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.
This is a good idea. The materials used and the dimensions can play a big part on the tone and volume. It's like a big acoustic box for the amp.
Some people like a closed back amp over a open backed amp. I have 2 small closed back practice amps that have a great tone to them.
One thing that you could do with a closed back amp is to make a port that can be opened/closed, either on the back to use this device or in the front (behind the grill cloth if you have one) like the 3-way stereo speakers have.
Materials used can definitely make a difference in tone.
Example: I have a 1965 Silvertone Tube Amp that I found on the side of the road. It worked once I put a cord on it, but the original cabinet wasn't in good shape. It had a cabinet made of what seemed to be pressed fiberboard.
I was going to make a nice wood cab for it, but ran low on funds. I had a couple of 3-way stereo speaker cabs made of pressed sawdust. The speakers were no good, but the cab was big enough for the 12" guitar speaker and amp so I transplanted the guts over to the speaker cab.
I'm so glad I did that. The tone from the original amp cab was kind of thin and too high. Now the amp has more lows and mids and sounds great. Doesn't look great and it's heavy, but that doesn't matter compared to sound. Had to use the back of the cab for the front of this amp, so the back has some open spots.
So materials and dimensions can make a difference in the resulting tone and volume.
I have built one amp stand and used flake or particul board and that thing was heavy ,odd shaped "similar to the looks of a chair ,but had a pitch/angel where you would set in a re actual chair. It weighed almost as much as the dang amp & wasn't worth the heavy load ,so needless to say I ended up giving it away. If I were to want to build another ,I would use a welder and a light weight metal ,but I'm running a half stack and monitors now ,so I really don't need anything else, but I agree a thin plywood would probably be your best bet if you are set on using wood and need a amp stand.
Oh ,okay Ron I see what your talking about now that I went to the link again. I was thinking "just a stand to angel&raise your amp ,but this one in the pic has ""port holes". I've never tried anything like that in order to get more sound or a different tone. Like I was saying When playing gigs we have all our amps run threw a board and personal monitors ,but I would like to hear how much of a effect these have on a amp ,but be more to carry to a gig is the only downside if you already have plenty of gear to load ,unload ,set up & break down to load everything back up ....lol So we try minimizing if you know what I mean ,but if your not carrying too much equipment already ,,,"may be worth the added load"? I get what your saying Tho and would like to see a video w maybe using a small amp.
And yeah, if you have lots of gear, thi coulbe just one more thing to carry. Harold Smith has been working on a lightweight foldable model to combat that problem...
The Sound Enhancers were first developed about 20 years or so ago. I suppose you could build an amp directly into the cab; that's a neat idea. Harold Smith's idea, though, was that this would work with ANY open backed amp. There's a fair amount of research Mr. Smith put into his design, which uincludes figuring out the mathematics of folded horns as applied to speaker size, something the Scandinavians have taken about as far as it can go, to boost bass and lower mid frequencies. The research I've done into their folded horn and transmission line passive speaker designs, has convinced me that the lower speaker size limit for effective bass boost is 8" (yes, I know, car companies use 6.5" speakers and tuned enclosures, but they also use electronic magic to boost apparent bass response).
Which doesn't mean you (Or anyone else) can't try this with a CBG amp. But I don't think it scales precisely linearly. Although, there are examples of the Swedes taking the dimensions of a human cochlea, and scaling them up in wood; IIRC, they still had to tweak the dimensions of the upscaled version to get it to work properly.
As a matter of fact, they did! Those seemed to give the best sonic response, but they also required the greatest wood working skills. A few of them als experimented with variable angle deflection baffles: they found that the frequencies that were enhanced changed depending upon the angle of the baffles - meaning that they were tunable, to a certain extent.
Replies
This is a good idea. The materials used and the dimensions can play a big part on the tone and volume. It's like a big acoustic box for the amp.
Some people like a closed back amp over a open backed amp. I have 2 small closed back practice amps that have a great tone to them.
One thing that you could do with a closed back amp is to make a port that can be opened/closed, either on the back to use this device or in the front (behind the grill cloth if you have one) like the 3-way stereo speakers have.
Materials used can definitely make a difference in tone.
Example: I have a 1965 Silvertone Tube Amp that I found on the side of the road. It worked once I put a cord on it, but the original cabinet wasn't in good shape. It had a cabinet made of what seemed to be pressed fiberboard.
I was going to make a nice wood cab for it, but ran low on funds. I had a couple of 3-way stereo speaker cabs made of pressed sawdust. The speakers were no good, but the cab was big enough for the 12" guitar speaker and amp so I transplanted the guts over to the speaker cab.
I'm so glad I did that. The tone from the original amp cab was kind of thin and too high. Now the amp has more lows and mids and sounds great. Doesn't look great and it's heavy, but that doesn't matter compared to sound. Had to use the back of the cab for the front of this amp, so the back has some open spots.
So materials and dimensions can make a difference in the resulting tone and volume.
I have built one amp stand and used flake or particul board and that thing was heavy ,odd shaped "similar to the looks of a chair ,but had a pitch/angel where you would set in a re actual chair. It weighed almost as much as the dang amp & wasn't worth the heavy load ,so needless to say I ended up giving it away. If I were to want to build another ,I would use a welder and a light weight metal ,but I'm running a half stack and monitors now ,so I really don't need anything else, but I agree a thin plywood would probably be your best bet if you are set on using wood and need a amp stand.
This thing is much more than just an amp stand! Read the whole thread and follow the links...
https://youtu.be/WLcZN4Sa-bA
And yeah, if you have lots of gear, thi coulbe just one more thing to carry. Harold Smith has been working on a lightweight foldable model to combat that problem...
Haven't seen this before, this is awesome. Hmmm, why not just build an amp into the cabinet? I wonder if it could be scaled down for a CBG amp?
The Sound Enhancers were first developed about 20 years or so ago. I suppose you could build an amp directly into the cab; that's a neat idea. Harold Smith's idea, though, was that this would work with ANY open backed amp. There's a fair amount of research Mr. Smith put into his design, which uincludes figuring out the mathematics of folded horns as applied to speaker size, something the Scandinavians have taken about as far as it can go, to boost bass and lower mid frequencies. The research I've done into their folded horn and transmission line passive speaker designs, has convinced me that the lower speaker size limit for effective bass boost is 8" (yes, I know, car companies use 6.5" speakers and tuned enclosures, but they also use electronic magic to boost apparent bass response).
Which doesn't mean you (Or anyone else) can't try this with a CBG amp. But I don't think it scales precisely linearly. Although, there are examples of the Swedes taking the dimensions of a human cochlea, and scaling them up in wood; IIRC, they still had to tweak the dimensions of the upscaled version to get it to work properly.
Did any of them experiment with a curved [ from top to bottom [ rear deflector that you know of Ron?
As a matter of fact, they did! Those seemed to give the best sonic response, but they also required the greatest wood working skills. A few of them als experimented with variable angle deflection baffles: they found that the frequencies that were enhanced changed depending upon the angle of the baffles - meaning that they were tunable, to a certain extent.
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