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#17157 - 08/09/2000 11:29 Loudness that changes with volume level
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31597
Loc: Seattle, WA
I've brought this up before, but I think it deserves its own entry in the wish list.

One upon a time, the loudness control on a stereo was meant to be sensitive to volume. As you turned up the volume, the loudness decreased, and as you turned down the volume, the loudness increased. The whole idea was to keep the bass up above the car's noise floor even when you turned down the volume.

Not many stereo manufacturers implement it this way any more (in favor of a front-panel switch to activate and deactivate the loudness). But I'd love to see this old-school loudness implemented on the Empeg. One of my problems is that I can get the bass sounding great at either high volume or low volume, but never both. When I drive by myself in the car, I crank the volume, so the bass sounds great. But when I have passengers (*COUGH*wife*COUGH*) and I'm forced to reduce the volume, the bass is weak.

The user interface could still be the same, you'd still have the same loudness scale on the screen to adjust how much extra bass you want. But in actual under-the-hood implementation, this value would be the "maximum" amount of loudness, with increases in volume chipping away at the loudness value.

It would take a bit of experimentation to get the right curve and cutoff points. You'd probably want the maximum loudness to top out at a certain point on the volume scale such as -40db. Likewise, the minimum loudness should bottom out at some high value like -5db. And you'd need to decide whether it was a linear or a logarithmic taper, and you'd need to decide whether or not to completely remove the loudness at -5db or whether to leave a little bit in there still.

Finally, we'd need two different loudness personalities: One for home and one for car.

How about it, Hugo?

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#17158 - 08/09/2000 13:46 Re: Loudness that changes with volume level [Re: tfabris]
dionysus
veteran

Registered: 16/06/1999
Posts: 1222
Loc: San Francisco, CA
In reply to:

One upon a time, the loudness control on a stereo was meant to be sensitive to volume. As you turned up the volume, the loudness decreased, and as you turned down the volume, the loudness increased. The whole idea was to keep the bass up above the car's noise floor even when you turned down the volume.


Hmm..I've got the opposite problem: too much base at a low-level, and not enough at a high-level... (mainly because my 2 10s have a hard time keeping up at the high-bass level..) something like that would definately not work for me, as it'd make my problem worst...
-mark

MK2: 36gb
Tivo: 90gb
CPU: 120gb
...I think drive manufacturers love me!

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#17159 - 08/09/2000 13:53 Re: Loudness that changes with volume level [Re: dionysus]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31597
Loc: Seattle, WA
Hmm..I've got the opposite problem: too much base at a low-level, and not enough at a high-level...

Well, as Hugo pointed out in another thread, the loudness is working this way already and I just never noticed it. A little experimentation reveals that it is working, just more subtly than I would like it to. I think I'll go crawl under a rock and die from embarassment now.

So do you have the loudness turned up on your empeg? If so, knowing this now, maybe turning it off and adjusting your EQ might solve that problem for you?

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Tony Fabris
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#17160 - 08/09/2000 15:05 Re: Loudness that changes with volume level [Re: tfabris]
dionysus
veteran

Registered: 16/06/1999
Posts: 1222
Loc: San Francisco, CA
In reply to:

So do you have the loudness turned up on your empeg? If so, knowing this now, maybe turning it off and adjusting your EQ might solve that problem for you?


I usually leave my loudness at 0, because the only time I wanna adjust it is when it's loud and it tends to not make a difference anyways - now I know why:) I just need to get bigger speakers if I want more bass though - my speaker box/speakers was designed for the back of a hatchback toyota celica (extremely loud in my old car), and they just dont' sound as good in the honda;(
-mark


MK2: 36gb
Tivo: 90gb
CPU: 120gb
...I think drive manufacturers love me!

_________________________
http://mvgals.net - clublife, revisited.

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#17161 - 09/09/2000 14:54 Re: Loudness that changes with volume level [Re: tfabris]
muzza
Pooh-Bah

Registered: 21/07/1999
Posts: 1765
Loc: Brisbane, Queensland, Australi...
Hugo, can you re-iterate over again (gotta love tautologies) the action & settings of the loudness control?
Also, is it done in the DSP or some pre-processing? could the same thing be done with simple Bass & Treble controls?

thanks.

(last Post before going to the Olympics )

Murray 06000047
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#17162 - 12/09/2000 00:35 Re: Loudness that changes with volume level [Re: tfabris]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31597
Loc: Seattle, WA
At the risk of embarassing myself further, I wanted to expand on a question that Hugo asked about this subject in another thread.

Hugo said that the loudness is dynamic, and it uses the DSP manufacturer's recommended spec for its programmable parameters. He asked if anyone had suggestions on how to improve it.

I spent some time playing with it, and I now know why I never realized it was dynamic in the first place: At the default parameters, it adds some loudness even when the volume is at 0db, meaning that the slope of the dynamic loudness application never bottoms out.

Since I adjusted my EQ to sound good at near-maxiumum volume without loudness, any time I tried to add loudness it just made everything clip at loud volumes while not improving the bass enough at lower volumes. The slope isn't drastic enough for my particular amplifier setup. So I assumed the loudness wasn't dynamic at all, turned it off completely, and complained on the BBS.

My dream would be to have the loudness reach its minimum (no boost) state at -14db on the volume scale. My reasoning? You can boost the loudness up to 14db above flat, so it should cap out in such a way as to not cause clipping at maximum volume.

I don't know where (currently) on the volume scale the maximum loudness boost is reached. But on my system, I'd think I'd want it somewhere in the -40s. In other words, I'd want the loudness fully boosted when the volume went down to -45.

As far as the shape of the slope between these points, I don't know whether I'd want it to be linear or logarithmic. But having the two cutoff points that close together would make the loudness dynamics change more quickly and be more useful.

