones. Disappointing, particularly as they show a "headphones icon" on that output. But it shouldn't effect the performance when driving an amplifier.
Definitely disappointing as product manual (p.7 (http://dlcdnet.asus.com/pub/ASUS/wireless/RP-N14/EEU8662_RP_N14_QSG.zip)) states:
"You can insert an earphone, powered speaker, or stereo system to the 3.5mm stereo audio port." At this stage I'd try an RMAA test on it. You can record the RMAA produced waveforms through the network device and record it on a laptop or something, and then later feed those recorded waveforms back into RMAA to analyse. It's kind of the same as a loopback test but done in two separate recording and playback phases. An RMAA test should definitively point to exactly what type of distortion you are getting.
I will try RMAA and report back. Thanks for the help, this forum is way more helpful than Asus support! Their answer to my questions was:
"RP-N14 is nor audio device. For audio connection you should use audio devices."
I will certainly check it, but it doesn't sound as ground loop. Ground loop sounds like hum (at least in my experience) and this sounds like distortion.
A ground loop just means that there is a voltage differential between the ground terminals of two devices. Thus a D.C. potential will exist between them, which may or may not cause problems at the input of an amplifier. The D.C. potential may vary with signals and this will introduce various forms of noise and possibly distortion.
A 1:1 transformer in the chain prevents the D.C. potential from passing through it thus removing this source of possible problems.
In my case there was a lot of noise on the signal from my sound card to my amplifier. Actually there was a lot of noise even without a signal.
On the other hand listening with decent headphones plugged into the sound card no such effects were audible.
It was a fairly long run but testing with short runs and other amplifiers showed the same effects. The insertion of a 1:1 transformer in the chain reduced these to the point of inaudibility. The only explanation I know of for this is that the transformer eliminated a ground loop.
With the transformer in the chain I think the sound from the computer is at least as good as the sound from the receiver's built in FM receiver on a local station.
Just want to be perfectly clear, although your original post was pretty well paid-out - you've had this distortion problem since you first used it?
And you've gone back upstream in the chain to make sure the Asus isn't being fed distorted audio?
Just want to be perfectly clear, although your original post was pretty well paid-out - you've had this distortion problem since you first used it?
Yes, I have immediately noticed it.
And you've gone back upstream in the chain to make sure the Asus isn't being fed distorted audio?
And yes, I have checked that as well.
RMAA test will definitely confirm it but this seem to be either badly designed or defective unit. Unfortunately none of the people I know has one so I am unable to compare it other units.
Just want to be perfectly clear, although your original post was pretty well paid-out - you've had this distortion problem since you first used it?
Yes, I have immediately noticed it.
And you've gone back upstream in the chain to make sure the Asus isn't being fed distorted audio?
And yes, I have checked that as well.
RMAA test will definitely confirm it but this seem to be either badly designed or defective unit. Unfortunately none of the people I know has one so I am unable to compare it other units.
Just wanted to make 100% sure, so the techy problem-solvers of HydrogenAudio aren't sent chasing red herrings. Are there any sites with lots of customer reviews of this unit? If there is a common complaint among buyers or some hint of a bad batch of products, that might provide a pattern.
I will certainly check it, but it doesn't sound as ground loop. Ground loop sounds like hum (at least in my experience) and this sounds like distortion.
A ground loop just means that there is a voltage differential between the ground terminals of two devices. Thus a D.C. potential will exist between them, which may or may not cause problems at the input of an amplifier. The D.C. potential may vary with signals and this will introduce various forms of noise and possibly distortion.
Hi Ed, just to clarify how a ground loop normally arises. The wiring of ac power outlets in homes is often quite adhoc, and even outlets that are in reasonably close proximity to each other sometimes have wiring that runs very different routes from the "fuse box" (or main point of entry). As a result, when a signal ground (like a coaxial audio cable for example) connect two devices who's power wiring runs very different routes, a significant amount of ac pickup can be induced in such a large loop. So in general this pickup is ac at the same frequency as the mains power (50 or 60 Hz depending upon the country).
When the ground loop pickup is not too excessive it just introduces hum. In some case however, the group loop pickup can be large enough to overload an analog input, and then you can get all sorts of nasty anomalies.
The solution is as you say, using an audio transformer to isolate the signal. Yes it's true that the transformer does block DC, but that's not it's main purpose here. The transformer just removes the need for a direct galvanic connection between the two grounds (isolates the grounds), thus breaking the ground loop.
Another simple solution that is adequate in many cases is simply to run everything (in the system with an interconnected signal ground) from the *one* common power outlet, using a short extension cord and "power boards" as necessary. This doesn't entirely eliminate a ground loop, but it does often make it manageable for devices that are in reasonably close proximity.
This is my first attempt at using RMAA so it's quite possible that I haven't done it correctly.
