#238162 - 20/10/2004 17:13
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: SE_Sport_Driver]
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carpal tunnel
Registered: 12/11/2001
Posts: 7738
Loc: Toronto, CANADA
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Most amp manuals and resources instruct you not to drive the amplifier (via pre-amp, the empeg in this case) at full volume. Instead, the recommend leaving a bit of head room, usually 3/4 volume on a traditional head unit. Is there any reason not to do the same here (ie. set the empeg volume lower than 0db when setting gain audibly)? Another way to set/test gain settings is to use test tones and a volt meter. This is a quantifiable approach as opposed to a qualitative one by using (and possibly damaging) your ears. In my previous installation I used the empeg as a fixed-output source device and then used a traditional head unit as a pre-amp. If I were to go to full volume on my HU, the amp would not clip, but I would be deaf.  I'd really like to grab a few good/clean repeating wave pattern files so I can go this route setting my gains with my multimeter. I just got my new amp so I'll be doing some initial testing (to make sure it works) this weekend. Right now I'm planning on how to attach it to the car in the most stealth way possible. Bruno
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#238163 - 20/10/2004 20:06
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: hybrid8]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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Quote:
Is there any reason not to do the same here (ie. set the empeg volume lower than 0db when setting gain audibly)?
Yes, the empeg does not distort at 0dB. It only begins to distort after 0dB. Most headunits don't operate their gain the same way, and usually don't count "up" to 0dB.
Quote:
Another way to set/test gain settings is to use test tones and a volt meter. This is a quantifiable approach as opposed to a qualitative one by using (and possibly damaging) your ears.
That's true, although in the case of the empeg (and select highend units), I don't think it's as much of an issue because distortion begins after 0dB. I'm planning a set of "advanced" tutorials that will go more in depth, and I may include this.
Quote:
If I were to go to full volume on my HU, the amp would not clip, but I would be deaf.
You might want to lower the input gain on your amp then to increase your signal to noise ratio! 
Quote:
I'd really like to grab a few good/clean repeating wave pattern files so I can go this route setting my gains with my multimeter.
The AutoSound CDs are a good route, but you could always make your own too.
Quote:
I just got my new amp so I'll be doing some initial testing (to make sure it works) this weekend.
My page is still in "beta" now, and I havn't even gone through step-by-step yet! Let me know if you learn anything that isn't vehicle specific..
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Brad B.
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#238164 - 22/10/2004 15:37
Parametric EQ sound files now online.
[Re: SE_Sport_Driver]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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The sound files for the Parametric EQ section are now online. WaveGain is a cool little ap! Keep in mind, using all 10 files results in settings that wont allow you to use the Treble and Bass controls without messing up your sound (correction to this coming soon). Also, the tutorial doesn't have info yet on how to compensate for the SPL meter's frequency response curve. That will be easy to do after the fact... so test away! I'm putting these files online due to popular demand... the tutorial isn't quite ironed out yet. But at least you guys have something to play with over the weekend.
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Brad B.
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#238165 - 24/10/2004 16:51
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: SE_Sport_Driver]
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new poster
Registered: 23/10/2004
Posts: 4
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I tend to disagree with some of your suggestions. In EQ'ing you never want to boost up, but rather only attenuate down. adding +6db or something can potentially cause clipping.
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#238166 - 24/10/2004 17:54
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: nukegoat]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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You are correct that adding too much boost will result in clipping. There was some discussion here that it'd be best to center your EQ around 0dB because applying too much gain (either negative or positive) would result in some bands overlapping one another. For example, giving a -10dB cut in band 5 would result in bands 4 and 6 also getting (which wouldn't be the case if band 5 were only cut -5dB). This is assuming that the Q value determines the "shape" of the curve.
Because of this, the tutorial was written with keeping the gain or cut as close to 0dB as possible.
