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#226721 - 12/07/2004 22:19 Re: 5th Meet [Re: peter]
AndrewT
old hand

Registered: 16/02/2002
Posts: 867
Loc: Oxford, UK
Quote:
There's no official secrecy or censorship of that information -- in fact, the release notes all recommend the BBS as a good place to discuss the new features.



So, would the BBS be a good place to post the release notes? Hint, hint! Is that allowed?

(Sorry, I can't hide my impatience after the serious appetite whetting that's gone on above!)


Edited by Rue (12/07/2004 22:20)

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#226722 - 12/07/2004 22:43 Re: 5th Meet [Re: AndrewT]
weasel
new poster

Registered: 09/11/2003
Posts: 7
Loc: Berkshire, UK
i have the VR working ... how cool!

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#226723 - 13/07/2004 00:07 Re: 5th Meet [Re: pgrzelak]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14472
Loc: Canada
I'm now back at home in Canada, and have a suitable mic with me here. All ya have to do is drop by to try it out. I also have one of the disc's here..

Cheers


Attachments
225758-bb.jpg (315 downloads)



Edited by mlord (13/07/2004 00:10)

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#226724 - 13/07/2004 08:22 Re: 5th Meet [Re: genixia]
JonnyGee
journeyman

Registered: 30/01/2002
Posts: 56
Loc: Cambridge, UK
Quote:
So how'd'ya get over the sampling rate issue?


I don't. But then I can't hear over about 14K so from a purely personal POV I don't care

In theory, since the (censored) is only measuring the RMS (censored), some sort of electronic hack could be performed eg calculating the RMS electronically and regenerating a signal of the correct level (it could just be a sinewave at a fixed frequency).

Maybe we should be collecting together this info somewhere for future reference - that will be easier if/when the veil of secrecy is lifted.

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#226725 - 13/07/2004 08:26 Re: 5th Meet [Re: peter]
JonnyGee
journeyman

Registered: 30/01/2002
Posts: 56
Loc: Cambridge, UK
Quote:
Quote:
It behaved funnily at the demo, partly because shuffle and partly because it heard our clapping and cheering.

The shuffle didn't stop it doing all the right things, just not necessarily in the right order. The clapping, cheering, cries of "Bravo", wolf-whistles, crowd-surfing, throwing of knickers etc. did skew the final part of the demo, but frankly, given the limitations of the sound system it was driving, that skewing provided a far more compelling demonstration of the principles than a perfectly clean demo would have done.

Peter


In fact it was unlikely to work properly in the demo even if I'd turned off shuffle - the mic was far too close to the speaker, which was far too quiet and there was way too much background noise.

Cheers, John

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#226726 - 13/07/2004 08:38 Re: 5th Meet [Re: peter]
JonnyGee
journeyman

Registered: 30/01/2002
Posts: 56
Loc: Cambridge, UK
Quote:
That's a much rounder number and so probably right (though maybe it does 22KHz normally and 29KHz in some kind of Super Pursuit Mode if you program all the right bits). But even if it's 11KHz, the comment still stands: all the action here is in the bass.


The input can be set to 11.025KHz, 22.05KHz or 29.4KHz. The 11KHz limit mentioned corresponds to a 22.05KHz sample rate which is probably the rate used when sampling aux or tuner for visuals generation (I think Toby wanted to use one of the "standard" rates for his algorithms).

I just maxed out to 29.4KHz for (censored) because the RMS algorithm doesn't care about the sample rate.

It might be a little strong to say that high frequencies are entirely irrelevent. There certainly seem to be fewer peaks and dips up there than in the bass range in real car systems, but you never know when someone's tweeters might have a horrible peak at say 17KHz - unpleasent for anyone who can hear that high.

Cheers, John

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#226727 - 13/07/2004 13:58 Re: 5th Meet [Re: JonnyGee]
genixia
Carpal Tunnel

Registered: 08/02/2002
Posts: 3411
Ah, I didn't know about the 29.4KHz rate. I don't believe it was mentioned in the old kernels and I've never read the full specs for the CS4231A. I'm guessing that makes a big difference. There's a lot of audible information between 11.05KHz and 14.7KHz.

If you're looking for a way to regenerate sine waves of a known frequency then I may be able to help. About a year ago I created a hijack patch to use the DSP's tone generators to produce any tone on demand. Unfortunately the patch never made it into the hijack tree, and since then some of the existing code that the patch relied on has been removed (I used the calculator UI for numerical entry), so it's not a completely trivial merge. The patch included ioctls and also included a fixed point library for the kernel which could be useful for doing other DSP related coding, athough I guess you've got such a library in the player codebase anyway.

