Saturday, May 9, 2015

Happiness and Fun Toys

So its been a while since I have blogged, been busy with some cool projects that I am having fun with. Oh, and hey, Kim and I got married and it is truly awesome! Who woulda knew? I like to take the important things slow and do them right. We have not had the party yet but will let ya know when we do.


**** warning extended sound nerdery ahead ****

Ok, so on another note about things that make me happy, the new wedge design I have been working on is coming along.and ready for some road testing



This is no ordinary stage monitor. In designing them I combined the cool stuff I learned from building the Rat L-Wedge, the MicroWedge and the double hung pa into a single product.




Which was that sonic advantages in clarity and volume can be gained with a 3-way triamped wedge design With conventional high quality biamped wedges, it is fairly easy to get an adequate level when testing the vocals by themselves but after kick, snare, bass and guitar are added, the vocal can become less clear and difficult to get on top of the mix. By using a triamped design that has separate LF speakers for the lows and the 10"/2" for the vocal region, much of the IM distortion issue is reduced, plus the vocals come from a small area in the center of the enclosure.




The MicroWedge series addresses those same IM distortion issues in a different way.  Rather than separating the the signal by frequency ranges, the compact size allows multiple mixes to be in close proximity. For high volume and demanding situations, a pair of MicroWedges can be set to reproduce vocals and an additional MicroWedge or two can be dedicated to reproducing instruments.  This totally eliminates issues of instruments blurring the vocals while adding the advantage of having the instruments radiate from a different monitor completely, further enhancing intelligibility.



With the double hung PA concept I was able to implement and demonstrate that having instruments and vocals coming from separate sources is not only an advantage for stage monitors but can be applied on a grand scale. Also, since I could move any instrument to either the outer or inner PA in real time, I became very aware of the important advantages gained in using separately located sources. With monitors, I would find out after the show if separate sourcing worked, with the double hung main system, I was in the listening position personally (along with 20,000 of my best friends) and could hear the immediate and direct effect.

The SuperWedge Series

SDW22


Combining all the advantages and pushing things even further resulted in the SDW22 and several similar offshoot designs. The SDW22 is a dual 12" with a 10"/2" coaxial mid high component.All four loudspeakers are separately powered, have high grade neodymium magnets and 4" voice coils. Yes, a 4' voice coil 10" with a 4" voicecoil beryllium compression driver coaxially mounted. I believe this is the first of its kind. Each 12" is separately chambered, ported to the floor and the monitor is about the same weight and size as the premium dual 12" two way wedges currently on the market. Additionally, what really makes it unique is that the SDW22 has the ability to operate in multiple different modes.

  • Mode 1 - Full Range Triamp. In this mode it is purely a single input high fidelity wedge that gets really loud, basically a modern hot rodded version of the L-Wedge
  • Mode 2 - Full Range Vocal Optimized. This mode rolls off the upper frequencies of one of the 12"s reducing the low mid buildup caused by both 12"s reproducing the 100hz to 200hz range while also extending the low frequency response.
  • Mode 3 - Full Range plus Guitar. One thing that PA speakers never do well is reproduce a guitar sound . This setting uses the one 12" and the 10"/2" as a full range triamp monitor and a separate input on the amplifier powers the second 12". Rather than mic the guitar cabinet, using a Palmer or similar DI box to capture the guitar sound after the amp and send it to the second 12", not only allows the guitar signal to be reproduced bypassing the microphone, but also reproduces the guitar from a separate dedicated speaker. Plus, for even more discerning musicians, one of the 12"s can be physically removed, replaced with a Celestion 12 and powered from a guitar tube amp. This means the guitar player actually gets his or her exact sound coming from a the wedge.
  • Mode 4 - Vocals plus Bass.  The same concept as Mode 2 except with the 10"2" operated full range like a high power MicroWedge 10 and both 12"s are dedicated to a separate bass guitar signal.
  • Mode 5 - Subs on an Aux. The 12'/10"/2" operates full range and the second 12" is driven as a sub on an aux.  A pair of SDW22s on a drummer in stereo plus subs on an aux for a powerful and versatile drumfill
  • Mode 6 - Dual 12" subs on an aux. The SDS22 is powered by a Powersoft X4 amplifier capable of 1600 watts per speaker x 4.or 6400 watts per wedge and can be used as a high power sidefill with or without a separate subwoofer. Full Range to the 10"/2" and 12's on a separate subwoofer send
  • Mode 7 - Multi-way multi-source. Full range to the 10"/2" and bass guitar to one 12" and guitar to the other 12"
  • Mode 8 - Dual Biamp. Full range to one 12" and the 2" plus full range to the other 12" and the 10". This is for applications where extended frequency response and power handling is needed from the secondary send.
  • Mode 9 - Conventional Biamp. If the sound of a dual 12"/2" is preferred for the specific application, the 10" can be bypassed and the SDW22 can be operated as a conventional dual 12"/2" wedge. That said, try finding anyone else making a dual 12"/2" wedge with all 4" voice coils and a full sized, 2" throat beryllium compression driver.
So far the reactions have been ranging from, "that's crazy, why would you need that?" to "Oh shit, that is the best idea I have ever heard, why hasn't anyone done this before?" These wedges are not for the faint hearted or easy to please, these are designed to deal with the top level, most discerning, most temperamental, most demanding and most deaf of the artists and applications where the highest of fidelity, maximum volume or utmost in versatility is required