(http://i57.tinypic.com/1zdum1y.jpg)
recorded wav: test3.wav (http://www9.zippyshare.com/v/55971517/file.html)
Recorded using Asus H81M-E on-boar audio (Realtek® ALC887):
(http://i62.tinypic.com/30vlnki.jpg)
Second attempt (@RP-N14), hopefully this time I have done it correctly
(http://i58.tinypic.com/10fxrbm.jpg)
recorded wav: test_rp-n14.wav (http://www61.zippyshare.com/v/20279372/file.html)
*@mods please delete post #18
The peaks on those sin waves are compressed. No idea if its bad analog or some kind of DSP.
BTW, rather than using the seedy file hosting site that tries to download malware onto people's PCs, you can upload files directly to these forums.
The solution is as you say, using an audio transformer to isolate the signal. Yes it's true that the transformer does block DC, but that's not it's main purpose here. The transformer just removes the need for a direct galvanic connection between the two grounds (isolates the grounds), thus breaking the ground loop.
Another simple solution that is adequate in many cases is simply to run everything (in the system with an interconnected signal ground) from the *one* common power outlet, using a short extension cord and "power boards" as necessary. This doesn't entirely eliminate a ground loop, but it does often make it manageable for devices that are in reasonably close proximity.
Although I haven't quoted the first part of your message it agrees with how I understand things. Ideally one should ground all equipment at a single point before trying isolating transformers. This is just not very feasible in my particular circumstances, so I gave a transformer a try and it worked.
Apologies Saratoga. Original shady link replaced by new one @Hydrogenaudio Forum > Uploads
Second attempt (@RP-N14), hopefully this time I have done it correctly
(http://i58.tinypic.com/10fxrbm.jpg)
recorded wavs: RP-N14 & MBO (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=106404&view=findpost&p=870392)
*@mods please delete posts #18 and #20
You can upload the images too.
(http://www.hydrogenaud.io/forums/uploads/monthly_07_2014/post-18295-1406260056_thumb.jpg)
Full image click HERE (http://www.hydrogenaud.io/forums/index.php?act=attach&type=post&id=7976).
OK, now that we can see those results it's very obvious that something is indeed wrong with that device. Assuming that the test was carried out correctly* those results are absolutely terrible!
THD: 2.4%
IMD: 7.7%
Those figures should be more like 0.1% or less for any device that's even half decent.
*Note. It's been a while since I've used RMMA and it was a slightly older version. From memory however, the program should make some calibration files. So make sure you record and play the calibration files so you know that the signal you're recording from the RP-N14 is at suitable levels.
Stupid question, but have you tried streaming from some other device? That link above says they have an iPhone/Android app, maybe try that see if its just a problem with your PC.
The peaks on those sin waves are compressed. No idea if its bad analog or some kind of DSP.
...
Wondering if OP set the system audio format to follow the settings found in RMAA (to avoid SRC) and also disable all audio enhancements?
Line in > Enhancements
screenshot click HERE (http://www.hydrogenaud.io/forums/index.php?act=attach&type=post&id=7977)
Line in > Advanced > Default format - 2 channel, 16 bit, 44100 Hz
screenshot click HERE (http://www.hydrogenaud.io/forums/index.php?act=attach&type=post&id=7978)
Stupid question, but have you tried streaming from some other device? That link above says they have an iPhone/Android app, maybe try that see if its just a problem with your PC.
I just did, check results HERE (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=106404&view=findpost&p=870420)
The channels on test_rp-n14.wav are inverted (though that fact alone doesn't explain the horrible measurements).
The channels on test_rp-n14.wav are inverted.
Yes I have noted that, but couldn't figure the reason way? All recordings where made using same 3.5mm to 3.5mm cable.
Yes I have noted that, but couldn't figure the reason way?
At this point I'm willing to accept that you may have stumbled upon one of the absolute worst audio devices currently available.
At this point I'm willing to accept that you may have stumbled upon one of the absolute worst audio devices currently available.
It's possible that I am doing something as this is the first time I am using RMAA and Audacity. That said I was never too obsessed with audio fidelity*, but my first reaction to this device was:
What the #$@&%*! *I grew up listening to punk demo tapes.
Could you clarify the way you are connecting this? I have difficulties to understand the whole setup, seeing the product description and the screen captures of RMAA that you showed.
The product page describes it as a wireless repeater, that also has airplay-like features.
Since we are interested in the audio side of the product, how does the audio reach the device? I should remark that I don't know first-hand what airplay is, but I do know and use DLNA on my TV, mobile and laptop. Is it correct to say that airplay acts similar to an "upnp controller"? As such, is it playing (and decoding if needed) the audio by itself or it simply receives a stream? I am quite confused since you show the digital out on that RMAA capture.