Anyway, if you are interested then once I get the new alpha then I can create a patch against it.
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#226728 - 14/07/2004 00:32 Re: 5th Meet [Re: mtempsch]
FireFox31
pooh-bah

Registered: 19/09/2002
Posts: 2494
Loc: East Coast, USA
Quote:
Development was made with a "Ultra-mini electret insert" from Maplins (part no QY62S)


Aw shoot, maybe I'm too electronically disinclined for this mic. Does it require soldering to get a cable and a jack on there? And... hm, I forget how the mic in line on the sled works. Is it just a bare mono line, or a single phono?

In other words, will it require me to learn how to solder and then tear up my install to use the cool newness of V3a8?
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FireFox31
110gig MKIIa (30+80), Eutronix lights, 32 meg stacked RAM, Filener orange gel lens, Greenlights Lit Buttons green set

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#226729 - 14/07/2004 02:03 Re: 5th Meet [Re: mlord]
Daria
carpal tunnel

Registered: 24/01/2002
Posts: 3937
Loc: Providence, RI
Can i drop by and try out the disc?

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#226730 - 14/07/2004 02:37 Re: 5th Meet [Re: FireFox31]
mtempsch
pooh-bah

Registered: 02/06/2000
Posts: 1996
Loc: Gothenburg, Sweden
Quote:
I forget how the mic in line on the sled works. Is it just a bare mono line, or a single phono?


It's a 3.5mm mono jack - it looks like the microphone is "bare", ie you'd have to solder on a wire (and the wire to a 3.5 mm mono plug at the other end)

Quote:
In other words, will it require me to learn how to solder and then tear up my install to use the cool newness of V3a8?


Solder: either you or someone else to do it for you. It's just 4 solder points in all.
Tear up: depends on where your mic input jack is currently stashed, if you can get your fingers on it or not, and if you can feed the wire from the mic from somewhere to the rear/top of the sled and connect jack and plug together w/o having to remove the sled.
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/Michael

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#226731 - 14/07/2004 03:17 Re: 5th Meet [Re: Daria]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14472
Loc: Canada
By all means, feel free!

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#226732 - 14/07/2004 03:52 Re: 5th Meet [Re: mlord]
Daria
carpal tunnel

Registered: 24/01/2002
Posts: 3937
Loc: Providence, RI
Hm. Wonder how far of a drive it is.

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#226733 - 14/07/2004 09:02 Re: 5th Meet [Re: Daria]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14472
Loc: Canada
Mmmm.. about 7-8 hours I should imagine -- it takes me about 6.5 hours to get here from the Mohonk Preserve (aka "gunks"), which is 70miles this side of NYC.

Cheers

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#226734 - 14/07/2004 23:29 Re: 5th Meet [Re: mtempsch]
FireFox31
pooh-bah

Registered: 19/09/2002
Posts: 2494
Loc: East Coast, USA
Thanks Mike.

Hm, I wonder if I should buy like 10 of these mic's (no, not possessive, just using an apostrophie to pluralize an abbreviated word). Since I'd have to ship from the UK, I might as well make it worth the cost.

.... scratch that. A quick attempt to register with Maplins shows that they don't ship to the US. Hm, ok. No "Build Brothers Certified" mic for me.
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FireFox31
110gig MKIIa (30+80), Eutronix lights, 32 meg stacked RAM, Filener orange gel lens, Greenlights Lit Buttons green set

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#226735 - 14/07/2004 23:32 Re: 5th Meet [Re: FireFox31]
Phoenix42
veteran

Registered: 21/03/2002
Posts: 1424
Loc: MA but Irish born
I'm sure some one here will do the honours of mailing over a bundle of them to someone for forward to others.

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#226736 - 15/07/2004 02:23 Re: 5th Meet [Re: Phoenix42]
genixia
Carpal Tunnel

Registered: 08/02/2002
Posts: 3411
I'm sure that we could find a local equivalent.
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#226737 - 15/07/2004 03:32 Re: 5th Meet [Re: FireFox31]
RobotCaleb
pooh-bah

Registered: 15/01/2002
Posts: 1866
Loc: Austin
apostrophe*

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#226738 - 15/07/2004 04:18 Re: 5th Meet [Re: Phoenix42]
jarob10
enthusiast

Registered: 07/01/2002
Posts: 274
Loc: Stockport, UK
Quote:
I'm sure some one here will do the honours of mailing over a bundle of them to someone for forward to others

I will gladly help out.
_________________________
A coward you are, an expert on bulls you are not.

