Auto-calibrate EQ with external MIC

Wouldn't it be cool to have a feature where you could connect a certain mic (one in which the freq. response is known for) and the empeg would emit a bunch of test tones to auto calibrate the Parametric EQ to a perfectly flat frequency responce?

12gig Mk. II BLUE
Detroit, MI USA
www.PfeifferBeer.com

This has been discussed before.

The primary problem is that the mic input can't sample high frequencies, so it would have to guess at those.

Also, a perfectly flat response isn't necessarily what you'd want. Although it would be an interesting starting point, from which you (or the calibration program) could apply more ear-pleasing curves.

Although I think both of those issues could be overcome with the proper software. My dream would be a program which puts the EQ into 4-way parametric mode, then calibrates test tones through each of the 4 speakers individually.

Question: Does anyone have the programming knowledge required to sample from the mic right now? If someone could get something working which spits out data, then it would be a start in that direction.

If you think about it, once a calibrated mic is chosen, it's purely a software problem...

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Tony Fabris

Yep, everytime someone brings this up I start to drool over an auto tuning eq. Someone will respond to mention that a flat eq is not really what we want, but it sure seems like a nice starting point.

-Mike

Exactly. I think some some sort of presets based on a "flat" setting would be great. In fact, I think that a flat frequency response would be desirable. At least to make up for deficiencies in any particular speaker set-up. And doing all four speakers independantly would be the only way to do it! :) Some home-audio receiver makers have been toying with this capabiliy.

About the input: To be honest, most of us aren't too good at hearing high frequencies and the car is not the best environment for them either.

I think that it is much more practical than noise cancelation techniques via the microphone.

What would be great is if a plug-in could adjust the timing between the rear and front speakers so that all speakers' output reaches the driver at the same time! drool

12gig Mk. II BLUE
Detroit, MI USA
www.PfeifferBeer.com

Just thought of another one... if the program could test the phase relationship between speakers! If one is wired out of phase, it would adjust the outpug of that channel so you don't have to change wires on the amp! I know it sounds very LAZY, but most good inventions are created out of laziness!

12gig Mk. II BLUE
Detroit, MI USA
www.PfeifferBeer.com

Alpine had an EQ that did this in 1988. They had a deck in 94-95 that had a mic and listened for road noise and turn the volume up. Surely we could do the same in todays world with the far more advanced toy we all now have!

Proud Owner of MK2 080000558 - 18gb Blue

Bump!

But with the Line-In and a SPL meter.

In reply to:

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listened for road noise and turn the volume up

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This sounds so empeg-implementable to me, Im almost tempted to have a crack at it myself.

If I wasnt so dumb

This sounds so empeg-implementable to me, Im almost tempted to have a crack at it myself.

And the more that I thought about it, the more I realized that such a system (road-noise-controlled volume) is best implemented as a line-level RCA-cable plug-in box. It could be totally analog, no software. And it would work for any head unit. Makes me wonder why I haven't seen one offered retail anywhere.

line-level RCA-cable plug-in box

The idea of passing audio through (another) black box doesnt really appeal to me.

Would a seperate box not have difficulty in seperating road noise from actual audio (unless it had some level of DSP function built in to differentiate).

Would a seperate box not have difficulty in seperating road noise from actual audio (unless it had some level of DSP function built in to differentiate).

It would be no different than the mic input on the empeg itself in that respect. You'd have the same problem.

My thinking was that the only way to get around this problem would be mic placement. It would need to be placed outside the cabin somewhere, such as under the car or in a wheel well. I'd say to put it in the engine compartment, but on my car I get more variation in cabin noise level because of tire noise than I do engine noise.

I'd prefer a system that was dependant on vehicle speed but they we'd need to know the pin out of every car's ECU to get that data right?

It was pretty cool when my Focus would lower the volume as I slowed down to a red light.

It was pretty cool when my Focus would lower the volume as I slowed down to a red light.

Did it also have a "homies' mode" that did the opposite?

Peter

I'd prefer a system that was dependant on vehicle speed

Again, I get more difference in noise due to changes in the road surface than I do changes in speed.

There's a stretch of Interstate 80, the one that goes over the mountain pass between California and Nevada, that's particularly bad. I travel this road quite frequently. It's some of the roughest road surface I've ever seen (for a heavily-traveled interstate, that is). It's not necessarily bumpy or full of potholes, it's just got a very rough, pebbly texture. It's in dire need of resurfacing. Certain sections are being resurfaced right now, but the project is taking a long time and it will be years before the whole road is smooth again.

The funny thing is that the state of Nevada seems to have a better budget for maintaining its highways. As you pass the sign saying "Welcome to Nevada", it's like someone hit a switch. Suddenly, all the noise is just GONE and it's whisper-quiet in the car again. This is with no change in speed, just crossing onto a better-maintained stretch of road.

My primary reason for wanting noise-sensitive volume control is to deal with this exact stretch of road, and with the various increases and decreases in road noise that go with its changing texture.

The funny thing is that the state of Nevada seems to have a better budget for maintaining its highways. As you pass the sign saying "Welcome to Nevada", it's like someone hit a switch. Suddenly, all the noise is just GONE and it's whisper-quiet in the car again. This is with no change in speed, just crossing onto a better-maintained stretch of road.

Sounds like driving out of Massachusetts and into New Hampshire. I blame the Big Dig.

Yeah, there's one like that in Kansas City, as well. I wasn't prepared for just how ugly some of those roads are, coming from FL and driving I-4 and I-95 so often, but these higyways are just UGLY with cracks, bumps, and holes...