A "tech-y" question about "analog"/BBD chorus/flanger/modulation pedals

Jack DeVille

Member
Messages
2,438
This is a little "tech-y" so bear with me, but I am an "engineer," and as such: tech lingo is the easiest way for me to communicate. With that disclaimer out of the way...

People say that they like "analog"/BBD chorus/flange circuits because they are "warm", right?
Is the "warmth" (upper/higher audio frequency reduction) simply and primarily a function/byproduct of the necessary/required filtering employed for basic adherence to sampling theorems and/or noise reduction, or is it sonically better/more-pleasing to reduce treble content?

By basic theory of operation, wouldn't a broader frequency response be more desirable for a "chorus" effect (at for least the single-modulated short delay method)? Certainly for a through-zero magnetic-tape flange approximation, unless I am missing something critical here.

Make no mistake, I can hear the differences between technologies/methods/approaches in final achievement of the processes (I have designed and sold multiple variants of each), but wouldn't it follow suit, and thus sound "best," to afford full, or as close to full as possible, human hearing frequency response in these types of effects?

I'm not being coy or cute here. This quandary has been directly eff-ing with me for the past seven hours (indirectly for the past nine years) and I am very curious to hear the replies and input from the group on this forum. I know y'all really like the finer details of effects. ;)

So what say you? Is the "warmth" (or high frequency content reduction) imparted from a BBD line circuit a good thing? Better than "full human audio frequency perception" response?
Please refrain from picking apart my choice of words and de-railing/arguing syntax; I'd really appreciate that.

What are your thoughts on the "warmth" of frequency limited modulation circuits?

Please tell all. I would like to learn!
 

Hawkmoon269

Member
Messages
1,554
Ok, I’ll bite.

I prefer BBD analog chorus and flange to their digital counterparts, but the word I would use is “smooth”, not “warm”. Warm, to me, is just a rolloff of highs, which is something that many older BBD pedals had to do to reduce clock noise, and is easily replicated. Smooth, however, is a result of the magic of two analog signals beating against each other.

I actually prefer digital phasers though.
 

Andy S

Member
Messages
172
Being a HUGE fan of the Shallow water, I've grown to love not only the "warmth" but also the lo-fi vibe to it. It screams analog from the first note.

I've used many digital approximations of chorus/flange over the years Many featuring tone controls and filters to add "warmth " .

None sound like actual analog/bbd circuitry IMHO.

I'm not saying some digital units don't sound very good.. I've used and enjoyed both over the years. But my favorites seem to be analog ( top two are my current shallow water and former Retro sonic chorus).

Interesting topic
 

Jack DeVille

Member
Messages
2,438
Ok, I’ll bite.

I prefer BBD analog chorus and flange to their digital counterparts, but the word I would use is “smooth”, not “warm”. Warm, to me, is just a rolloff of highs, which is something that many older BBD pedals had to do to reduce clock noise, and is easily replicated. Smooth, however, is a result of the magic of two analog signals beating against each other.

I actually prefer digital phasers though.
Thank You for your thoughts, experience, insight and reply. Your words are very helpful to me. :)

So the "smooth" thing I can immediately relate to and identify with.

I've been working on this BBD modulation circuit; frequency response rivals the digital equivalent I developed concurrently, but the BBD realization had this "smeary" quality that I could not define or explain.
On paper, the frequency response, delay times, impedances, transfer functions and other BS tech stuff was all so close that it became strictly academic, but that unexplainable/intangible "smear" thing that I heard was very "there," and no matter how I augmented and tuned each circuit, the BBD realization continued to exhibit the same quality/characteristic.
My guys heard it too! That human response had me say to myself: "Okay, this is probably real and you aren't imagining this, or falling prey to the math you did."

The main question remains...
 

Glitch Magnet

Member
Messages
2,013
My rambling thoughts. Some might apply.

People casually say "warm" to mean different things, just like "gain," "transparent," etc. One guy's warm is another guy's dark or muddy. Some just say it to say it,... because analog is supposed to be warm, almost synonymous, so they drop the word in by rote.

