Low-end realignment...

[aron]

I don't know what the S&S does, but if it is entirely passive, then there is an excellent chance that what it does is more in the realm of EQ and not alignment.  Alignment of any degree of simplicity will involve splitting the spectrum so that portions can be shifted relative to each other.

Yes, but what about the phase shift when going through a capacitor?

Just joking... but yes, I was talking in context to the S&S. Modern digital equipment in pro-loudspeaker setups do time alignment on different bands of audio frequencies. Pretty cool.

[hairyandy]

Thanks Doug.  Nicely put.

For those who are new at this, note that EQ and "alignment" are not the same thing.  Where EQ adjusts the amplitude/level of different portions of the audio spectrum so that nothing stands out in an annoying way (all frequencies are "equalized"), alignment involves an adjustment in the timing relationship between different parts of the audio spectrum.  There is no requirement that the levels of different frequencies be changed, although it wouldn't surprise me if there was some change, simply as a consequence of what needs to be done to re-align.  As well, when the fundamentals and harmonics of any sound source are properly aligned (so that the harmonics start at the same time as the fundamental and remain in proper phase relationship), some frequency content may to be "clearer", but that is not necessarily because it has been made louder.

Alignment is particular an issue in full-bandwidth program material.  Between the problem of trying to blend what comes out of multiple frequency-band-specific drivers into a coherent image (especially when they are different distances from the listener), and the many places and ways from input to speaker terminals where HF content can get "unyoked" from the fundamentals, there are plenty of reasons to be concerned about alignment of the spectrum so that it behaves as if all sounds coming from a given source sound like they had the same poijnt of origin.

I don't know what the S&S does, but if it is entirely passive, then there is an excellent chance that what it does is more in the realm of EQ and not alignment.  Alignment of any degree of simplicity will involve splitting the spectrum so that portions can be shifted relative to each other.  No way you could do that passively without serious passive signal loss.

Thank you Mark.  This is pretty much the info that I was looking for yesterday when I initiated this thread.  I wasn't sure what the S&S did either and the literature kinda makes it sound like it's more than just an EQ (too many "Tone Icons" in the description?  ).  What excited me was the thought of something like the BBE process in pedal form for guitar.  I hear what you're saying about this being much more noticible on full-bandwidth program material like a live mix (which is how I always used the BBE back in the day), but I do remember hearing one through an amp with just a guitar and it was pretty cool.  It sounds to me that the S&S is more similar to something like an old Altec passive filter matrix which could still be pretty cool if optimized for guitar.  It's just different from what I originally thought it was.

Thanks all for the info guys.  I now have a little better idea of what I'm looking for and how to go about researching it.


 

[calpolyengineer]

Interesting - but there would still be a record of the patent application being filed, right?  I cannot find anything filed with the USPTO by anyone with the name Ayan (or Holguin) relating to musical instruments or sound.  Either I'm not looking in the right place (highly possible - I only checked two patent sites, and applications only go back to 2001), or no application was actually filed.  Even if a provisional patent application was filed, that only gives an additional 12 months to file the actual patent.  The S&S has been around since 1998.  A patent cannot be pending for 8 years, can it?

Well, in order to say "patent pending" there is a legal obligation to actually have filed a patent. Now to get the actual patent approved or denied can take many years, so 8 is still in the realm of possibility. As for whether there is any public record of a confidential patent being filed, that I have no idea about. I suppose the patent number would come up if searched for and might give you the title of the patent, but I doubt that any part of the actual patent is searchable.

Now I also want to point out that even if we can find a patent application, I don't condone spreading it like wildfire. Personal use is OK (the patent office even says so), but beyond that is pretty disrespectful of a fellow builder. Any information I have supplied about the patent process is merely for generalized knowledge.

-Joe

[GFR]

I don't know what the S&S does, but if it is entirely passive, then there is an excellent chance that what it does is more in the realm of EQ and not alignment.  Alignment of any degree of simplicity will involve splitting the spectrum so that portions can be shifted relative to each other.

Yes, but what about the phase shift when going through a capacitor?

Just joking... but yes, I was talking in context to the S&S. Modern digital equipment in pro-loudspeaker setups do time alignment on different bands of audio frequencies. Pretty cool.

I think digital pro equipment for time alignment of loudspeakers do rely on measurements, with a known signal source and extremely precise microphones. Not like a simple BBE (no matter how good the BBE can sound). There's no simple way to blindly realign anything in an open loop system, and it's problaby impossible if the "realigner" is not the last thing in the chain - Alignment of any degree of simplicity will involve at least an estimative of the misalignement.