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#226739 - 15/07/2004 11:46 Re: 5th Meet [Re: FireFox31]
JonnyGee
journeyman

Registered: 30/01/2002
Posts: 56
Loc: Cambridge, UK
Don't worry too much about which mic element to use - I'll try and calibrate mine this weekend but I expect to find it's flatish from about 100Hz to 10KHz and just droops a bit outside this range. Pretty much any small condenser element should behave similarly.

Maybe someone over there in the US could choose an easily obtainable element and calibrate it (or you could post a sample to me and I'll do it, but my setup isn't exactly professional ).

One with a published curve would be better of course.

Cheers, John

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#226740 - 15/07/2004 12:02 Re: 5th Meet [Re: JonnyGee]
robricc
carpal tunnel

Registered: 30/10/2000
Posts: 4931
Loc: New Jersey, USA
Does this work for you? I can get this and send it over asap.
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80GB 16MB MK2 090000736

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#226741 - 15/07/2004 12:56 Re: 5th Meet [Re: robricc]
genixia
Carpal Tunnel

Registered: 08/02/2002
Posts: 3411
That mic. is unidirectional, not omnidirectional.

A more likely RatShack candidate is this one.

If that's not suitable then digikey have a long list of mic's. I'd be willing to do a bulk order.
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#226742 - 15/07/2004 13:08 Re: 5th Meet [Re: genixia]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14472
Loc: Canada
It has to be a condensing microphone -- dunno if that one is or not.

On a related note -- running AutoEQ with NO MICROPHONE attached currently does not do what one might expect of it.. needs some fine tuning, I guess.

Cheers

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#226743 - 15/07/2004 13:11 Re: 5th Meet [Re: robricc]
pgrzelak
carpal tunnel

Registered: 15/08/2000
Posts: 4859
Loc: New Jersey, USA
Wow... And I was looking in the entirely opposite direction when it came to a microphone...
_________________________
Paul Grzelak
200GB with 48MB RAM, Illuminated Buttons and Digital Outputs

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#226744 - 15/07/2004 15:05 Re: 5th Meet [Re: mlord]
genixia
Carpal Tunnel

Registered: 08/02/2002
Posts: 3411
Hmm. I thought that all electret microphones were condensers...

What we do need to know is which parameters are important for this use. We know that we don't need a response beyond 15KHz as the sampling rate is 29.4KHz, although a microphone with an extended range may be flatter for longer. What what about the low end? The Maplin model goes down to 50Hz. We know the DSP is capable of EQing lower than that (17Hz IIRC), although it was limited in software (to 50HZ IIRC). How low does the autoEQ measure?

Is the sensitivity important? Presumably, because the software doesn't know anything about amp gains, it cannot make any assumptions about the audible volume vs the empeg's logical volume. As such, I would also presume that the software has to be fairly smart and would level the frequency response to the average volume, without caring what that volume actually was, hence making the sensitivity of the microphone non-critical.

Voltage and impedance requirements? The Maplin one is 4.5V (optimum) and 1Kohm. How much variance is acceptable?
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#226745 - 15/07/2004 16:27 Re: 5th Meet [Re: genixia]
JonnyGee
journeyman

Registered: 30/01/2002
Posts: 56
Loc: Cambridge, UK
Hi

Both Radio Shack microphones are condensor types and will be compatible with the car player's input (I think the phantom power supply is about 3V in a car player). There's a data sheet for the KUC1515-01-0850 at http://support.radioshack.com/support_supplies/doc9/9798.htm which specifies a wide voltage range of 2-10Volts. From this, and thinking about how these mics work, I believe the exact voltage isn't critical in general.

We do however need to use an omnidirectional mic, since omni mics measure the pressure due to the sound not the air velocity (hence we get a true SPL).

I also prefer the KUC1515-01-0850 as a "standard" unit because it has wires on. Soldering onto those mics is a bit tedious for someone with "normal" soldering skills like me.

I love the Behringer ECM8000 measurement mic - in fact the idea of AutoEQ came from a rainy day in Somerset with Roger, John Ripley and me in Roger's car with my ECM800 and UltraCurve2496 basically trying to determine how Roger's EQ should be set for a flat response. Sadly the ECM8000 specifies 15-42 volts DC supply (typical for pro equipment). It might just work anyway at 3V, but I couldn't guarantee it would still be flat, making the excercise a bit pointless. Another option might be to pre-amp the mic properly and use that signal.

The frequency ranges specified for the microphones is likely to be a "reasonably flat in this range" type thing. We should be able to compensate as long as the microphone doesn't lose so much sensitivity out of range that its signal drops below the noise floor.

