little clicks and pops

Discussion about my Wifi Radio project at http://mightyohm.com/wifiradio/ or my WL-520gU talk at NOTACON.
lostmyshape
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Joined: Thu Mar 31, 2011 11:16 am

Re: little clicks and pops

Post by lostmyshape »

crap... I was having the same problem. Tried Kamikaze and Backfire, oss and alsa, and three different sound interfaces (from the cheapo "3D Sound" to an M-Audio Quattro). All changes resulted in the same pops and clicks, through mdp and madplay. I'm also getting those strange percentages and multiple instances of mpd in top, although the free command shows ~200k of ram available and almost all of the 512 of swap (on an external flash drive) available.

It's awfully disappointing to find out that the 520gu can't handle mpd after-all. mieczotronix, could you supply details about your install on the 500gp that got things working? if this is a driver issue, is there a way I can troubleshoot?

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mightyohm
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Re: little clicks and pops

Post by mightyohm »

Glad you got it fixed, that is interesting that 500gp + UHCI fixed your problem!

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pasdesignal
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Re: little clicks and pops

Post by pasdesignal »

I have the same problem with clicks and pops on my WL-520GU. Very frustrating considering everything else is working so well.

My goal is also a high-end network audio player. The compact WL-520gu and its low power consumption means I can fit this nicely into a little chassis and run it with my DIY valve DAC and power amps...

I am using Kamikaze 8.09.2 and have mounted an NFS drive which contains the media library. Everything works smoothly and I am controlling the player using MPOD on my ipod touch. Nice interface!

The clicks and pops are irregular, sometimes they don't begin immediately but usually every couple of seconds. I have also tried all sorts of settings within mpd.conf

My USB DAC is irrelevant in this case. It happens with whatever DAC I try. Same results as reported earlier in this post: some DACs just pop, another hisses and switches from side to side.

My thoughts are that this may be related to the clock timing issue that I keep hearing about. 200Mhz versus 240Mhz? see: http://www.dd-wrt.com/phpBB2/viewtopic. ... 599#231599 and there are other bug reports from openwrt users see: https://dev.openwrt.org/ticket/4083 and here: https://forum.openwrt.org/viewtopic.php?pid=107594.

I am by no means an expert though, it is just a hunch.

But I will persevere with this device for a while. I am trying newer versions of openwrt, but looks like I will have to use extroot or similar technique to load the inflated mpd and dependencies...they got big,non? Boo bloatware!

mieczotronix
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Joined: Tue Nov 23, 2010 2:48 pm

Re: little clicks and pops

Post by mieczotronix »

I've been busy lately and haven't enough time to listen to my asus.

Sorry if I disappoint somebody, but I've noticed that pops and clicks are still there on both my 500gp /520gu

What I also noticed is that they only appear on:
- .flac - (that's for sure)
- on high-rate mp3s as well
some high rate mp3s however seemed to play ok - I haven't checked it carefully enough (can't tell bitrate of files playing w/o going to another room).

I've just listened to some calm and quiet internet radio music for a couple of hours last night and haven't heard any clicking. I also played a couple of .flacs and clicks were there, but again I also played some mp3's and results were mixed.

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mightyohm
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Re: little clicks and pops

Post by mightyohm »

Sounds like there is a limit to what the WL-520 can decode, or a bug in the decoder.

I don't have any information on this, all I can say is that I have never experienced this on any of the streaming stations I listen to. Maybe I have just been lucky, although I suspect it is partially because most streaming stations are <= 128Kbps MP3.

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pasdesignal
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Re: little clicks and pops

Post by pasdesignal »

Yes, I can confirm the above behaviour as well Jeff. So I suppose that is important to note: this only happens when decoding 'high quality' information.

I am trying to play FLAC's only. As this is the point of my dream machine: a high-end music player. When I stream internet radio it is fine and very enjoyable but just not 'hi-fi'.

Haven't found any forum comments here or otherwise that pin down the exact cause of the clicks and pops. I am stubborn and want to believe that the wl-520gu can handle flacs!

Trying a Backfire 10.03.1-rc4 install with external overlay so I can run alsa and will report back. Am I dreaming? maybe.

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pasdesignal
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Re: little clicks and pops

Post by pasdesignal »

Success!

I can happily say that using the latest trunk of Backfire (snapshots 11-April-2011) and using ALSA output driver, I have high quality, clean audio on my ASUS WL_520GU. No clicks and pops. Finally!

A brief description of the setup:

NFS server with FLAC library >> MPD on ASUS WL-520GU (Openwrt Backfire 10.03.1-rc5) >> USB audio output device >> Amplifier and speakers. All controlled using MPOD on an Ipod touch (4th gen). This provides a very nice interface and stable platform to work with. The browsing on the MPOD has a fast reaction time and is intuitive.

ONE PROBLEM: wifi still doesn't work for the ASUS WL-520GU using the 2.6 Kernel. Shouldn't be long though....(?) So for now the device is using cat5 between player and FLAC server. Not a big issue for the moment, but ultimately this will be a wireless solution.

It is cool being able to rip cds on my laptop and then drag them onto the fileserver while MPD is still playing. Doesn't interrupt audio play at all. Then tell mpd to update database and hey presto! New files there and waiting to be enjoyed.

If anyone is interested I will post any details that they need.... I am not an expert though, just one step above noob! Can't really help with setup issues beyond very basic level. :roll:

lostmyshape
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Re: little clicks and pops

Post by lostmyshape »

pasdesignal, that's awesome and fast! that snapshot must have been 2 min old! where did you get the 11-April-2011 snapshot? downloads.openwrt.org/snapshots/backfire/10.03.1-RC5-testing/brcm47xx/ gives me a 403 Forbidden. I'd love if you ran through your install for us.

Disheartening that wifi still doesn't work. I ran Backfire 10.03.1-rc4 brcm47xx with the 2.6 kernel and wifi was fixed. There were strange memory issues and random freezes/crashes, but wifi worked fine. Have you tried brcm-2.4? That has the 2.4 kernel, right? The openwrt wiki seems to indicate that wifi was working with the 2.4 kernel.

Thanks for posting this! Time for me to go back and give this another go.

mieczotronix
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Re: little clicks and pops

Post by mieczotronix »

Hi, great news!
I'd be also interested in details. Like for now, I don't know where to get the image from and what packages exactly are needed to get alsa runnig (I did it once but that was a month ago and it just evaporated off my mind).

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pasdesignal
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Re: little clicks and pops

Post by pasdesignal »

Hi chaps,

I will put up a few details when I get home from work.

To clarify : The backfire image I used was the very latest available in the trunk repository as of yesterday. ( Thats NZ time by the way!, we are living in the future over here remember? :lol: ) Putting "rc-5" is probably misleading, sorry. Got carried away!

The reason I couldn't use the 2.4 kernel is because extroot won't work on the Backfire images using 2.4 kernel. And you need to do extroot in order to engorge your ram.

I tried to do it on 2.4 kernel first and then, after hours of work, I saw the fine print at the bottom of this Howto: http://wiki.openwrt.org/doc/howto/extroot - made me cry almost! But we learn as we go.

Must say, its working like a charm and I'm very very happy to finally have a working model. I have been trying to do this for MONTHS. Ironically, I had just given up on the WL-520gu and had ordered a significantly more powerful (read: expensive) router when I made the break-through. Don't you just love the irony!

Big thanks to Jeff and other forum members is due. I found the original wifi-radio project so inspiring. The quality of the blog tutorial is superb Jeff.

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