Do you listen to mp3's while riding?

[HaulinAshe]

There is a post on Zumo Forum about using the MP3 Gain, and I think it said to use 97 dbs. I have not tried it yet, but they say it works.

Thanks RR. That would seem to be in keeping with my findings thus far. I'll sweep the entire SD card and report back with tomorrow's test.

 

[Fred W]

What are you running the audio through after the zumo? Starcom or autocom? Just curious. I'm still using a Motocom (mono) because my starcom is on backorder with Jeff at Bike Effects.

Zumo 550 to Starcomm Advance to wired headset(s).

The Starcomm Volume is about 50%, which gives it the best compensation for wind noise/speed/etc. Two problems with that setting is that it requires an appreciable input from the incoming audio sources, and it will blow out your ears when I sing inside the helmet!



Typically I run the Zumo's; NAV Audio at 100%, MP3 Audio at 80%, Master Volume at 3-bars below max.

Today I ran MP3 Audio at 100% and Master Volume at 2-bars below max. That's about where I set it for older MP3 files with the low volume gains. So I'm thinking that I need to normalize the files at a higher setting.

OK, I understand now.

My thinking is that you want to normalize to the lower amplitude (89 dB) to reduce the playback distortion due to clipping, and then adjust the MP3 volume to 100% and set the nav volume lower to whatever is comfortable compared to the MP3's. Mine is set at 80% right now (the C550 has the same configuration as the zumo). I find that all the music sounds clean (many songs sounded muddy from the Garmin before) and I can run the master volume up to max (all bars) and not get any distortion. I'm typically running it at -1 or -2 bars.

If you raise the normalization level to a higher value, and if you have the "Don't clip when doing track gain" option turned on (as I do) any songs that would result in clipping will be normalized to a lower amplitude. That means you will still end up having to adjust the volume for those songs.

The alternative would be to not use "Don't clip..." and just live with the distortion when the clipping occurs.

 

[DaSpyda]

Since I started this mess of a thread, I guess it's ok if I help it drift a bit.
Along the same lines as intarwebs ray-dee-oh is a web site called Pandora that I've played with. It let's you input a music selection or more and it forms a "station". It then goes out and tries to find other music to stream to you that is similar. As they pop up on your computer you can give the selections a thumbs up (yeah I like that) or thumbs down, in which case it aborts playing that song and looks for more that you will like.

Supposedly the thing learns from your inputs and after a while you have a "playlist" of sorts, except that there is no list, it just grabs music in the same genre. You can have multiple stations configured in your free account.

I have an RCA Lyra wireless transmitter connected to my desktop PC and 2 wireless receivers attached to entertainment centers in two rooms in my house (Living room and Family room). I can set the thing playing the same music all over the house, never listen to an advertisement, and it's like I was picking the music!!

It's tres cool...

https://www.pandora.com/

edit: I forgot to mention they will intersperse innocuous ads on the free version every so many songs. Subscriptions get no ads.

Pandora is way-kewl...

In order to use the Lyra Wireless properly, you need a Windows based PC running Windows 98 SE, WinME, Win2000, or WinXP. The PC must be capable of supporting USB devices.

No Vista???

 

[Fred W]

No Vista???

I have no need for Vista, but I bet the Lyra will work on Vista.

The one PITA thing about the Lyra is it installs as an alternate sound card. So if you want to pipe the music through it you have to go into control panel and select it as the audio playback device so that your browser sends it's sounds there instead of whatever sound card you have. What I've been trying to find is an applet that will allow you to send program sounds to multiple sound cards at once, that way my PC speakers will still work plus the sounds go to the Lyra.

Anyone know of such a thing?

 

[HaulinAshe]

I finished collecting a whord of favorite MP3s last night. I re-ripped a bunch of CDs so that I have fresh MP3 files at my preferred bit rate, from which to start.

Planning to play around with the target threshold for comparison sake tonight. The program shows you how much %clipping is likely to occur, based on the overall analysis and current settings.

I just love being wrong. So I edited this post and included the HELP text notes on Lossless Gain Adjustment. Seems you can jack the MP3 Global/Master Gain up and down without losing any data. Here's why...

The bad news: MP3Gain can only adjust the volume of your mp3 files in steps of 1.5 dB.
The good news: 1.5 dB is a small enough step for most practical purposes. Most humans can just barely hear a volume change of 1 dB.

The other good news is that this volume adjustment is completely lossless. In other words, if you adjust an mp3 by -6 dB and then change your mind, you can adjust it again by +6 dB and it will be exactly the same as it was before you made the first adjustment.

Here's the technical reason why it's lossless, and also why the smallest change possible is 1.5 dB:

The mp3 format stores the sound information in small chunks called "frames". Each frame represents a fraction of a second of sound. In each frame there is a "global gain" field. This field is an 8-bit integer (so its value can be a whole number from 0 to 255).

When an mp3 player decodes the sound in the frame, it uses the global gain field to multiply the decoded sound samples by 2(gain / 4).

So if you add 1 to this gain field in all the frames in the mp3, you effectively multiply the amplitude of the whole file by 2(1/4) = 119% = +1.5 dB.

Likewise, if you subtract 1 from the global gain, you multiply the amplitude by 2(-1/4) = 84% = -1.5 dB.

 

[Wicked Webby]

Nice find!

WW

 

[Fred W]

I finished collecting a whord of favorite MP3s last night. I re-ripped a bunch of CDs so that I have fresh MP3 files at my preferred bit rate, from which to start.
Planning to play around with the target threshold for comparison sake tonight. The program shows you how much %clipping is likely to occur, based on the overall analysis and current settings.

One nice thing about this little application is that once you have analyzed the music it remembers what the found levels were (unless you explicitly tell it to delete the analysis) so you can go back later and tweak the gains up and down at will.

