Rockbox Technical Forums

Support and General Use => Recording => Topic started by: bot47 on December 19, 2006, 02:48:02 PM

Title: Recording on ipod (was: nano recording volume)
Post by: bot47 on December 19, 2006, 02:48:02 PM
Hi!

I just started recording using my iPod nano and current rockbox cvs using the headphone jacket, but it's REALLY quiet (but works) even though I used a quite powerful input. Is there any trick to make it record more usefully? Increasing the volume and the record gain does not help that much!
Title: Re: nano recording volume
Post by: petur on December 19, 2006, 05:34:00 PM
see commit 18 Dec 01:52 by Barry Wardell:

Quote
FS#6096. Recording on PortalPlayer targets (H10, iPod Video, iPod 4g, iPod Color, iPod Nano). * Fix failed compile of enc_config.c when HAVE_MPEG2_SAMPR is not defined. * Fix bug in AIFF encoder header creation on little endian targets. * Add recording screen keymaps for H10 and iPod. * Move pcm_playback PP specific code to target tree. * Add recording code to wmcodec drivers. * Add pcm_record code. Some problems still remain: * Playback doesn't work after recording until Rockbox is restarted. * Gain control not implemented. * Only 16-bit/44KHz for now. The hardware should be capable of up to 24-bit/96KHz. * Line-in recording not tested on H10

Title: Re: nano recording volume
Post by: linuxstb on December 19, 2006, 08:54:36 PM
All evidence so far suggests recording doesn't work on the Nano.  It was enabled in CVS by mistake, and we decided to leave it just to try and confirm for sure that it doesn't work.

Are you sure it's working at all?  Do your recordings contain recognisable audio?

(I would be very happy to be proved wrong).
Title: Re: nano recording volume
Post by: bot47 on December 20, 2006, 06:00:48 AM
Yes, they do. Do you want me to upload some?
Title: Re: nano recording volume
Post by: barrywardell on December 20, 2006, 09:57:07 AM
It looks like the mic through headphones socket has to be specifically enabled on  4g/color iPods through a GPIO port. I wonder if the same thing is the case for the nano? See pcm_init_recording() in firmware/target/arm/pcm-pp.c for an idea of what I mean.
Title: Re: nano recording volume
Post by: linuxstb on December 22, 2006, 04:16:40 AM
Yes, they do. Do you want me to upload some?

No, but I'm curious to know what kind of input you used.  i.e. was it a mic, or something at line-in level?
Title: Re: nano recording volume
Post by: Febs on December 23, 2006, 08:47:12 AM
I recorded last night with my 5G iPod video, using a line-input dock made by Soap.  

Using a Sony ECM-907, the recorded signal is present, but barely audible above the noise floor.  As  a point of reference, what I was recording is a show that I play seven times a week.  I had previously recorded the show with an iriver H120, using the same microphone, same mic placement, etc.  In that recording, AGC safety mode limited the overall gain to about 28dB.  

I also tried using my Total BitHead headphone amp to boost the signal.  That gave me a little more signal, but also more noise.

I haven't yet had a chance to try recording from a line-level source.

Recording was unstable generally.  Rockbox would almost invariably eventually freeze during the recording.  I wasn't able to detect any pattern about what caused the freezes.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: linuxstb on December 23, 2006, 10:09:17 AM
Just a warning - don't judge the quality of recording on the ipods by the code in Rockbox at the moment.  It's only really "proof-of-concept' code, and no effort has yet been made to setup the ADC optimally.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Febs on December 23, 2006, 10:57:46 AM
I understand completely.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: podshot on December 31, 2006, 11:48:51 PM
well recording with a nano works. tried it with line out from my computer and it shows some activity... but its barely hearable in playback..  sorry for my english but i am still a bit drunk...  yeah i know this is just a "proof of consept"  but i tought i would just verify that recording on a nano works!;D i hope someone would work on improving it. ( i would do it if i had any coding expiriense)

