Rockbox Technical Forums

Support and General Use => Recording => Topic started by: Mmmm on June 01, 2006, 05:35:37 AM

Title: A simple test everyone with a remote can try - Remote Recording interference
Post by: Mmmm on June 01, 2006, 05:35:37 AM
You can test this easily as long as you have a remote handy..

-Go into the recording screen (make sure input is set as line in and no microphone is attached)
-Make sure the remote is plugged in
-Turn gain up until you see a readout on the peakmeter (mine starts at about 26db on right channel)
-Turn it up a bit more so that you can see the readout clearly (about 35db is fine for mine)
-Now pull out the remote. Has the peakmeter gone blank?
-Plug remote back in. Interference?

If yes vote yep....

I'm curious as to whether this is just my unit or is it a universal problem or maybe it has something to do with the ticking phenomenon.

Maybe the ticking fix being active on the recording screen may fix this. Who knows....
Title: Re: Interference in recordings with remote?
Post by: Hansmaulwurf on June 01, 2006, 06:56:54 AM
Just tested it. I see a readout on the right channel, but only if gain is at 47dB or higher(you can only go up to 48dB). And it is a really thin line, only the first line of pixels. When I pull out the remote the readout is gone.

I have "Reduce Ticking" 'on'.
Title: Re: Interference in recordings with remote?
Post by: whatboutbob on June 01, 2006, 08:02:18 AM
crap crap crappety crap.

I just did some tests on this remote interference.  Can't believe I haven't noticed it before.  I just wrote the noise off to mic shortcomings...how wrong I was.

As Mmmm suggested, I set source to line in, didn't plug a mic in, then recorded w/ a varety of gain, then measured noise floor (in dB):

First with no gain (left channel, right channel):
           
w/ remote: -84, -81
w/o rem:    -84, -84

20dB gain:
w/ remote: -72, -63
w/o rem:    -81, -81

48dB gain:
w/ remote: -42, -36
w/o rem:    -52, -52

I repeat: crap crap crappety crap.

LinusN suggested that the main iriver units aren't grounded properly...some worse than others.  I think this idenitifies the damn source of cell phone interference I've encountered in some of my recordings.  Unless I'm mistaken (and that's entirely possible) the remote is essentially acting like a giant antenna.

So, now all we need is an electronics guru to confirm this issue and find a fix (please!). :)

edit: oh, and 'reduce ticking' makes no obvious impact on the interference.
Title: Re: Interference in recordings with remote?
Post by: Mmmm on June 01, 2006, 09:00:42 AM
Just tested it. I see a readout on the right channel, but only if gain is at 47dB or higher(you can only go up to 48dB). And it is a really thin line, only the first line of pixels. When I pull out the remote the readout is gone.
Hansmaulwurf it seems you have the interference but so slight as to be unnoticable...Do you usually have ticking when you listen to music with the fix off?


crap crap crappety crap.
Yep.... isn't it just?

Quote
First with no gain (left channel, right channel):
           
w/ remote: -84, -81
w/o rem:    -84, -84

20dB gain:
w/ remote: -72, -63
w/o rem:    -81, -81

48dB gain:
w/ remote: -42, -36
w/o rem:    -52, -52
Ahhh some solid data to chew on......

Yep...its crap!  :D
Quote
edit: oh, and 'reduce ticking' makes no obvious impact on the interference.
I don't think that the ticking fix is active during recording even if you have it set to on (could be totally wrong there though).
I thought maybe if it was active it may fix the problem...may be worth a try eh?
Title: Re: Interference in recordings with remote?
Post by: Hansmaulwurf on June 01, 2006, 10:40:10 AM
Hansmaulwurf it seems you have the interference but so slight as to be unnoticable...Do you usually have ticking when you listen to music with the fix off?
I hear the ticking only when im at the WPS and music is stopped or Volume is set lower than -82dB. And even with that Volume you have to listen very carefully to hear it.

Ah, and its no difference if the "Reduce Ticking" is On or Off. the interfernece stays the same.
Title: Re: Interference in recordings with remote?
Post by: whatboutbob on June 01, 2006, 08:35:41 PM
Mmmm, have you confirmed that the cell interference only occurs with the remote attached?
Title: Re: Interference in recordings with remote?
Post by: Mmmm on June 02, 2006, 02:37:16 AM
Hansmaulwurf it seems you have the interference but so slight as to be unnoticable...Do you usually have ticking when you listen to music with the fix off?
I hear the ticking only when im at the WPS and music is stopped or Volume is set lower than -82dB. And even with that Volume you have to listen very carefully to hear it.