The next stage for this adventure is to put powered pairs of these out on the road with select musicians and engineers. I will try and stay on top of posting progress reports and if these look like a solution you have been seeking for your application, give me a shout.

Next up in the audio adventure, the SDS30, a high power sub that is the size of one but replaces 3 dual 18 boxes....

DR

Thursday, September 11, 2014

Perception and Failed Illusions

Perception and Failed Illusions


Does a muffled band in a rehearsal room down the street sound more 'live' to you than a high def recording played through high quality stereo? Or have you listened to a recording and thought "whoa shit, I thought that was band, but it was just a recording played through speakers?"  Is it just live music that defies realistic reproduction or do these same perceptions apply to voices, fireworks and just about everything else we try and recreate through loudspeakers?

It seems there is something about a live band playing, even muffled and far away that divulges its aliveness. A certain rawness, dynamics, dispersion from the sources, perhaps multiple source locations. If these observations are taken to be correct or at least in the realm of close, what is especially interesting is that frequency response appears to have little to do with whether we perceive something to be real-time live. Comparing the muffled band a block away versus direct exposure to Hi-Fi wherein clearly the Hi-Fi has a distinct advantage in presenting a wider and less altered frequency response, yet somehow the live band sounds more real.

Quite puzzling indeed and perhaps this perspective lends some credibility to why so many audio people have such an affinity for audio gear that exhibits less than flat response and less that technically ideal sonic characteristics. Perhaps, just perhaps we are focusing on the wrong aspects as a starting point and that is why sonic realism is so illusive.

Oh, and just a thought on making sound reproduction more real. What if rather than focusing on frequency response and accuracy of the reproducer we instead focus on eliminating introducing aspects that identically alter all the instruments? For example; we can significantly compress a single instrument without undesirable side effects yet even minor compression on the whole mix is readily audible. Think FM radio versus the CD or when the PA vendor puts a left/limiter on the PA. Looking at the dispersion of instrument, cymbals have a 360 degree radiation pattern whereas a kick drum has more of a figure 8 radiation pattern.  Guitar rigs can be figure 8 or somewhat cardioid pointed forward. Each of these instruments have vastly differing and unrelated frequency responses that can be readily altered  by choosing a differing cymbal manufacturer, switching to a felt kick beater changing the guitar cab type, yet none of those changes alter their "liveness".

Frequency response can be altered before or after the sound reproduction process so it is important for things sounding desirable but has little to do with things sound real or live.

So based on this I am thinking I can add the concept:

"Nowhere in nature do multiple unrelated sound sources offer identical dispersion patterns, yet in pro audio we do it all the time"

to the two other fundamental concepts I have been distilling, which are:

"Nowhere in nature do multiple unrelated sounds radiate from a single point in space, yet in audio reproduction we do it all the time."

and

"Nowhere in nature does the exact same sound radiate from multiple points in space but in audio reproduction we do it all the time."