well keep up the good work!
rock box rules!
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Llorean on January 01, 2007, 01:42:59 AM
Have you actually got a recording that is recognizable as the source material clearly enough to be definite, or are you judging that it works just from peakmeter movement?
Title: Re: Recording on ipod (was: nano recording volume)
Post by: mlind on January 01, 2007, 04:29:41 AM
...its barely hearable in playback.. 
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Llorean on January 01, 2007, 04:43:24 AM
Yes, but "barely hearable" could mean "I can barely hear a faint staticy noise" or it can mean "I can barely hear anything at all" or it can mean "I can barely, but significantly, identify the audio I was trying to record" and I would like a clear clarification of this.

I would also like to know if he used the dock adapter or the headphone jack.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: podshot on January 01, 2007, 09:42:34 AM
i used the headphone jack.
 "I can barely, but significantly, identify the audio I was trying to record"!
well i recorded a song and i was able to listen to it in playback but in realy bad quality and it was realy quiet. but it is recognisable!
Title: Re: Recording on ipod (was: nano recording volume)
Post by: bot47 on January 03, 2007, 05:19:52 AM
Sorry for me not answering immediatley ;)
I tried two things. Both worked (at least kind of):
1st) A quite loud output from my soundcard to the headphone jack.
2nd) The Line-In Pin of the Dockconnector works, too. I attached my (!!broken!!) iPod Radio Remote and I got a static noise which sounded like the 87.5 Mhz background noise and 87.5 Mhz is the default channel it gets tuned into when attaching it the first time to the iPod original OS.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: axlgreasetires on January 05, 2007, 08:18:33 PM
Doesn't work for me.  Maybe I am doing something wrong.  I'll try hooking it up to my amp.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: homielowe on January 06, 2007, 04:25:41 AM
I just read this thread and decided to try to record on my 5G through line-in to an oldschool CD player crankin some Gnarles Barkley at full blast. To my amazement the peak-meter actually moved (broke playback after though so wasn't able to listen to it on my iPod). Booted into APPLE OS (disk mode usb lags my comp)  and got itunes to add the recording onto iPod. With the volume cranked full on my cans I can definitely  hear some audio(if any) that was recorded. I would have hosted it but itunes kindly decided to hide it the in iPod control folder and I'm too lazy to find it   :P
edit: headphone jack srry
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 06, 2007, 07:40:41 AM
I am surprised a CD player at full blast would create recordings of such low level.
The first day the patch was committed I went from headphone out of my wife's iPod into line-in on my iPod, and made a nearly flawless recording.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: gnu on January 06, 2007, 02:30:22 PM
What ipod have you got?
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 06, 2007, 02:38:25 PM
Did the recording on a 5th generation.
If homielove was using a homemade line-in connector, I suspect he used the wrong ground.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: LurkAzusa on January 06, 2007, 03:06:45 PM
Soap,

Do you have a link to instructions for the homemade line-in?
Title: Re: Recording on ipod (was: nano recording volume)
Post by: homielowe on January 06, 2007, 03:47:45 PM
I'm just using a line-in connector from a previous(deceased) mp3 player, maybe ill try again, anyone else have the problem when playback ceases to function after recording?
(http://www.nexxdigital.ru/upload/accessory/8/img/78/a_LineIN_cable_400x400.jpg)
used something similar to this
I could probably go sacrifice a usb cord or find one somewhere(web)
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Febs on January 06, 2007, 06:40:28 PM
As far as I am aware, the only line-in on the 5G is through the dock connector.  Prior generations of iPods allowed recording through the headphone jack, but the 5G does not.   So I am not sure how you got ANY signal recorded using that cable.

The issue with recording breaking playback is a known issue.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: axlgreasetires on January 06, 2007, 06:50:23 PM
Holy crap It works!!!!!!  I put my distortion pedal on the highest gain possible and put my amp on the highest volume it can go.  In the background if you listen very closely, you can hear me playing Killing in the Name of by Rage Against the Machine.

It's uber quiet but it is distinguishable.  Nice job whoever working on the ipod recording thing.

