I've been meaning to post this for awhile now, and finally got around to it.

So, I built three of these thingies a few months ago. A bandmate and I were having lunch, and talking about various pieces of gear. He asked me if 8'd ever heard of the "Sound Enhancer," a passive device used to do the following:

1) Take the back pressure wave from an open backed guitar amp speaker, and send it forward, resulting in
2) increased volume with the amp running at lower gain levels
3) increased bass frequency response, giving you a warmer stage tone, and
4) tilting the amp up toward your ears so you can hear better what you're playing.

Here's a vid from 2012 Summer NAMM of the inventor and his device:

https://www.youtube.com/watch?v=WLcZN4Sa-bA

I researched it, including the patent, and decided I could build one myself. I ended up building 3 of them.

The first, smaller one (pic 1) was based on an attempt at scaling a picture of a Sound Enhancer Mini from the TDPRI website. I slapped it together out of 1/4" plywood.

The second (center of pic 2) was an upscaled version, based on a discussion with the inventor on TDPRI, where he revealed the height, width, and depth dimensions. It's the one with the amp sitting on it.

The third (left side of pic 2) was my attempt at building the actual patent schematic.

Soundwise, they all have measurable (as in 10 dB) increases in volume versus just the amp itself, for the same gain setting. The center one had the best overall tone, with increasing warmth, and the bass frequencies seemed to be in phase with the speaker. The smaller one works OK with a smaller amp, like my Fender Champ 600, which definitely needs help with bass response from the 8" speaker. The patent schematic clone had the largest overall volume increase (it has a slightly larger interior volume than the middle one) but had a discernable warble or filter of the bass frequencies: loud, but unbalanced.

This was a fun afternoon project. Each one took about two hours to cut out and build. They are glued and screwed together, and are actually fairly lightweight.

Unfortunately, I forgot to record video / audio of my buddy playing through them. I can get drawings and dimensions for you if you PM me.

Views: 3349

Attachments:

Reply to This

Replies to This Discussion

Sorry, they were all built out of 1/2" plywood.

Any effect on closed back amps that you know of Oily?

Yeah. The Fender Champ 600 is technically a closed back amp. The effect is very much reduced. So I simply took the back off. Then the effect was quite pronounced. Basically, the back on a closed back amp seems to muffle or baffle the back wave from the speaker. So this device is really only applicable for an open backed amp ( or a closed back you've opened up).

But it still works great as an amp stand for a closed back amp, directing the sound upward toward your ears, meaning you don't need to run the gain quite so high.

thx

This is awesome! Totally cool do it yourself kind of thing.

On your large build. Cut back those 'horns' you have on the bottom. Completely back. Reduce it to a shelf big enough to support your amp. The sound has way to much area to reflect in all sorts of weird ways. 

Listening to their vid. The low end is enhanced. But so is the twinkly highs. This simulates a drop in midrange. I'm wondering and speculating. ( based on studio and live experience) It would be interesting to try one of these in a live full band setup. A drop in midrange may actually make it harder to hear wile playing with a second guitar player and drummer. For a single or a few players banging out a tune this would be cool. And to be honest, anything you can do to make an 8 inch speaker sound good gets to thumbs up from me. 

Actually, I figured out how to reduce the warble on that one, and why the Sound Enhancers are shaped the way they are. If you look at a pic of the commercial version ( http://www.tdpri.com/data/attachments/99/99760-d55ea10317f3b652e917...), you can see a front edge that is approximately 3" wide ( and where the brand "Sound Enhancer" is embossed). I tested several widths, and found that a 3" wide strip attached to the front of the Boomer dampened the warble almost completely. It acts like a focusing baffle.

And remember, that version was from his first patent. The link I posted above is his second patent, which is virtually identical to the middle version in the pic, and can handle any size amp ( my buddy and I tried about 6 of them between us). All of them from the largest amp we tested (the Soultone shown in the pic), to the smallest (my Champ 600) had a pronounced effect.

What's happening is that the bass frequencies, and some of the lower mids, are actually being enhanced, while being rotated to be in phase with the waves coming directly from the amp speaker. Then there's all sorts of interesting EQ you can do with a large enough amp with treble, mid an bass controls. On my Crate V16, which has a boost circuit that enhances the lower mids, I discovered that with the Sound Enhancer, I didn't need to use it.

Another thing is that the effect is more pronounced at 10+ feet than it is close up. That's due to the wavelengths of the bass frequencies being much longer than the folded horn design of the enclosure. That's the purpose behind a folded horn: to compress those wavelengths in a relatively small space. Same reason the Victrola featured an exponential horn.

It's an ingenious design that solves two problems at once, which is why I liked it so much I decided to tinker with it and build 3 versions, as test cases. The next two I build will be finished better, and incorporate a movable sliding internal baffle, so that you can change the angle of it, to dial in the enhanced frequencies a little better. After doing lots of reading about folded horns, I decided that that would make a rather interesting experimental "improvement," since the current internal baffle is at a fixed angle of approximately 22-23 degrees.
Rat,

I spent numerous hours looking at folded horn and transmission line speaker cabinet designs. The Scandinavians seem to be the ones pushing passive sound reinforcement recently, after a brief commercial spurt in the 70's by Klipsch, Heil, JBL and others. There are dozens of designs available on the Intermet using only 8" speakers that appear to offer substantial passive bass and lower mid frequency enhancement. Bass reflex porting is another area that was widely explored, and is now used extensively in commercial speaker cabinet designs.

