I'd want one.

I'd be up for 2 of em.

I think this will help with any (hopeful) future development.

I would definitely buy one in anticipation of the day when the auto-eq feature actually becomes available to me.

Heck, I'd think that a purchase of the mic should include a copy of the Amersfoort CD.

I'm in for a mic, by the way, if they are made available. I had no luck with the Radio shack parts.

Quote:
I would definitely buy one in anticipation of the day when the auto-eq feature actually becomes available to me.

Yup, I'd take 2.

Hmmm, now I just have to talk with Shonky about a vasectomy reversal!

Mic input on the sled was probably usurped for some other feature such as custom subwoofer output or digital audio out....

Since he specifically referred to me, he might be noting the fact that the harnesses I built did not have a mic input At that time I saw no need for it - the VR stuff didn't look like happening. I did supply the spare pins though so if someone wanted it, they could add it reasonably easy.

Simply get a 3.5mm socket on a cable (something like a 3.5mm socket-plug extension cut in half)and crimp it on to the two pins. The crimps can be done with small pliers quite easily if you're only doing a couple.

Either way there was no cutting involved.

Ok, I've been looking at this to see whether anything could be done in the kernel to prevent the transients. I added a hijack menu option to enforce muting whenever the eq was applied. I had thought that this would slow down the manual EQ interface, hence not just enforcing it period. Strangely enough it doesn't and it removes the nastiness that is present when you try to change a bands frequency when a large gain/cut is already applied to it.

However, it does not fix the problem with Auto EQ. And I realised that Auto EQ adjusts in small steps whilst measuring, rather than measuring then applying one large step. This means that as long as you start from a flat EQ, this fix wouldn't do anything to help anyway and in fact may screw up the measurements. So that patch will probably hit the bit bucket - I don't remember anyone complaining about the manual EQ glitch before so it would seem strange to have a hijack option to fix something no one cared about.

Back to Auto EQ, I played the files in XMMS. Sure enough, the transients are present in the files. It sounds like the files were bandwidth limited first and then cut in the time domain, resulting in a square transient at the beginning of the file. I'm guessing that no effort was made to cut at zero crossing points...

Is anyone set up to re-generate the files from scratch?

Looking at the files for the first time, I'm surprised that they are mp3s and not wavs.

I assume Cool Edit Pro could be used to generate the files... any drawback to using wavs?

Only the size, which I don't see as being a problem. JohnnyGee didn't think that mp3 was a problem either though.

It would be interesting to convert the mp3s back to wavs and look at the beginnings/ends of the waveforms though.

Quote:
Since he specifically referred to me

Oh, Oh! Brain fart! Brain fart!

I suffered some segment overwrite. I really need to talk with *maczrool* (Stuart, Eutronix) about reverse vasectomey -- what to do with my digital output? or how to add a new Mic input? Sorry!!

Put me down for one.

I have microphone extension cables wired in two cars that are ready to go!

Would this work for us NZ/Aus users?
Would save me faffing about with the unassembled type..

I found a similar microphone commonly available in the US here.

70-16,000Hz response. 1000 ohms

Is there any reason we couldn't use a full size microphone or is there an advantage to one of the tiny ones? I don't plan to keep any microphone permanently wired in the car. I just have a 1/8" extension cable running to my armrest and would remove any microphone after use.

Success!

I just got done doing the AutoEQ setup and it went great! I used a $25 clipon lav. mic from RadioShack along with an extension cable so that I can remove the microphone but keep the cord hooked up.

I printed out Rob's post and brought it into the car with me. You have to make absolute sure that you have all the sound features turned off (we have a ton of them!) He managed to include most of them, but you have Auto Volume Adjustment in both HiJack and the empeg software as well as "Stereo Seperation" and "Left/Right Time Alignment" to turn off (empeg and HiJack respectively).

Turn off repeat and shuffle too.

The microphone I picked up is a clipon type, so I clipped it onto my shift, right by my shoulder and set the volume to -20dB.