Ah, and its no difference if the "Reduce Ticking" is On or Off. the interfernece stays the same.

So you have very minor ticking and very minor interference too....this supports the theory eh?


Mmmm, have you confirmed that the cell interference only occurs with the remote attached?
I got the cell phone interference without the remote attached! (I don't use the remote anymore bacause of the interference!)
Title: Re: Interference in recordings with remote?
Post by: whatboutbob on June 02, 2006, 03:57:46 AM
I got the cell phone interference without the remote attached! (I don't use the remote anymore bacause of the interference!)

bugger.
Title: Re: Interference in recordings with remote?
Post by: petur on June 02, 2006, 05:13:12 AM
I got the cell phone interference without the remote attached! (I don't use the remote anymore bacause of the interference!)

bugger.

This doesn't surprise me at all. There's no shielding in the player and cell phone signals are strong enough. I even have a recording with interference on, the cell phone must have been 50cm away (concert with seats).

Damn cell phones!
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: whatboutbob on June 02, 2006, 05:18:46 AM
peutr: that's what i'm talking about...interference actually getting onto the recordings...it happens on prolly half my recordings. 'tis really p!ssing me off.
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: Mmmm on June 02, 2006, 05:24:24 AM
I suppose you could put it in a nice lead box when you want to record!  :D
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: whatboutbob on June 02, 2006, 05:52:31 AM
see...you jest...but i've actually looked into these:

http://en.wikipedia.org/wiki/Faraday_cage
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: renho3k on June 02, 2006, 12:49:57 PM
mine starts at about 28dB.
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: Mmmm on June 02, 2006, 04:21:12 PM
see...you jest...but i've actually looked into these:

http://en.wikipedia.org/wiki/Faraday_cage
Heh heh  :D

When you build one i'll be your first buyer!
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: RedBreva on June 03, 2006, 01:17:01 AM
on the top line 31
on the bottom line 26

With remote unplugged, both channels start to show a signal at about 43
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: whatboutbob on June 03, 2006, 02:00:53 AM
to everyone who has reported figures above...is it safe to assume that your min peakmeter range is set to -89?  Otherwise it doesn't tell us much...
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: Mmmm on June 03, 2006, 04:59:52 AM
to everyone who has reported figures above...is it safe to assume that your min peakmeter range is set to -89?  Otherwise it doesn't tell us much...

Good point..heh heh..hadn't thought of that!  :)

Although you can still see that everyone (so far) has some interference...

It would be interesting to know whether the people that have voted  can also hear ticking when they have the ticking fix set to off when playing music (press pause and listen carefully while playing a track)

I would just like to point out that the interference that I initially started the thread about is an entirely different problem to the cell phone interference that whatboutbob was talking about.... Looking at some other comments elsewhere, I think some people are getting confused! Hope that clears it up.
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: whatboutbob on June 03, 2006, 06:00:21 AM
Sorry to confuse things Mmmm!

Apparently the MicroTrack may have a similar issue (not the cellphone thing...the bit that Mmmm's on about).  It seems a strategically placed piece of foil may fix it...or at least improve it.  Looking into it now.
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: Hansmaulwurf on June 03, 2006, 06:06:39 AM
to everyone who has reported figures above...is it safe to assume that your min peakmeter range is set to -89?  Otherwise it doesn't tell us much...
Yes, its safe :).
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: fatoldpig on June 07, 2006, 06:39:33 PM
starts at left gain 31 and right gain 26. no change with ticking on or off.
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: Mmmm on June 13, 2006, 08:27:44 AM
For the person who voted No: Do you get ticking with the ticking fix off when playing a track? (pause playback and listen, you should hear some weird bup bup bup noises)
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: renho3k on July 07, 2006, 11:34:36 AM
what exactly does the ticking interference sound like (both the cellphone type and the thread topic)? is it loud, overbearing, continuous, subtle, etc? i tried to listen for it on whoever's myspace page (i think mmmm's) but didn't hear anything that sounded off. is it something subtle that can only be detected if you're recording something rather quiet, like acoustic settings? i can see the interference in the meters but i've never actually heard anything in the recordings that showed distortion/interruption of sound. if it's a shielding problem, i suppose it can't be fixed but i was just wondering how concerned one should be about it ruining recordings. i've grown to love the remote for recording purposes, especially stealthing concerts, but if it's a big concern, i'd rather not risk ruining a show and just not use the remote during recordings.
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: Mmmm on July 07, 2006, 04:16:19 PM
what exactly does the ticking interference sound like (both the cellphone type and the thread topic)? is it loud, overbearing, continuous, subtle, etc? i tried to listen for it on whoever's myspace page (i think mmmm's) but didn't hear anything that sounded off.
Yeah, that's me. The recordings you listened to were made without the remote attached (because of the interference). The interference is not extremely loud and you probably couldn't hear it if there was some other sound being recorded at the same time. But if you are trying to make professional recordings you don't really want this kind of noise in the background.