BTW Behringer has some BBE-alike stuff, including a tube model

http://www.behringer.com/T1954/index.cfm?lang=ENG
http://www.behringer.com/EX3200/index.cfm?lang=ENG
http://www.behringer.com/EX2200/index.cfm?lang=ENG

[amz-fx]

I know absolutely nothing about the S&S...

If I were looking to make a passive device to control low end, I would probably start with the Craig Anderton notch eq from the EPFM book.

Set the notch to the low freq of interest and then dial in the depth.

regards, Jack

[Doug_H]

  I hear what you're saying about this being much more noticible on full-bandwidth program material like a live mix (which is how I always used the BBE back in the day), but I do remember hearing one through an amp with just a guitar and it was pretty cool.

I was in this band in 1979 and we had a pretty cacophonous mix, with loud marshall half-stacks and etc. Our sound man got a piece of rack gear called a "sonic expander" or something. When he turned it on it cleared the mix right up. It was really pretty amazing how effective it was. It was the closest thing to one-button tonal nirvana (that many gear ads promise but few deliver) that I had ever heard.

I don't know if "expander" meant the same thing back then that it does now and whether it was analog or digital. That was back near the dawn of commonly-available digital audio. But it was a cool tool that really did what it claimed. In retrospect though, I think we just played too loud back then...

Doug

[WGTP]

If you look into high end audio speakers, you start getting into time/phase alignment issues and their resolution, either thru passive means, or now digital.  The Thiel speakers seem to accomplish this, as does Dunlevy Audio passively.  Others do it digitally.  It appears that some are including a sensor/mic that is placed at the listening position, a signal is sent thru the system, and then digital correction occurs in the time/phase and frequency response domains.  This is just for that particular speaker in that particular listening room.

I don't know much about it, but with multiple micing/eqing/etc. I'm not sure how you would go about reassembling those things for an entire recording.  Plus the devices we us for FX deliberately scramble those things. 

[Mark Hammer]

  I hear what you're saying about this being much more noticible on full-bandwidth program material like a live mix (which is how I always used the BBE back in the day), but I do remember hearing one through an amp with just a guitar and it was pretty cool.

I was in this band in 1979 and we had a pretty cacophonous mix, with loud marshall half-stacks and etc. Our sound man got a piece of rack gear called a "sonic expander" or something. When he turned it on it cleared the mix right up. It was really pretty amazing how effective it was. It was the closest thing to one-button tonal nirvana (that many gear ads promise but few deliver) that I had ever heard.

I don't know if "expander" meant the same thing back then that it does now and whether it was analog or digital. That was back near the dawn of commonly-available digital audio. But it was a cool tool that really did what it claimed. In retrospect though, I think we just played too loud back then...

Doug

The only stuff I remember from those days that would use the word "expander" was:
- Dynamic range expanders, like those from dbx
- Tone "expanders" on Traynor amps, which I gather simply trimmed and untrimmed top and bottom
- "Image expanders" like those from Omnisonic, Carver, and eventually Radio Shack which spread the stereo field out by crossfeeding channel difference information to the opposite side with a bit of delay.  Those would only help if you guys used a stereo mix, though.  I have a couple different ones from Omnisonic, and another I built from a Radio Electronics project article.  The effect is similar to what is presently done digitally with the SRS Wow software on your Windows Media Player.

[GFR]

A link with some basics and history:

http://www.soundonsound.com/sos/1995_articles/feb95/exciters.html

[Mark Hammer]

Excellent link.  At first I was dubious, because the BBE process and what gets called exciters and enhancers are different things.  However, once you get into the article, it does a nice job of differentiating the varuious processes, what they do, and why it does what it does.

Very useful read.  Thanks.

[Doug_H]

The only stuff I remember from those days that would use the word "expander" was:
- Dynamic range expanders, like those from dbx

Now that you mention it Mark, I think it was actually called a "dynamic expander".

Cool box!

Doug

[WGTP]

Excellent article, it would be cool to have some simple DYI circuits that did the EQ/Phase stuff.  I think we got the distortion down pretty good.   

Wonder if any of those designs are using Germanium?   

