Experimental Fully Modular Bass Rig.

[Flux Jetson]

WELCOME TO PAGE 11 AND MY NEXT ENTRY

Ok, since the meanderings of Page 10 and the inclusion of the needed synth modules to get the routing abilities assembled for STAGE 2 (Parallel Processing), it's time to put some of this stuff to work and begin experimenting with the various filtering and tone shaping gear.

To recap, at this point in my life my own tonal preferences lean heavily towards 70s rock bass sounds ..... in other words I am focused on getting The Geddy from my bass. I'm also working towards creating my own personal flair on that family of sounds. My theory is to use parallel processing to be able to shape the sound in ways that series processing hits certain limits and is unable to provide much flexibility. I want to be able to use distortion and overdrive without losing any of the low end foundation. I also want to be able to use certain band pass filters to help with producing that fat FAT FAT Geddy Lee tone while retaining total control over the bottom end. Artists like Lee and others over the decades have relied on using rather elaborate setups that paralleled processors to produce the right recipe of tones which included racks full of gear, mixing boards, sidechained mic'd amps/cabs hidden backstage or under the stage, and a technician stationed at the mixer to ~ride the faders~ and mix all of this stuff together to produce the just right sound. I'm trying to emulate that effect but do so by using a miniature version of the heaps of gear they used to get their sound.

So this set of entries will focus on the things I am trying to take me to those ends. The 2-channel bass is a success and quite useful, as is the pickup switching rigging and the pickup settings preset capability. That set of processors is what compiles STAGE-1 of this rig, STAGE-2 is the parallel processing setup that will enable me to use various filters in various arrangements to produce the tones I'm seeking. STAGE-3 is the output stage which allows me to route signals to the amplifiers and speaker cabs. For a bit here I'm focusing on STAGE-2 until I at least discover a successful "base" of routings and filter choices that will alow me to move forward. Keep in mind that the end-goal here is NOT to create the hugest pile of rack and floor gear I can accumulate, it's exactly the opposite ... discover the least amount of gear needed to produce the results I'm seeking.

MONDO FILTEROLA:

Keep in mind that technically EQs are filters. So are amps, and speaker cabs, even strings are ~sorta~ like filters. All of those things create different tonal changes and they all filter out the sound in various ways. While "strings" really aren't ~filters~ per se ..... they most certainly have a focused affect on the way the bass sounds. Certainly pickups, body woods, neck woods, fretboard woods, the cord one uses to connect their bass to their gear, and many other things are also "filters" in their own ways. But my goal isn't to create a single bass guitar to achieve the tones I want, the goal here is to build "the last bass amp I'll ever buy" (as I've repeated over and over in this thread).

Ok then ... so with all of that said, I'm moving on to introduce the filtering gear I've selected SO FAR. If you've been following along then you already know that I already did some preliminary experiments with using Modular Synth filters (both State Variable and fixed state voltage controlled filters) back a few pages. And I also recorded some SoundCloud demos and posted them in this thread to share their abilities and tone. And you also already know that I have stamped them as "Plan B" due to their noise issues. They worked GREAT for creating wonderfully useful sounds, but they have a bit if a noise problem that is kinda part of their nature being fully resonant filters and all.

So I'll be playing with the following tone processors in various ways in the upcoming posts over the next 6 weeks or so:

- Presonus EQ3B Parametric EQ.
- Rolls RPQ160b Parametric EQ.
- Rane RE-17 Parametric EQ.
- Dunlop "Cry Baby" wah pedal, highly modified for use as a "parked" fully tunable Band Pass Filter (BPF).
- Rolls SX21 Tiny Crossover.
- Aphex Xciter stompbox.
- MXR 109 10 band graphic EQ stompbox.
- Line 6 original POD Pro.
- Line 6 M13 and it's various EQs and filters.
- Antares "Filter" VST four band fully configurable software EQ.
- Marshall JTM45 36 watt all tube amp powering a 2x12 open back cab loaded with Celestion Vintage 30s.
- Marshall Lead/Bass 20 watt all tube amp powering the same cabinet.
- Fender 100 watt 2-channel solid state head.

Alrighty then, the rig is all set to go, it's time to bring on the players.

[Flux Jetson]

I suppose I should show you how I had the bass rig setup before I go too much farther. I didn't use the parallel processing stage for these initial checkouts of the EQ/filters. I simply came straight off of the distributor module that is the actual "SEND" unit for the parallel processing stage. I just went straight off of those sends directly to the Mackie power amp and out to the 2x10 and 4x10 cabs, using the distributor's channel level controls to adjust the sound level "balance" between the 2x10 and the 4x10.