The phone interference you can hear is in the track "capricho arabe" and appears at about 2:10. this is just normal mobile phone interference that you have probably heard when your phone is near your headphone wire or some other speaker cable.


Quote
is it something subtle that can only be detected if you're recording something rather quiet, like acoustic settings? i can see the interference in the meters but i've never actually heard anything in the recordings that showed distortion/interruption of sound. if it's a shielding problem, i suppose it can't be fixed but i was just wondering how concerned one should be about it ruining recordings. i've grown to love the remote for recording purposes, especially stealthing concerts, but if it's a big concern, i'd rather not risk ruining a show and just not use the remote during recordings.
I would say that if you haven't noticed it then it probably isn't a big concern for you! Personally just knowing it is there even if I cant hear it is enough to stop me using the remote...stupid eh? :D
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: renho3k on July 08, 2006, 12:44:59 AM
Personally just knowing it is there even if I cant hear it is enough to stop me using the remote...stupid eh? :D

haha, actually that's why i was asking because it seems like some of you are taking the step to not use it and i was wondering if that was extreme or something i should also consider.
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: whatboutbob on July 08, 2006, 04:04:15 AM
I first noticed the remote inteference when you're recording a quiet gig and using a lot of gain (30+).  Its not a major prob for me cos I use an external pre/adc, but I'm anal so I only use the remote when recording when I have to.

Also, just to temporarily hijack the thread again (sorry Mmmm)...but to clear up some suggestions I made earlier in the thread...after a bunch of tests I've isolated the cell phone interference issue to my mics (ie not the iriver) being sensitive to RFI.

Apparently it is much more of an issue in Australia (compared to the US) because of the nature of its mobile phone network (pretty much everyone is on GSM 900/1800 Dual Band).  I think many Euro countries may be similarly affected (but don't quote me on that).

Anyways, it has become the scourge of my recording existence so I think I'll eventually buy some rfi-protected mics for far too much money.
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: petur on July 08, 2006, 07:22:42 AM
I have at least one recording that's ruined by a nearmy cellphone. Was using a cheap skytronic mic and on external pre-amp though...
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: renho3k on July 08, 2006, 10:43:15 AM
thanks for the clarifications guys  :)
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: Davide-NYC on July 27, 2006, 10:01:22 PM
I don't know about interference, but I most certainly get a ticking sound when I record from line-in with the remote plugged in.

Urghh. (crappity)
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: Zeke on March 25, 2008, 08:05:41 PM
Hi All:

Sorry to make a zombie thread if this has been covered elsewhere - but is the remote noise issue still a problem?  I haven't used it during recording yet and I'd like to.

I suppose tonight I won't until I hear a def. yes or no.

Cheers,

Zeke
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: Davide-NYC on March 25, 2008, 10:10:13 PM
There is a "sort-of" fix, but it simply turns off the remote LCD by pressing Vol(-) on the remote.
Whenever the display on the remote changes it induces a noise. Since the peakmeters are constantly changing, as well as the Time and Size lines, you'll always get noise.

On the other hand, if you get good with the "Remote Display Off" trick you'll do well, especially if you combine this with the Remote clip-light feature, which works even when the remote is "Disabled".

But, in my opinion, if you are serious about recording do not use the remote. Too risky.
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: petur on March 26, 2008, 03:50:46 AM

Sorry to make a zombie thread if this has been covered elsewhere - but is the remote noise issue still a problem?  I haven't used it during recording yet and I'd like to.

To be complete: the remote noise is a hardware issue, some irivers/remotes suffer more than others.
Title: Re: A simple test everyone with a remote can try - Remote Recording interference
Post by: Zeke on March 27, 2008, 12:13:45 PM
Thanks, guys.

I will check it out with my rig and see what sort of noise I encounter.

I appreciate the fact it's a hardware issue.

Anyway, these days I set the gain conservatively and usually don't babysit the levels during a set -- with a clean signal it's easier to just add gain later than to try and repair a file where you changed it mid-song.

Zeke.