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Zten
2005-10-11, 17:59
On a bit of a whim, I bought a new computer and a SB2 last Saturday. They will arrive this Thursday or Friday. I got a BIG HD (250GB). Reading some of the info, I think I will plan to go FLAC most of the time. However, I think I am also going to get an iPOD. So when at home, I will listen to FLAC files, when mobile, I'll listen to AAC files (I guess that is the file format?)on my iPOD. Anyway, what is my best way to go here? Should I first rip my CDs down to flac, then rip down to AAC? What tool do I use to rip flac files? What tool should I use to organize the music files? Should I keep the FLAC files seperate from the AAC files? On AAC, do I need to get iTUNES on my computer to rip down to AAC?

Confused,
Zten

ceejay
2005-10-11, 23:54
Hello, welcome, and good luck with your new toys! My situation is slightly similar - I listen to flac, my son uses AAC for his ipod, and my daughter uses MP3s!

Heres a suggestion. You will need a whole bunch of stuff to download, fortunately its all free and it all works.

(1) EAC (Exact Audio Copy) for ripping the CDs
(2) FLAC for compressing to flac
(3) iTunesEncode (not official, but calls iTunes for creating AACs)
(4) MAREO - this is a front end to EAC, specifically designed to invoke multiple compressor programs such as FLAC, iTunesEncode, LAME (for MP3) etc
(5) A tagging program such as MP3TAG

Personally I don't use a tool other than Windows Explorer for organising my files - you just need to think up a directory structure. For example

/music/flac/artist/album/trackname.flac

I keep my FLACs, AACs (and MP3s) in separate directories, then just point slimserver at the FLACs. EAC and/or MAREO will put files in the directory structure you specify.

You'll find lots of detailed discussion on most of these tools over at hydrogenaudio.org

Here, there's lots of good info in the forum if you search for it, also the FAQ covers a lot. There's a wiki, which is not well populated though this http://wiki.slimdevices.com/index.cgi?HowtoBestAudioQuality is good.

Have fun...

Ceejay

Robin Bowes
2005-10-12, 03:59
Zten said the following on 12/10/2005 01:59:
> On a bit of a whim, I bought a new computer and a SB2 last Saturday.
> They will arrive this Thursday or Friday. I got a BIG HD (250GB).
> Reading some of the info, I think I will plan to go FLAC most of the
> time. However, I think I am also going to get an iPOD. So when at home,
> I will listen to FLAC files, when mobile, I'll listen to AAC files (I
> guess that is the file format?)on my iPOD. Anyway, what is my best way
> to go here? Should I first rip my CDs down to flac, then rip down to
> AAC? What tool do I use to rip flac files? What tool should I use to
> organize the music files? Should I keep the FLAC files seperate from
> the AAC files? On AAC, do I need to get iTUNES on my computer to rip
> down to AAC?

OK, here's what I do.

I rip to FLAC [1] using Exact Audio Copy [2].

I then convert from FLAC to MP3 for use on my iPod using my own utility
"flac2mp3" [3] which is a perl [4] script and uses LAME [5]

I'm assuming you're using Windows.

You'll need the following software:

[1] FLAC - http://flac.sourceforge.net
[2] EAC - http://exactaudiocopy.de
[3] flac2mp3 - http://projects.robinbowes.com/flac2mp3
[4] Perl - http://www.activestate.com/Perl.plex?hdr=1
[5] LAME - http://www.rarewares.org/dancer/dancer.php?f=3

Give it a go and come back when you're stuck!

R.
--
http://robinbowes.com

If a man speaks in a forest,
and his wife's not there,
is he still wrong?

Zten
2005-10-13, 14:18
Thanks for the responses! I still haven't gotten my new computer;I cheaped out and got UPS Ground delivery from Dell.

:o)

Anyway, I've gotten started on using some of these tools on my new work laptop coomputer. Its pretty fast. Pentium M, 2GHz, 2GB of RAM. I got EAC going using FLAC. I set the command line to:

-V -5 -T "artist=%a" -T "title=%t" -T "album=%g" -T "date=%y" -T "tracknumber=%n" -T "genre=%m" %s

Not that I know what all this stuff means, but the -5 above means it should be operating in the fastest mode possible, right? I ripped a CD, but I was surpised at how long it took. It says it ran at 1.8x and took about 35 minutes.

