Hardware EQ for Ipod 5th gen.

[h.finn]

Hi everybody,
I read an old thread on the forum about a previous RB release which allowed to "equalize" the ipod hardware.
Apparently the results were excellent!
Does anybody know about it?
Is the release still available?

Many thanks,
H.

[Chronon]

I believe the current Bass and Treble controls correspond to that.

[soap]

When the hardware EQ was enabled as such only the low and high shelf filters actually worked.  My memory matches Chronon that the 3 band / 2 shelf interface was scrapped because of this and the two shelves renamed Bass and Treble.

[h.finn]

Hi,

And thanks for the answer.
So I'll just use these settings and maybe tweak the cutoff.
I just have a question about something that puzzles me (I don't know if this is the right place for the topic  ):
I have both a 5.5 gen. video and a Mini 1st gen.
They both have RB with same settings.
The Mini sounds WAY better!!
I thought it was supposed to be the other way round !!
The bass on the 5.5gen one, in particular, is extremely distorted while it's absolutely fine AND great on the Mini!

Does anybody have any suggestions?
Thanks
H.

[saratoga]

The Mini sounds WAY better!!
I thought it was supposed to be the other way round !!

They should sound the same.  If they don't, you're probably doing something wrong or one is broken.

The bass on the 5.5gen one, in particular, is extremely distorted while it's absolutely fine AND great on the Mini!

Does anybody have any suggestions?

Let me guess, you used the EQ to boost the bass?

[h.finn]

Hi Saratoga,
Yes, i boosted the bass.......on the two ipods,
and the result i sooo different
..........
I must add that I've had the Mini since it came out and bought the video a year ago (also because I can't fit everything on the Mini anymore)
But through iTunes they sound the same
But then again.......iTunes is kind of "flat" compared to RB!
I bought the video from "reputable" sellers, I must add

[saratoga]

Hi Saratoga,
Yes, i boosted the bass.......on the two ipods,

Don't do that, it'll distort.  The manual has some info about how to use an EQ:

http://download.rockbox.org/daily/manual/rockbox-ipodcolor/rockbox-buildch6.html#x9-1150006.8

Basically, you want to lower frequencies, not raise them, so either lower then explicitly or apply enough precut that you don't distort.

[h.finn]

Look,
I'll experiment during the w-end (with the 5.5gen. that is, 'cause the other one's just so good).
And I undertsand your point...........still I don't understand this difference between the two!
The 5.5gen one even distorts a little (on the bass frequencies) on the equalizer preset that comes when you first install RB.
Sooo frustrating!

...............
P.S.: How do I know which one is the current eq? I mean: where do I look?
H.

[saratoga]

The 5.5gen one even distorts a little (on the bass frequencies) on the equalizer preset that comes when you first install RB.

Post you config file from the Video.

[h.finn]

Thanks Saratoga.
That's nice of you......I'll just do it on monday........I'm in europe and I'm finishing the day at work now............family rules say: no posting from home
 
so it will have to be monday 'cause ipod is not with me
Thanks again and, ............have a good w-end!!
 

[h.finn]

Ok,
Here's my setup:

Graph. Eq:
2.5   60         6.4
5.5   450       6.0
1.5   4000     2.1
2.5   15530   2.2

Bass:   +8
Treble: +12
Volume:-76dB

And the Bass is way more distorted than with the same settings on the Mini!!
I use a good quality LOD (Line Out Dock) and "class T" amp + excellent Italian loudspeakers from the early 80s.
The files are almost all uncompressed flac.

Many thanks,
H.

[torne]

You're using the software graphic equaliser *and* the hardware tone controls? That's kind of an odd thing to be doing. You are boosting the bass twice: first Rockbox's equaliser adds 2.5dB to all the frequencies under 60Hz, then the DAC is doing it again by 8dB (not sure what shelf it uses). That's a lot of boost and doing it in two seperate ways probably doesn't help. Also, your Q value for the bass shelf is 6.4 - the manual explicitly says that you should leave it as 0.7 for the shelf filters. You're doing the same for the treble, of course...

-76dB volume is incredibly quiet. You mention you are using line out, which means that the entire top range of the volume adjustment will do nothing, since line out is line level by definition; however, Rockbox supports a wider range of volume adjustment than the DAC does, and we simulate the extra range by digital processing of the audio to reduce the volume before passing it ot the DAC. If you have it turned down to -76 in order to reach this, then this means you are introducing a *third* set of audio processing. You shouldn't use the volume control this way; leave it on a normal setting and control the volume externally if you are using line out.

The DACs and analogue hardware are not identical between the different models, so while yes, normally people expect the Video to sound better, your settings are highly abnormal and it's hard to say what to expect

[h.finn]

Hi Torne,
I appreciate your precious suggestions!
So: I should use either the graphical eq or the hardware, right?
If I go for the former: any suggestion about a good bass boost?

I put the volume at -76dB (and obviously increase the volume on my amp) to avoid any distortion.
That's the only effective way I found to do it.

I don't understand:
 "You mention you are using line out, which means that the entire top range of the volume adjustment will do nothing, since line out is line level by definition; however, Rockbox supports a wider range of volume adjustment than the DAC does, and we simulate the extra range by digital processing of the audio to reduce the volume before passing it ot the DAC"

Thanks again,
H.

[torne]

Line out is line level, 0dB, i.e. it's not affected by volume changes. This is normal and should not cause distortion.

Turning the volume down *very* far, as you are doing, switches Rockbox to a mode where it actually reduces the volume of the digital audio in the DSP stage; this is not something you should have to be using to avoid distortion.

Read the manual for suggestions as to how to configure the graphical equaliser; it's a matter of taste, but as saratoga pointed out, you generally want to either *lower* certain frequencies, or set the precut (overall volume reduction) to be at least as big as the highest boost amount, to avoid distortion and clipping.

The hardware tone controls (the bass/treble settings) automatically precut the volume as needed, but I'm not sure if this precut actually works on line-out. If you can get the audio effect you want using only those, then it's more efficient to leave the equaliser disabled, since the tone controls are "free" whereas the EQ uses CPU time.

[h.finn]

Allright,
.........so basically you suggest I stick to the bass/treble settings (by the way, the bass precut works through the LOD dock) and leave the graphical  eq "untouched" (i.e. the way it is when first installing RB)?

Thanks
P.S.: could you tell me how to know the "current" eq settings, the ones using at any given time?
P.P.S.: just found this:
http://www.rockbox.org/tracker/10768
"Details
I'm reporting a bug which we tracked down in the german rockbox forum.
Rockbox plays a loud distortion (without music) if you have bass and equalizer both turned on. Any bass setting above 0 shows this behavior.
Tested with a current build after reseting the settings. (r23566-091108)

steps to reproduce:
01. download current build
02. reset settings
03. apply bass
(no distortion this far when resuming playback via menu)
04. apply EQ, > distortion when resuming playback after stop
05. turn off bass > no distortion"