I just looked at the EQ code, and can't find a trace of the limits that I added based on some research by someone on this BBS into which low-frequency settings make the EQ go wrong. It's in there somewhere, I'm sure . Basically it replaced the old 50Hz limit with a combination of limited boost/cut limits at frequencies below 50Hz.

AutoEQ bands are centred on:
  • 25
  • 40
  • 63
  • 100
  • 160
  • 320
  • 800
  • 2k
  • 5k
  • 12.5k
In the absence of calibration data you should only rely on the results for bands comfortably inside the mic's flat range. Other bands can be set to 0dB or set by ear.

Best microphone positioning is near your head, because that's where your ears are. You also need to keep background noise as quiet as possible (including handling noise). While AutoEQ is running, the level should be within the range of the cute little VU meter and ideally >=10dB higher than the background noise level. AutoEQ won't do this for you, you have to do it yourself and that may take a few trial runs.

Cheers, John

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#226746 - 15/07/2004 16:32 Re: 5th Meet [Re: JonnyGee]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31563
Loc: Seattle, WA
Quote:
I just looked at the EQ code, and can't find a trace of the limits that I added based on some research by someone on this BBS into which low-frequency settings make the EQ go wrong. It's in there somewhere, I'm sure

That was me, and the reason you can't find it is because that's one of the things that went into place after the codebase tree split. It's in the 2.0 tree and not the 3.0 tree.

Please don't put the limits back into the 3.0 tree. I did the research hoping to find out why I was getting strange distortions and I thought it might be an easy bugfix. I didn't want to be artificially limited in the EQ ranges.
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Tony Fabris

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#226747 - 15/07/2004 16:48 Re: 5th Meet [Re: JonnyGee]
pgrzelak
carpal tunnel

Registered: 15/08/2000
Posts: 4859
Loc: New Jersey, USA
I love the Behringer ECM8000 measurement mic - in fact the idea of AutoEQ came from a rainy day in Somerset with Roger, John Ripley and me in Roger's car with my ECM800 and UltraCurve2496 basically trying to determine how Roger's EQ should be set for a flat response. Sadly the ECM8000 specifies 15-42 volts DC supply (typical for pro equipment).

I can think of no better recommendation. And, because I have a 9V battery operated phantom power supply (as linked to in the other thread), I think this will be a good choice. Thanks!
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Paul Grzelak
200GB with 48MB RAM, Illuminated Buttons and Digital Outputs

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#226748 - 16/07/2004 00:39 Re: 5th Meet [Re: RobotCaleb]
FireFox31
pooh-bah

Registered: 19/09/2002
Posts: 2494
Loc: East Coast, USA
Quote:
apostrophe*

Aw, man. What have I ever done to you? And where were you for my past nearly 2 years of horribly spelled posts?
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FireFox31
110gig MKIIa (30+80), Eutronix lights, 32 meg stacked RAM, Filener orange gel lens, Greenlights Lit Buttons green set

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#226749 - 16/07/2004 01:03 Re: 5th Meet [Re: tfabris]
Miltoid
journeyman

Registered: 17/10/2002
Posts: 57
Loc: Republic of Texas
Quote:
Please don't put the limits back into the 3.0 tree... I didn't want to be artificially limited in the EQ ranges.

I'll second that! I've been afraid to ask if the 50Hz limit from 2.0final had migrated into 3, since I've been too chicken to subject "Tux the tunebox" to any alpha builds.
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#226750 - 23/07/2004 16:41 Re: 5th Meet [Re: JonnyGee]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31563
Loc: Seattle, WA
Quote:
I also prefer the KUC1515-01-0850 as a "standard" unit because it has wires on.

Mister Graley, sir, I have a question.

In preparation for the autoEQ feature, I just bought a Radio Shack 270-092, which I think (from what I can gather from this thread) is the unit described in that datasheet you linked, Model # KUC1515-01-0850.

Depending on where you look, the last digits of the model number are either 092 or 0092, but I think those two are synonymous in the ratshack parts system. Anyway...

The part I purchased doesn't look like the photo at the radio shack web site linked above. It has three wires coming off of it when I expected two. There is a red and a white wire, as well as a sheath to the white wire. Photo attached...



I thought that the mic connector on the empeg was only two conductors, i.e., mono 1/8". I thought that three conductors meant a balanced connection. So here are my questions:

- Will this mic work?

- I've purchased a mono 1/8" male jack to solder to this microphone so that I can plug it into the empeg's mic connector. If this mic will work, then which wires do I solder to the tip and sleeve of the mono 1/8" jack?


Attachments
227175-mic.jpg (226 downloads)

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Tony Fabris

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