Just get the gain thing working and it'll rock.

P.s. it does work line-in on a 5g.  That's what i used to record my amp.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: LurkAzusa on January 06, 2007, 07:05:55 PM
So what is everyone using for a dock connector line-in on a 5g Video?  Belkin?
Title: Re: Recording on ipod (was: nano recording volume)
Post by: linuxstb on January 06, 2007, 09:33:26 PM
Please, can anyone posting in this thread state the following:

1) Which ipod you are using
2) If you are attempting to record through the headphone jack (called "mic" in Rockbox), or if you are recording via the line-in pins in the dock connector.
3) Which setting (mic or line-in) you're using in the recording screen.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: petur on January 07, 2007, 04:49:58 AM
I do hope that what some are experiencing isn't just crosstalk between two analog inputs on the ADC
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 07, 2007, 08:49:44 AM
Soap,
Do you have a link to instructions for the homemade line-in?
So what is everyone using for a dock connector line-in on a 5g Video?  Belkin?

I purchased a dozen dock connectors from the Ipod Linux group buy, and used the pin-outs here:
http://ipodlinux.org/Dock_Connector

I'm just using a line-in connector from a previous(deceased) mp3 player, maybe ill try again,
Holy crap It works!!!!!!  I put my distortion pedal on the highest gain possible and put my amp on the highest volume it can go.  In the background if you listen very closely, you can hear me playing Killing in the Name of by Rage Against the Machine.
homielove - The headphone jack is not the line-in connector.
homielove and especially axlgreasetires:
There is nothing good which can come from pumping that much voltage in through the headphone jack.  There is potentially a lot of harm which you could cause.

Please, can anyone posting in this thread state the following:
1) Which ipod you are using
2) If you are attempting to record through the headphone jack (called "mic" in Rockbox), or if you are recording via the line-in pins in the dock connector.
3) Which setting (mic or line-in) you're using in the recording screen.

1-Ipod 5th Gen, 60GB
2-Line-in pins on the dock connector
3-Set for "line-in" on the recording screen.
4-Gain and quality are near perfect when using a proper line-out source.
EDIT:I lied on #4 - it sounded good, but looking at the wav in Audacity showed me the gain was too low.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: homielowe on January 07, 2007, 12:53:56 PM
sounds good, will go buy one now
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Hajaz on January 08, 2007, 02:16:03 PM
hello.

would it be posible to make a connector that would allow line in recording and charging at the same time?

i need to record an 8 hour set soonish and im pretty sure my G5's battery wont last that long.

ive been looking at the belkin tunetalk stereo thingie but it seems it looses alot of the low and mid tones during its recording.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 08, 2007, 06:37:02 PM
hello.

would it be posible to make a connector that would allow line in recording and charging at the same time?

i need to record an 8 hour set soonish and im pretty sure my G5's battery wont last that long.

ive been looking at the belkin tunetalk stereo thingie but it seems it looses alot of the low and mid tones during its recording.


Yes.  It would also be worthwhile to experiment with powering the FireWire pins instead of the USB pins, so you can plug and unplug the power at any time w/o fear of triggering Rockbox's reboot into Apple Disk Mode.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Hajaz on January 09, 2007, 01:43:22 PM
cool.

the voltage is the same right?

(iow i could charge via the firewirepins with a usb connector?)
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Chronon on January 09, 2007, 01:58:39 PM
I believe that USB uses 5 V while firewire uses 12 V.  You should verify this before applying power to your iPod, though.

Clearly you have to make an adapter that delivers the correct signals to the correct pins in your dock connector.  How you do this is up to you.  I would avoid using any USB connectors at all to avoid confusion.  
Title: Re: Recording on ipod (was: nano recording volume)
Post by: zlp on January 11, 2007, 12:38:28 PM
Another partial success story recording with the Nano (1G of course.)

I plugged the headphone-out of my tuner into the Nano's headphone-out, turned it up a good bit louder than I should have (don't want to fry the Nano!) and got healthy-looking levels...

