What is the midrange center frequency of popular OD pedals?

[Kelsey]

I've been doing some critical listening to OD pedals lately, especially my Catalinbread DLS and SFT. Different ODs have a single tone control to roll off highs or T/B tone controls that may be either active or passive, but I've been wondering about the midrange center frequency of different ODs. I recall that the folks at Catalinbread mentioned 666 Hz as the center for the mids on the SFT, but what about the DLS, WIIO and Formula No. 5? From the Baxandall diagram for the Blackout Effectors Mantra, it looks like the center for the mids is 1,000 Hz for that OD. What about others?

[chervokas]

I've been doing some critical listening to OD pedals lately, especially my Catalinbread DLS and SFT. Different ODs have a single tone control to roll off highs or T/B tone controls that may be either active or passive, but I've been wondering about the midrange center frequency of different ODs. I recall that the folks at Catalinbread mentioned 666 Hz as the center for the mids on the SFT, but what about the DLS, WIIO and Formula No. 5? From the Baxandall diagram for the Blackout Effectors Mantra, it looks like the center for the mids is 1,000 Hz for that OD. What about others?

I dunno the answer, but it's a great question.

[CJReaper]

I recall that the folks at Catalinbread mentioned 666 Hz as the center for the mids on the SFT

The OD of The Beast!! :dude

Cheers,

CJ

[kevinhifi]

I wouldn't call it a "popular" OD pedal, but when I designed the single knob tone circuit on my pedal, I found that I liked the action when it centered around the 700-900Hz range. Centering around 1kHz works well and is probably a common starting point, but I found 700-900 to be warmer yet still effective.

[Kelsey]

kevinhifi -- I just listened to the clips of your OD pedal, and I am impressed. Is it opamp of transistor based? Cool design.

OK, let's add some more info to catalog the midrange character of some other OD pedals...

[kevinhifi]

kevinhifi -- I just listened to the clips of your OD pedal, and I am impressed. Is it opamp of transistor based? Cool design.

OK, let's add some more info to catalog the midrange character of some other OD pedals...

Thanks! It's based around a TL082 opamp.

[KevinFinn]

Great question/thread.

This is the kind of info manufacturers need to get better about sharing.

[catalinbread]

The OD of The Beast!! :dude

Cheers,

CJ

Oddly enough that is where we found a lot of old Ampegs to have a resonance at. +/- a few points.
:Devil

[ChristianShepherd]

Thanks! It's based around a TL082 opamp.

Ahhhh, an OCD inspired clone perhaps?

[Kelsey]

OK, Catalinbread, can you give us some info about the midrange resonant frequency of the DLS, WIIO, and Formula No. 5? I realize that we could ask amp manufacturers to provide the same info about their products, but could you shed some light on this topic for your "amps-in-a-box"?

[catalinbread]

The pedals mentioned of ours we looked for different things...

The SFT we felt should hit you in the gut. A tad slow on the attack but full, possessing the potential to be firm.
DLS was definitely a shot in the chest.
FN5 at your throat, with the sag you'd feel hitting a person there.
WIIO is more like you being hit by a wall... It never wants to give up or sag until much later. It is more or less full frequency and really fast.

So I guess you could find an associative frequency of these pedals if you hit yourself where I've told you to aim... But don't do it so hard that you hurt yourself, please!

Honestly the midrange frequency is one of the first things we look for when approaching an amp. We look for signature (from a listener not player's POV) yet superficial character there first. After that we pay a ton of attention to the actual dynamic response of the amp.

Identifying and talking about the qualities and characteristics of amps one of my favorite subjects. :)

[Kelsey]

So, based on the old anatomy-to-midrange conversion chart, that suggests that the FN5 has a higher mid resonance than the DLS, which from my listening and playing is much higher than that of the SFT. It sounds like the WIIO is off the chart, so to speak, so I don't know how that fits in. Your descriptions seem to focus more on the dynamics, which is another facet of great interest, but what about the mid freq?

BTW, my SFT is starting to overtake the DLS in the race for my affections across a range of amps. Must be all that time I spent with my old VT22 back in the day (the way back day).

[JimmyR]

FWIW, when I use my Maxon graphic EQ to simulate a treble boosted sound (or maybe cocked wah) I find that it's the 800Hz slider which I boost most to get that vocal kinda tone. That fits neatly with Mr Choad.

[spentron]

666.66666... Hz is the exact center of the range from 20 Hz to 20 KHz, considered to be the range of human hearing (log scale, middle of 10 octaves).

Tubescreamers roll off drive below 700 and filter highs above 3K or so, with tone maxed there may be a peak around 2.5 KHz. Big Muffs roll off drive above 1K or so and the tone control shifts about 1K plus tends to put a mid scoop at 1K (varies). If you compare the drive rolloff to a wideband treble attenuation, it's kind of a peak at 1K, complementing the tone scoop.

[Steve Mavronis]

How would you tell the center frequency of overdrives that do not have any tone control?

[spentron]

^-- there are almost always more pre-set filters in a dirtbox than user tone controls. A lot of them would be the same circuits otherwise. Some of these are more than that, example on the Tubescreamer there is some clean signal allowed through and this does not get the drive filtering but does get everything else, including the volume control. So it ends up mostly clean bass and low mids, vs. the dirt portion is really just distorting the high end of the guitar (the olde treble booster thing), although with enough gain it gets almost muddy again.