The files seem to be about right. About 60% the size of the CD audio file. Am I doing something wrong or is this speed about what is expected?

ceejay
2005-10-13, 14:37
I set the command line to:

-V -5 -T "artist=%a" -T "title=%t" -T "album=%g" -T "date=%y" -T "tracknumber=%n" -T "genre=%m" %s

Not that I know what all this stuff means, but the -5 above means it should be operating in the fastest mode possible, right? I ripped a CD, but I was surpised at how long it took. It says it ran at 1.8x and took about 35 minutes.



I believe the -V option tells it to verify, which I would have thought slowed it up somewhat. Also -5 isn't the fastest ... its the default, meant to be a reasonable compromise between speed and compression. If you really want faster try leaving out the -V , and with -0 instead of -5.

Most of my ripping is done on 2.8GHz machines and is a bit faster than 35 mins... The other factor of course is EAC itself, there are lots of options there for going faster (but losing the secure rip which is why most people use EAC in the first place).

Ceejay.

Zten
2005-10-13, 15:31
Thanks again, Ceejay. I got rid of the -V and also changed the -5 to -0 and am trying it again. It doesn't seem to be going too much faster. I am still wondering if I am doing something wrong. As it is working it gives status:

Copy Track 4
Reading Track ==> this seems to be about 99 % of the time
Copy OK ==> seems to happen instantenously
Compress Track by External Program ==> a window pops up and this executes in about 5 seconds.

So does this mean I am limited by simply the spped of the CD ROM drive? That seems hard to believe, becuase it is a 48x drive. Thanks for putting up with my questions.

JJZolx
2005-10-13, 16:01
Thanks again, Ceejay. I got rid of the -V and also changed the -5 to -0 and am trying it again. It doesn't seem to be going too much faster. I am still wondering if I am doing something wrong. As it is working it gives status:

Copy Track 4
Reading Track ==> this seems to be about 99 % of the time
Copy OK ==> seems to happen instantenously
Compress Track by External Program ==> a window pops up and this executes in about 5 seconds.

So does this mean I am limited by simply the spped of the CD ROM drive? That seems hard to believe, becuase it is a 48x drive. Thanks for putting up with my questions.
Yes, it's most likely your CD-ROM drive. The DAE (digital audio extraction) speed isn't really related to the rated 48x data speed of the drive. Some drives just happen to do DAE better than others. In fact, just a few years ago, some CD-ROM drives were nearly incapable of DAE and you'd see 0.1x ripping speeds.

One thing you might try, though, is to use an ASPI interface for the means by which EAC controls the CD-ROM drive. Download the Nero ASPI driver here: http://ww2.nero.com/nero6/eng/WNASPI32.DLL.html

Drop the .dll file into the EAC program directory then open up the EAC Options (F9) and go to the 'Interface' tab. If EAC sees the ASPI dll you'll have the option to change the interface from 'Native Win32 interface' to 'Installed external ASPI interface'. It may improve your ripping speed, but it's just as likely to have have no effect. :-)

The FLAC encoding options generally have little effect on the overall ripping time. As you've noted, the bulk of the time spent is in reading (ripping) the data from the disk. The encoding is very fast in comparison. I'd recommend dropping the -0 and just using the default -5 compression level. You gain little speed by using the minimum compression level.

Zten
2005-10-15, 07:23
Yep. I'm rocking now. Got my new computer. Its converting to FLAC files at about 15 or 16x real time. Working great. Thanks for all your help.

Zten
2005-10-25, 14:55
I got my SB2 last week as well. I was a bit obsessive and ripped all my CDs in a few days. I now have over 3000 songs on my computer, and I just love being able to select any song instantly. It is so cool, although my wife thinks I'm nuts. :o)

The microwave oven does interfere with it. After running it for about 2 mins, the song starts to cut out. It of course recovers, but it is a little annoying. Its an old Microwave. I will probably get a new one soon. Is there any metrics out there on what Microwave Ovens have the lowest RF emissions?

Also, I noticed in setting up my SB2 that I could "see" all my neighbors WLANs. Is there any way I can tell what WiFi Channel is best for me given the presensce of my neighbors signals?

Finally, I am using a tool called GX Trancoder to convert FLAC files to MP3/AAC. Does anyone have any experience with GX Trancoder they would like to share?

Thanks again.