I may play with some of my files also to see what the optimum target gain is, ie can I get more volume without adding much clipping distortion.

BTW - what is your "preferred" bit rate? I typically use 128k to keep the files small so I can fit more on the 2GB SD cards. I know I can't hear the difference of any higher bit rates through my earplugs.

 

[Ari Rankum]

For Linux users:

The SourceForge page only mentions Windows and Mac versions.

I went ahead and downloaded the source and built it on a custom 2.6.33 X86_64 kernel using gcc 4.1.2 on a machine whose pedigree is listed at the bottom of this post, for the true DORKs, like me. 12 MB of mp3 analysis and modification in 7.5 seconds wall clock time.

[mon@butterwheel NYC_Man_-_The_Collection__disc_2_]$ time /opt/MP3GAIN/mp3gain *.mp3

02_-_Temporary_Thing.mp3

Recommended "Track" dB change: -6.340000

Recommended "Track" mp3 gain change: -4

Max PCM sample at current gain: 37172.140581

Max mp3 global gain field: 210

Min mp3 global gain field: 7

12_-_NYC_Man.mp3

Recommended "Track" dB change: -4.580000

Recommended "Track" mp3 gain change: -3

Max PCM sample at current gain: 31850.390447

Max mp3 global gain field: 210

Min mp3 global gain field: 114

13_-_Dirty_Blvd.mp3

Recommended "Track" dB change: -7.710000

Recommended "Track" mp3 gain change: -5

Max PCM sample at current gain: 39230.272657

Max mp3 global gain field: 210

Min mp3 global gain field: 67

Recommended "Album" dB change for all files: -6.020000

Recommended "Album" mp3 gain change for all files: -4

real 0m7.249s

user 0m6.674s

sys 0m0.040s

[mon@butterwheel NYC_Man_-_The_Collection__disc_2_]$ ls -l *.mp3

-rw-rw-r-- 1 mon mon 5034530 2008-05-03 09:33 02_-_Temporary_Thing.mp3

-rw-rw-r-- 1 mon mon 4727330 2008-05-03 09:33 12_-_NYC_Man.mp3

-rw-rw-r-- 1 mon mon 3373730 2008-05-03 09:33 13_-_Dirty_Blvd.mp3

[mon@butterwheel NYC_Man_-_The_Collection__disc_2_]$

Pedigree:

[mon@butterwheel ~]$ cat /proc/cpuinfo

processor : 0

vendor_id : GenuineIntel

cpu family : 6

model : 15

model name : Intel® Core2 CPU 6600 @ 2.40GHz

stepping : 6

cpu MHz : 1596.000

cache size : 4096 KB

physical id : 0

siblings : 2

core id : 0

cpu cores : 2

fpu : yes

fpu_exception : yes

cpuid level : 10

wp : yes

flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm

bogomips : 4813.45

clflush size : 64

cache_alignment : 64

address sizes : 36 bits physical, 48 bits virtual

power management:

processor : 1

vendor_id : GenuineIntel

cpu family : 6

model : 15

model name : Intel® Core2 CPU 6600 @ 2.40GHz

stepping : 6

cpu MHz : 1596.000

cache size : 4096 KB

physical id : 0

siblings : 2

core id : 1

cpu cores : 2

fpu : yes

fpu_exception : yes

cpuid level : 10

wp : yes

flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm

bogomips : 4810.96

clflush size : 64

cache_alignment : 64

address sizes : 36 bits physical, 48 bits virtual

power management:

 

[HaulinAshe]

I have settled on settings for now.

95.0 db

190 kbps data rate

Zumo MP3 at 90%

Zumo Master Volume at 3-bars below max.

Starcom Master Volume at 60%

Not completely certain, but on some songs I can hear the difference between 128 kbps and 190 kbps with my helmet speakers. I'm running a 4 GB SD card in the Zumo and that gives me 40 hours of MP3 time.

 

[Fred W]

I have settled on settings for now.
95.0 db

190 kbps data rate

Zumo MP3 at 90%

Zumo Master Volume at 3-bars below max.

Starcom Master Volume at 60%

Not completely certain, but on some songs I can hear the difference between 128 kbps and 190 kbps with my helmet speakers. I'm running a 4 GB SD card in the Zumo and that gives me 40 hours of MP3 time.

Thanks for the follow up and your settings Jeff and I'm glad it's working out for you.

I'm curious to know, when you gain adjusted to 95 dB, did you have the "Don'r clip when doing track gain" option set on or off? The reason that I ask is that even with the default 89 dB I have a few tracks that are gain adjusted lower because they would clip at 89.

Also, for anyone interested, earlier in this thread I posed a question about how to send sound to two sound cards simultaneously on a Windows XP box so that I could send sound through my RCA Lyra wireless audio to the home stereo and also on the PC audio. After much searching I found a nifty utility (also free) that will do that for you. It's called "AudioRepeater.exe" and it is part of the shareware trial download for another program called "Virtual Audio Cable". You don't need to keep (or even install) the shareware program, just grab the AudioRepeater.exe out of the zip file and trash the rest.

You just have to go into Control Panel Sound settings, Audio, Sound Recording, Volume button and select "Stereo Mix" as the source in the Recording Control window. Then whenever you want to split the audio to a second device you just run the Audio Repeater and select Microsoft Sound Mapper as the Wave in Queue and your second sound card as the Wave out Queue. Works like a champ.

 

[HaulinAshe]

I did not check the "Do Not Clip" box.

I ran some tests both ways and could not tell much difference. So I decided to take the default (disabled) setting.

 

[Fred W]

I did not check the "Do Not Clip" box.
I ran some tests both ways and could not tell much difference. So I decided to take the default (disabled) setting.

OK thanks. I'll try it.