The 2x10 was pretty much left alone once I got the basic low end tone I needed out of it, most of the attention for these first few tests was placed on the 4x10. As I have explained a few times in this thread already, the 2x10 is a front shelf ported cab that produces a shipload of low end that is nice and tight .. very focused and muscular, and the danged thing is FRIGGIN LOUD, too. The 4x10 is a sealed cab that produces much more midrange than the 2x10 but not nearly as much raw low end. Consequently the two cabs get used in ways that exploit their strengths -- the 2x10 for low end foundation and the 4x10 for definition and midrange. So once the 2x10 was set up with a good solid bottom end sound I pretty much left it alone throughout these first few tests and focused on using the 4x10 to produce whatever sounds these filters and EQs could best produce. Movin' on here ......

So I used the two pickup mixing presets as per normal with STAGE-1..... here's both pickups ON (equal mix levels of each pickup)


Here's what happens when I hold the momentary footswitch down (the switching module switches over to mixer channels 3 and 4, which provides a NECK PICKUP ONLY setting) ...


And as you can see with either of the pickup setting presets above, the mixer has a single feed output. I patched that output the the parallel processor stage "SEND" distributor, and instead of hooking up processors then coming back in to the "RETURNS" of the parallel processing mixer module, I simply ran the SENDS out to the Mackie's two amp channels and then out to the 2x10 and 4x10. I routed the 4x10's feed (channel 1 of the distributor module) to each of the EQs/Filters that I was testing, one at a time, then out of the EQ/filter to the 4x10's Mackie amp channel inputs, then out to the 4x10. It should be noted that both of the amp channel feeds hit the Aphex 204 before they hit the Mackie inputs. So ... like this ..



So the signals came out of the distributor and into the Aphex, then into the Mackie, then out to cabs. The only variation from that was the EQ/Filters were inserted between the distributor ch1 out and the Aphex ch1 in.

It was done like this to make the routing as simple as possible and to eliminate any possible issues due to having other things within the setup. Just wanted to test the eqs and the filters so that is how I patched it up, for just esting the Eqs and filters! That's part of the beauty of this whole modular rig, it's so danged flexible and easily reconfigurable!

Here's a picture of the actual patch .....



The two long cords dangling off to the left out of frame are the two pickup feeds coming from the two ART Mic Preamps I use to boost the signal levels and provide the pickups with some nice juicy hi-Z (high impedance) inputs. So it comes out of the mic preamps and into STAGE -1, then out of STAGE-1 into the distributor as the patch drawing above shows. Here's the Aphex 204 (the silver thing under the POD Pro)


Testin Filtahs!!!



More of this in the morning .... it's nearly 3am, time to get some rest.

And now I do happy dance ....

[icecycle66]

It's boneriffic.

[Flux Jetson]

These have been out of production for a while now (I'm not sure exactly how long). I had one years ago and remembered that it worked pretty well. So while sniffin' around on Ebay one night about a month ago .. I stumbled on to one .... BRAND NEW IN BOX!!!!!! And the best part ... $79 shipped! The seller is a Presonus dealer so the warranty is even valid! When it arrived everything was still all sealed up, it looked to be "brand new in box" indeed!



It has three fully parametric bands, each band having control over Frequency, "Q" (aka "bandwidth"), and level (+12db to -12db .. so 12 db of cut and 12db of boost at whatever frequency the Freq control is set at.

(NOTE: I'll finish this post shortly, supper is on the table!)

Ok, I'm back. The Presonus is one of those 1/3rd rack space units that is rather small. It's freq bands go from:

20hz - 300hz

200hz - 3khz

2khz - 20khz.

Q = 0.1 to 10.

The knobs have little detents all the way around their sweeps, making repeate settings easy to do.

SOUND: Easily the most important aspect of an EQ is how it sounds. It sounds WONDERFUL. It has a character all it's own that's pleasant and highly musical. I'm able to get a fairly decent amount of honk out of it by setting the center band at roughly 600 to 700hz and adding a full-on 12db+ of gain to that freq setting. The Q is roughly set around 1 o'clock position. The EQ3B is not capable of self oscillation, at least the one I have isn't. It comes just short of self oscillating when the bandwidth is set to it's most narrow shape.

NOISE: This is one of my favorite things about this EQ. Noise/hiss is virtually nonexistant. This is one of the cleaner sounding resonant EQs I've owned.

SO FAR....: Ok, I used it in the 4x10 amp feed so that only the 4x10 cab was getting the EQ'd sound. I set up the 2x10 in a typical low-end scoop tone to provide the low end component, and the 4x10 was set up with a mostly midrange feed. The Presonus was set as described with the freq at roughly 600hz, the Bandwidth at 1 o'clock and the gain maxed out. I then used the distributor module to set the ~balance~ between the 2x10 and the 4x10 cabs as it suited me.