With the underlying idea being that the more we stray from what occurs naturally, the more illusive realism will be.

Ok and on another note, I have been putting together a small playback studio with some spare and older bits of gear from Rat.  I have a lot of old multitrack DA88 tapes from various past tours and am looking to do some multi-channel mix downs for use in sound seminars and demos and such. The tapes have all been backed up to ProTools but rather than buy or tie up one of Rat's Pro Tools rigs and since we have 5 DA98/88/38 series machines laying around, I figured why not bring them home and use them.

What I quickly found is that they were very hungry and had a overwhelming urge to eat tapes. I cleaned the heads and ran the error rate option and all 5 machines were all over the place so I opened them up to see what I could find. What was happening was the tape tension seemed to be low and excess loose tape was building up in front of the pinch roller. For some reason they lacked tape tension.

After a bit poking around and found some good info here that helped a bit and got me in the right area

http://www.tangible-technology.com/machines/springfling.html

And thought I would share what I found was the exact same issue with all 5 machines. The tape tension arm shown below was no longer moving freely



When you press play, the arm should wing to be on the tape as shown here. but instead was barely moving


So, with a very small tweezers and exacto knife, I removed the two plastic split washers


Which are very small, do not drop them in the machine!


Removed the tension spring


Removed the tension arm by gently rotating back and forth with a needle nose pliers. I snapped a wood q-tip in half and soaked it in some WD40 and used it to clean out the pivot hole. Then used alcohol on a q-tip to clean the pivot shaft. Then put a drop of some multi purpose ultra lube on the pivot shaft. Dont put any lube on the tension shaft that contact the tape.


 And then reassembled it all back together and everything worked perfectly and all the error rates dropped to zero. 


And since there is more to life than pure audio. a few adventure pics to lighten the load. There was a most wonderful week of amazing waves that came to visit our southern California shores


but not without consequences for the unprepared and when the waves get big enough to break things


It can become a spectator sport as well




But when it looks so good I just can not resist


DR





Sunday, August 24, 2014

Building New Toys

So Peppers tour has ended and  walking into the production office after the last show at Isle of Wight I could not resist taking a photo. Three years of on and off travels and another chapter comes to a bittersweet end. I will miss seeing all my friends on world adventures till next time and oh the thought of being home for a while is very very wonderful.



It is a shame those set lists did not go to fans but some things ya just got to let go. It has been a while since I have blogged.  Partially due to recovery from my bike crash, partially due to focusing on dedicating time to finishing Peppers tour, partially from immersing in the business side of Rat Sound and also because I have been working on some new speaker designs and concepts.

As far as bike crash recovery, I am mostly back up to speed with only the odd lump from my broken collar bone, a slight bit of shoulder rotator motion loss and most oddly, I seem to have an altered sense of smell. Some things I just can not smell at all and other things I am quite sensitive to. My sense of taste seems fine though. Ha, maybe light losing sight improves hearing, maybe losing smell will help hearing too.  Lucky me.


Here is a blog post I started a while back and never posted:

Comb filtering is a description of the cancellations created when a signal is re-summed with a time shifted version of itself.  The 're-summing' can be electronic or acoustic.  

If you wish to eliminate comb filtering you need to either reduce the number of source such that only one source can be heard at the listening positions. not allow time shifted versions of the same signal to sum electronically or alter the signals so they are sufficiently dissimilar.

In real world reinforcement applications, comb filtering typically is not solved, it is mitigated. Where it gets interesting is that the humanly configuration of our bodies and location of our ears is such that undesirable effects of comb filtering occurring in the horizontal domain is actually minimized when the sound sources are sufficiently far apart from each other and we are located somewhere between those sources which is why we prefer stereo instead of mono home stereos even when the sound radiated from both speakers is identical or similar.

I personally strive to minimize sending the exact same signal to multiple horizontally spaced speaker arrays. I want the guitar mic sent to the left PA stack to be a different signal than the guitar signal sent to the right.  I want them both to sound good, but not to be identical.  Same with bass, and as many other instruments as possible. This reduces comb filtering and minimizes creating power alley.