Jeff52
2005-10-26, 04:16
Also, I noticed in setting up my SB2 that I could "see" all my neighbors WLANs. Is there any way I can tell what WiFi Channel is best for me given the presensce of my neighbors signals?

Check out Network Stumbler: http://www.netstumbler.com/downloads/

Zten
2005-10-26, 10:43
Some intersting stuff I found. It seems some channels are for sure worse than others depending on the make/model of your microwave

....Curious to know what channels the microwave would affect the most, I ran the throughput tests again with the access point set to different channels. On channels 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11, the throughput was 660pps, 658pps, 655pps, 651pps, 643pps, 574pps, 434pps, 258pps, 178pps, 191pps, and 210pps, respectively. Based on these numbers, the microwave was most critically impacting channels 8, 9, 10, and 11.

I also found that the impact is more severe near edges of the range boundary of the access point where signal levels are lower. To test this, I lowered the transmit power of the access point to 1mW, which caused the signal power to decrease to -77dBm. This level is close to the range boundary of the WLAN.

As one would expect, the hit on throughput was even more with the weaker signals. The resulting throughput was about 10 percent lower than the case where the signal levels from the access point were higher at -63dBm.

What do you do about interference from microwave ovens?

Consider the following countermeasures:

Change access point channels. The microwave in use with this testing didnt severely degrade channels 1 through 6. As a result, avoid the use of these channels in areas of the building where microwave ovens operate. In fact, web browsing was very fast with the microwave running and the access point set to channel 1 and channel 6. Keep in mind, however, that your microwave ovens may operate at different frequencies within the 2.4GHz band. Check the label on the back of the microwave, which should provide the center operating frequency.
Avoid using the WLAN near microwave ovens. Keep at least ten feet away from operating microwaves while actively using WLAN applications. This eliminates working from most company break rooms when the microwave is in use. The actual impacts would only be intermittent, though, when someone runs the microwave for a few minutes while heating up a burrito or cup of soup.
As you can see, microwave ovens wont completely bring down your WLAN. Just be aware of the situation, and of the applicable countermeasures.

Table A-2 Channels for IEEE 802.11b

Channel Identifier Frequency in MHz Regulatory Domains
Americas (-A)
1
2412


2
2417

3
2422

4
2427

5
2432

6
2437

7
2442

8
2447

9
2452

10
2457

11
2462


So, I know what I am going to do when I get home tonight!

Zten
2005-10-26, 21:27
So I looked into things tonight. My Microwave oven is running at 2450MHz. This is approximately WiFi channel 8.5 . Turn out I was using channel 7 on my WLAN. It makes sense that I get interference from the microwave. I doubt a the WiFi recevier has that great of rejection to strong energy only 1.5 channels away, Also, I am no expert on Microwave ovens, but I suspect the are not the most spectrally pure of noise generators. Running at 2450MHz, they are still probably pumpin out some junk at 7 or 8 MHz away.

So then what channel should I use? To answer that question I took my laptop computer and used it as a receiver to measure my neighbors WiFi Channels they are using. I am in ear shot of signals from my neighbors on channels 1, 3, 6 (several folks on Ch 6), and 11.

So, I changed my WLAN to channel 4. Seems to be a channel that no one near by uses and best of all, no more drop outs when my wife runs the microwave oven!

MrC
2005-10-26, 22:57
Its awesome to see someone actually work through the problems with a more scientific approach. Nice work!

seanadams
2005-10-27, 00:05
Its awesome to see someone actually work through the problems with a more scientific approach. Nice work!

Agreed, nice work!

Seems it'd be worth cataloguing all the micrwave oven frequencis on a wiki page so we can easily see what band not to use for a given make/model...

ceejay
2005-10-27, 03:17
I suspect that trying to catalogue the frequencies used by all the microwave ovens out there could be a thankless task - there are an awful lot of them! I just checked mine and it also says 2450MHz: my suspicion would be that the generators they use must be highly commoditised and standardised, so in practice they are all likely to be 2450-based ?? Perhaps someone could post if they have something different.