Also, I guess that the audio is sent back to the computer with a 3.5mm jack connecting directly the laptop and that headphone connector. Are the playback and recording volumes setup adequately?
At last, if you had to use the test signal wav directly on another player and generated it with RMAA, could you verify the .wav file itself? I remember seeing on another thread (that i can't find now) that somehow, the wav was generated with bad audio.
You also said that the android test had to be done with mp3. You mean that the player does not support wav, or that trying to play a wav was unsuccessful?
On the other hand, seeing the small device, and knowing that it has two WIFI antennas inside that not only send, but also receive signals, it is not unfeasible that the device receives interferences.
Could you clarify the way you are connecting this? I have difficulties to understand the whole setup, seeing the product description and the screen captures of RMAA that you showed.
The product page describes it as a wireless repeater, that also has airplay-like features.
Since we are interested in the audio side of the product, how does the audio reach the device? I should remark that I don't know first-hand what airplay is, but I do know and use DLNA on my TV, mobile and laptop. Is it correct to say that airplay acts similar to an "upnp controller"? As such, is it playing (and decoding if needed) the audio by itself or it simply receives a stream? I am quite confused since you show the digital out on that RMAA capture.
I don't know how Airplay or Airfoil function. I used Foobar2000/Airfoil/Airplay as I was unable to get Foobar2000/DLNA working. Ironically, I picked this device instead of Airport Express just because I thought it has capability to act as DLNA renderer.
test_rp-n14.wav sample:
source: Foobar2000 to Airfoil to RP-N14 to MBO Line in (3.5mm to 3.5mm cable to connecting RP-N14 and MBO Line in)
recorded: using Audacity
and than loaded in: RMAA Analyze WAV
Also, I guess that the audio is sent back to the computer with a 3.5mm jack connecting directly the laptop and that headphone connector. Are the playback and recording volumes setup adequately?
I'm not sure whether I have set levels correctly as I have zero experience doing this. Both Playback level and Line in recording level where set to 0.0 db while recording test_rp-n14.wav sample. Playback level in AiPlayer was also set to max while recording test_android.wav sample.
At last, if you had to use the test signal wav directly on another player and generated it with RMAA, could you verify the .wav file itself? I remember seeing on another thread (that i can't find now) that somehow, the wav was generated with bad audio.
You also said that the android test had to be done with mp3. You mean that the player does not support wav, or that trying to play a wav was unsuccessful?
AiPlayer supports .wav but attempt to play it on RP-N14 was unsuccessful.
.wav and .mp3 test signals HERE (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=106404&view=findpost&p=870427)
I was able to do some testing and alternate ways of trying this, to see if we can pinpoint more clearly to the device as being faulty or to something else.
I downloaded the trial version of airfoil (works for 10 minutes, then it needs to be closed and opened again), and also, installed airfoil speakers in my android phone. This way, i could sort of simulate your device.
Configured the soundcard line in for the corresponding frequency, opened airfoil, and setup it to use the android phone as a speaker. Also i setup it to run RMAA. I setup RMAA for directsound on output, and mme line in on input, 16bit 44Khz, mostly like you have. volume to max on android phone and 3.5mm cable from phone to laptop.
I played the signal and recorded it in audacity. To do so, I used the "playback only" button. This way, it is possible to control the gains properly, since it plays the calibration signal first.
Then in audacity, cut the silence at the beginning (leave around 100 milliseconds previous to the sound start), save to wav and load this in RMAA, with the analyze wav button.
The "playback and record" mode cannot be used, because there is too much latency (added by airfoil), and RMAA cannot sync. I tried at 96Khz and it worked, but the results were completely wrong (like +16.9, -13.11 frequency response, 100 IDM , and so on), so probably it didn't sync correctly either.
So if you can try it this way, to see if it improves that gets recorded, it would be nice.
At last, inspecting the wavs that you uploaded, seems that they have been resampled with a bad resampler. I wonder if maybe the RP-N14 can only play 48Khz and resamples everything to it.. So try the same test, but at 48Khz to see what happens.
I was able to do some testing and alternate ways of trying this, to see if we can pinpoint more clearly to the device as being faulty or to something else.
I downloaded the trial version of airfoil (works for 10 minutes, then it needs to be closed and opened again), and also, installed airfoil speakers in my android phone. This way, i could sort of simulate your device.
Configured the soundcard line in for the corresponding frequency, opened airfoil, and setup it to use the android phone as a speaker. Also i setup it to run RMAA. I setup RMAA for directsound on output, and mme line in on input, 16bit 44Khz, mostly like you have. volume to max on android phone and 3.5mm cable from phone to laptop.
I played the signal and recorded it in audacity. To do so, I used the "playback only" button. This way, it is possible to control the gains properly, since it plays the calibration signal first.