And for some newer stuff, last week I did a Dave Rat Seminar for Disney sound technicians. Super cool and I felt quite proud that I have shoveled enough knowledge into my sandbox that I am asked to interact with such a highly respected organization.




Doing the Dave Rat Seminars has helped me clarify some basic fundamental concepts. One of those concepts is:

"One of the driving reasons that humans gather in groups is to experience lasting memories."


We attend rock shows, sporting events, houses of worship, theme parks or political rally's in order to create a memory for ourselves and for others.Those memories are created by connecting the people that have something to say with the people whom desire to listen, watch or interact. The more of our senses immersed in the experience, the more powerful the memory. 


As sound reinforcement professionals, our specialty is the audio spectrum and to work with the visual, and other specialists to create the most powerful connections we can. If we keep our grand purpose in focus we greatly increase the probability of a desirable outcome. 



Sooo, on another note

As far as projects, I am currently working on designing what I believe to be the best sounding, loudest, clearest and most versatile stage monitor ever created. With the assistance of (in no particular order) Mario DiCola, Eighteen Sound, Jefferey Cox, Powersoft, EAW and the key people at Rat Sound, we are creating a stage monitor so clear and powerful, using only the most premium components, that no other stage monitor even comes close to its capabilities.

oooh, powersoft visit



Taking everything learned from building the Rat Sound dual 15"/10"/2" L-Wedge and everything learned from designing the EAW MicroWedge series of monitors and creating a stage monitor that is about the same size as the leading high power wedges and exceeds the capabilities of the L-Wedge and MicroWedge combined. I would very much like to share more as we have a working prototype that literally makes the top wedges currently available sound like they are broken when put side by side. Soon Rat will have 4 pairs of wedges with power that we will put out with some key clients and I will give more details.

Here is a photo of Mario, this is not the wedge but rather an early stage of component testing. 



Working with Mario and Eighteen sound has given us access to fine tuning every aspect of the custom loudspeaker design from voice coil material, voice coil length, cone type, weight, magnet type, strength and material and more. I wanted components for this wedge that have never before existed. Here is a laser testing parameters of one of the custom components.



My long standing relationship with EAW is the foundation for the cabinet construction, testing, specs and processor settings. The developing relationship with Powersoft will optimize the amplification and aspects while us at Rat have developed the actual design look, features and capabilities.


Can't have a new design without napkin drawings



Another project I am excited about is I am building a super compact portable sound system that is 8 inputs, 8 processing channels, 8 outputs at 50 watts per channel and the whole ting fits in a suitcase. I intend on using this as a demo system for future seminars to show the differences between mono, stereo and multi-source audio reproduction as well as use it to test some concepts I hope to apply on a larger scale for future arena tours.



As you can see, the small cabinets have mini pole mounts so you can build erector set type structures.

And now for the serious stuff:



Proof that beer and sound go together


That Leonardo guy was a sharp cookie


Oh, Another project was building a head mounted iPhone steady cam for Josh. I love power projects where you just make something useful from stuff laying around the garage



And finally, a video from Thailand at a little zoo on the beach of little otter with something to say.





Saturday, February 1, 2014

Big Owie

I am blogery slacker, just mining for the time to set aside and brain data dump some things to share. I did have a bit of a hutch in my get-a-long as well. I love surfing and snowboarding but decided to take divergence into a 40 mile bike ride.


Which seemed like a reasonable enough idea. Off to the trails in Ojai staring in Ventura and oh maybe 15 miles in or so, KABLAAAM. Another bike rider flying down the trail on a brake-less fixie bike broadsided me and sent me flying. Owie to the bicycle

Owie to my shoulder


And super owie to my head left me 8 days in intensive care and a multi-month recovery


 Anyway, I am mostly healed up and getting back to my scatterbrained and quirky self enough to do some surfing


Hang out with My dog Bones




And especially spending time with my awesome gal and amazing daughters.  Oh yeah, and Gene too! 