In the meantime, just checking for the situation outside the US I found the following:


On an 802.11b or 802.11g wireless link, data is encoded using direct-sequence spread-spectrum (DSSS) technology and is transmitted in the unlicensed radio spectrum at 2.5GHz. IEEE 802.11b/g wireless nodes communicate with each other using radio frequency signals in the ISM (Industrial, Scientific, and Medical) band between 2.4 GHz and 2.5 GHz. Neighboring channels are 5 MHz apart. However, due to spread spectrum effect of the signals, a node sending signals using a particular channel will utilize frequency spectrum 12.5 MHz above and below the center channel frequency. As a result, two separate wireless networks using neighboring channels (for example, channel 1 and channel 2) in the same general vicinity will interfere with each other. Applying two channels that allow the maximum channel separation will decrease the amount of channel cross-talk, and provide a noticeable performance increase over networks with minimal channel separation.

The radio frequency channels used in 802.11b/g networks are listed below:

Channel 1 2399.5 MHz - 2424.5 MHz

Channel 2 2404.5 MHz - 2429.5 MHz

Channel 3 2409.5 MHz - 2434.5 MHz

Channel 4 2414.5 MHz - 2439.5 MHz

Channel 5 2419.5 MHz - 2444.5 MHz

Channel 6 2424.5 MHz - 2449.5 MHz

Channel 7 2429.5 MHz - 2454.5 MHz

Channel 8 2434.5 MHz - 2459.5 MHz

Channel 9 2439.5 MHz - 2464.5 MHz

Channel 10 2444.5 MHz - 2469.5 MHz

Channel 11 2449.5 MHz - 2474.5 MHz

Channel 12 2454.5 MHz - 2479.5 MHz

Channel 13 2459.5 MHz - 2484.5 MHz

Note: The available channels supported by the wireless products in various countries are different. For example, Channels 1 to 11 are supported in the U.S. and Canada, and Channels 1 to 13 are supported in Europe and Australia.

The preferred channel separation between the channels in neighboring wireless networks is 25 MHz (5 channels). This means that you can apply up to three different channels within your wireless network. There are only 11 usable wireless channels in the United States. It is recommended that you start using channel 1 and grow to use channel 6, and 11 when necessary, as these three channels do not overlap.


Several interesting points here - note the frequencies for channels 12 & 13, note the spread for each channel - and the overlap!

Ceejay

Zten
2005-10-27, 09:36
Thanks for the kind words, guys. I am having some fun with this. I actually am no novice to radio interference. I am an Electrical Engineer and have been working for Motorola for the last 17 years designing cell phones!

Amazing how things have changed in the world of electronics in the last 17 years. :o)

I love my Squeezebox, though!

MrC
2005-10-27, 09:54
My Thermador operates int the 2450MHz range as well.

Zten
2005-10-27, 11:22
Ceejay's info on the spreading of the signal is interesting. Last night when I was using my laptop as the receiver, I was noticing how some channels had higher noise levels than others. It ultimately is Signal to Noise ratio (SNR) that is important. Even though some channels did not seem to have a neighbor's WLAN on it, they still had some elevated noise. I chalked it up at the time to perhaps some Radio Frequency Interference (RFI) coming from my TV or other home electronics (or my computer itself). Maybe I was actually just seeing some of that adjacent channel energy spreading over.

Anyway, again SNR is what's important and I seem to be getting the best SNR on channel 4 with no interference from my microwave oven, so thats what I am going with.

I've had my WLAN going for almost 2 years using Ch 7 and never noticed a problem. Its probably becuase not until I got the SB2 have I ever truly demanded a continuous, reasonably un-interruptable flow of bits through the WiFi stream....

MrC
2005-10-27, 11:28
Here's a reasonable picture showing the channel overlap:

http://img.cmpnet.com/nc/1310/graphics/1310ws1b.gif

Zten
2005-11-07, 08:15
Yesterday I turned on my SB2 and started playing some tunes, about 15 seconds into it, I started getting regular, periodic dropouts at a duty rate of about 3 seconds of silence for 1 second of music. It was bizarre. I listen to FLACS 95% of the time, but I have a few MP3 files, so I switched over to an MP3 song, and it played fine with no dropouts. I concluded there wasn't enough BW to get the FLAC signal through. So then I looked at my WiFi configuration and noticed that my WLAN was set to 802.11b or .11g "mixed". I don't really know what "mixed" means, and I know I certainly haven't intentionally changed anything with my WLAN, but I switched to to 802.11g ONLY. Then everything was fine. Does this make any sense? Even if changing to 802.11g ONLY gives more BW, isn't 802.11b enough? I upgraded to SlimServer 6.2 a few days ago. Is this issue somehow related to that?