WOOPS, NEARLY FORGOT .... : I should mention that I removed the DR Lo Rider Stainless Steel strings from my modified VMJ and actually reinstalled the 4 month old-X-many hours stock strings that came on my VMJ when I bought it new back in August of this year. I didn't like the scooped sound of the DRs and that scoop was totally undermining my attempts to coax The Geddy out of my bass. So I put those old tired stock strings back on. I have NO FRIGGIN IDEA what Squier puts on the Vintage Modified JAzz 70's Bass, but whtever they are I like their sound. Nice and midrangey. I measured them with a dial caliper and the largest string came in at .105 and the smallest string measured out to .045. Ok, back to the EQ stuff ....

So with the ..... .... 4x10 being hit with fairly heavily pumped-up midrange in the 600hz area, and the 2x10 taking care of the low end, the sound was pretty good. With the distributor sending adjustable amounts of signal to each cab and controling the volume of each ~sound~ I saw serious promise with that setup. But just as a test for the Presonis EQ3B it proved that it is most certainly a keeper and will make the final cut.

I like the EQ3B, a lot! It's a little hard to see the tiny graphics in certain lighting situations, but other than that I have zero bitches. The knob layout is a little odd, the center band has the three controls in an inverted layout compared to the 1st and 3rd bands, so you have to pay attention when adjusting it. It would be a little more versatile if it had more overlap between bands, as it is you can only use the 2nd band as a midrange carver, as the first band is too low and the 3rd band is too high for midrange sculpting. But it does what it does very well. It as noise free as can be expected of an EQ of this nature, and it was WAY WAY worth the $79 buckets I paid for it. So it gets set aside to be used in more comprehensive tests soon.

[Flux Jetson]

I'd bought this PEQ before I was presented with the opportunity to pick up the Rane PE-17. The price of the Rolls was great ($150 shipped, brand new from BH Photo). As far as Parametric EQs go it's a solid performer. It has all of the basics that you'd expect in a fully parametric EQ (freq adjustment, gain, and the all important "Q" which is also known as "bandwdith").

SPECS:

*** Four Fully Parametric Bands.
*** *** Band 1 = 70hz to 1.5khz.
*** *** Band 2 = 150hz to 3khz.
*** *** Band 3 = 300hz to 10khz.
*** *** Band 4 = 600hz to 20khz.

*** Q (bandwidth) = 0.3 octaves to 3 octaves. As you turn the knob "up" the bandwidth becomes more narrow. 0.3 octaves is fairly narrow, think of it as one third of an octave (4 half steps .. or said another way, four frets). The Rolls RPQ160b does not self oscillate.

*** Gain = (-15db cut) to (+15db boost) for each parametric band.

It also has two shelf filters, a low cut (high pass) and a hi cut (low pass). Each of the two shelf filters offers 3db of cut at whatever frequency you set them at. The Hi Cut (LPF) shelving filter has a range of 1khz to 30khz, the Low Cut (HPF) shelving filter has a range of 16hz to 500hz. So there is a 500hz gap between the two shelving filters that is not touched, that's where the four parametric bands come into play. I'm not precisely certain what the rolloff figure is for the two shelving filters, but if I had to guess from looking at the graph in the operator's manual I'd say they are 2-pole (aka "12db per octave" ... aka "2nd order") filters. Which is a decent rolloff, not too sharp, not too lazy.

There's also an overall gain knob. It offers (-12db cut) to (+12db boost). A clipping LED and a total bypass button are also provided. There are no individual bypass buttons for each of the six bands, you simply zero out their gain controls to bypass them.






I really like how relatively shallow it is, it doesn't reach very deep inside of a rack. If used as a desktop unit it doesn't take up much space. It is powered by a supplied wall wart.



The Rolls RPQ160b sounds nice enough. It does what is expected of it. It offers quite a bit more equalization power than the Empress ($300) or WMD ($200) stompbox parametric EQs, for a lot less money as well! At $150 the Rolls is a great value. If you absolutely MUST HAVE a true bypass footswitch, then simply use a Bypass send/return loop pedal. It really is that easy. The +/- 15db of adjustment range is pretty cool, it allows for deeper scoops and taller humps. All four parametric bands are arranged in parallel with each other.

CONSTRUCTION: I am impressed by the use of securing nuts on most of the control pots. This means that stresses placed on the controls are not directly transferred to the circuit board. Likey! However the "Q" knobs are not secured to the front panel, but they are those little tiny shaft-knobs where the pot's shaft is actually the knob itself. And those controls are kinda tucked under the larger knobs that are on pots that are secured to the front panel. So at least the unsecured ones aren't sticking out there waiting to damage the pcb. The chassis is steel, and made in a clamshell configuration and held together with small machine screws. The 1/4 inch I/O jacks are not secured to the chassis, but since this is a rack unit that fact has less bearing on the stresses placed on the pcb. I mean it's not like this thing is going to get stomped on and repeatedly plugged and unplugged, so the unsecured I/O jacks aren't too bad of a sin.

