Closed cabinet:
http://www.audiovideo101.com/dictionary/acoustic-suspension.asp

Open back (similar to ported) cabinet:
http://www.audiovideo101.com/dictionary/bass-reflex.asp

It is a THD 2 /12" with Celestion classic 80's

Closed-back cabinets come in two major types. First is the totally sealed variety, called acoustic suspension, or "sealed baffle". These are found mostly in home stereos and smaller sound systems. They are compact, and fairly efficient. However, due to their sealed nature, they tend to have a rather flat, "muffled" sound. This is usually overcome by the addition of mid-range and tweeter devices being added to the cabinet. Large speakers used in acoustic suspension cabinets are often of the "foam suspension ring" design. They have a very flimsy foam ring that supports the speaker cone, and improves efficiency and low-end response. These speakers, however, usually aren't rugged enough for musical instrument applications.

That brings us to the second most popular musical instrument enclosure, the closed-back design known as the bass-reflex, or "tuned baffle". This design uses ports, or "tuning holes" to smooth out response, and is very efficient. It tends to accentuate the lower frequencies, giving a fuller, more "rounder" sound. The very large ones are especially good at very low frequencies, and they are often used for bass and organ applications. The speakers are mounted on a baffle which usually has holes (or holes with tubes) that let the back pressure escape and reinforce the front-throw sound. (This is what makes them so efficient.) Their sound is quite "focused"...they project very well, but consequently, dispersion is sometimes a problem, with the higher frequencies falling off very rapidly as you move off axis. They tend to be bulky and heavy, too, but the richness of their sound (especially when multiple units are used), is very impressive.

This brings me to this, will I need to pop in a couple tuning holes in the back, if so, I can remove the horns and make a plug for the front with tuning holes in them.

These are for the house and not the job at this time. Also, please note, that there are two for a stereo sound from a tubefex and DPC 1000. I rather have the sound coming up at me, rather than to me.

Anyone care to comment?

[This message was edited by Gary Dunn on 02 June 2002 at 09:58 AM.]

Gary: I've posted this before but I'll repeat for your information. I had always used an open back configuration. Never even thought of trying a closed or partially closed back.

Then I got into my current band and our front singer is a Vet in a wheel chair and I was set up right in front of him. He said I was killing him so since I build my own cabinets I simple got two closed back units I made for a bass player and used them.

First night I was ready to quit ! They were now killing me. I could not deal with the level of all that sound now coming in my direction so I had to come down. And the sound was so clean it was scary. A steel playing pal said he heard me in the parking lot and the notes (Chimes) were running out there like glass and breaking off. A drummer friend dropped by and said: What did you do to your sound ?? You sound like a concert or show.....

Several other friends making the some complimentary statements convinced me to keep it that way and I still use them. Now I wouldn't have anything else but I can vividly recall when I wanted to take them out back to the dumpster. Follow that old sage advice and go with what you like. Someone else in another thread put it very well. He said the old critisism of steel players that always did what someone else with a good sound did or had, wasn't true at all. He found most steel players were into their own sound and techniques and that is as it should be. Be your own man of steel !!

I found a link to these JBL speakers in case anybody is interested in the specs: http://www.jblpro.com/pub/obsolete/G-Series.pdf

[This message was edited by Pete Burak on 02 June 2002 at 11:56 AM.]

Infinite Baffle-

A type of speaker enclosure which essentially forgoes the enclosure by using only a baffle or front panel onto which the speaker drivers are connected. Infinite baffle designs do not make use of sealed enclosures or ports.

Admittedly, the open back cabinet we are all so used to is usually ignored by acousticians because of all its technical shortcomings. Nevertheless, it is still the most popular as far as instrument amps is concerned. And, for all intents and purposes, the "infinite baffle" definition fits it most closely.

[This message was edited by Donny Hinson on 02 June 2002 at 01:25 PM.]