MK2, 2.0b7

AM, FM, and MP3 volumes seem to be very different on my Empeg. I'm wondering if anyone else notices this... I would say that, using the MP3 volume as the constant, FM is minus 15% in volume and AM is somewhere around +25%. Like, if I'm listening to MP3's and switch to the radio, the FM will be noticably quieter. Then when I switch to AM, the AM volume nearly blows my eardrums out. In fact, when switching from FM to AM, you actually hear the *FM* output go WAY up in volume for a split second before it switches to AM.

Now, I remember some people had found some loudness parameters were in the kernel source, and could be tweaked. Do these same adjustments exist for volumes for FM and AM?

If not (and I suspect they might not be) then I think we need one of these two fixes:
(a) The player could correct these differences, assuming everyone else has the same behavior
or
(b) Empeg could create a new Sound Menu option for a "volume modifier" per source. So that the user can correct these problems themselves.

This is a rather large inconvenience for me, because in order to keep consistent volume when changing sources, I am constantly raising and lowering the volume when I switch between them. I'd like to know if this happens with anyone else, and I'd like to suggest that Empeg do something about this for an upcoming release, or let us know how we can hack it ourselves.

I've got the same issues here with the volume changing between MP3, FM and AM. Both with B3 and B7, never tried it with 1.03 though.

Empeg guys, is this on your list for 2.0 or at least a post-2.0 release?

If they didn't do it then it is probably something that Mark could build into the HiJack kernel. He already detects whether the tuner or player is active so with some settings in config.ini he could probably tweak the volume in the different modes.

Have you tried to the volume multiplier (Auto Volume Adjust) on Hijack. I know it works great for mp3's and keeping them equal volume, no idea if it works for radio.

-Greg

If they didn't do it then it is probably something that Mark could build into the HiJack kernel. He already detects whether the tuner or player is active so with some settings in config.ini he could probably tweak the volume in the different modes

I of course thought about a Hijack solution first. But... Hijack doesn't (to my knowledge) know if you're in AM or FM mode, just that you're in the tuner. Like I said, using the MP3 volume as the constant, the AM volume is WAY too high and the FM volume is too low. In order to make those adjustments, it needs to know which band you have selected. There *might* be a bit or two in the state block that tells you which you're in but I'd have to double check.

Besides, right now Hijack could only accomplish this by sending fake IR codes to change the volume. So when you switched to AM from FM, the AM volume would still be loud as hell, and would have to send, say, 10 or 12 "volume down" commands until it was at the correct volume. That's an okay hack, but it stinks as a long term solution. This problem should be handled by the software itself.

I'm pretty sure the answer is no. The VolAdj code works on the digital form of the signal before it is passed off to the DSP. The signal for the tuner bypasses this stage going straight from the tuner to the DSP.

I thought we had enough access to the DSP to turn the volume up and down if needed ?

The FM/AM problem is tricky. I guess screen scraping might work, but I haven't seen the 2.0x tuner interface yet as I don't have the tuner installed yet.

Have you tried to the volume multiplier (Auto Volume Adjust) on Hijack. I know it works great for mp3's and keeping them equal volume, no idea if it works for radio.

Yes I've used voladj... It doesn't work on the tuner, only on the MP3 source. Furthermore, voladj does dynamic compression, which is not the same as changing the volume for a source. I *want* the quiet parts of a song to be quiet, and the loud ones loud. But this problem is where the relative volumes of each of the tuner bands are way off... So if an AM station, an FM station, and my Empeg's MP3 source were all playing the same song at the exact same time, and I switched between the three sources, the AM would be MUCH louder than the MP3, which would be louder than the FM.

The easiest example of this is to switch between an FM and an AM station. Unless there's something quirky about my setup, you should notice that for a split second after you switch to the AM station, the volume of the FM signal shoots up higher. Then when the AM signal kicks in, it's very loud. If the two stations were playing the same source material (sending them at the same volume of course) the AM would sound much louder.

So even if voladj worked on the tuner signal, it wouldn't be the right way to fix this.

I thought we had enough access to the DSP to turn the volume up and down if needed ?

Maybe, I'm not sure. I don't remember any ioctl()'s which give it to us, maybe from inside the kernel one can do it. I forget how rjlov does it actually. Obviously silently changing it at the DSP would be preferable to sending a bunch of volume IR commands.

The FM/AM problem is tricky.

Maybe not *that* tricky. If there's a state block bit assigned to it, it'd be real easy. I'll look for it tonight.

I agree that switching between an AM and an FM station, as well as switching between the radio and MP3s, tends to have significant volume differences.

I think what happened was that the empeg guys tested this out and adjusted it to what they thought sounded good. But perhaps English radio stations do things a little differently than US radio stations.

I think this is similar to the bass boost on the tuner. The empeg guys got it sounding right for the radio stations in Cambridge. I think the bass boost sounds PERFECT for all of the AM radio stations I can pick up here, but it's too much for FM radio stations here.

I think it would be nice if we could adjust the global volume offset between FM, AM, and MP3. I also think it would be nice if we could select the bass boost to be on or off for FM and AM independently.

Yah, exactly. I had asked in my original message if these adjustments were tweakable in the kernel but nobody "in the know" responded. My assumption is that the kernel wouldn't know anything about whether you're in AM or FM mode on the tuner, so it'd be some kind of Player software feature instead.

I forget how rjlov does it actually.

He adjusts the volume of the digital signal before it gets sent to the DSP, he doesn't use the DSP to change the volume.

The bass boost is obnoxious. When I switch to FM the car is shaking in its boots. Ugh.

Calvin

I'm going to keep bumping this thread until someone with authority tells me if there are plans to fix this or not. I apologize for being so persistent but at this point I don't even know if this appears on the bug list or not, and being a developer, I am well aware that things that aren't documented as bugs don't get fixed.

It's bug #1649.

Thanks muchly!