But really, the warm sound of analog delay is so much more than just attenuated highs, don't you agree? All the artifacts and distortions, the non-linear approximation of the original signal, the noise... it all adds up to that characteristic "warmth" that's unique to BBD technology, yet different from tube warmth or tape warmth. It's almost more about how it makes you feel than how it sounds.

Sometimes warmth just means a slight bump in low mids, with no loss of highs at all. Muffling my ears doesn't add warmth to what I hear. But, recontouring the lows, maybe adding some subtle harmonics to the highs, or enhancing the perceived spatiality, might.

A well designed digital system can sound warm. But, outside of deliberate emulations, digital lacks the inherent non-linearities and artifacts that give analog its characteristic warmth. Pure digital chorus/flanging is somehow too perfect and unappealing. Not enough chaos, I guess.

Anyway, to your point, I generally prefer close to full frequency response in the wet signal for chorus and flange effects. Otherwise, it gets muddy with just the additive build up of lows. The essential swirling effect relies on those upper frequencies to provide the illusions of space, motion, and multiple sound sources. Still, some rolloff is good to psycho-acoustically place the wet signal behind the primary dry signal.

Also, if I remove the dry signal for vibrato, of course I want full bandwidth.

Whether it's achieved digitally or BBD just comes down to how good it sounds, and it just seems we mostly prefer the way BBD, tape, and other analog mediums sound. I just think it's so much more than just the LPF.

Hope I said anything meaningful there.
 
M

Member 202408

I have no idea. All I know is I always end up selling whatever digital pedals I buy and end up keeping only analog ones.
 

MGJ

Member
Messages
35
I don’t think it’s always nice to roll off the high frequencies, but it seems to be a common thing that many pedals of many different functions do. There are the BBD delay, chorus, flange, etc. that are at issue here, but also boosts, overdrives, compressors, and more that remove some high frequencies and are deemed to be more “toneful” (is that a word?) by many people over similar devices that present a more accurate version of the source signal. I tend to think of these as darker, rather than warmer. Warmth (for me) doesn’t just mean a rolled-off top end, but an overall more full and pleasing sound. I’m sure there is a scientific definition of what we perceive as “warm” sounds, and I think it would be very interesting to design an effect based on such research (but of course there are so many other variables in the signal chain that such designs would yield inconsistent results from rig to rig). Now to Google that...

BBD circuits do seem to have something else going on; I’ve never quite been able to get my digital units to sound exactly the same. I think your choice of “smeary” might be the best word for it. I use digital multi-modulation units for convenience, but always prefer analog when I take the time to compare.
 

amz-fx

Silver Supporting Member
Messages
1,670
I don’t think it’s always nice to roll off the high frequencies, but it seems to be a common thing that many pedals of many different functions do. There are the BBD delay, chorus, flange, etc. that are at issue here...
Isn’t the high frequency roll off a result of the series capacitance of the bucket brigade circuit?
The low pass filtering (which cuts high frequencies) is necessary in all discrete-time devices to remove clock feed-through and switching noises, but also prevents harmonic signals that develop when the upper audio frequency is too close to the sampling frequency. This includes BBDs and digital delay/reverb circuits. There are a very few digital devices that claim that output filtering is not necessary, but they are the exceptions to the general rule.

How low the audio filtering is set will depend on the sampling rate being used (for the most part). The highest audio frequency must be no more than one-half of the sampling frequency, and one-third is even better since low pass filters are not perfect and roll off gradually. This is why you often see 4-pole (or greater) low pass filters in BBD circuits so that a steeper cut to the highs is achieved. Obviously, the faster the sample rate, the wider the audio bandwidth can be.

regards, Jack
 

Riffa

Member
Messages
4,565
The warm sound of analog delay is so much more than just attenuated highs, don't you agree? All the artifacts and distortions, the non-linear approximation of the original signal, the noise... it all adds up to that characteristic "warmth" that's unique to BBD technology, yet different from tube warmth or tape warmth.
Yes. Great description of what I tend to hear. But then again, there are boxes like the Ibanez EM-5, which sound so purely analog somehow. Makes you wonder how they pulled it off.

