Russ

I created a 3 Band EQ plugin. I decided to make it, because I wanted a little more then the timbre plugin had to offer, and the only other options currently (with 3538j), are the 10 Band EQ, or chaining together other EQ plugins (and my resources are very limited on my 10k1 card, making the use of multiple 10 Band EQ's not practicle (3 Bands is about my limit, while still being able to use the other plugins that I want to use, etc, and, it should use slightly less resources than chaining together the individual plugins for similair functionality)).

It is basically a Low Shelf/Peaking/High Shelf connected together in series, with an option for input gain reduction.

I used info from the following sources to create this plugin:
Soeren Bovbjerg's excellant biquad implementation (DSP microcode).
Cookbook formulae for audio EQ biquad filter coefficients (Audio-EQ-Cookbook), by Robert Bristow-Johnson.
Sound Filtering For The Masses, by Maverick (Fabio Bizzetti).

I let the bands overlap more then they might typically, because, I wanted to be able to use it for filtering regular music, as well as electric guiter:
Low: 20-800 Hz
Mid: 200-7000 Hz
High: 1000-22000 Hz

This is my first attempt at this type of plugin, so let me know if anything seems wrong, and what you think about the ranges of the various parameters, etc. The GUI is kinda big (I might add a mode switch to be able to switch to a basic graphic EQ type interface, but I have not decided as of yet). It is not intended to be anything fancy, it purpose was to just fill a hole in the avaialble EQ options, and to suit my purposes.

It is only compiled for kX 3538j at the moment.
You can download the plugin (eq3band) here. It will be listed as 3 Band EQ on the kX effects menu after registering the plugin.

Added a mono version ( 3 Band EQ (m) ).
As always, let me know what you think.

-Russ

peate

Good idea for 10k1 users, it seems to work fine and it allows me to add a chorus somewhere. What's the difference between the Slope and Q sliders and their functions? I managed to almost replicate my 10 band EQ setting but somehow it sounds different. More smoothed out but a lot better than timbre could provide. Thanks

Pierre

Russ

Thats a good question, I wasn't really sure what to label that slider on the Peaking filter as it wasn't completely clear in any of the sources of info I was looking at.
Soeren Bovbjerg labeled it as slope on his Peaking EQ (it is the same parameter), but the Audio-EQ-Cookbook, looks as though it should be Q (or A*Q), so that is how I labelled it. If anyone thinks that is wrong, let me know (and an explanation would be helpful) and I will correct it.

Thanks for the feedback. Your comments perfectly reflect my reasons for making this plugin.

Russ

I recompiled the plugin and added a mono version ( 3 Band EQ (m) ), for those times when stereo is not needed.

-Russ

Tiger M

Good idea

Russ

Thanks Tiger,

As I said previously, one of my reasons for making it, was for use with the guitar, and I have been using it with your EFX Tubedrive (post distortion EQ), and I gotta tell you, it sounds pretty sweet

Maddogg6

Nice work Russ!

Seems to work as expected.

Only thing is - its seems like the mid band should be parallel with the low-pass>Hi-pass
(mid band I imagine is a low-pass>hi-pass combo)
I guess - I expect the mid range controls to still affect audio even when the Low's and Hi's are attenuated -12db. But it seems in this case, the mids are attenuated as well - which to me just doesnt *seem* right.??

Other than that - its all good over here.

Russ

Thanks Maddogg6,
I find that the MID band works with the other bands attenuated (-12dB), but how much, depends on how close the bands are together and the Slope/Q settings, if the bandwidth is too high for the space between the bands, it is obviously going to effect the other bands.

In any case, as I said before, I am still learning this stuff, so I cannot be sure which way would be optimal. Have you tried connecting the individual plugins together manually in the DSP (EQ Lowshelf / EQ Peaking / EQ Highshelf), with the EQ Peaking (not EQ Bandpass, which would make sense in a parallel configuration) in parallel to see how it works (working within the same ranges that the 3 Band EQ uses)? I would be interested to know which way you think works better. Since these filters only effect a certain frequency range, and pass the other frequences, I figured that connecting them in series was the way to go (i.e. the frequency ranges that pass through each stage unfiltered, would end up adding together in a parallel configuration, and you would possibly have unwanted phasing effects with the filtered frequencies in that configuration. no?).

Anyone else have any info about that? I am also still looking for feedback about the ranges of the controls, etc.