The most defined "center frequency" would be a midrange control, or the Muff style control which varies the entire spectrum into a low and high band (split in the mids) and varies their mix. With a rolloff or boost, there is a "corner" frequency ... these will often overlap the midrange or be very subtle, what may be considered only the midrange of all audio is comparatively huge to the guitar.

[kevinhifi]

Ahhhh, an OCD inspired clone perhaps?

Actually, my choice of TL082 was just from listening to a bunch of options and choosing the one I thought sounded the fullest and worked the best with my main amp (68 Bassman). I don't actually know the particulars of the OCD enough to know how similar my circuit is to that one. The Choad Blaster started as a quick breadboard of the Gretsch Controfuzz. I tweaked plenty of things in that circuit, played around with some unique ideas in voicing the gain stage, and ended up with a two-gain-knob pedal...

[Kelsey]

JimmyR -- good to know. I have a Radial JX-2 Switchbone, and its mid-boost settings are +9dB at 800 Hz or +5 dB at 1KHz as another point of comparison. Those particular freq boosts appear to be unique in the Radial Tonebone line.

spentron -- cool info on the 666+ Hz frequency as the center of the human hearing range. I won't touch the mystical aspects of that one...

Anyone else, especially any other pedal mfrs and designers, care to chime in?

[Kelsey]

Seriously, no other pedal builders want to get in on this action? What's the hesitation about? Maybe it's me.... I even showered this morning...

[chervokas]

Seroiusly, no other pedal builders want to get in on this action? What's the hesitation about? Maybe it's me.... I even showered this morning...

Seems like an inocuous enough question to me, but I guess designers feel like the voicing of their circuits is their secret sauce.

[Kelsey]

Maybe so, which I can understand to a degree, but I like to see some in-depth specs before I buy a pedal that I can't try first -- saves time, postage, and aggravation. After trying many OD's, I think I'm starting to hone in on what I prefer, and the midrange center seems like an important trait that I'd like to know in advance.

[spentron]

Seems like an inocuous enough question to me, but I guess designers feel like the voicing of their circuits is their secret sauce.

Well the subject line asked for POPULAR pedals, so that eliminates anything I build. :bonk

The other problem, as I already tried to point out, is it can easily be a nonsensensical question that doesn't show understanding of how these things work. Ideally, ODs shouldn't necessarily affect the tone balance at all, you should be able to click it on and it sound exactly the same except dirtier. However, even to get that right it is usually needed to revoice the guitar signal for distortion, and then undo that at the end. In my experience that contouring needs to be not at any single frequency but more a gradual shift over a wide range of frequencies. I use several subtle rolloffs below 500 Hz and a bright circuit that gives more 600+ at lower gains, pre-drive, for one thing to get a better balance between high and low notes. The post-drive tone circuit includes a bass boost and a treble function that has a "corner" way down at 300 Hz or so, but it's 600 or even higher before it really has a lot of effect. Plus more trickery that is difficult to describe accurately nor am I yet willing to.

[chervokas]

Maybe so, which I can understand to a degree, but I like to see some in-depth specs before I buy a pedal that I can't try first -- saves time, postage, and aggravation. After trying many OD's, I think I'm starting to hone in on what I prefer, and the midrange center seems like an important trait that I'd like to know in advance.

Yeah, I agree with you. In the guitar world it can be hard sometimes to find even basic specs. A lot of pedal producers don't even publish input and output impedances. Weber doesn't publish frequency response specs or Q values for it's speakers. It's frustrating.

[chervokas]

Well the subject line asked for POPULAR pedals, so that eliminates anything I build. :bonk

The other problem, as I already tried to point out, is it can easily be a nonsensensical question that doesn't show understanding of how these things work. Ideally, ODs shouldn't necessarily affect the tone balance at all, you should be able to click it on and it sound exactly the same except dirtier. However, even to get that right it is usually needed to revoice the guitar signal for distortion, and then undo that at the end. In my experience that contouring needs to be not at any single frequency but more a gradual shift over a wide range of frequencies. I use several subtle rolloffs below 500 Hz and a bright circuit that gives more 600+ at lower gains, pre-drive, for one thing to get a better balance between high and low notes. The post-drive tone circuit includes a bass boost and a treble function that has a "corner" way down at 300 Hz or so, but it's 600 or even higher before it really has a lot of effect. Plus more trickery that is difficult to describe accurately nor am I yet willing to.


Well, that's one ideal. Obviously there are plenty of ODs that, by design DO, not only add gain and clipping but also tone shaping and those are traits that some users are looking for in an OD.

But your point about there being more to tone shaping than simply, say, designing in a boost half an octave wide at 800hz is very well taken.

[amz-fx]

The Tube Screamer has a big mid-hump at 720 Hz, due to the high pass on the first opamp stage at 720Hz, which is then followed by a 1k/.22uf low pass filter, also at 720Hz. This makes it very mid-rangy.

Considering how popular the TS models are, I would say that 720Hz is the starting point, and you could vary a above or below that by a few hundred Hz to change the voicing.

regards, Jack

[Kelsey]

Thanks, Jack. That helps frame the discussion.