Also, I’ve got a digital vibrato pedal that sounds very warm (smooth?) to my ears, but then again I’ve never tried something like the mighty Boss VB-2.
 

songtalk

Member
Messages
3,487
This is a little "tech-y" so bear with me, but I am an "engineer," and as such: tech lingo is the easiest way for me to communicate. With that disclaimer out of the way...

People say that they like "analog"/BBD chorus/flange circuits because they are "warm", right?
Is the "warmth" (upper/higher audio frequency reduction) simply and primarily a function/byproduct of the necessary/required filtering employed for basic adherence to sampling theorems and/or noise reduction, or is it sonically better/more-pleasing to reduce treble content?

By basic theory of operation, wouldn't a broader frequency response be more desirable for a "chorus" effect (at for least the single-modulated short delay method)? Certainly for a through-zero magnetic-tape flange approximation, unless I am missing something critical here.

Make no mistake, I can hear the differences between technologies/methods/approaches in final achievement of the processes (I have designed and sold multiple variants of each), but wouldn't it follow suit, and thus sound "best," to afford full, or as close to full as possible, human hearing frequency response in these types of effects?

I'm not being coy or cute here. This quandary has been directly eff-ing with me for the past seven hours (indirectly for the past nine years) and I am very curious to hear the replies and input from the group on this forum. I know y'all really like the finer details of effects. ;)

So what say you? Is the "warmth" (or high frequency content reduction) imparted from a BBD line circuit a good thing? Better than "full human audio frequency perception" response?
Please refrain from picking apart my choice of words and de-railing/arguing syntax; I'd really appreciate that.

What are your thoughts on the "warmth" of frequency limited modulation circuits?

Please tell all. I would like to learn!

I really love how you think and engage "pedal theory" so much that I may end up buying a Mr. Black device on principal one of these days!

I totally feel everything you are feeling/saying.

I think the way we articulate our preferences and limit our choices is silly and frustrating.

Guitar players are not typically the kind to employ academic thought when approaching their sound and as a result they can be super closed-minded.

I totally think that every sound is a sum of all of its parts and not just a frequency amplitude and pitch. It's not always so much how a repeat or modulated delay line sounds but how the circuit as a whole responds to your expression.

Some circuits transfer those ephemeral/intangible details that feel like "us" better than others despite the frequency, amplitude and pitch of the effect telling a different story.

I definitely feel like it's not even necessarily a circuit thing but even sometimes an individual pedal thing.

Like literally I have owned 20 Tubescreamer reissues and liked each one a different amount and the ones I kept and still own are unique and perfect FOR ME. RATs, Tonebenders from the same builder, analog Boss pedals.......tons of examples. To the point that I know now that even if I don't like a pedal I buy, it is entirely possible that in the future I could buy another and would like it because it is actually different sounding/feeling than the first one I tried. The same is entirely true of analog modulation and digital modulation pedals. They all have general nature and specific nature.

Pedals are like guitars. Each one is different (obviously to different degrees depending on the pedal). Keep the ones you like and sell the ones you don't. I just try to keep the ones that make me wanna play music!
 

Buddy67

Member
Messages
1,355
Analog __________________________________________
Digital ------------------------------------------------------------

Carry on.
Except: While BBDs are analog in the amplitude dimension, they are discrete samplers in the time dimension. This isn’t a big deal for chorus or flanging where the delay times are so short, but when you get into delays you’re going to get aliasing at longer times as the capacitors aren’t able to sample all the frequencies with accuracy.
So to use your methodology:
a BBD with lots of repeats will sound like:
———— / — / - / -
/ - / -
while a digital delay with high enough sampling rate (eg a Spin or SHARC chip) will sound like:
__________________________________________________

And is ultimately why I prefer my BED over my RKM for edge of oscillation type stuff.
 
