[Vinnie R.]

All,

Not sure if this has been mentioned before, but I took apart my 20gb iPod (4th gen) and noticed that the coupling caps used for the headphone outputs are only 100uF! This means that if you are using 32-ohm headphones, you can expect the cutoff to be at approx. 50Hz.

If you are using 16-ohm headphones (not sure if these are common), the cutoff will be at approx 100Hz.

Larger SMD caps can be installed that would give you bass all the way down... When I pick up a Nano, my guess is that they are using the same undersized caps.

Me? I'm more interested in the line out

What is the most common headphone impedance?

Hope this helps shed some light on the bass-rolloff issue.

Regards,

Vinnie

 

[bangraman]

The primary problem is with low-impedance canalphones, which can range from 16 to 24 ohms (fairly consistent across the frequency range).


Graphs here:
http://phonephile.blogspot.com/2005/...-fall-off.html


The photo has similar in terms of falloff, but suffers from higher distortion.

 

[Vinnie R.]

Quote:

Originally Posted by bangraman The primary problem is with low-impedance canalphones, which can range from 16 to 24 ohms (fairly consistent across the frequency range). Graphs here: http://phonephile.blogspot.com/2005/...-fall-off.html The photo has similar in terms of falloff, but suffers from higher distortion.

Thanks for the link. I'm not sure why they don't make the iPod with larger SMD caps...they WILL fit in the location where the stock ones are. This is an easy fix IMO.

Maybe they want to limit the bass going to the earbuds that come with the iPod so they don't distort?

 

[bangraman]

It's a potential factor, especially given the crappy EQ implementation. Certainly none of the other (even Portalplayer-engineered) players I've measured exhibit as bad a falloff as the iPod. The only player which I've seen worse on is the 'legendary' Sony D-555 discman.


I had a poke around the 3G, and if my SMD soldering skills were up to scratch (my abilities still rest at being able to almost set fire to PCB's) I would have tried my hand at cap replacement. I hope you work it out... we all do I think

If you also get your mitts on the iAudio X5 as the discussions at iAudiophile seem to indicate, I'd like a solution not only for the headphone / line out fall-offs but also the unusually narrow soundstaging on the X5 too (apparently a lack of stereo separation).

 

[ScubaSteve87]

I have to use the bass booster Eq with my amp to get decent base out of the ipod

 

[sonick]

Quote:

Originally Posted by ScubaSteve87 I have to use the bass booster Eq with my amp to get decent base out of the ipod

when i used my friend's mini with my eggos (which some may know to be lacking in bass), i tried bass booster, i found that all it did was distort the bass HORRIBLY. it was quite bad.

 

[l_simon_l]

I thought the MS-1s bass out of an ipod was fine, and didn't notice a roll-off. But on the other hand there are people who think otherwise. The 16-ohm etymotic ER-6i doesn't have much bass out of an ipod though.

 

[Daemos]

So what good quality earbuds have an impendance of 32 ohms or greater? Most to my knowledge are 16 ohms...

 

[fjf]

Etymotic ER4p..

Regards

 

[ScubaSteve87]

I use a external amp and sik din ram line out, so I think then by using bass booster EQ, i don't get that horrible distorted sound, because I do notice that out of the headphone jack.

 

[Daemos]

Quote:

Originally Posted by fjf Etymotic ER4p.. Regards

Ouch those are pricy