The only problem with my choices of parameters is that they are only appropriate for my car and my amps. If someone tended to run their stereo at -25 DB all the time instead of between 0 and -10 like I do, then those cutoffs would be wrong for them.

So I think it would be cool if there were a way we could control those cutoff points. Even if it's just having to hand-edit config.ini on the developer kernel, it would be enough for tweakers like me.

It's after midnight and I'm sleepy, so my apologies if the above post is incoherent. I'll read it again in the morning and see if I really did embarass myself...

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Tony Fabris
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#17163 - 12/09/2000 02:22 Re: Loudness that changes with volume level [Re: tfabris]
bryan
journeyman

Registered: 25/06/1999
Posts: 57
Loc: New Zealand
My dream would be to have the loudness reach its minimum (no boost) state at -14db on the volume scale. My reasoning? You can boost the loudness up to 14db above flat, so it should cap out in such a way as to not cause clipping at maximum volume.

Agreed, but does anyone actually run their eq. at max boost? Personally I adjust gain down and even then I've found a few dB make a huge difference. I think you could be a bit less conservative and say zero boost at -6dB. Considering that currently loudness is having an effect at zero attenuation, and no one is complaining about clipping.

If you are cranking on more than this I would think there'd be a serious deficiency in audio reproduction (or hearing)

The only problem with my choices of parameters is that they are only appropriate for my car and my amps. If someone tended to run their stereo at -25 DB all the time instead of between 0 and -10 like I do, then those cut-offs would be wrong for them.


Herein lies the problem, it all depends on your setup. Standard listening for me is about -30 dB. I guess the default setup has to assume that you are using the full range.

A next step of loudness control:
peek loudness (I guess that this is the one we have already)
attenuation value of zero loudness. default loudness reaches zero at -6dB
attenuation value of peek loudness. default loudness reaches peak at -45dB

It would make sense to move the peek between -14dB at +30dB (the opposite extents of the eq.)

I'm going with a linear function between the two points. (Since we already have logarithmic volume and trying to superimpose logarithmic functions makes my head hurt.)



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#17164 - 12/09/2000 08:02 Re: Loudness that changes with volume level [Re: bryan]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31597
Loc: Seattle, WA
Agreed, but does anyone actually run their eq. at max boost?

No, of course not. One shouldn't do that. It's better to use the EQ to cut frequencies than to boost them. I run my EQ so that the loudest frequency is at 0db. The others are cut lower than 0db by varying amounts. That one loudest frequency happens to be one of the bass frequencies, which is why I'm concerned about the loudness.

See? If the bass is EQ'd at 0db, and you play the stereo at 0db, then the loudest bass peak in the music is at exactly 100% and doesn't clip. If there's some loudness applied at 0db, then it would start to clip. That's why my ideal setting would have no loudness at -14db. No matter how much I cranked the loudness, or the volume, it wouldn't clip. (Unless of course my EQ had the bass boosted above 0db, but then that would be my problem and it would clip at 0db anyway.)

Standard listening for me is about -30 dB.

You should consider backing off the input gains on your amplifiers. At that level, you're amplifying the system's noise floor quite a bit, and not taking advantage of the full dynamic range of the Empeg.

There's an item in this FAQ which describes how to tune the input gains on the amplifiers.

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Tony Fabris
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#17165 - 12/09/2000 16:19 Re: Loudness that changes with volume level [Re: tfabris]
bryan
journeyman

Registered: 25/06/1999
Posts: 57
Loc: New Zealand
See?
Nope, I'm going to disagree, probably totally misguidedly but here goes.

If the bass is EQ'd at 0db, and you play the stereo at 0db, then the loudest bass peak in the music is at exactly 100% and doesn't clip.
Agreed.

If there's some loudness applied at 0db, then it would start to clip.
Agreed.

That's why my ideal setting would have no loudness at -14db. No matter how much I cranked the loudness, or the volume, it wouldn't clip.

Hang on, the idea is that the loudness tends to zero at that -14dB. This means that there would be no adjustment between 0 and -14dB.

At say -16dB there would only be a bit of loudness adjustment say ~1 dB, i.e. not enough to push it above the zero point.

So if you assume that the eq. is never boosted, then you can quite happily set the zero point of the loudness to 0dB since this is the point at which loudness has no effect.
Also as long as you keep the point of max loudness below -14dB (and have a linear scale) then there should be no clipping.



You should consider backing off the input gains on your amplifiers. At that level, you're amplifying the system's noise floor quite a bit, and not taking advantage of the full dynamic range of the Empeg.

But for those rare times when you just want to give yourself a hearing loss or need to attempt removal of the rear windscreen, I'd find it inconvenient to grovel around in the boot with an allen-key.

Actually I even tried it and noise-wise, I think the output is superb across the whole range. In fact for given (average) listening level, I couldn't tell the difference between low-gain amp, high-gain empeg and the reverse. That's why I choose to run the amps at their normal gain.




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#17166 - 12/09/2000 16:36 Re: Loudness that changes with volume level [Re: bryan]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31597
Loc: Seattle, WA
Hang on, the idea is that the loudness tends to zero at that -14dB. This means that there would be no adjustment between 0 and -14dB. At say -16dB there would only be a bit of loudness adjustment say ~1 dB, i.e. not enough to push it above the zero point.

I see your point. You're right, in order to prevent clipping at 0db, you wouldn't necessarily need the cutoff to be as low as -14db.

I'd still like to have no loudness at all near the top 10-15db of the range- but that's just because it's the way my amps are set up, and I really would want it that way. Like I said, allowing those cutoff points to be user-definable would be cool, so we could adjust it however we wanted for our own systems.

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Tony Fabris
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