To best honest, I'm not sure I agree with this theory 100%. I always thought that as gain was increased (either by a positive or negative value) the shape of the curve became more "pointy". My assumption was that the Q value determined the high and low end of the range of frequencies that were to be modified (in absolute terms). My view was based on an interactive flash animation at one of the major car-audio sites. This animation let you adjust the gain, center frequency and Q value for a virtual parametric EQ. As gain as increased, the curve became more pointed. As Q was increased, the beginning and ending frequencies were moved "away" from the center frequency. For the life of me, I can't find this web page that shows this.
I guess you could change steps 10 and 11 to try to apply only cuts in the EQ. Because the empeg stores multiple presets, you can do EQs for both. The process of using the SPL meter doesn't change, so you can use your findings for both.
Maybe you can give it a shot and see which sounds better?
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Brad B.
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#238167 - 24/10/2004 18:17
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: SE_Sport_Driver]
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carpal tunnel
Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
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I think you're missing the point of the clipping. There's a maximum output that the empeg can produce. Call it 5V. If you tell it to produce a greater output than that, by, for example, having a track that has 100% amplitude and playing it at +2dB, it simply won't produce an output that loud. So instead of having a nice curve that goes up and comes back down, it produces a curve that has a flat top. This sounds bad, and actually causes more power to go through your speakers than you had your system set up for, potentially blowing them out.
That being said, I don't know how modifying the EQ plays into that. I don't know if it means that any band over the peak would cause problems or if the average being over the peak would cause problems, or if it wouldn't be an average, but weighted. It's possible that having positive EQ settings can cause clipping, but perhaps not to the point of prodicing too much power. I don't think that's right, though. If you had a track that was a simple sine wave and the EQ at that point was set too high, it could produce too much power, depsite the fact that the rest of the EQ bands were set way down, since they wouldn't be affecting the output much, if at all.
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Bitt Faulk
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#238168 - 24/10/2004 18:43
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: wfaulk]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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No, I understand clipping quite well. We were also referring to digital clipping, which is different than analogue clipping. Any signal raised above 0dB in a digital signal results in bad clipping. Sometimes, with analogue equipment, over driving a signal "just a touch" can give a nice type of distortion, but with digital, it's all bad. On the empeg, you would only notice this as the volume got closer to 0dB.
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Brad B.
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#238169 - 25/10/2004 02:56
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: SE_Sport_Driver]
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new poster
Registered: 23/10/2004
Posts: 4
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Quote:
No, I understand clipping quite well. We were also referring to digital clipping, which is different than analogue clipping. Any signal raised above 0dB in a digital signal results in bad clipping. Sometimes, with analogue equipment, over driving a signal "just a touch" can give a nice type of distortion, but with digital, it's all bad. On the empeg, you would only notice this as the volume got closer to 0dB.
well, for what its worth, you could boost it up 6db and then never set the volume higher than -6db...
i mean there are ways around it, but it may be worth noting the limitations. it sounds like you're familiar enough with parametric EQing that I shoudl just let you do your job
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#238170 - 25/10/2004 09:55
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: nukegoat]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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hehe, The page is very much "in progress" so feel free to offer any comments. I did suggest maxing out the volume at -10dB (-6 would probably work too) in another thread after you posted... It's a sloppy work around, but it seems it would work.
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Brad B.
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#238171 - 25/10/2004 11:07
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: SE_Sport_Driver]
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old hand
Registered: 27/02/2003
Posts: 770
Loc: Washington, DC metro
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I think I see a nice Hijack feature: the ability to set a maximum volume below 0 dB.
-jk
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#238172 - 25/10/2004 15:52
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: jmwking]
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old hand
Registered: 28/12/2001
Posts: 868
Loc: Los Angeles
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I'm curious about something, is overdriving always bad no matter what the source material? Yes, clipping would always occur on anything over 0db if the original song is normalized and uses all of the 16 bits that CDs offer, but more than a few of my cds, especially the ones made early, have not been normalized in the studio at all and the maximum signal (stupidly) never reaches higher than 80% of the cd maximum. And it seems that every CD has sections where it never comes close to the peak volume for long periods of time, especially with classical and musical CDs, where those max volume levels are saved for certain sections. In those cases I would think that overdriving the Empeg would actually not cause any clipping at all. Am I wrong?