NOT-SO-MUCHES: The Rolls sounds ~fine~ ... that is to say it doesn't really stand out as some bright beacon among PEQs, and it is certainly quiet enough (although the Signal to Noise ratio is spec'd at 90db of sound to 1db of noise .. "90db" so to speak, which as S/N ratio specs go isn't top of the pile). I found the obvious misspelling of the word "Equilizer" in great big letters to be a bit odd on the cover of the operator's manual (correct spelling = "Equalizer"). It may be intentional, but I'm not sure I believe that. There are other high school level misspellings in other places in the manual as well. While that's really not that big a deal, it indicates a lack of attention to detail. (picky picky!! Geez!). But a bit of proofreading and a simple correction in the PDF file that the unstapled folded-paper manual is printed on could fix that, I wonder why they haven't?

YEA .. AND? I found the Rolls to be a total keeper ..... that is until I stumbled upon the Rane PE-17 for basically a little less money than the Rolls. The Rolls is made in USA by the same guy that started DOD. It's a well made unit, sounds fine, works great, and the price is TOTALLY right. Had I not come across the Rane I would have gladly placed the Rolls EQ in my rack. It did create a nice combination of cut and boost in the frequencies I am working with for my purposes. Sadly I was not able to record any tracks with the Rolls before it was traded off. But it certainly worked well enough to be added to my system. The problem was I could only afford to keep either this Rolls or the Rane. No brainer there!

[Flux Jetson]

The Mighty Rane PE-17. What a monster of a Parametric EQ. Seven total bands, five of which are fully overlapping fully parametric filters. Each band is bypassable with a button and each band's status is indicated with individual LEDS. Oddly enough when their LEDs are lit, that means that band is bypassed (totally opposite of a stompbox). There is also a master bypass button that operates a "fail safe" relay. That means that if for some reason the power to the Rane fails the bypass relay will default at "bypass mode" .. said another way if you turn the Rane off, you still have sound.

USA made, steel chassis, easily read graphics, excellent design, SOOPER DOOPER sound, as silent as a resonant parametric EQ can be built, 100% all analog design.


The Rane PE17 is pretty unique. It has five bands of PEQ. Bands 1, 2, and 3 are in parallel with each other. Bands 4 and 5 are also in parallel with each other BUT those two bands are in series with the first three bands. Perhaps this drawing will help explain it better ......



This sets up a very useful and versatile filter bank. It's kind of like having a 3 band PEQ patched into a whole separate two band PEQ. Most PEQs are arranged completely in parallel, so the PE17 is like having (at least) two separate PEQs. Actually like having three separate EQs in total. Look at the diagram, you have...

*** A low shelf EQ and a hi shelf EQ (so that's like a having one box with "Bass" and "Treble" controls).
*** Then you have a gain stage (think of it as a boost/cut pedal).
*** Then the 3-bands of parallel PEQ (like a WMD stompbox).
*** Then another pair of parallel PEQs (yet another two band PEQ stompbox).
*** And lastly one more gain stage (yet one more boost/cut stompbox).

Holy Radioactive Coyotes, Batman!!! Don't forget that each parametric band has it's own dedicated bypass button as well!

We're not done here yet .....

Each one of the parametric EQ bands is fully 100% overlapping. That is to say that each band is identical to the others ... all five of them are exactly the same and have exactly the same frequency range. Each band has a range of ...(get this)... 10hz to 20khz. Each band's frequency control knob only has a 1.9khz ~spread~, said another way each band can be adjusted a total of 1,900 hz. So the frequency control is not all super touchy and twitchy, it's easy to adjust. The trick lies in this teensy tiny little slide switch located under and between the gain level and frequency knobs. It has three ranges ... 0.1 - 1.0 - 10.0. Thos are your frequency knob "multipiers". So if the switch is set to 0.1, and the freq knob is set to (let's say) 1khz that means the frequency is actually only 100hz (1,000 multiplied by 0.1 = 100). See how that works? Each of the five parametric bands are set up identically, so you have 100% overlap.

Are you beginning to see how much control and sheer power this thing offers?

We're still not done here yet .....

Let's talk about the bandwidth control. Oh yes, let us talk about that friggin bandwidth control. You want spread? You want nearly (literally) pinpoint control over frequencies to be able to target a nearly precise frequency? The "Q" control on the Rane PE17 has a spread of 0.03 octaves to 2.0 octaves. Ok, wrap your head around that first figure .... that is point zero three ...

That translates to 2.5 divisions of a half step! So take the musical distance of one fret .. one fret! ... and divide that by 2.5!!! Said another way, it divides up one octave into THIRTY divisions! Your bass divides up an octave into twelve divisions, so does a piano. The Rane PE17 divides an octve up into THIRTY separate divisions. That means you can pinpoint a problem frequency area down to the tiniest of slices. You can zero in on such a precisely narrow band of frequencies and either cut it by 12db or boost it by 12db.

