The iPod Poor Bass Response

[scorche]

If you are using an amp, the "correct" way to use it is to go out of the line out anway, so the impedance of the inputs wouldn't matter...

And the only on-topic use of this thread would be to talk about the Rockbox EQ settings.  The headphones are offtopic as well technically...

[mamboman]

tried various settings but could not find one that really works all that well without distorting the sound. I guess there are only 2 alternatives if you care about the response at the lower end :

1. listen to your music through line-out with an external portable amp

2. listen to your music with headphones with impedence of at least 80 or 100. or better yet, combine with option 1

[Febs]

tried various settings but could not find one that really works all that well without distorting the sound.

What do you mean by "distorting the sound"?  If you mean that the EQ causes clipping, you can correct that by reducing the pre-cut.

[Chronon]

And the only on-topic use of this thread would be to talk about the Rockbox EQ settings.  The headphones are offtopic as well technically...

I didn't quite understand your reply at first.  I had started to type a response defending that headphone selection represents an alternative and legitimate strategy for mitigating the iPod's poor bass response (which is the current topic).  But then I realized that it is not a strategy that lies within the scope of Rockbox.  EQs represent a patently Rockbox-related way to deal with the current problem.  Headphone selection really has nothing to do with Rockbox.

[TexasRockbox]

My point about the headphone selection and impedence was that in doing so one could avoid the use of the Rockbox EQ functions altogether and achieve a near flat output (as related to impedence) and thus maximize battery life.

Subjective sound quality of the headphones is an off-subject matter but I used the Koss as an illustration that a reasonable quality 60 ohm headphone does exist materially, rather than theoretically.

The end result of the discussion may that that some users will find the bass response satisfactory using higher impedence phones (such as the Koss) and not use any EQ, maximize battery life and increase their enjoyment of Rockbox.

[senab]

@PHK Brasil: Can you outline how you did the test please? Method, equipment, etc, etc.

I'd like to repeat the test using the hardware EQ instead. Obviously only the shelf filters work on the hardware eq, and the lowest cutoff frequency is 80hz, therefore I wouldn't expect as good an output; but the hardware eq has no effect on battery life therefore would be preferable.

[Chronon]

It's probably a lot more efficient in terms of battery usage, but it will still consume some battery.  You don't get gain for free.  

Lisa! Get in here.
[Lisa walks in, chuckling nervously]
In this house, we obey the laws of thermodynamics!

 

[senab]

The hardware EQ is built into the Wolfson DAC, therefore shouldn't require anymore battery power afaik. A dev will know better than me though  

[mamboman]

usually even if the function is implemented in the hardware, it will still take more processor cycles thus using a little more battery. but seriously i think the part which uses the most power is still the HDD and the LCD. i don't think the DAC matters as much.

just gotten a headphone amp from Mseedlabs and listening through the dock line-out makes a world of a difference for me at the same listening levels.

[senab]

No, it won't use ANY CPU cycles because the hardware EQ not implemented in software, the DAC implements it. The CPU, HDD, LCD and every other component have no idea about it lol.

A headphone amp is a viable fixed location solution, but with portability in mind, it doesn't really work

[Llorean]

No CPU cycles doesn't mean No Power though. And the CPU does have an idea about it, because it has to enable and set it.

If a chip does more work (Hardware EQ on) vs less work (Hardware EQ off) it's going to draw more power. You can't ignore thermodynamics, as was stated earlier in this thread. Whether it uses more CPU or not is irrelevant to whether it adds a little to the battery drain.

[mamboman]

Okay, I stand corrected. It'd be more clock cycles in the DAC and not the main CPU. Thanks

[mamboman]

No, it won't use ANY CPU cycles because the hardware EQ not implemented in software, the DAC implements it. The CPU, HDD, LCD and every other component have no idea about it lol.

A headphone amp is a viable fixed location solution, but with portability in mind, it doesn't really work

Headphone amps does impede some portability, but the portable ones are indeed quite small and they do allow listening for up to 60 hrs with their rechargeable batteries (more than the ipod anyway )

[TexasRockbox]

In any event, using the Rockbox ipod 5G with 60ohm phones has given me even greater enjoyment of Rockbox/ipod.  Battery life is great, I'm enjoying the heck out of my WPS, I'm finally able to utilize OGG as I've been wanting to for some time, not being tied to a program or bloatware to upload/offload music is a joy, and it all sounds great so a big THANKS to the Rockbox developers.

[PHK Brasil]

@PHK Brasil: Can you outline how you did the test please? Method, equipment, etc, etc.

♪
Hi, Senab. The RMAA is very intuitive and simple to use. It will generate 2 audio signals in wave format: A Calibration and a Test signal. Put them on the iPod and run according to the RMAA wizard.

You will need a stereo headphone splitter. One stereo out goes to your PC line in. The other one is where you must plug the headphone which impedance you want to test.

1) Do the measurement with no headphone (No Load) and no EQ
2) Do the measurement with the headphone(XX ohm) and no EQ
3) Now,  measure with the headphone(XX ohm) and the EQ

OK?