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Ninti - MK IIa 60GB Smoke, 30GB, 10GB
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#238173 - 25/10/2004 16:19
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: ninti]
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carpal tunnel
Registered: 20/12/1999
Posts: 31566
Loc: Seattle, WA
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Quote:
In those cases I would think that overdriving the Empeg would actually not cause any clipping at all. Am I wrong?
You are not wrong, you are correct.
So it's not always bad to put the sliders past 0db. You just have to be careful and logical about it, just don't crank all the sliders past 0db.
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#238174 - 25/10/2004 20:43
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: SE_Sport_Driver]
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addict
Registered: 29/06/2002
Posts: 531
Loc: Triangle, VA
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Just picked up my SPL meter today at RadioShack and hope to get out there tomorrow and give this a shot. Only thing I am gonna have to do different is I cant fade from front to back cause I use the same amp to power my front and rear speakers. 1000watt 4channel in a VW Bug Its not as great as it sounds written out but it gets the job done. Drowns out my engine just nicely
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-D
Modifying and Tweaking is a journey,
not a destination................................
MKIIa : 60gig - 040103286 - Blue - v2 + PCATS tuner
MKIIa : 20gig - 040103260 - Blue - v3a8 + Mark Lord Special Edition Cherry Dock
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#238175 - 25/10/2004 21:40
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: SonicSnoop]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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I guess you can unplug the speaker connections at the amp to test the fronts and rears independently.
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Brad B.
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#238176 - 26/10/2004 00:32
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: SE_Sport_Driver]
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addict
Registered: 29/06/2002
Posts: 531
Loc: Triangle, VA
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I hadnt even thought of that. Thanks!
_________________________
-D
Modifying and Tweaking is a journey,
not a destination................................
MKIIa : 60gig - 040103286 - Blue - v2 + PCATS tuner
MKIIa : 20gig - 040103260 - Blue - v3a8 + Mark Lord Special Edition Cherry Dock
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#238177 - 31/10/2004 21:12
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: SE_Sport_Driver]
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pooh-bah
Registered: 31/08/1999
Posts: 1649
Loc: San Carlos, CA
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Quote:
That's great! Most microphones you buy include a frequency response graph, but the SPL meter does not. He mentions the cost as being $35 which makes me think he is referring to the analouge display model (I used the digital one, and that seems to be the more common).
This implies that the frequency response for the digital meter is the same as the analog and provides a similar compensation chart. Incidentally I followed your directions to tune my EQ yesterday. I'm not sure if I like the results or not (definitely needs more bass) but the guide was clear and easy enough to follow. Nice work.
Now that I have this SPL meter I wanted to play with tuning my home stereo as well. Most music I listen to is played through iTunes which has a 10 band software equalizer, but the frequencies are different. I found this free tone generator which looks like it would work, but I was wondering if there is anything special I should know about making these?
Thanks,
-Mike
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#238178 - 31/10/2004 22:38
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: mcomb]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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Thanks for the links.. it looks like that free tone generator only creates tones.. what I did (and what empeg did for the AutoEQ files) was create pink noise, then filter out all frequencies except for the targeted ones. So, the test file for the 50Hz band actually covers 20Hz to half way to the next band. You don't want just 50Hz. Here is what JohnG emailed me: Quote:
A reasonable estimate for the cutoffs would be would be the geometrical mean given by
Fcutoff = sqrt( Fcentre_high * Fcentre_low )
So between the 50 and 100 Hz bands you get 70.7Hz as the cutoff.
To make the tones I generated pink noise and applied FFT filter to pick out bands. Out of band freqnecies were set to 0% and in-band were set to 100%. To avoid ringing I sloped the walls of the filter to create transition regions of about 1/5 the width of the band.
There are some other steps to take too... you want to make sure all the tones have the same SPL (normalizing won't help). "WaveGain" is a good free program to do that...
I'm going to include a little tutorial, based on the very helpful emails from JohnG, on how to make your own test files..
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Brad B.