Think of it this way, a 31 band graphic EQ divides up an octave into thirds ... while this EQ divides it up into thirtyeths .. that would be the same as a 310 band graphic EQ!. That's three hundred and ten bands! (relatively speaking).

And the bandwidth control goes as wide as 2 full octaves. So from two full octaves down to 1/30th of an octave of bandwidth spread.

SOUND: I have used this EQ a LOT over the past three days. It sounds excellent. And well it should. These EQs are no longer made but when they were made they had a street price of $499. So it sounds every bit of what a $500 parametric EQ should sound like. Rich, full, nearly noiseless, clear, open .... in a word ... expensive. This PEQ is just great. I'm glad that I was able to take advantage of the deal that was offered to me and pick it up. It offers a lot more potential than I have had the time to exploit just yet, For instance since you have the series/parallel arrangement, you can dial in a particular frequency on two of the series bands (let's say 1 and 4). That setup can provide up to 24db of boost or cut on a single frequency bandwidth because you're stacking the gain structures. You can create complex filter arrays with it as well. So far I've just been using it in simpler setups. But what it has demonstrated so far, I know that this eq will be with me for a very long time. I plan on buying another one at some point just to have as a spare.

It drove the 4x10 beautifully. I even set it up to overdrive the Aphex a little in a narrow frequency band (in "that sound" area of roughly 600 to 700hz or so). That setup ROCKED BONES!!! It really worked well.

Many notes taken.

A well spent (roughly) $150 after shipping. It actually became mine in a trade for some gear I did not want! Win Win!!

And I do happy dance now ...

[Flux Jetson]

This is the last one that I tested so far. It is a very modified Dunlop Cry Baby wah pedal. It is setup as a band pass filter, and it has revoicing switches and some gain structure changes within it as well. I've increased the pedal's internal mechanical drag so that it really stays put when the pedal is set to a given frequency. The gain structure is such that it can overdrive itself somewhat. And there are a couple of voicing options available via the toggle switches. As well as having a true-bypass 3pdt footswitch and a status LED installed. It has two fazel elements in it and there is a switch to lock them both on at once, or swap between them to offer more voicing options.

I've left it in the foot-pedal chassis for now, but I fully intend on rehousing it all in either a blank modular synth panel, or a rack enclosure, or perhaps a stompbox chassis. I'm not exactly certain what format I will choose just yet.

This filter is one of the happy surprizes I have received while assembling the gear for this modular bass rig. One of those happy surprizes was how quiet the signal switching/routing/distributing/mixing synth modules turned out to be. Another happy surprize was this wah pedal when used as a midrange tonal device. I use it as a bandpass filter (BPF) instead of an actual wah pedal. So I connect it up, set the controls to the settings that I've worked up and know they provide the best results, park the foot-sweeper pedal to tune the unit, and jam.



This is the odd part .... it sounds SO FRIGGIN GOOD when used in parallel with a typical bass signal. I offers up a nearly perfect Geddy tone when the right balance of bass signal and processed signals are achieved. The actual tone of the thing is just about perfect (not quite totally "it" but very VERY danged close!). I suspect that with a little EQing it will produce a most excellent midrange honk.

So my goofy mega-tweaked wah pedal creates the right stuff for the right sound ... who knew? It's also pretty quiet for an overdriven midrange filter. It is most certainly going to be part of the completed rigging.

I just need to figure out how I want to rehouse it! Rack? Synth module? Stompbox? Ugh ... I also plan on building in a control voltage input jack so that I may use an oscillator to modulate it (like a phaser or flanger would be modulated). Using that same jack if I wish to use it as a wah pedal I can simply connect one of my CV Footcontrollers in the patching jack that I'll build on to it. So it can be a fixed BPF, or a sweeping BPF that uses an outboard LFO to sweep it, or a standard foot operated wah pedal that uses one of our foot controllers. This one is a for sure keeper! It has a ton of cut, meaning that t cuts through the mix like a hot knife through soft butter.

I will most defintely post the rehousing modification process when I get around to doing that.

The 4x10 responded excellently to this filter's use. It's a good match between the two. Really gives my bass with the four month old stock Squier strings some seriously huge nuts. This module is a keeper, no two ways about it! A SoundCloud demo track using this module is a for sure certainty.

And now I do happy dance ...

[Flux Jetson]

Ok folks .... I've finished with this week's entries. So far the whole parallel idea is working ridiculously good. I can tell it will take me a while to hone this all down to some degree of greater simplicity because there's so much friggin potential here. The main thing is to remain focused and keep my head on straight while I go through this process of trial and error.

Next comes the use of guitar amps as the "vox boxes" to take the place of the 4x10 to produce the midrange voice. And these filters will be a big part of those upcoming tests, coupled with the guitar amps and cabs to further this quest to build a bass amp that is as versatile as possible and yet still simple.

Gettin' there!

And once more ..... I dance ....