The original WAV file (1.5M)
http://www.zachpoff.com/guests/guestbox/R070110-221826.wav

An MP3 version, amplified so you can hear it better (128K)
http://www.zachpoff.com/guests/guestbox/R070110-221826.mp3

The levels turned out to be -24dB, not as healthy as they looked. The recording is quite distorted but it verifies that the Nano does indeed have an ADC. It has been suggested that the Nano has no connection between the headphone jack and the ADC, and that we are really hearing crosstalk between the headphone amp circuit and the ADC (which I presume is wired to the dock connector). After listening to the recording I would agree. I haven't tried the dock connector line-in yet but I'm hoping it will be a step closer to usable.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: drumthrasher109 on January 11, 2007, 05:25:51 PM
okay i tried this on my 5g. i plugged my computers audio into the headphone port (volume all the way up), recorded through line in and mic, then played it back on my computer (volume all the way up) and didn't hear jack crap.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 11, 2007, 06:16:07 PM
okay i tried this on my 5g. i plugged my computers audio into the headphone port (volume all the way up), recorded through line in and mic, then played it back on my computer (volume all the way up) and didn't hear jack crap.

You don't have a mic-in port.
Unless you bought (or made) a dock connector you don't have a line-in port.
It is no wonder you didn't hear anything.

People!  There is Nothing Good which can come from pumping amplified signals into the headphone jack of your iPod w/o a mic-in.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Febs on January 11, 2007, 06:19:17 PM
okay i tried this on my 5g. i plugged my computers audio into the headphone port (volume all the way up), recorded through line in and mic, then played it back on my computer (volume all the way up) and didn't hear jack crap.
So basically, you totally ignored what I told you in the other thread, and you're surprised that it didn't work?
Title: Re: Recording on ipod (was: nano recording volume)
Post by: drumthrasher109 on January 11, 2007, 06:25:28 PM
i guess this recording thing doesn't work either way.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Febs on January 11, 2007, 06:29:02 PM
As recording functionality is improved on the ipods, recording WILL work on the 5g through the line-in on the dock connector.

Recording will NEVER work on the 5g through the headphone jack because the 5g has no input through the headphone jack.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Chronon on January 11, 2007, 06:53:45 PM
Soap,

What sort of gain do you see for recording through line-in?  It sounds like you got decent quality -- how low is "too low"?
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 11, 2007, 07:03:27 PM
What sort of gain do you see for recording through line-in?  It sounds like you got decent quality -- how low is "too low"?

According to Audacity, my recorded copy was 10dB quieter than the original.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 11, 2007, 07:36:33 PM
@soap: Im keen to try out recording on my nano. Is there a particular dock to use as there seems to be quite a few slightly different ones on the market?
I make my own with parts purchased from http://home.swipnet.se/ridax/connector.htm.
Parts A and E are not as sleek as B and F, but are much easier to work with.  Using a strain relief boot (J) is highly recommended, you can use a drill bit (note:  not a drill) and your hand to enlarge the through-hole quite easily to accommodate larger wires.  I also suggest gluing your cable to the relief boot, as it would not take much in the way of twisting to damage the very small pins on the inside of the connector.
A pin-out and further illustrations of the connectors in question is available http://ipodlinux.org/Dock_Connector.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: iPodFoo on January 11, 2007, 07:42:39 PM
Cool. Thanks soap! I actually deleted my post as you mentioned the http://ipodlinux.org/Dock_Connector site earlier which i missed. Youre too quick.  ;D

Though the extra info is most helpful. Need to see if I can find those components in the UK.

By the way, do you make one purely for cost reasons or are official docks not "wired" properly?

Cheers.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 11, 2007, 08:02:59 PM
Need to see if I can find those components in the UK.
The group buy shipped overseas for me, I see no reason they wouldn't ship to the UK - and the price is right.