Oh, and ya know something really cool about doing some hospital time and getting all screwed up? All the friends and family that come to visit. I can't begin to describe how magic it was to be laid up in a hazy world and feel so loved. Truly amazing and thank you so so much.


On another note, I have designed some BSS 960 fader link knobs 


and printed them out on my 3D printer 



that allow us to EQ left and right at the same time.


ILet me know if you want a set and will print some up. Am thinking 30 in a light gray color plus 2 printed in glow in the dark plastic so you can have a few that mark 250hz and 2.5K
 

Oh, so today I am in Brooklyn for a Peppers gig at Barclays Center today where I have the most curved line array hang I have ever mixed on.  Hmmmm, not sure I am digging it but we will see.


and then tomorrow Peppers play the Superbowl Halftime show.


And how about some audio nerdery I was working on before I got bike crashed.



Some thoughts on Equal-Loudness Contours (Fletcher-Munson curves)


Compensating for Fletcher-Munson curve effect was quite popular in home Hi-Fi for many years with the "loudness" button that boosted some lows and highs on nearly every home stereo receiver for decades. Interestingly it has all but vanished on current home hi-fi equipment.  Also of note is it has never become popular in live audio reinforcements systems. My personal experience is that it is something where studies and measurements show that it exists yet when I push the loudness button on my home stereo receiver, it makes the music sound unnatural and overly bass and treble heavy. Plus and more importantly the adding of a perceptual based compensation network brings with it some doubt.  Was the recording made with a predictive intent for this button to be pressed to induce a desired alteration? When the band plays soft or loud in the rehearsal space, where is Fletcher and Munson compensating for my hearing? Am I hearing it incorrectly so it needs to be fixed?

My take on it is, yes I believe that it does exist, at low volumes sub lows and HF are less perceptually prominent.  Yes, they can measure and approximate a compensation that electronically corrects for volume dependent frequency perceptions. And I believe that the utilizing the concept of attempting to compensate may be short sighted.

Perhaps just perhaps we as humans already naturally expect to hear less sub-lows and high frequencies at lower volumes, we expect naturally to hear a differing balance at higher volume levels. Perhaps an  automated volume dependent compensation circuit is an unnatural event and though it may correct for our hearing, perhaps these loudness buttons have faded from favor, vanished from usage because though technically an argument can be made that it is a valid correction. For us live engineers there are additional challenges in as we deal with a dynamic range that is so great and the distance variations to listeners so vast and then add in ear plug usage, differentials in age related hearing loss/sensitivity of the listeners and so on.

That is not to say that having control over volume dependent tonality is not useful and valuable. And conversely, a major issue with many sound systems is that the tonality changes with volume in undesirable ways. Most typically when turning up a sound system resulting in having everything go into limit except the 2" drivers which creates a reverse Fletcher-Munson curve scenario, that is difficult to compensate for.

I have had some success with applying Fletcher-Munson curve type compensation in live audio in the form of implementing subs and tweeters on auxillary sends with manual control of the volume that the subs and tweeter limiters.  Soft songs have full subs/tweets, louder sound push subs/tweets into limit offering a Hi-Fi sound at lower volumes and a 'rock' sound at higher volumes.  I do find this useful as a manual control and this had a side effect of increased intelligibility of  the artist speaking between songs. That said, it has been years since I felt compelled to implement that control and on modern high end systems, it just does not seem necessary to add that complexity, at least for the artists I have been mixing.

One aspect I have been focusing on more recently is "Should we try and force the sound systems to maintain the same HF EQ at long distance listening positions or is it a do we as humans prefer to hear some HF roll off when the source is far away?"  As systems improve, we are gaining the ability to throw HF father and farther yet in my opinion, a bit duller less edgy sound when listening from long distances can often be a more enjoyable experience and it sounds more natural as long as sufficient intelligibility and volume is maintained.


Ok, no promises but will try and blog and share more soon.

DR


.