[RAMUSIC]

I envy you sir. I've been wanting a modular for a loooonnnngg time now, and to see someone implement one into their rig so wonderfully just makes it worse! I have plans to build my own modular but I still have much to learn, as I have not mastered pedal builds even. But this makes me want to continue all the more!

So much beautiful, analog filtery paralleled gonkulating goodness!

[Flux Jetson]

Originally Posted by RAMUSIC

I envy you sir. I've been wanting a modular for a loooonnnngg time now, and to see someone implement one into their rig so wonderfully just makes it worse! I have plans to build my own modular but I still have much to learn, as I have not mastered pedal builds even. But this makes me want to continue all the more!

So much beautiful, analog filtery paralleled gonkulating goodness!

Thank you! (PM'd)

I also have a secondary set up going on using a set of Hammond organ bass pedals that I'm converting to midi .. here's a link to that project thread ....

Cygnus midi bass pedal conversion project-1

So not only will my modular be this cool part of my bass rig, but it will also be one of the voices of my midi-bass pedals!

Like I don't have enough to do already! Haahaa!!

Fluxoid.

[RAMUSIC]

Pm'd back, and replied on your other thread. This is a beautiful thing

[Flux Jetson]

I'm in the process of compiling an entry that deals with setting up a system like this on the cheap. I'm going to try to get it done now. So hold tight for a bit.

[Flux Jetson]

Hey all. I have said that I was going to post a simple and easy way to provide you with a system sorta-kinda like what I did with my modular synth modules to obtain a parallel processing rig.

Theoretically, it's a simple and basic rigging that requires something to create some "SENDS" and something to remix those sends back as one signal line .. a mixer if you please.

Sure, anyone can buy a simple mixer and tear it up. If you're lucky the mixer may even have an FX buss, maybe even a 2, 3, or 4 channel FX buss or auxilary buss. The more little number that get stuck on the description, the more little numbers get added to the price as well. Most desktop mixers aren't small, or very robust either. But they will work.

Keep in mind I used synth modules because I had some of that stuff already kinda going on from building my own modular synthesizer, so I elected to go that route. But there's another way.

First let's look at the basic idea of what is going on here.



This block diagram pretty much tells the whole story. One input, four SENDS, four separate audio processors of some type, four returns, and a single output.

The idea here is to split your bass's signal up into a few parallel chains, process them individually, mix them together at levels that sound best to you, and kick the sum of the mix back out in a single output. This is the basic ethos of the idea, there are many other ways to take advantage of this setup.

(on to the next post ..... )

[Flux Jetson]

There's any number of ways to use something of this nature but the main reason you would wish to do it at all comes down to one razor sharp mindset:

Retaining your bass's integrity and low frequency tone.

As most anyone that plays bass knows, when you start using stuff like distortion pedals, fuzz pedals, and some types of modulators (phasers flangers, etc ..) the tone of your bass can get totally wrecked. Sometimes the low end suffers, other times the midrange gets sucked right out of your sound, and still other times the low end becomes very boomy and muddy. No amount of EQing seems to really fix it either, most of those attempts sound exactly like what they are ..... attempts to fix some sort of problem. Your tone is never quite right once that whole circus has begun.

You buy this thing and that thing to try to fix what the effect you're using has fuddup. And it's never seems to be quite what you're looking for ever again. Any time you kick in "that one chorus" (or whatever) everything goes to shyte.

So using parallel processing may be able to correct the problem before it ever begins by allowing an unchanged route for the bass sound to pass through unmolested. At which point you can mix in any amount of wet/dry sounds you want to carve the rigth sound out of the gear.

Practically, the paralleling setup might end up being used something like this ....



This is a hypothetical parallel/series FX setup I am using to illustrate the point here. I did it this way to demonstrate that this type of rig isn't limited to parallel arrangements, you have so many .. SO MANY .. freedoms with this type of rig. You can put several things in series within a parallel chain, you can even cross-chain and do multi-cross-chain-parallel/series setups. Whatever flicks your thrillswitch! Note that the 4th processing block has no real "processing" going on at all. The bass signal is simply piped through a "really good DI" so that you have something ~clean~ to remix the other stuff back with. So the Tube Screamer can't suck all of the low end out of the sound, and the chorus can't make things over-boomy, and the compressor and the overdrive can be used a little heavier to provide some serious kick in the nuts to the gain structure without being too compressed.

This type of arrangement allows you to create a custom mix of whatever sounds best to you. Unlike placing all of these same effectors in SERIES which would screw your tone up so bad you'd never recognize it. With the above layout you are able to mix in any level of any of the 4 chains (channels?) until things sound exactly as you wish them to sound, with few compromises. Now you can crank the piss out of that boutique Tube Screamer you paid (A LOT) for. Now you no longer have to use "only" overdrives that have "blend" controls on them, because you have FOUR CHANNELS OF BLEND!!!!!