Tiger M

I'm glad to hear that there are other guitarists around other than Max and me.

Russ

Yup, there seems to be a few of us (Maddogg6, ROBSCIX, radiocolonel.it, and Lex seems to play some guitar too (didn't know about Max though ).

Max M.

[color=gray] yep, actually i'm an ancient guitarist although i wonder how Tiger has known that [/color]

Tiger M

I have my sources...

peate

Count me in. ;-]

Maddogg6

I just realized you used the shelfs and peaking - so yes in series makes sense - but I never really found EQ peaking usefull personally, so I only really just 'played' with it.
I think a better name for your EQ would be '3 band shelf' or something to indicate its functional nature. I don't think its wrong or anything - I just felt having mid-band parallel (still do actually) is more useable.

Now, if I was as smart as you (and enough DSP resources) - I would make a filter that:

Used the same F adjustor/control for the low pass shelf - also control the high pass Fr of the band pass section. as well as the F control the high pass shelf also control the low pass Fr of the bandpass.

So in otherwords - the mid band will always be 'between' the hipass and low pass shelves and the ONLY overlap in passbands would in the transition (Q/slope areas) - to avoid the phasing issues you mentioned.
There would be only 2 F conrtols (Flo and Fhi), 2 Q/slope controls (Lo-shelf slope = Bandpass Q(highpass); and Hi-Shelf Slope = BandPass Q(lowpass) - but still have 3 gains/attenuates (lo/mid/high bands)
Because a bandpass is a lowpass in series with high pass
if we adjust the stop band of the bandpass(hi) at the same time as the High-shelf - as well as the Q and slopes - we can adjust away, with little fear of phase issues from the minimal (or even better - adjustable) overlap of pass bands.

Nevermind if that sounded like gibberish.. lol Just drooling out loud.

Other than that - I feel the ammount of gain found in EQ peaking as well as your EQ is not quite enough - maybe if if could be +/-24db instead of +/-12db..?? (is +/-18 db in EQ peaking) may make it more usefull to me.

Another tip would be to label the 'LOW' as 'LOW SHELF' (and 'HIGH' to 'HIGH SHELF') to avoid idiots like me jumping to assumptions so easily. And be more obvious of the types of EQ's implemented in 100 years from now.

Russ

I kind of thought that you were thinking bandpass type filters when you mentioned that.

As for the MID's, I personally do not need more boost there, conversely, I tend to reduce the MID's (even on my home stereo (i.e. not just guitar related stuff)), which kind of gives the effect of boosting the lows/highs (and then I do not need to boost them as much), although I suppose it would depend on which frequency you are working with.

For the advanced stuff, I think I will wait for UFX 39, and Max's excellent 5 Band Parametric EQ.

Russ

I did some testing with the coefficients, and, a 24dB boost/cut option would require scaling the coefficients by more than I would like, with the current range of the other parameters. However, I am considering increasing it to 18 dB, if you think that would be more useful (I probably will not need it myself)

BTW: One more thing to note about the MID range, is that I did not intend it to cover the entire range between the Low and High settings (so that might also cause some confusion). What I wanted was to be able to dial in a specific frequency/bandwidth (in the MID range), and boost/cut only those frequencies (I guess I am more picky with the MID's then I am with the LOW's and HIGH's). It basically works (now) the way I wanted it to, but I think maybe a more typical 3 Band EQ (using Bandpass filters), might be a good idea as well.

<edit>
Actually, even 18dB would require more scaling then I would like.

Maddogg6

Nah.. dont make any change on my account - seems I'm the only complaint - and if the 5 band EQ is a good as you made it sound previously - maybe that 3 band(pass) EQ would be a lost cause - other than the probable lower resource use from a 3 band compared to a 5 band, or the gratification you would get from the challange.. ??

BTW: I finally tried it with DI guitar (and TubeDrive) - and notice the mids affected are more pronounced - as was the EQ Peaking - but, I prefer the tone I get from the J-Stations Amp/Cab sim. But I do see now why - as is - is enough for ya.

Like I said - its not 'wrong', just - IMHO, seems more 'specialty' than the name implies as is.

hehe - I can see it now - Russ' next plug-in release:

'Here it is my __________________ plugin. If anyone (other than that a-hole maddogg6) has comments or suggestions - feel free to post them here.
@Maddogg6: Take it or leave it!'

