After diggin through some old posts, I see this has been brought up before, but with no clear answer given. So put simply, What are the parameters for the loudness contours?

For example Is there a fixed wheighting and the loudness "level" just effects where the curve is flat? or is the contour flat at some fixed level and the loudness varies the wheigting? Is this outlined in the DSP spec (part number?) and what are the recommended parameters?

Here's a site with some brief backround info:
http://www.sfu.ca/sonic-studio/Equal_Loudness_Contours.html
http://www.sfu.ca/sonic-studio/Sound_Level_Meter.html

#080000512 green 12GB

I don't think it's been disclosed what the parameters are for the loudness contour. Hugo, would you like to fill us in?

I, personally, would like to see an adjustable set of parameters for the loudness contour, perhaps in CONFIG.INI.

Hugo did say that the loudness doesn't ever disappear completely-- there's still some loudness present even at 0db. This is why I initially thought that the loudness wasn't dynamic.

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Tony Fabris

I would like some information on how one should set the loudness level on the empeg. I have balanced the amps so that everything is just under distortion at 0db and normally listen between 20 and 5db. Should I increase the loudness and lower the bass amp so that it sounds right at 20db?

I presume the effect of the loudness will be negligable at 5db.

MK2 Red S/n 949

The reason that you would want to use the loudness control is if you tend to listen to the stereo a lot at lower volumes, and you want more bass during that time.

I have been experimenting with the loudness lately, trying different settings and using different EQ curves for "with loudness" and "without loudness".

Right now, I've got loudness set at 3db all the time and have been making tiny little tweaks to the EQ, then living with it for a couple days to see how it works out in the long term.

But it's all about personal taste. You should experiment and do what works best for your listening habits, your car's environment, and your equipment. There's no single "you should do this" formula when it comes to equalization.


I presume the effect of the loudness will be negligable at 5db.

It's not. It's noticeable at all volumes. It's LESS at louder volumes, but it's still there and noticeable. That's why I want to be able to set my own cutoff points: I want it to disappear when the volume is still somewhere below 0db.

I'd also like to know what frequencies it's boosting...

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Tony Fabris

I'd also like to know what frequencies it's boosting...

I *think* (IIRC) that the relevant detail, and a lot of other useful stuff, is in the designer's manual (a PDF file) for the 7705 DSP that the empeg uses. This is available on the Philips Semiconductors web site. I might have a copy of this stashed somewhere if people are desperate to see it; I could post it on my web site if people are interested.

One of the few remaining Mk1 owners... #00015

I actually keep a copy of the spec sheet for that DSP on my hard disk. I will check to see if it has that information.

I don't know if I have a designer's manual for that DSP. If it's different from the file I already have, I would like to know where I can get it (exact link).

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Tony Fabris

I am finding it very difficult to get a good all round sound. I will set the EQ for a couple of my favorite tracks but then every now an then I hear a track that doesn't sound right, re-adjust etc..

Is there some sort of calibration track available which gives the full spectrum of freqs so that I can set the profile of the car and be happy that all is equal?

MK2 Red S/n 949

I created a set of frequency sweeps in CoolEdit and encoded them myself, thinking that I would do the same thing you are thinking of doing.

In the end, the frequency-sweep tracks didn't really help me. The test tracks don't sound like songs, and you want the empeg to sound good with songs. In order to get an EQ that sounds good across your entire music collection, you will have to spend some time listening to your collection and tweaking the EQs a bit.

What makes the Empeg different from, say, a CD player, is that it lets you shuffle everything mixed up. So songs from two albums that were produced completely differently, will play one right after the other. This makes the differences in album production techniques stick out like a sore thumb.

So you're going to have to find a balance between accepting the fact that different albums will sound different, and tweaking your EQ to get a good compromise across your entire music collection.

At least until we get a per-song EQ feature...

It's taken me a while, but I've got my EQ to where my whole collection sounds pretty good. You end up making some compromises, but it's do-able. You just have to take your time about it and make your changes in small increments. Live with each change for a while before moving on to the next change.

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Tony Fabris

Wouldn't it be possible do use the pink noise tracks and a meter to do a curve fit to the Flecther-Munsons? You could then do this at a few loudness settings and volume levels (and amplifier gain settings as well) and end up with a reasonable transfer function. You would only need to take a few frequencies like low, mid, and high clusters to characterize it accurately.

#080000512 green 12GB

Wouldn't it be possible do use the pink noise tracks and a meter to do a curve fit to the Flecther-Munsons?

Or better yet, use the Mic input for metering and do it all in self-contained software?

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Tony Fabris

Thanks Tony,

I think that you have politely proved my suspision that I am far too impatient :)

I was also thinking of making some test files in Goldwave but thought there may be a good set that is commonly available.

I never noticed the mastering differences with my old Kenwood 10xCD changer on random but I suspect that was because I wasn't listening as intently as I have with the empeg. I think I may be trying to listen for artifacts/problems with compression and therefore paying more attention to detail than I used to.

I will take your advice and make EQ changes sloooowly over a range of CDs.

MK2 Red S/n 949