Ok, so enough with the theory. Where is this magical low-bux set up at I've been promising?

Nest post ..... (ha!)

[Flux Jetson]

The SUB-$100 Semi-Solution:

I give to you the Rolls MX41B 4-channel passive mixer and splitter. Most places sell these for around $45 each, you'll need TWO of these to make it work. So roughly $90 buckets or so.

http://www.redco.com/shopexd.asp?id=2143



Here's the official Rolls info page ....
http://www.rolls.com/product.php?pid=MX41b

And a link to download the manual ....
http://www.rolls.com/pdf/M_MX41b.pdf

Now this isn't like "perfect", I mean it has some limits. The manual explains these limits fairly well. But this little gem is a nice inexpensive way to gain access to this whole principle. For less than $100 you can employ this system on your own pedalboard. These mixer/splitters are pretty small, 3.6" X 2.7" .. so roughly 3-1/2 inches by 2-3/4 inches. That's smaller than most any stompbox. And being totally passive it requires no input power at all ... no batteries, no wall warts.

They are simply 1x4 routers. If used in one direction they'll mix four signals down to one. Routed the other way around and they'll split one signal into four sends. So by using two of these you have four sends and four returns. As a bonus, they are full-stereo! So in a sense you have EIGHT sends and EIGHT returns! Each channel is set up to deal with a stereo signal.

As I said, they aren't "THE" solution, but they will certainly get you introduced into the whole parallel processing trip. Being passive there are some things they simply cannot do, but they do a pretty good job of creating the basic send-return setup.

If you're any good with a soldering pen and can read a simple schematic, look on Page 2 of the operator's manual at the provided schematic and without much trouble you can easily build your own. 4 pots, a few jacks and a few resistors and you've got half of the system built. Do it one more time and you have the entire 4-send/4-return rig constructed. Roughly $25 worth of parts or so.

So there you have it .... the sub-$100 solution.

And, you are quite welcome!

[Flux Jetson]

SOMETHING TO NOTE:

The input impedance of the Rolls MX41B is rated at 10kohms. Ok, at 10k you're not going to be able to plug your passive bass directly into one of these things (probably not an active bass either). That input impedance is WAY too low to plug straight in to without totally killing your tone. You'd HATE the sound, your pickups would be so loaded down and muddy sounding that no amount of EQing would ever put Humpty back together again. That having been said ....

You're going to need some sort of input module in front of the Rolls. Something like a good bass compressor or a DI or perhaps a relatively inexpensive mic preamp. Ultimately you'd want to see about 750k to 1meg/ohm input impedance for a passive bass, and AT LEAST 100k for an active bass. So you'll need to plug your bass into something that has a high impedance input spec and then on to the Rolls splitter.

I suppose you could run these in your bass amp's FX loop (if so equipped) as-is even though the input impedance is as low as it is, but you're best off checking your owner's manual for your amp to be sure.

Also, when using one of these as a 4-way splitter all four sliders must be set to MAX. Otherwise the split signal will want to go to the channel that is offering the least resistance and nearly none of the other channels will receive any signal at all. So all four sliders have to be set to the exact same levels to use these as splitters. Now when used as a mixer, you can set the channel levels to whatever suits you. so the return levels have some liberty in their settings. But the sends must be set to full volume. If these units were active and had buffers in them you could set the inputs to any levels you desire, same with the output levels. But these units are totally passive and have practical limits.

Like I keep saying, it ain't perfect but it's better than nothing. And they are so small that you will most likely be able to find a spot for both of them on your pedalboard.

Ok .. so that's it for tonight. Gonna plug in Rush's new album "Clockwork Angels" and crash. And of course .....

Now I dance ....

[pwsharp]

Also, when using one of these as a 4-way splitter all four sliders must be set to MAX...

IOW, is that the same as saying you don't need to use pots at all on the input/splitter side, but just fixed impedance/resistors?

[Flux Jetson]

Originally Posted by pwsharp

IOW, is that the same as saying you don't need to use pots at all on the input/splitter side, but just fixed impedance/resistors?

Yup. This being a passive device with no input or output buffers to sortof ~null~ the imbalances caused by differently set controls for different input levels, the inputs need to be identically balanced.

But, don't forget that you're going to need some sort of input stage before this simple splitter. And, I'm not totally certain but you also may experience some signal level drop depending on what things you place in parallel with each other. You're essentially using a sortof voltage divider here that will cut the available volume to each parallel device divided by the number of devices.

Let's say you start out with a signal level of 1vac going into the splitter. Now, let's say you split that signal 2 ways. Depending on some variables that signal may turn into two 1/2 volt signals (half as loud) sent to each device. Which means you'll have to turn their input and output gains up to compensate, which translates into raising the noise floor. This is why simply making a "Y" cable (1 input - 2 outputs) doesn't work worth a crap.