By the way, do you make one purely for cost reasons or are official docks not "wired" properly?
A - Soap is a cheap bastard.
B - I've made line-in jacks, line-out jacks, USB jacks, video-out jacks, and about every combination of the four.  (Still have yet to make a FireWire jack for 12v charging purposes, though that is a long-standing goal of mine.)  All told I've made about twenty different adapters for myself and others, and all for less than the cost of two PocketDocks:  http://www.sendstation.com/us/products/pocketdock/lineout-usb.html (though Soap must say those are sexier than his)
C - The websites selling dock-"dongles" with 12 gauge silver cryogenicly treated wire are selling snake oil.  There is no way they are connecting anything larger than 18 gauge wire to the actual dock pins (14 gauge wire is larger than pins 1, 3, 5 and the spaces between), and if 2-3" of 18 gauge wire causes discernible voltage drops at line-level amperages I'm a monkey's uncle.



Title: Re: Recording on ipod (was: nano recording volume)
Post by: homielowe on January 12, 2007, 11:25:19 PM
I was astounded by the prices in general, Just ordered two dock connectors plus two cable guards. I will most likely have to sharpen my soldering gun's tip though. Might have multiple cables coming out of one of them (usb, male recording jack).
Title: Re: Recording on ipod (was: nano recording volume)
Post by: axlgreasetires on January 23, 2007, 08:25:15 PM
I didnt really read any previous posts.  but the reason i replied is to say recording does work through the headphone jack.  i tried it and i can hear distinguishable sound.

i can't wait for the gain thing to work.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 23, 2007, 08:50:42 PM
I didnt really read any previous posts.  but the reason i replied is to say recording does work through the headphone jack.  i tried it and i can hear distinguishable sound.

i can't wait for the gain thing to work.
What model iPod?
What source form the recording menu (line-in or mic)?
What did you input into the headphone jack?  A microphone?  A line-level output?  A speaker-level output?  Other?
Title: Re: Recording on ipod (was: nano recording volume)
Post by: dan gii on January 24, 2007, 03:34:52 PM
I too had some excellent results recording through the headfone jack, details are:

Ipod Photo, 60gb

Dynamic Microphone - XLR to 1/4" input with a (stereo) 1/4" to 1/8" plug.

I recorded some drums at 16bit 44khz with just the one mic, it sounded fantastic, I was really excited about it.  But all of a sudden my XLR to 1/4" cable stopped working and when I tried with my mate's I started getting conciderably less volume - It hasnt been the same since...   ::)

I have a Griffin iTalk - the unit that plugs into the top of the Ipod - it has a Mic Input on it but I cant get this to work - I bought a little Sony stereo microphone and would love to use the iTalk, iPod and stereo microphone to record samples at 16bit 44khz... any idea if there is Griffin iTalk functionality planned?

Peace.
Dan.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: axlgreasetires on January 25, 2007, 08:53:49 PM
yeah basically what he said except i have a 30gb video and i was recording myself playing guitar.  I recorded with a wire that looks like:
-=---------------=-

so it has two little sterio mini end things.  i'm not sure whether i used line-in or mic.

the song i was playing is uber hard to hear but it is distinguishable.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 25, 2007, 10:46:35 PM
yeah basically what he said except i have a 30gb video and i was recording myself playing guitar.  I recorded with a wire that looks like:
-=---------------=-

so it has two little sterio mini end things.  i'm not sure whether i used line-in or mic.

the song i was playing is uber hard to hear but it is distinguishable.

Did you go straight from the 1/4" jack on your guitar to the headphone jack of the ipod, or did you go through an amp?
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Chronon on January 26, 2007, 12:56:58 PM
I think in dan gii's case the recording through the headphone jack is plausible.  On the iPodLinux site they list the photo as only being able to record via "microphone".  So at least in principle that target has the hardware to allow it.  

It is not clear to me that the nano or video have this capability.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: axlgreasetires on January 26, 2007, 04:22:12 PM
my guitar was connected to the amp.  the amp was outputting to my ipod.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 26, 2007, 04:34:31 PM
my guitar was connected to the amp.  the amp was outputting to my ipod.

