Built in test and tuning features

I think it would be extremely useful to have a 1/3 octave pink noise generator as well as a sinewave generator built into the unit, and it should be easy to implement. Additionally, an RTA using the mic port would be golden, but that might be quite a bit more effort.

#080000512 green 12GB

The sinewave and pink noise generators would, IMHO, only be useful in conjunction with an RTA system.

The discussion of an automatic spectrum analyser has happened before. I really like the idea, and would love to see it implemented. There is a problem, though, which is the mic input can't sample the really high frequencies. I forget where its upper limit is, but it's within the range of normal hearing. Still, if the RTA system could just cover all the other frequencies, it would be cool.

You know, someone could simply WRITE one. It doesn't have to be integrated into the player software...

In the meantime, you can create your own sine waves, frequency sweeps, and pink noise bursts in Cool Edit. I've done that very thing, it's really easy. When 1.1 comes out, you'll even be able to put them on the Empeg as native WAV files without having to compress them first.

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Tony Fabris

15 kHz was the sample limit.

You know, someone could simply WRITE one. It doesn't have to be integrated into the player software

How do you propose to automate it, then? The idea was that the player samples it's own output and sets up an EQ setting that's compensated to give a flat 0 - 15 kHz response, which you can then use as a basis to adjust to your hearing preferences.

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

How do you propose to automate it, then?

Well, you could figure out how to program the DSP (I'm told there's specs available somewhere), and have the RTA do automatic trial-and-error adjusting on the EQ until it's perfect. It could then dump those parameters (band, Q, gain) to the display or to the serial port. You could write those down and apply them to the EQ yourself. Not completely automatic, but very close.

Or, perhaps, if you'd gotten that far with the app, then maybe the Empeg guys would take notice of your incredible skills and write you some sort of a hook into the player software that let you set the empeg's EQ directly from your applet.

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Tony Fabris

Another interesting idea would be to have a preset playlist of frequency wavs loaded, then use external dsp hardware to analyze the sound and send ir or serial commands to adjust the equalizer and change songs. Obviously, you would have constant frequency, frequency sweeps, and phase wavs for testing. This would give you the ability to test a much higher frequency.

Also, one of the previous posts mentioned a 15kHz sample rate. Did you mean 30KHz sample rate and 15kHz max frequency component? Or, 15kHz sample rate with a 7.5kHz max frequency component. If it is a 30kHz sample rate the empeg could come pretty close to accomplishing the auto-eq feature but if its only 15kHz sample rate there really is no point.

Alex Lear

No, the Nyquist sampled bandwidth is 15 kHz.

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

Good answer . You do know how to flatter a girl, don't you Tony?

My solution so far was a notebook with a spectrum analyser program. Using the IASCA uncorrelated pink noise track from the empeg, I could sniff the in-cabin response and then adjust the EQ manually. Problem with this is that the Pink Noise is of course compressed. One day when I find a halfway decent bettery powered CD player I'll take it into the car and feed the original through the AUX and try to sniff that, then do a comparision.

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

My main thought on the sine generator was for level setting, finding true crossover corners and for finding car resonances. Sure you could generate these externally, but to be able to adjust the frequency realtime, with the encoder knob for example, would be much more convenient as well as not eat up HD space.

The clock on the mic A/D is a bummer.. no way around that to make useful RTA.

#080000512 green 12GB

Problem with this is that the Pink Noise is of course compressed.

When 1.1 comes out, it won't have to be.

Wait, what am I saying. Hasn't someone already written a third-party wave player applet?

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Tony Fabris

Yup, me and Henno tested it (sorta) at his place through his Mega-Fi Spaceship Control Centre (TM). That's how we can make pronouncements on how good the hardware sounds as a source - Henno reckons it's (to his educated ears, anyway) almost as good back-to-back with his $25,000 CD player as a source (slight exaggeration, there )

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

Henno
mk2 6 nr 6