Last edited:

apoyando

Silver Supporting Member
Messages
948
Regardless of the technical aspects that create the sounds I think there are many cultural elements that are unavoidable...
Some of us like sounds that remind us of an older time/tech...the nostalgia colors what we hear. Others embrace newer methods/sounds. For me it’s all about musical context and intention. Originally the effects were created with the means at hand...If you wanted a delay that didn’t use tape and it’s idiosyncrasies you used BB chips ( with their idiosyncrasies lol)..our ears got accustomed and we developed preferences. We can also now choose to recreate the past. Builders/designers seem to usually target one area of this..or offer different emulations/engines that reflect the idiosyncrasies of previous tech etc.
Having owned a lot of delays (2290, Lexicon, Eventide, analog/digital pedals etc) I find the neglected area is often the attendant circuitry ( usually analog preamps/mixer /filtering etc) that seems to contribute more to the sound at times than chips etc.
Delays that are little more than “ software players “ with this stuff modeled often suffer to my ear by comparison.
Just as a general thought re:treble etc...I prefer the ability to dial it out than something “pre-voiced “ in a dark way. Some delays like the Boss DD -500 , Free the Tone Future Factory have several bands of EQ that allow tonal shaping of the delayed signal.
I think ultimately it depends on whether you’re creating/using a tool that high personality or high versatility...they rarely seem to co-exist:)
 

Jim Marciano

Silver Supporting Member
Messages
2,615
I'm not very techy or anything but when I started playing in the 90s the only chorus pedals available near me were left over 80s digital pedals with zero bass than were thin and not great so I hated chorus, that was just my experience and/or stupidity but in the last few years I finally noticed there are chorus pedals with more bass or have a bass knob and it's more full frequncy and I definitely prefer them

As far as analog v digital I prefer analog, whether its true or not I feel like analog has more depth or feels very 3d and responds better, but the first digital pedal I absolutely love is the Mr black mini chorus, I havent played a ce1 but it nails those bssm tones
 

JaiRamana

Member
Messages
1,206
Yes. Great description of what I tend to hear. But then again, there are boxes like the Ibanez EM-5, which sound so purely analog somehow. Makes you wonder how they pulled it off.

Also, I’ve got a digital vibrato pedal that sounds very warm (smooth?) to my ears, but then again I’ve never tried something like the mighty Boss VB-2.
My Eventide H9 has some great quality effects for Digital.

I think I still prefer analog in a A/B but because I’m more a 80% of the time playing completely dry guy with my Friedman amps, the H9 is close enough and brings so much to the table and the amps sound so good, it wins out for pedalboard space. Buts it’s the only digital kit the appeases me. Sent the Strymon back. Sounded too digital!
 

Sam Xavier

Member
Messages
5,465
Beats me, Jack. Funny thing is, I was watching TPS earlier today, regarding flangers. Dan said the digital stuff he tried had some annoying upper frequencies that analog pedals don't have, even the Mistress which is known for being trebly - or at least, hacking off a huge chunk of low frequencies - doesn't appear to have these characteristics. Went on to mention something about the filtering that's applied to digital stuff creates some weird frequencies that are more like presence than treble. Guy usually knows his stuff - AFAIK - so I'll defer to his knowledge.

Me, I don't know. On me board, I have a Mooer ELady, a Boss BF-2, Alexander F-13N and your Shepard's End. All of 'em sound good to me but I'll allow the ELady isn't a patch on the real thing, even if it is analog.

TL;DR - I don't much care. If it sounds good to me, I use it, digital or analog.
 

Sam Xavier

Member
Messages
5,465
Another thing...

Since it seems it's a non starter to rebuild the SAD 1024 as the original stuff is lost, would it be possible to create a software replica? I know it's theoretically possible to rebuild a chip from scratch by shaving it down and tracing the circuit but that's beyond the means of most builders, so the software option seems the obvious way.
 




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