Unless Apple has been lying to us, you have no microphone input through your 5th generation's headphone jack.
That leaves a very scary probable explanation for the results you were getting.
Through the act of pumping an amplified signal into your headphone jack, you pumped enough power into your output lines to jump over and induce voltages on other wires, wires not physically connected to the headphone jack.

Think about that for a second.

as I said over two weeks ago...
okay i tried this on my 5g. i plugged my computers audio into the headphone port (volume all the way up), recorded through line in and mic, then played it back on my computer (volume all the way up) and didn't hear jack crap.

You don't have a mic-in port.
Unless you bought (or made) a dock connector you don't have a line-in port.
It is no wonder you didn't hear anything.

People!  There is Nothing Good which can come from pumping amplified signals into the headphone jack of your iPod w/o a mic-in.

Title: Re: Recording on ipod (was: nano recording volume)
Post by: axlgreasetires on January 29, 2007, 08:33:07 PM
Yo thats because your a noob.

It works i tell you>.. It works!

I recorded again.  WITH EVEN BETTER RESULTS.
i recorded on line in
Format : MP3
It still sounds crappy but i can hear sound that is easyly distinguishable from background hum and hiss.

I could upload a recording for you.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Chronon on January 29, 2007, 08:38:06 PM
Hey, I don't care if you fry your iPod.  It's your decision.  But I will wait to get a proper line-in dock connector so that I don't have to supply amplified signals to my iPod and hope for pickup due to crosstalk.  I mean I can generate crosstalk in separate channels of a ADC in my lab, it doesn't mean that this is a preferred  method of recording signals or keeping usable equipment.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: axlgreasetires on January 29, 2007, 08:40:20 PM
I could upload a recording for you.
http://www.sharebigfile.com/file/72049/R070128-195344-mp3.html
go to that and listen to the file.

i'm not sure if its the right file.

put it on your ipod and listen to it at full volume.  If your really good at hearing you should be able to hear it.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 29, 2007, 10:44:26 PM
axlgreasetires, compare your attempt at burning iPod traces with my proper line-in recording:

http://www.cleansoap.org/rockbox/files/soaps_recording.wav

When gain is implemented, it won't fix your underlying issue.


(short enough I believe it constitutes fair use)
Title: Re: Recording on ipod (was: nano recording volume)
Post by: homielowe on January 29, 2007, 11:20:31 PM
Success  :o
(http://img329.imageshack.us/img329/1171/0129071855wc5.th.jpg) (http://img329.imageshack.us/my.php?image=0129071855wc5.jpg)

I might have screwed up th soldering because midis outputed from my phone comes up as http://www.sharebigfile.com/file/72145/R070129-191423-mp3.html (might be dual  mono)
but the midi is below
the midi from my phone is
http://www.sharebigfile.com/file/72146/god-test-4-mid.html

I wish playback wouldn't die though :(

any help would be welcomed
edit: further testing reveals there is little if none audio coming from the left channel(mighy have soldered the ground) :D
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 30, 2007, 06:15:24 AM
Success  :o

edit: further testing reveals there is little if none audio coming from the left channel(mighy have soldered the ground) :D

Before you go and disassemble your whole adapter, double check that you are actually getting full insertion into the iPod's dock connector.  I wasted a lot of time once trying to find fault in a line-in / line-out pair after testing revealed a weak channel, only to find that the problem was simply a failure to seat the plug firmly in the dock.   ;)
Hopefully your fix will be as brain-dead simple.  If not, don't give up!
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Febs on January 30, 2007, 08:26:02 AM
I could upload a recording for you.
http://www.sharebigfile.com/file/72049/R070128-195344-mp3.html
go to that and listen to the file.

i'm not sure if its the right file.

put it on your ipod and listen to it at full volume.  If your really good at hearing you should be able to hear it.

Congratulations.  You've recorded noise.  I don't hear ANY guitar in there at all.