Then in audacity, cut the silence at the beginning (leave around 100 milliseconds previous to the sound start), save to wav and load this in RMAA, with the analyze wav button.
So if you can try it this way, to see if it improves that gets recorded, it would be nice.
I'll give it a tray and report back.
At last, inspecting the wavs that you uploaded, seems that they have been resampled with a bad resampler. I wonder if maybe the RP-N14 can only play 48Khz and resamples everything to it.. So try the same test, but at 48Khz to see what happens.
I think Airplay is 16-bit/44.1 kHz only (using ALAC).
It's possible that I am doing something as this is the first time I am using RMAA and Audacity. That said I was never too obsessed with audio fidelity*, but my first reaction to this device was: What the #$@&%*!
Ok, then it looks like the simplest way to get to the bottom of this would just be to make a 30 second recording of any well know song played through that system, and upload it here for people to listen.
RMAA is excellent for spotting subtle flaws in an audio system, but this one seems to be far from subtle. So direct listening may be a simpler option in this case. If you have a good original (pref ripped straight from CD, but any good quality mp3 etc should do), and the flaw is really obvious, then just upload a recording and I'm sure someone here will be able to pick the artefact.
Note: If you've got something very well known, like a "classic" track, then just uploading 30 seconds of the recorded track should be sufficient. If however you want to record something more obscure, then please upload the recorded and original tracks. Copyright considerations allow at maximum 30 seconds uploads here, but that should be plenty.
Music samples HERE (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=106404&view=findpost&p=870456)
Music samples HERE (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=106404&view=findpost&p=870456)
Yeah that definitely sounds woeful papucar. I'd say it's probably a faulty unit. If it's not straight out faulty then I think you've just found the worst sounding audio device on the market. Take it back and tell them you want your money back as it's "not fit for the purpose sold".
I just trimmed the noise from the beginning of "Glory B" and aligned it for an abx. It really wasn't necessary as the difference was that obvious, but here are the results anyway.
foo_abx 1.3.3 report
foobar2000 v1.2.6
2014/07/26 08:56:58
File A: E:\MyDoc\Downloads\Glory_a.flac
File B: E:\MyDoc\Converted\Glory_b.flac
08:56:58 : Test started.
08:57:12 : 01/01 50.0%
08:57:24 : 02/02 25.0%
08:57:32 : 03/03 12.5%
08:57:38 : 04/04 6.3%
08:57:46 : 05/05 3.1%
08:57:59 : 06/06 1.6%
08:58:09 : 07/07 0.8%
08:58:21 : 08/08 0.4%
08:58:28 : 09/09 0.2%
08:58:36 : 10/10 0.1%
08:58:48 : 11/11 0.0%
08:58:50 : Test finished.
----------
Total: 11/11 (0.0%)
I wonder which codec is internally used to stream to this device. To be honest, the samples remind me of a2dp/sbc compression artifacts. Android had a too low bitpool setting in the past, resulting in a similar sound when streaming stuff over bluetooth. Maybe a2dp is used here too and ASUS has specified a too low bitpool compatibility in their device, so that airfoil sends an overcompressed stream?
Just wanted to thank everyone for all the help provided. Asus refuses to acknowledge that unit is malfunctioning (as it is not audio not an "audio device" according to them). I will probably give it to someone who needs repeater.
Asus refuses to acknowledge that unit is malfunctioning (as it is not audio not an "audio device" according to them). I will probably give it to someone who needs repeater.
Where did you buy it papucar? Online or from a "bricks and mortar" retailer. I'd be definitely trying to return it due to the fact that it cannot do what it claims to be able to do - audio. "Streaming Audio" is the second from the top of the list of features on their website. If Asus's own support is now telling you "
it is not an audio device" then it seems to me you have excellent grounds for asking for your money back.
I bought it online, but it's not big deal as it was not too expensive. I just undecided now whether I should buy Airport express or get rid of the amp and by relatively cheap AVR like Denon AVR-X1000. Currently leaning towards AVR as it would solve all my connectivity issues.
Netgear makes another DLNA enabled AE alternative called WN3500RP but after Asus fiasco I am reluctant to buy untested device.
The AVR will give you a lot more flexibility The Denon amps can be controlled from Android/iPhone apps as well I believe. Might be worth reading up on the streaming features to see how well they work.
The AVR will give you a lot more flexibility The Denon amps can be controlled from Android/iPhone apps as well I believe. Might be worth reading up on the streaming features to see how well they work.
I didn't think that Danon amp had WiFi capability?
Good catch, AVR-X1000 has Ethernet only. Newer model AVR-X1100 has WiFi. Any recommendations regarding AVR choice? Any known issues with Pioneer/Yamaha/Denon/Harman Kardon units?