Thursday, August 22, 2013

Amiga, Makerbot and Line Arrays

Anyone remember trying to render graphics or print anything other than text from a computer in the mid 80's? I recall having to wait till sleep to hit the render button with a 50% probability that the computer will crash, only to end up with a crude version of the graphic that took another whole eternity to to create and when it finally came to printing it out after 20 false starts to get the layout formatting correct between lock ups and those darned reboots that required a reload of a shit ton of floppy disks because hard drives were not yet a common consumer item of affordability.


Well, the reason this comical now but frustrating then memory comes to mind is my adventures with 3D printing. Though nowhere near as archaic, the nuances of creating printable drawings and sit and wait adventure while the little nozzle moves around squirting hot plastic brings back those old memories. For those not familiar with how the most common 3D printers operate, basically all they are is a hot glue gun nozzle attached to a plastic wire feeder that can move around in the X and Y axis and a plate that moves up and down in the Z axis while it squirts hot plastic in hopefully all the right places to end up with what was on the computer screen.


Line Array Adventures!
(as promised to answer a twitter question)

OK, so how about taking a look at some aspects of line array HF design? One of the major challenges with designing a line array is getting the sound to radiate out of all places of the enclosure at the same time. This may sound more trivial than it is. Sound likes to radiate outward in circular waves like rings from a stone dropped in water. But line-arrays need sound to radiate more like a flat stick shape from each horn.  If you just use a horn that has a tall narrow opening, the sound will exit the shortest distance first which is the middle and still have an arc shape as it leaves the horn/waveguide.

To get around this, there are several methods that the various manufacturers employ with varying degrees of success. I will divide these up into the three basic types/approaches and gives a brief description of some assets and issues with each as well as a few links to patents from the manufacturers.

The Equal Path Length Waveguides

Three examples of companies that patented this type are L-Acoustics, Adamson and Turbosound.  The concept is to create a waveguide wherein the the shortest distance from the horn driver diaphragm to anywhere the sound can exit, is exactly the same (or of a predetermined minimal offset).

L-Acoustics does this by first determining the distance from the driver to the top/bottom of the waveguide exit, which is the longest distance.  Then designing the waveguide shape such that the sound travelling out of the middle area of the exit has to travel an equal distance. The patent explains it in depth.


Since L-Acoustics had already patented the most simple and direct design, indirect designs started being developed. Nexo came up with an interesting method. How about sending the sound from a compression driver down a horn and reflecting the sound off of a curved surface such that the reflected sound was correctly timed by the time it leaves the horn. 


Adamson came up with another work-around. I heard rumors that some potential infringement questions that arose but I guess the patents were differing enough that Adamson's held. Basically what the Adamson design does is it divides the process into two parts.  The first part over corrects the sound wave so it comes out the top and bottom of the initial waveguide first and the middle last.  Then the second part lets the sound wave expand naturally in the secondary waveguide.  The two waveguides are designed such that the over correction and natural expansion combine to have the sound exit the secondary waveguide at the same time.


Another way to try and solve the equal length conundrum is to divide the sound up into a multitude of smaller tubes of equal length and then rejoin them at the exit. This is the path that Meyer Sound and  Turbosound followed to develop their line array waveguides as shown in. 



You can almost feel the minds churning to create a solution to get in the line-array game. In general, my experience has been that the more complex the design is, the more room for error, resonance issues and unwanted reflections.

The Multi-Driver Designs

This concept goes back pretty far and I was able to find a patent by RCA from 1927. Basically it is simply using a higher quantity of smaller drivers instead of one, two or three larger 2" drivers.  This gets the sources close together and all radiating at the same time.


So with L-Acoustics having a patent on the simplest most direct solution in 1988 and the other 'equal length' concepts to get around the L-Acoustics intellectual property patent yet to be concocted, companies started coming up with various multi-driver contraptions that basically use a multitude of long narrow horns with on each.


Unlike the L-Acoustics and Adamson solutions, the Clair multi-driver approach does not fully create an output where all the sound radiates at the same time. Instead there are a bunch of smaller arcs, one from each horn/driver.  The more drivers the better but the drivers tend to be physically a bit of an issue limiting the maximum quantity. Though Clair did an admirable job by employing nine 1" drivers I believe in their I5 rig, every other driver offset to the left or right so the vertically fit in the box.