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#238179 - 31/10/2004 22:43
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: SE_Sport_Driver]
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carpal tunnel
Registered: 20/12/1999
Posts: 31566
Loc: Seattle, WA
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What about creating a set of test tones that are deliberately "humped" a bit in the midrange, so that your straight-line compensation ends up with a "smiley face" true EQ curve? Anyone thought of doing that?
This way, your system wouldn't need (as much) hand-tweaking after flattening the curve to those test tones.
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#238180 - 01/11/2004 10:23
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: tfabris]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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That's a good idea. The purists might be a bit discouraged about it.. I'm not sure. I'd at least like to be able to include some manual instructions on how to add that type of curve.. (maybe those values can be built into the adjustments you'll need to make to compensate for the SPL meter's response curve?)
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Brad B.
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#238181 - 01/11/2004 20:41
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: SE_Sport_Driver]
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pooh-bah
Registered: 31/08/1999
Posts: 1649
Loc: San Carlos, CA
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Quote:
I'm going to include a little tutorial, based on the very helpful emails from JohnG, on how to make your own test files..
Cool, that would be helpful as most of the rest of what you said was a bit over my head. (well, I get the concepts, but have no idea how to turn the concepts into actual audio files). If there is any free software out that that you can link to that will generate these it would also be helpful.
This would also help my in car tuning as I know I want to boost the bass quite a bit above a flat curve using my amp gains so there isn't much point in EQing the low end, and the top (16khz) band seems to be above what my speakers can adequately reproduce so I have the feeling I would be better off with more test files that where lumped closer to the middle of the spectrum and ignoring the high and low ends.
-Mike
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#238182 - 06/11/2004 22:55
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: SE_Sport_Driver]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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The empeg sound site has now been updated to provide a more complete Parametric EQ guide. I'd like to thank everyone who engaged in the discussion on the various topics that came up (including digital clipping past 0dB and SPL meter frequency response.) That include Bitt, genexia, Mike Comb and Tony. To anyone who has messaged me for custom test tones or tutorials, I havn't forgotten about you - I've just been short on time. I'll be sure to let you know when I've completed the requests. PS - I'm not too happy with the formatting on the Parametric page.. It just looks cluttered with my "Notes". If anyone has any suggestions, or corrections on grammar, don't be shy. The top menu is going to be removed soon, and that'll let me come up with a better color scheme.
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Brad B.
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#238183 - 05/12/2004 20:17
Configuring EAC?
[Re: SE_Sport_Driver]
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enthusiast
Registered: 26/01/2002
Posts: 278
Loc: Massachusetts,USA
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Hi, I've used audiograbber in the past but I figured I'd try EAC.I found it difficult to use and too get the settings correct.However I finally got it running and making MIPS The problem I noticed now is that it doesn't seem to fill out the ID tags at all.Just the filename no track number no year no album,artist etc.I guess there is a setting somewhere for that ,that I missed. Also sometimes it wont encode a track because there are errors,how do I get around that?
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MIKE 80Gb RIO
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#238184 - 05/12/2004 20:48
Re: Configuring EAC?
[Re: newguy1]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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The errors mean that there is something wrong with the CD. Sometimes, a differant CD-ROM drive will be able to deal with those errors better, but you may also want to look into repairing the CD. If the CD just has scratches on the underside of the disk, and they aren't deep enough to have scratched the data layer, I've had great results with the "Skip Dr." I have a link to this on my EAC Tutorial Page.
EAC does fill out the tags correctly, so it must be some setting with EAC that is turned off. In the "Compression Options" (found by clicking File > Compression Options), select the "External Compression" tab. Now, make sure the "Add ID3 Tag" box is checked as pictured .
If that doesn't work, look me up on IM (in my profile) and I can help you out. here
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Brad B.
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#238185 - 05/12/2004 22:16
Re: Configuring EAC?