Does it sound good though? I kept the curve from one of my more sucessful auto-eqs and compared it to one I did myself. I still prefer the manual one.

All that matters is what you prefer but in my case, the speakers had a lot more detail to them and sounded less "muted". It just brings a flat curve, and that's not what we all want, but it gives a good starting point that makes up for deficiencies in our setups. From there, we can tailor the sound to our tastes.

Ok, so we got to play with Auto EQ a little at the Cinci meet, and I have another observation about the clicks and pops. It is possible for Auto EQ to try and boost the bass response too high such that the audio stage becomes unstable, resulting in oscillation. In EE terms, it looks it's trying to boost below DC.

This appears to be especially prone to happen in cars with a poor bass response to begin with. Auto EQ still trys to get a response, thus causing the problem. This problem could probably be fixed by capping the amount of boost that the bass EQs are allowed to apply, although I haven't determined what level is safe and what isn't.

I only did this experience w. the sound files I created at www.motorcityimprov.com/autoeq/ but I had no clicks and pops.. Just tones and humms.

Also, my mic had poor bass response (but my system has a subwoofer) so the first band cranked itself to +9dB with AutoEQ. I'm going to bring that number down a bit because it's due to my microphone not picking up that frequency.

Rob also mentioned that having the proper volume level helps. His recommendation of -20dB worked great for me.

well, per the faq entry, there should be a celing to prevent clipping, i.e. only adjust with the celing at +0db and lower.

This isn't clipping which is what that FAQ entry addresses. The Auto EQ appears to compensate for this anyway - when boosting on band, every other band is cut a little, presumably to keep the average at 0.

What I think is happening here is that the high dB gain pulls up the boost curve such that there is a positive boost extending below 1Hz, ie to DC. If you look at figure 4 halfway down this page, perhaps you'll understand what I mean. At low boosts (green line), the boost extends less than at high boost (blue line).

Are you saying that because of the Q (range of frequencies affected by the gain to the left and right of the target frequency) that at high gain, other frequencies are being boosted by two bands? (Hope I'm using the correct terminology here.)

From my notes, here are the values that the AutoEQ sets and adjusts:

Band 1: 25Hz, Q=1.33
Band 2: 40Hz, Q=1.33
Band 3: 63Hz, Q=1.33
Band 4: 100Hz, Q=1.33
Band 5: 160Hz, Q=1.33
Band 6: 520Hz, Q=0.83
Band 7: 800Hz, Q=0.83
Band 8: 2 KHz, Q=0.83
Band 9: 5 KHz, Q=0.83
Band 10: 12.5 KHz, Q=0.83

EDIT: It seems that one should be able to take the values given by AutoEQ and reduce them so that as few fields are given boosts as possible (ie, adjust so you are doing mostly cuts).

edit2: corrected the Q values I had.

This is more or less my impression. I am glad someone has had some success: it's a damn nice feature.

My current impressions - I am sure (and to be honest, having spend some serious pub time with John G) that there is a definite bass bias. and hell! I like it that way!

The change to the sound is not incredible, but definite and a great improvement. I have a lot more vocal clarity and more definite bass. I have had to wind down the initial +9 dB bass boost somewhat, but overall, I would rate the improvement in sound in my car at 100% over most driving conditions. One notiveable side effect: I don't keep turning the volume up and down so much. I can pretty much set the volume level and leave it alone without having to rely on HiJack's excellent compensation tools.

On balance: worth persisting with if you take the trouble to do your preparation properly first. Thumbs up for the biggest single change in empeg player functionality in a long time. Don't forget Peter's incredible 16 bit character set support is also way up there, but seems to have been forgotten in the immediate excitement of AEQ - but it is just as welcome.

But I have a question for you lot. What's the future of software releases going to be like now that Rob has departed? What is going to be available for next year's empeg meet?

I will confess to a serious worry at this point. Your opinions?

I'd be happy with bug fixes at this point, but it looks like the only justification for releases at this point is to test new features...

Given that Rob was the initiator in many cases for recent releases, I can't see much happening from now on, unforch