It all depends on the input impedances of the devices you put in the parallel chains.

Now you may have a little better idea why I chose to use the modular synth distributor ... the powered buffers in them keep the output levels identical to what is input. You put in 2 volts at the input, you'll have 2 volts AT EACH OUTPUT. There is no signal division.

So with the synth modules, if I put in 2 volts at the input of the 4ch distributor, run those 4 chains through ~stuff~, and remix them with the 4channle mixer ... I still have 2volts output coming out of the mixer, even after all of that splitting and mixing and such. And since those units are based on the TL074 IC chip there is NO noise added from the splitter or the mixer.

So you see there are flaws with the passive splitter/mixer rig. but if your choices are good and your use is moderate and prudent you can work around those issues with reasonably acceptable results. Lotta ~ifs~ there ... but hey, what do you expect out of a $90 solution to a $600 problem.

Another way around some of this is to use two amps and two cabs. I did a thread on using guitar amps in parallel with a bass amp. There are some 1:2 splitter solutions that take one input and send out 2 outputs. Such as the Line 6 Pod. It has a "guitar" input, and a left/right output. It sends a carbon copy of the output signal to each of the two outputs.

So with something like that, you can send one of the outs to a bass amp, and the other out to a small guitar amp. On the way to the guitar amp place your distortion pedals so that only the signal going to the guitar amp is processed by the distortion/fuzz pedals. You retain all of the your bottom end, and you get your distortion ... with none of that pesky signal loss or noise level increase crap. It isn't the full-on parallel send/return setup, but it is yet another solution to think about.

You get yourself some small little modeling practive amp, like a 1x8 or a 1x10 with like 15 watts of output. Split your signal with a good DI. Done! Most of the little practice amps have any number of "amp models" in them for creating different tones and different types of distortion. It doesn't take very much from the practice amp to keep up with the bass amp as far as audible mix is concerned. A 25 watt guitar amp will easily keep up with a 400 watt bass amp for providing some top end clarity and/or some distortion.

I'm doing something along those lines right now! My latest tests were done in that sortof manner. I'll be posting explanations and results tomorrow or the next day.

I hope this helped.

Fluxola.

[superdick2112]

Wow! You have really taken your amplification system into the realm of deep science!
Can't wait to see how your Taurus pedal project turns out.

[Flux Jetson]

Originally Posted by superdick2112

Wow! You have really taken your amplification system into the realm of deep science!
Can't wait to see how your Taurus pedal project turns out.

Thanks! Good to see you in here. Yes, it's like I've said (probably too many times already - ) I got tired of buying different amps/cabs/stompboxes/rack stuff every time I needed a change of tone or in the name of creating a better tone. So I figured if I designed a modular amp system it would be much easier to modify small aspects of it to refit it towards whatever ~new~ needs I had.

I took a look at a buck-standard bass amp, and I thought that if I had the ability to change just the bass knob (and the circuitry that is associated with it) or just the midrange knob (and the associated circuitry it has) that I could easily "retune" the bass amp to suit different venues, needs, and/or whims.

Then I got into modular synths, and as I learned more about the modular synthesizer and learned more about the literally FLOODED market that feeds the modular synth industry with all of the variety it offers .... it hit me....

..... Build a modular bass rig! ..

So this thread is a photo-journal of my travels down that road. I've assumed a completely modular approach toward designing a bass amplification system that is 100% modular ... from input gain stage to speakers. Every single component is to be a replaceable module.

So when you look at a bass amp, imagine every single knob as being removeable and exchangeable with another totally different knob with different characteristics. And you can rearrange the knobs in different orders to suit your needs as well. Exactly like a modular synth.

It becomes a little confusing at times ... lots to keep track of. But I use this thread to help me maintane some degree of focus. I find that I am able to understand some things better by writing out detailed descriptions of how certain portions work, too. Those drawings I create actually help me create visual imagery which helps me keep things aligned and organized in my head. Not to mention helping others get a better grasp of various concepts as well. I get PMs from subscribers that have told me that they now better understand what a Low Pass Filter does, or what a resonant filter is capable of doing .. all thanks to my stupid little drawings and posts. It makes me feel good knowing that I've helped someone to better understand some little aspect.

So yea .... "deep science" ..... er sunthin like that ... Heheh ...

One thing I have learned in all of this is that string selection has a HUGE roll in the creation of tonal character. I changed strings a couple of weeks ago to a set I had stored away from my 5-string bass days. That nearly completely undid all of the progress I had made up to that point with my modular bass rig in the pursuit of The Geddy.

I found myself retweaking everything, repatching everything, just to reestablish the sound to the place where it was before I changed strings

Then I finally figured out what I was doing and I put the four month old stock Squier strings back on the Jazz bass .... ahh .. home again.

GIANT eye opener there.

Anyhow, thanks for poking your head in. Good seeing ~you~ in here!

Fluxation