[Re: newguy1]
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enthusiast
Registered: 20/11/2000
Posts: 279
Loc: Pacific Northwest
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Save yourself a lot of grief and setup EAC the way this guy has: Chris Myden There are step-by-step instructions with detailed elaborations for things which may not be clear. Also the biggest plus is that he has several configuration files which you just download and drop in the right place and EAC is largely configured for you. It has been my experience to always get good quality rips off of these. YMMV. Enjoy.
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#238186 - 05/12/2004 22:45
Re: Configuring EAC?
[Re: SE_Sport_Driver]
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enthusiast
Registered: 26/01/2002
Posts: 278
Loc: Massachusetts,USA
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Quote:
EAC does fill out the tags correctly, so it must be some setting with EAC that is turned off. In the "Compression Options" (found by clicking File > Compression Options), select the "External Compression" tab. Now, make sure the "Add ID3 Tag" box is checked as pictured .
That was it thanks
Ok now what is the correct version to use?V095 pre beta 4?V095 prebeta 5?I couldn't find the version 0.9 beta 4 listed in your guide.
If I had a brand new disc and compressed it with the lame alt preset standard settings in both Audiograbber and EAC,would there be any difference?If not is the reason EAC is better because it tries to correct for scratches and stuff?
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MIKE 80Gb RIO
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#238187 - 05/12/2004 23:17
Re: Configuring EAC?
[Re: time]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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Quote:
Also the biggest plus is that he has several configuration files which you just download and drop in the right place and EAC is largely configured for you.
I worked with Chris for some time and the tutorial I have posted in the link above was developed along the same lines as the one posted on his site. I also have a config file as part of that tutorial, ready for download, but I know that he has several others for unique circumstances, such as when a person has more than one drive they wish to rip from. At one point, my setup was even more anal than his "uber" standards, but it has been quite a while since him and I have kept in touch, so I can't speak for what he has done in the interim.
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Brad B.
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#238188 - 05/12/2004 23:26
Re: Configuring EAC?
[Re: newguy1]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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Quote:
Ok now what is the correct version to use?V095 pre beta 4?V095 prebeta 5?I couldn't find the version 0.9 beta 4 listed in your guide.
Thanks for letting me know about that. It looks like my page is a bit out of date. EAC V0.95prebeta4 is fine, but prebetas can be buggy from time to time, so personally, I'll stick with EAC V0.85beta4. Because EAC is pretty stable, most newer versions simply have more support for additional drives. The EAC site will always have details on what the different versions do.
Quote:
If I had a brand new disc and compressed it with the lame alt preset standard settings in both Audiograbber and EAC,would there be any difference?If not is the reason EAC is better because it tries to correct for scratches and stuff?
You're right on the money there. All these programs do is extract the audio data from the disk and then hand that data over to the LAME encoder. Audiograbber is easier to get up and running with because it's more user friendly, but EAC is the best at detecting and correcting errors (using the error-correction schemes built into the CD format that most players don't bother with at all.)
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Brad B.
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#238189 - 06/12/2004 04:12
Re: Configuring EAC?
[Re: SE_Sport_Driver]
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enthusiast
Registered: 20/11/2000
Posts: 279
Loc: Pacific Northwest
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Right on! No surprise you've worked together as in one sense, this (uber-ripping bunch) is a smallish community. Brad, I must say again a HUGE THANKS for your efforts in the empeg community. Your "empeg sound" site is just awesome! It is a great augmentation to the most excellent FAQ we have for the player. You have my vote for billing on the Quick Links list at the top of the boards.
Again, thanks for the good work!
-Tim
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#238190 - 06/12/2004 11:01
Re: Configuring EAC?
[Re: time]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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Hey, thanks alot Tim! Maybe once I actually finish the guide I can start worrying about getting it better advertised! I still owe Bruno some files as well..
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Brad B.
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#238191 - 19/12/2004 12:53
Re: empeg sound: A Tutorial for a great sounding empeg!
[Re: SE_Sport_Driver]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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I updated the site a little bit, making it much easier on the eyes! The only new content is in the "Goodies" area. Those tools are not yet finished, but I did create some test tones for hybrid8, Bruno to check out.
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Brad B.
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