Hm, I am affraid that simple approach with correction table works only if people use EQ in simple graphics mode (i.e. if they don't change default frequencies and Q factors for each band, only attenuation/boost).

Hm, I am affraid that simple approach with correction table works only if people use EQ in simple graphics mode (i.e. if they don't change default frequencies and Q factors for each band, only attenuation/boost).

Yeah, I've been turning my head inside out with this one all day. I think that you're probably right...the only way to do what Mark suggested would be to obtain all of the current eq settings, 'draw' the graph, add the adjustment and then factor the graph back into new eq settings that then get applied. I doubt that this is trivial to do, or desirable in k-space.

Assuming that everyone has default frequencies and Q factors in their eq settings would force users to make a choice of severely limiting their eqs or not being able to use this desired functionality.

IMO, the 'best' solution would be to overload bands 9 and 10 for bass and treble settings in 2x10 mode, or just band 5 for bass if the eq is being used in 4x5 mode.

Either have the user set up appropriate bass/treble frequencies and Q factors in these bands for all their eqs, or have config.ini/HiJack settable values that overload whatever the eq bands are set to.

Then make the dB adjustments easily accessible via the HiJack menu (lock all channels together!)

The only real issues are that you'd need to know whether the eq is in 4x5 or 2x10 mode, and to ensure that these new values stick if the user changes which of his 16 eq modes he is using. (Do you have visibility into this? Or is brute-forcing the bass/treble settings once per second an option?)

I've just played with some eq setting, and 200Hz,Q=0.15 and 8KHz,Q=0.15 seem to effect a reasonable bass and treble change.

As to clipping distortion caused by bass boost (definately an issue) I'd suggest reducing the volume as bass gets increased above 3dB boost. I don't know whether it'd be possible to change and limit the volume dynamically based upon what the current bass/treble settings are or not.

I'm not too concerned about conflicts with Q settings and whatnot. Like probably 90% of empeg owners out there, my EQ is set completely flat, because fussing with those detailed controls is impossible when driving. Yes, I know I can park and play with it, but I don't. And probably neither do 90% of the owners.

This bass/treble is for those 90%.

Cheers

If that's the case (and I agree that it is), wouldn't it be easier to just set a few EQ settings that would emulate bass/treble sliders? Some folks here could come up with some good ones. And then, maybe, have a hijack setting that would use those instead of trying to dynamically tweak them?

For me, a simple tone control, or perhaps a pair (bass/treble), would be a heck of a lot simpler than having to also go into the ultra-complex EQ menus and create a bunch of presets. That's the idea.

Cheers

I was suggesting that some nice folks might create some handy presets to distribute that would be easy to import. Then again, that's all stored binarily (it's a word now), isn't it? I was thinking that it was in config.ini, but I'm wrong, aren't I?

HeHe, pseudocode time..

int BassdB = 0, TrebdB = 0;





if (current_eq=="Flat"){

  AddHijackMenuItem(&BassAdjust,"Bass");

  AddHijackMenuItem(&TrebAdjust,"Treble");

  

  for (channel=1;channel<=EqChannels;channel++){

    SetEqBand (1, BassFreq, BassQ, BassdB);  /* Band, frequency, Q, dB  */

    SetEqBand (2, TrebFreq, TrebQ, TrebdB);  /* frequency / Q from config.ini */

  };

};



void BassAdjust() {

  while (true) {

    Key = GetKeyPress()

    switch (Key) {

      case "Up Button": return();

      case "Knob Right": { if (++BassdB >12 ) then{BassdB=12;} }       

      case "Knob Left": { if (--BassdB <-12 ) then{BassdB=-12;} }

    }

    

    for (channel=1;channel<=EqChannels;channel++){

      SetEqBand (1, BassFreq, BassQ, BassdB);

      }

  }

return(0); /* should never get here */ 





void TrebAdjust() {

 /* Ditto. */

}

Would that principle work??

It's too bad you'd have to go to all that trouble (offsetting the EQ) to get bass/treble.

Because I know that the DSP has bass/treble control registers built-in, and those registers are completely independent of the EQ.

Too bad there's no way to directly access them, sigh...

There must be a way to access them, why can't they be accessed ?

There must be a way to access them, why can't they be accessed

Well, there probably is a way to access them. The problem is that only the Empeg guys have access to the required documentation to do so, and they had to sign an NDA to get that. Mark doesn't work for Empeg so does not have the information. Even if he did, it'd be difficult to write a Hijack modification to access the treble/bass without revealing that information (hence breaking the terms of the NDA).

So, we either wait for the Empeg guys to include simple bass/treble controls in the player software, which isn't likely to happen anytime soon given that the unit is EOL and it isn't a bug fix, or Mark kludges it somehow.

I'm not too concerned about conflicts with Q settings and whatnot. Like probably 90% of empeg owners out there, my EQ is set
completely flat, because fussing with those detailed controls is impossible when driving. Yes, I know I can park and play with it,
but I don't. And probably neither do 90% of the owners.

That's why I suggested to use bands 9/10 and completely overload any existing settings on these bands. With a low Q factor, it shouldn't be necessary to use more than one band to effect a bass or treble slider. People who still wanted to set up eqs would still have the other bands to play with.

Anyway, I'm only suggesting solutions for fun - I also have Bass/Treble control on a separate HU..

Bass/Treble controls could just reserve one of the presets for its purposes, overriding any user settings in it (or first checking it for flatness).

Can I just tell you how excited I am that this is even being discussed?
I thought it was a long shot, but youse guys are real sharp.

Keeping my fingers crossed, hoping it comes to fruition.

Z~

Ok, I'm working on it, and teaching myself C in the process.