Reminded me of this in the schematics listing.  http://www.montagar.com/~patj/harmswtn.gif

[Mark Hammer]

Yeah, that one is a product of some correspondance between RG and myself some years back, and the original design and article from Jules Ryckebusch in Electronic Musician around 1987 or so.  We added variable highpass tuning and variable gain adjustment.  An adaptation of this ( = "blatant ripoff") found its way into the Woody as the bright art of the signal path.  I added the single allpass stage just for the hell of it because I had an op-amp left over and had read somewhere many years earlier that Aphex introduced some phase shift into the exciter path.  I had no idea how much, but the single stage and components used bump all that added harmonic content over 90 degrees and it seems to sound kinda nice.

I think we got the distortion down pretty good.   

I dunno.  I'm thinking we need at least 30 more TS variants, 47 more Fuzz Face variants, 16 more Dist+ mods, and some things that just, I dunno, have more "fuzz".

Now that you mention it Mark, I think it was actually called a "dynamic expander".

Well hell, that's easy enough to do.  It's just a matter of rerouting the FET used for attenuation in the Orange Squeezer over to the ground leg of the nonverting op-amp so that transients produce a brief rise in gain.  570/571 companders can also be used for that.

[Doug_H]

Well hell, that's easy enough to do.  It's just a matter of rerouting the FET used for attenuation in the Orange Squeezer over to the ground leg of the nonverting op-amp so that transients produce a brief rise in gain.  570/571 companders can also be used for that.

It wasn't just a simple expander, Mark. IIRC (my memory is very hazy from those years) it was more complex, a la the items described in the article that GFR posted. It did things based on frequency ranges, did something to the phase relationships and so forth. Whenever we turned it on the toilet flushes would rotate in the opposite direction, we saw an aurora borealis in Florida for the first time, my lucky mood ring turned purple, etc. That sort of thing...

Doug

[sssteeve]

I bought a used Ayan Smooth and Slim from GC tonight for $99.99 (the back is marked "MII 05/07".) I was checking on-line to see if Gil had posted one of his schematics and this thread came out at the top of the list. First of all... no spoilers. :-(

The soldering and design is a work of art in its simplicity and execution... I wish my builds looked as good as his or accomplished the intended task so effectively.

Two jacks, two single pole rotary switches, 3 capacitors and 3 resistors- that is it, but it certainly does its intended job. Single coil pickups can be a bit thin or harsh, but the first switch (labelled "Bright" and "Dark") can darken the sound by shunting some of the signal to ground through a combination of one capacitor and two resistors. (The "Bright" setting bypasses that filter.)

The second switch selects  "Bypass", "Smooth" or "Slim" with both of the namesake settings running the signal through a combination of the two remaining resistors and capacitors. Hint: both of those settings are connected to all 4 of those components but are configured differently.

Humbuckers can get a bit boomy, so you can smooth it out or slim it down with the second switch, or darken it with first switch. So far I have found the "Slim" setting to be othe most useful with humbuckers although the other settings could tame a too-harsh bridge pickup.

All in all there are 6 settings of the two switches with one of them bypassing the S&S circuitry. I remember reading how Bill Gates wrote the OS code for an early computer making a very efficient use of the limited bytes available by having one set of instructions starting at the initial bit and a second set of instructions offset by a specific number of bits. Gil Ayan's circuitry here reminds me of that accomplishment. His "Smooth and Slim" pedal allows you to switch back and forth between humbucker and single-coiled guitars without having to keep messing with the tone controls on your amp. And with a minimum of components- all high quality- there is no unnatural degradation of the signal.

Two thumbs up!

Steve Ahola
(Janitor at The Blue Guitar)

[sssteeve]

Correction: Two jacks, two single pole rotary switches, 3 capacitors and FOUR resistors...

[ashcat_lt]

Why would you switch from a single coil to a humbucker if you don't want that change in tone???  Aw well.  Some people's kids...

I think there's a lot that could be done with all-pass stages that really doesn't get the attention it deserves.  I guess it's a very subtle effect that in practice affects more the way that effects down the line affect the signal.  Not super sexy, but interesting.

A lot of times, it's not even a matter of precise alignment.  Even just the "random" way that the phase gets changed going through the filter is enough.  I use "phase rotation" on about all of my vocal tracks lately.

Anyway, we have quite a few phaser schemes around.  If you rip out the LFO and stop mixing the dry signal back in...

...but then, a "stuck phaser" is another deal altogether, a quick and easy way to change the character of a tone in a relatively complex and "organic" way.

[PRR]

Welcome, Steve!