LOL

Russ

lol

Here is a picture of it (Max's 5 Band Parametric EQ) for reference: EQ P5
You can select the filter type, frequency, gain, and bandwidth for each band (i.e. fully parametric), as well as enable/disable each band, modify the input gain (boost or attenuate), and, all the settings are shown on a graph, so you can see exactly what they do. Additionally, it only uses 55 instructions and 49 gpr's (compared to 52/46 with my 3 Band EQ), so resources are not really an issue in comparison. Once it is avaialble for newer kX versions, it will make my 3 Band EQ unnecessary (which is fine with me, as I only made it because nothing else was currently available (and for the learning experiance, etc.)).

Maddogg6

Russ: Ive never said this to ANY OTHER GUY before (really I swear) ... but you just gave me a woody. j/k

That DOES looks pretty cool . AND uses same resources. WOW.

Very impressive Max.

It raised my anxiety level for 3539 a bit. (as Im pretty happy with 3538j actually)

ROBSCIX

Yes, I miss UFX and I can't wait for UFX39-hopefully. That Parametric P5 (pictured above) is very useful for electric guitar, I was using it for wave shaping but I have since moved to a Audigy 2 SB400, so I cannot use that until the new version comes out. I added your 3 band to my collection. Can never have enough filters in my opinion. Russ have you tried putting the 3 band on both ends of the tube drive. SO your shaping the signal going in as well as leaving the distortion? Yes us guitarist can get some cool things happening with KX. I am gonna add a old SB LIve back into my rig so I Can use it for just effects on a channel insert on my external mixer...then I can use UFX for that. I wish some more plugins would come out with guitarists in mind..I can only hope. Here's waiting for UFX 39..

Max M.

[color=gray]>but I have since moved to a Audigy 2 SB40
i'm sorry can you give me any hint on why 38 is preferable over 37 for A2?
[/color]

ROBSCIX

Oh you mean me..lol ..I bought the Audigy 2 Value the SB400..so I cannot use any previous version of KX on 38 and above.. IF I could use 37 and UFX I would.. Thats why I am waiting for UFX39

Maddogg6

I think Max was asking what more specifically is broken in 37. Im curious as well.

I *think* its a matter of your card model not being recognized during KX install. And if so... I also *think* it may be possible to modify the .inf file in 37 so it would be recognized. ??

Just putting out ideas..

Russ

I seem to recall that it was more than just a model detection issue with the SB0400.
iirc, there was something that required the use of the newer ProFX (which wasn't available for 3537), and there was a couple of issues with the outputs (had to use digital pins of k2lt for analog output or something, and some other stuff... I do not remember completely). TravelRec had a whole thread about it, and I remember John Lodge mentioning some things about it as well.

ROBSCIX

Yeah, this model has some different circuitry AFAIK. Support wasn't added until 3538, I waish I could get it working with 3537 then I would have everything I want. So if you guys have any ideas..that would be great. IF I Could mod the INF file that would be great..

ROBSCIX

@maddogg6, My card is on that list under partially supported. Althought for what I have seen everything works..

Russ

As far as modifying the .inf file goes, that is easy.
Just open kx.inf from 3538j and find the 2 entries for "DeviceDesc100".
Add those same entires to the 3537 version of kx.inf (with slight modifications to match the 3537 entires (i.e. change 3538 to 3537, etc)).
Of course that will only make kX recognize the model, it will not fix any support issues that may have existed in 3537.

Maddogg6

What Russ said

I kind of dis-reguarded that list - as theres no indication of KX version in there, nor does the changelog indicate more details on card model specific issues corrected in a release.

I was just putting out ideas of things I thought I seen in the forums here - Russ is way more knowledgable on that than me. But I don't suppose it would hurt to give it a try - as you have more to gain than loose.

Max M.

[color=gray]
Ah, ROBSCIX i'm sorry. I thought you mean classical A2 model (not A2Value). for a2v, yep - no doubt you have to use kx38.[/color]

ROBSCIX

Yes, very unfortunate. That's why I am waiting for UFX39..but I have a older SB Live 5.1 that runs UFX 37 and PROFX. I will be using this card as effects processor for 2 channel inserts on my external 12 channel mixer, or a master FX insert. I think thats a pretty good use for my old live and when using UFX thats a very powerful FX processor for my mixer. I can't wwaint for UFX39 -thats when you said you be releasing them right? version 39? Please, please some of us have big plans..lol..I really appreciate your effort.