Later the speakers were front loaded and a grill was made removeable to get to them.

Sound wise, I would think front loaded would be the most efficient. This is because back loaded speakers have to pass by the edge of the baffle. Thus causing some deflection. When I replace the baffles on cabinets with back loaded speakers, I run a router on the front edge of the speaker hole and do a 1/4 round edge. This helps open the hole up a bit and alows the dispersion of the speaker to be better. This is especially true on the thicker baffles like 3/4".

Joe

[This message was edited by Joe E on 06 February 2004 at 07:24 AM.]

I do this same route on the front edge of a back loaded speaker as well. If you can picture a hole cut in a piece of plywood. There is the thickness of the plywood that the sound waves of a back loaded speaker needs to pass. Thus the edge of the wood can change the dispersion of the waves.

By routing the front edge with a 1/4 round you have effectively reduced the amount of baffle the sound wave has to pass. Meaning that if your baffle is 3/4 inch thick and your 1/4 round is 3/8 inch deep. You only now have a 3/8" lip the wave can refract on. Now if you smooth this out real nice, you can reduce it some more.

You might question just how much dispersion is effected, but at that close to the speaker, quite a bit. Remember the waves are not just coming straight forward but raidiating too, like a puddle.

Just like some older baffles were cut not as a complete circle. But had a flat spot on the top and bottom. Thus covering a small portion of the cone. This changes the efficeintcies of the sound wave. Thus changing the sound. I think my Super reverb has a spot where part of the speaker is covered with wood to mount the Fender plate. It no doubt has some impact on sound. Not sure how much on a multi speaker cabinet.

I have done some comparisons to this and that is what I have found to be true to my ears.

I was involved in testing some high end amplifiers with different cabinets made from different woods and dimensions. It didn't work like I wood have thought it wood (too many woulds in one sentence)

quote:

---

Remember the waves are not just coming straight forward but raidiating too, like a puddle.

---

On my Evans, I had to do some "wood work" to get an Altec to fit.

[This message was edited by chas smith on 06 February 2004 at 03:14 PM.]

In back loaded speakers, the felt "gasket" squeezes the paper cone onto the basket.

In a lot of front loaded speakers where you can see the felt {or other material} "gasket", the only thing holding the speaker cone into the basket is the glue.

Peavey did this on my '79 Session 500 because there was no way to back load it. After 23 years my cone came unglued from the basket because there was nothing else securing it to the basket. I'd like to think that more modern glues hold better, but then it's hard to say what the foreign specs are. I doubt Peavey knows either.

Sound wise, I doubt if it makes a nickel's worth of difference. Especially in an open back cabinet.

Chas, I heard you spent some time recently with my good friend Ken Goerres and Danny M. Could you drop me an e-mail? I'd like to talk to you. Many thanks.