By the way, what output on your amp are you using to do this?  PLEASE tell me that it's not a speaker output.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: homielowe on January 30, 2007, 06:25:46 PM
I have a question. I am using an RCA cable to 3.55 female. When "1" and "3" are on "R", and "2" and "4" on L it works, but I'm not sure if this is correct(dual mono?) There are four wires: right, left, ?, and ?. I have no expertise in audio wiring so help would be welcomed.

(http://img262.imageshack.us/img262/2585/0130071507ny2.th.jpg) (http://img262.imageshack.us/my.php?image=0130071507ny2.jpg)
(http://img262.imageshack.us/img262/7207/0130071508le3.th.jpg) (http://img262.imageshack.us/my.php?image=0130071508le3.jpg)
Soap: Did you have a ground (pin#1)?  Could you explain your wiring technique?
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 30, 2007, 07:29:22 PM
homielowe,

Assumption 1 being you want a line-in
As for photo one:
(convention says...)
The white wire is Left+, and should be attached to dock pin 6.
The (black / green?  can't tell) insulated wire is probably Right+ and should be attached to dock pin 5.
The bare copper braids/sheaths/wires seen in your first photo are grounds, and should both be attached to dock pin(s) 1 and/or 2.  (For even if both the bare copper lines are attached to the common ground of the 3.5mm jack, the one not attached to ground at the ipod dock end of things will not work as a shield, and could even pick up stray signals.)

As for your second photo, not knowing what you have those two wires connected two inside the dock (or even if they are individual wires seeing as the photo is blurry) I can't comment.


EDIT:  I goofed before and said R+ goes to 6 also, it goes to 5
Title: Re: Recording on ipod (was: nano recording volume)
Post by: homielowe on January 30, 2007, 07:44:22 PM
ok thanks

edit: sorry about craptacular cameraphone pics.

I figured that out myself, wondered why only left earphone make noise
Title: Re: Recording on ipod (was: nano recording volume)
Post by: saratoga on January 30, 2007, 08:30:30 PM
I could upload a recording for you.
http://www.sharebigfile.com/file/72049/R070128-195344-mp3.html
go to that and listen to the file.

i'm not sure if its the right file.

put it on your ipod and listen to it at full volume.  If your really good at hearing you should be able to hear it.

Well the static on that track is at -60 dB, and I can't hear any music.  So you're getting a SNR of at most 10 or 15 dB.   Maybe not even.

I think its pretty safe to say you're just coupling some noise into the power plane, and then registering that on the ADC pins.  If you keep doing this, you'll more then likely destroy your iPod.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: gnu on January 31, 2007, 12:04:01 PM
I read this whole thread and tried to record with my nano through the headphone jack (although I knew it wouldn't work); I did not pump in thousands of volts ;) just a normal line in volume. In the resulting file you can't hear anything at all. I haven't tried it with a dock connector; would that work with a nano?
Title: Re: Recording on ipod (was: nano recording volume)
Post by: saratoga on January 31, 2007, 05:00:13 PM
I read this whole thread and tried to record with my nano through the headphone jack (although I knew it wouldn't work); I did not pump in thousands of volts ;) just a normal line in volume.

To be honest, I'd be afraid to even try that.  Putting voltages into circuits that are not made to accept inputs is generally a bad idea.  Particularly when its a very expensive circuit made of very cheap IC components :)
Title: Re: Recording on ipod (was: nano recording volume)
Post by: axlgreasetires on January 31, 2007, 09:11:20 PM
My ipod still works fine.  Maybe i uploaded the wrong file or something but it definitely. worked my way.

I got one of those gold audio things that you can get cheap from radioshack that fits in the input/output jacks on a standard amp that you stick one of those sterio mini cords that are basicly the same thing as a headphone plug head except it has 2 of them.

i dont know if that made anysense to anybody.

Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on January 31, 2007, 09:24:18 PM
My ipod still works fine.  
Count your blessings.
Maybe i uploaded the wrong file or something but it definitely. worked my way.
A - In your own words you had to play back at maximum volume to hear any signal.  This indicates crosstalk, not a lack of gain.

B - I still think you are missing the point.