I've got the Hijack stuff sorted to add Bass and Treble adjustments to the menu, and to control the gains.

Now I've just got to work out the format that the eqs are stored in, and figure out how to modify them. The hard stuff. If anyone has any clues, then feel free to share.

Well, I assume you have found this starting point:

linux/arch/arm/special/empeg_mixer.c:



        case EMPEG_MIXER_SET_EQ:

        {

                struct empeg_eq_section_t sections[20];

#if MIXER_DEBUG

                printk(MIXER_NAME

                       ": mixer_ioctl EMPEG_MIXER_SET_EQ %08lx\n",

                       arg);

#endif



                copy_from_user_ret((void *) sections, (const void *) arg,

                                   sizeof(sections), -EFAULT);



                empeg_mixer_eq_set(sections);

                empeg_mixer_eq_apply();

                return 0;

        }

Yeah, found that. I'm trying to work out the format of each section. There is 2 words per section that somehow encode freq, Q, and gain. The preliminary spec wasn't any help here..

I would guess that the frequency (band) is just the array index. But the others.. gotta dump em out as they change and see which bits are different (which you no doubt are doing already).

Cheers

Partial success!!!!!!!

OK, I have bass and treble adjustments working...kinda. If I'm on AC power then everything is great, but when on DC trying to change the values sends the player beserk. I'm guessing I have to learn more about this ir_translation thing.

It's coming soon!

I wonder if the EQ setup is different for DC mode (with fader and whatnot..)?

There are two different personalities for each EQ setting, and the in-car mode has the 4-channel option....

Sorry, I meant player as in the Empeg as a whole, as opposed to the player software..

What's happening is that the Empeg tries to toggle back and forth between aux in and mp3 when I turn the knob - turning the knob more than one click acts like pressing the 'source' button on the remote repeatedly.

In reply to:

---

do what the fanatical home stereo/theatre guys do and go boy a sound pressure level meter

---

wouldn't a "fanatical" home stereo guy invest in an RTA instead?
--
sancho

Problem solved.

I changed 2 things, not sure what fixed it.

Firstly, I defined FAKE_BASSADJ and FAKE_TREBLEADJ and added them to the buttons table to allow ir_translation.

Secondly, I removed the copious amount of serial debug output that I had wedged into my eq write function. (I seem to remember that serial port is slower in DC mode?)

Anyway, I have working bass and treble control. Who wants it?

Sure! Where? Is it Hijack enabled?

Buy that man a beer!
In fact... beer for everybody!!

Ok!

hijack233-basstreb.zimage is up. (Rightclick and save!)

This is a preliminary beta - and isn't fully functional. By that I mean that you're going to have to use the player's eq to initially set some values which the Hijack-menued Bass and Treble Adjustment need. Eventually I hope to get these values in config.ini and ignore the player supplied values completely, but I need to crack the internal format for them first. It also only works in 2x10 eq mode at the moment. (4x5 mode will have a funny effect - you'll get bass adjustment at the front and treble at the rear or vice-versa, I'm not sure which.)

Note that there are 2 complete sets of eq settings, one for DC mode and one for AC mode - so you need to set these values whilst in the mode that you intend to use (or both if that's what you need).

Set the ninth band of each channel to have dB=0, f=100Hz, q=0.2 and the tenth band to have dB=0, f=10KHz, q=0.2. I think there may be a bug in the players eq channel lock code so I'd do this with left/right channels unlocked. (I'm still looking into that.)

Exit from the eq menu, go into Hijack and test away
You can tweak the f and q values if you think that the ones I've provided don't suit your needs. Keep q small (under 0.3) so that the adjustment is smooth and wide across the frequeny range.


Any bass/treble level adjustment gets lost when the player is rebooted. (only the level, not the f and q settings).
The bass/treble will only work when the selected eq has the f and q values set appropriately in bands 9 & 10.

You should be able to set ir_translations to call these menus. Pseudo buttons are named "BassAdj" and "TrebleAdj".
You should also be able to do the other wonderful Hijack stuff with these: Remove from menu, add to Popup menus etc. This is untested, and any feedback on these is welcome..(especially feedback like "ir_translation works for Bass and Treble menus" )

I'm going to keep working on this to try and get those values in config.ini so we can ignore the players eq settings completely, see if we can store the levels over a reboot (is this important enough to warrant the flash usage?), and generally work it a bit more. Then I'll send Mark a patchfile

...and that beer will hopefully be gratefully accepted at the Boston Owners meet - it'll help offset the cost of buying Mark's!

I'm probably missing the obvious, but I cant figure out how to do this:
Set the ninth band of each channel to have dB=0, f=100Hz, q=0.2 and the tenth band to have dB=0, f=10KHz, q=0.2
I can see when I'm in the eq mode I can change the DB levels which in turn changes the q level, but how do I independently change them to the specific levels you mentioned? Is there some other method than just turning the knob, that I'm missing?

Z~

Yes. You can independently set the Q and band frequency (hence the term "parametric" to refer to this equalizer). Please refer to the button guide at www.riocar.org to show you how to select those parameters.

OK, I'm dumb. My co-worker showed me the error of my ways. Thanks to you Tony too.

This works great!!!

(cue the rays of sunshine, ethereal music and release the doves)
I'm gonna go play with it out in the car.

With this new functionality I will no longer be endangering the lives of my fellow motorists while playing with the EQ and driving.
You have saved hundeds of people from certain traffic related trauma.

I'll give more feedback as I play around.

Z~

I have another question about the bass treble thing, but since my wish has been granted, should I move this thread on over to programming? That way those who read that thread who maybe dont read Wish list will be in the know.

Is that OK? I dont want to do anything inappropriate.

Z~