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Comment by Mark on July 5, 2010 at 12:22am

It's a neat coincidence that you posted your comments at this moment. A while ago I noticed there's a big difference in the amp's tone depending on whether I have the back panel on the box or not. With the box open it seems much more trebly - or to put it another way, when the box is fully closed I hear more bass. I've recently begun experimenting with sliding the lid very slightly open so there's just a small opening, the idea being to see if there's an optimum position where I get the best tone. It's too early to say for sure at the moment. I'm aware that design of speaker enclosures can get very complex - I've read a little about it but I haven't had the time to start digesting the detail properly. I know some designs feature a "reflex port" and your description of a "pump hole" sounds similar to that.

I do think there's a lot of potential in experimenting with enclosure design. One of the limitations of these simple cigar box combos is that the speakers tend not to be specialist guitar speakers, which, combined with the small size, means you lose significant aspects of the sound of a proper purpose-built guitar combo. I'm wondering if it's possible to compensate for those shortcomings by building a simple box enclosure with acoustic characteristics that provide the type of frequency response you want with a guitar? I don't think I have the knowledge to come up with a design by using precise mathematically-based methods, but I guess there's no reason why I shouldn't attempt a bit of trial and error development.

Comment by LittleBigOne on July 4, 2010 at 10:36pm

Hi Mark, I did some too and I have found an interesting tip maybe you will want to try. A few years ago
I made some tests with measurements tools and found the speakers can give more sound when they can
"pump" air. That is, you drilled little holes in front of the speaker so more sound can go out of the box,
but if you watch at the speaker when running,
it is moving fast, and the air around it is moving fast too, so you can create "a pump" if you drill another little
hole somewhere in the box but outside of the speaker area. Most often hi-fi speakers have the "pump hole" in
front side, but you can really place it anywhere, we used to place it rear of the speaker. I think the best
place to drill the "pump hole" is near the
little amplifier, and so the air have to go through the whole box and is thus cooling the box, meanwhile
it will give you a louder sound :-)