Another version of the multi-driver as implemented in the JBL Vertec systems was just to use 3 drivers and not really be too concerned that the sound all leaves the horns at very close to the same time. Though this was consistant with the JBL design in that the Vertec system allowed for much more drastic angles between boxes as well.  I huge asset in versatility and a detriment in sound quality.

Also there are some other designs that utilize diamond or other shaped 'obstructions'  in the horn that assist in aligning the timing of the sound leaving the differing parts of the horn

Here is another multi-driver patent that I am not familiar with any large format systems employing but is interesting as well,


The No Waveguide Solution

Hey, why not just use a ribbon driver? That's what we want, right? All the sound to radiate at the same time in the vertical domain. I do feel that ribbons logically are the best solution, practically though, there are some challenges. Conventional drivers are most efficient when centered in the gap and as you drive them harder, there is both a mechanical limitation can be a decrease efficiency. This parallels other components in the system to a degree. Most ribbon designs have a perforated magnet in front and behind the ribbon, not only are there artifact from sound passing through the perforation, the harder you drive the ribbon the closer it gets to the magnets creating almost a sonic expander.  Yes, electronics can correct for this perhaps. I do believe major headway has been made in increasing the efficiency and frequency response of ribbons but in my opinion, they are just not yet fully on par with the top level voice coil driven systems, yet.

Other Stuff

A couple other older patents where we can see designs that control the distance sound travels to leave a horn



An older form of line arrays were products like the Shure Vocal Master

A few advantages of the equal path length designs is simplicity and that conventional drivers that are readily available can be used.

Multi-Driver Minimal Waveguide

The multi-driver designs can get costly very quickly but they do allow for separate amplification and processing of each driver. Which brings me to what I believe to be the best version of the multi-driver design is currently what EAW has implemented in the new ANYA system, just as I believe that L-Acoustics has the best version of the equal path length design, Anya has the best multi-driver design.

EAW's solution was to develop a very compact, high power 1" dome driver and use 14 of them on very short waveguides, therefore minimizing the timing errors to the lowes of the multi-driver designs to date, almost forming a perfect ribbon.  Except unlike using a ribbon, each segment of the ribbon can be independently processed and new levels of control realized that no other system has capabilities of accomplishing.

Here is a link to a video that explains more


If it sounds like I am a fan of the L-Acoustics design and EAW designs, you are correct. If you think that I am a fan because Rat Sound owns both those systems, you are incorrect.  The reverse is true. Rat owns those systems for many reasons and one of which is that I believe that the HF waveguide design is a core and critical aspect of line-array design, and also I have a special affinity for the early innovators with the most finessefull solutions. Yeah, 'finessefull' is not a real word but it should be as it is so useful.

Ok, enough brain dump.  How about a few pics to lighten the load.?

So we make the Soundtools.com products at Rat and Bryant orders some new tube samples and normally this would be just a simple misprint but....


Ha! Rock and roll.... Off to the big rock show.... I bet you cant come up with any other one-liners. 


One of the wheels broke on the Midas Script Scroller 


Here is what the good wheels look like 


So I printed a new pair of wheels on my Makerbot2 3D printer, and back to good again.


I just had to share this. Left to right, my mom, Mark Schoenfield (former step brother), Me, Steve Schoenfield (other former step brother), my sister Tiffany and my brother Phil. And this was only a tiny smidge glimpse of the oddity of my previous life as David Levine before I somehow was renamed Dave Rat by my pals and peers.


Oh yeah! Did a 9 day train trip in Europe with Daughter Sammy.  It was her turn as Maddie and I did a solo pair run 2 years back. I would not trade those adventures for five worlds!


Not disturbing enough to make you want to poke out your mental eye but a fashion statement none the less


And just a pic that makes me smile from the the trip up to Anchorage for a few Peppers gigs.


Ok, that's enough.  And tomorrow one daughter moves out into an apartment with roommates and saturday the other is off to college in New York. Could not be more proud and filled with apprehension of a major life shift at the same time than I feel right now.

Dave Rat