One of my next CBG builds will feature an internal baffle plate, to essentially incorporate a folded horn inside the box, just to see if it makes a difference in getting the tinny out of the tone. Theory says it should have a small, but discernible, effect. And maybe a bass port...and an external horn...yeah, that's the ticket! ;-)

Interesting. Looks like a larger version of the gizmo Daniel Hulbert posted last year...the iPhone amplifier.

Yeah I looked at a lot of pics of iPhone and iPad passive horns while researching this. A friend of mine demonstrated his at work. It does actually work. The kewlest version I found was an origami folded paper horn ;-)

Here's the link:

http://www.instructables.com/id/The-Whirlwind-An-iPhone-horn-speake...

You could do the same thing with an acoustic CBG and a kitchen funnel (ask me how I know, hehehe. The big orange plastic automotive funnel I use for winemaking had the largest effect, but was a tad unweildy. ;-) ).
Ron, I am very interested in the dimensions to this enhancer. I apologize if this is not a PM but I am new to this site and I didn't see where I could send you a pm. I am a drummer who also works with sound. Trying to quiet the stage volume down where we perform but keep the guitar players happy with there amp sound. Volume is an issue. Unfortunately we are all a little long in the tooth and a little hard of hearing. I have been researching these enhancers and would love to try and build a pair.

Rick
Rick,

Presumably, you'd like the dimensions of the center one, which had the best performance of the 3. I have recently moved back to the States, and am still unpacking, so not quite sure where I put my notes. However, I'd be happy to reconstruct the design for you with dimensions...hmmm. Now that I think about it, I may have an idea where those plans are. If I can find them, I'll share them. To PM me here on CBN, send me a Friend request' then we can exchange messages off thread.

Re guitarists and stage volume: yeah, I'm 57, have suffered from tinnitus my whole life. And attending rock concerts in my teens during the 70's didn't help. So I finally started looking at smaller amps, and mic'ing them onstage, like most pros do, sending that signal through the soundboard and house PA, while simultaneously dialing down my stage volume. The difference in being able to hear my band mates has been palpable. Convincing younger band mates, or those who feel the need to drag a Marshall half stack to a backyard gig, to TURN IT DOWN, has been a bit of a struggle, especially if the git players have high wattage tube amps. I then try to appeal to the gear head in them, and tell them to get a Variac or variable power attenuator, so they can get the tubes to break up at lower power settings. I refer them to Ruby / Noisy Cricket DIY tube amp specs showing incredible volume from 0.5-2 watts, and tell them they are buying hype at anything over 20 watts, unless they are playing Shea Stadium next week ;=).

And then I try to convince my drummers to play behind a plexiglass shield, so that they don't further deafen me, as I like to stand next to the high hat on small stages :-)...
OK, here's the dimensions and design of the DIY Sound Enhancer, based on Harold N. Smith's patented E-2 design, and comments from him on the dimensions form an online forum. I will happly send the PowerPoint pesetaion I made of this to anyone who wants it; just PM me here on CBN, or e-mail me at oilyfool@yahoo.com.
Attachments:

RSS

The Essential Pages

New to Cigar Box Nation? How to Play Cigar Box GuitarsFree Plans & How to Build Cigar Box GuitarsCigar Box Guitar Building Basics

Site Sponsor

Recommended Links & Resources


Forum

crossover guitar.

Started by Timothy Hunter in Other stuff - off topic, fun stuff, whatever. Last reply by Timothy Hunter Mar 21. 11 Replies

Tune up songs

Started by Ghostbuttons in Building Secrets, Tips, Advice, Discussion. Last reply by Timothy Hunter Mar 9. 5 Replies

Duel output jacks

Started by Justin Stanchfield in Building Secrets, Tips, Advice, Discussion. Last reply by Taffy Evans Mar 8. 6 Replies

How to Get Your Own Music on Spotify

Started by Cigar Box Nation in Feature Articles. Last reply by Southern Ray Feb 21. 2 Replies

CB Bass Guitar

Started by Mi Rankin in Building Secrets, Tips, Advice, Discussion. Last reply by Justin Stanchfield Jan 27. 5 Replies

Music

© 2024   Created by Ben "C. B. Gitty" Baker.   Powered by

Badges  |  Report an Issue  |  Terms of Service

\uastyle>\ud/** Scrollup **/\ud.scrollup {\ud background: url("https://storage.ning.com/topology/rest/1.0/file/get/963882636?profile=original") no-repeat scroll 0 0 transparent;\ud bottom: 25px;\ud display: inline !important;\ud height: 40px;\ud opacity: 0.3 !important;\ud position: fixed;\ud right: 30px;\ud text-indent: -9999px;\ud width: 40px;\ud z-index: 999;\ud}\ud.scrollup:hover {\ud opacity:0.99!important;\ud}\ud \uascript type="text/javascript">\ud x$(document).ready(function(){\ud x$(window).scroll(function(){\ud if (x$(this).scrollTop() > 100) {\ud x$('.scrollup').fadeIn();\ud } else {\ud x$('.scrollup').fadeOut();\ud }\ud });\ud x$('.scrollup').click(function(){\ud x$("html, body").animate({ scrollTop: 0 }, 600);\ud return false;\ud });\ud });\ud \ua!-- End Scroll Up -->