Nobody is doubting that you could obtain discernible audio from your technique.  What people are saying is that if you obtained audio through your technique it was as a result of the equivalent of a short circuit inside your iPod.  Chronon flat out verified that you can create crosstalk in a circuit such as in your iPod.
The iPod Video does not (to the best of everybody's understanding) have an audio-input through the headphone jack.  Even if it did, pumping speaker-level signals into it is a recipe for damage.
I really hope you aren't defending (analogy warning) driving a car on the wrong side of the road.  You might get away with it once - you might get away with it a dozen times, but to suggest that it is a safe and effective way to operate is foolhardy.  Damage will surely result sooner than later.
I also hope (and trust) that everybody else reading this thread realizes what a silly, silly thing you are doing and won't attempt the same ignorant experiment.  If I didn't trust people to realize the folly of your ways I would delete your threads for encouraging damaging behavior.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: Llorean on January 31, 2007, 10:09:54 PM
C - You can find out if you uploaded the right file by listening to it after you upload it. Though generally it's a good idea to listen first so you can upload the right one.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: BigMac on February 25, 2007, 11:33:16 AM
So has anyone got around to making a guide to making the dock connector dongle for the ipod? I read the wiki pages people have linked me to, but is there a more simplistic guide because I couldn't make heads or tails of that. Or is there possibly a place where I could buy one of these dongles?
Keep ROCKing on!
Title: Re: Recording on ipod (was: nano recording volume)
Post by: homielowe on February 26, 2007, 07:17:42 PM
If you go back a few pages(or read the whole entire thread), there will be links to places to buy the necessary parts and find the required information. Search the iPodLinux wiki also. I just used the provided information found thoughout this thread
Title: Re: Recording on ipod (was: nano recording volume)
Post by: BigMac on February 27, 2007, 09:03:30 AM
Alright all the parts I needed will be ordered today, but I am still unsure about grounding. I was linked to some tutorials and I read the basic ones and watched the videos, but I still am foggy on this subject. From my understanding, I will attach the R+ to pin 5, the L+ to pin 6.Then for grounding I attach *both* to pins one and 2. I have no idea how to do this, my best guess would be twisting those two wires together, tinning them then laying it across both pins and soldering it. http://ipodlinux.org/Dock_Connector
Title: Re: Recording on ipod (was: nano recording volume)
Post by: gnu on February 27, 2007, 09:26:08 AM
Does line-in through the Dock Connector work with nanos?
Title: Re: Recording on ipod (was: nano recording volume)
Post by: BigMac on February 27, 2007, 09:51:26 AM
No I don't believe they do.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: linuxstb on February 27, 2007, 09:54:01 AM
No I don't believe they do.

Have you tried it?  If not, please don't speculate...

AFAIK, no-one has attempted to record via the line-in on the Nano, so we simply don't know.  However, if the hardware supports it, Rockbox should work (unlike the headphone-input on the Nano, which isn't implemented in Rockbox).
Title: Re: Recording on ipod (was: nano recording volume)
Post by: BigMac on February 27, 2007, 09:55:45 AM
No but I have heard people say they have or say they tried, only to be shot down on the grounds that it does not work.
I researched the thread and found one success story on the nano so I guess it could be possible.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: soap on February 27, 2007, 05:42:15 PM
BigMac, people were "shot down" (as you put it) not because they tried but because they tried in a very dangerous manner.  (Not to mention a very arrogant, defiant, and ignorant manner.)

It is strongly believed that the Nano and 5th generation iPods can not record through the headphone jack.  The headphone jack was, on earlier iPods, a mic-level monaural input.
Those who were "shot down" didn't simply decide to test recording through the headphone/microphone port, they decided to pump (heavily) amplified signals into said port.
Title: Re: Recording on ipod (was: nano recording volume)
Post by: gnu on March 01, 2007, 11:21:50 AM
The question remains whether line-in is possible on nano or not.
It has a line-in test in its emergency-debug menu, so I guess it could; but since I haven't got a spare dock connector I can't try.