closed back amps

[jon reed]

In what way does a closed back speaker cab sound different to an open back?

[bclaire]

Closed back have more Whoompf. Low end, I'd say.

[Zeb Chadwick]

Whoompf indeed good decriptive Billy amd if its a Orange cab a very tightly focused Whoompf

Zeb

Night owl

[AstroDan]

Why do they not close them all? Hmmm...

[Quadbox]

Open back amps or cabs tend to feel and sound a lot looser, particularly in the bass frequencies and some people really prefer that sound. If I'm playing blues or soul etc, I much prefer an open back amp. Also, open backed amps tend to be less directional in the way they spread the sound. You don't need to be directly in the line of fire (so to speak)to be able to hear them properly as the sound is also spilling out the back of the amp. It's for this reason I prefer them when playing as a 3 piece or on a small stage where you can't get some distance between you and the amp.
Closed back amps on the other hand, tend to have a lot tighter bottom end with more cab generated "thump" and as a result I believe they are a lot better for rock and metal type styles. Contrary to the open back cab, they tend to sound very directional (to me anyway) and if you get off axsis with the front of them you can hear a noticable difference in volume in some frequencies. I find them good when I am playing with another guitar player as it allows me to isolate my sound from his. The reason most 4x12's are closed back is because the extra speakers compensate for the lack of sound spread simply by moving more air, yet you have the benefit of more bottom end due to the cab design comming into play.
I have a Mesa Boogie 2x12 rect cab that offers both configerations but I have to use open as with it closed the sound spread is just too directional for the type of places I play and unless I'm standing right in front of it, I can't hear the bloody thing!
I also just bought the Orange Alan Dunlop signature 4x12 with a slant front and it's the best sounding cab in the world in my humble opinion! Do yourself a favour and buy one! (better still, buy my Recto cab as I don't need it anymore<img src=icon_smile_approve.gif border=0 align=middle>

I love all things orange and all orange things!

[bclaire]

There's also the fact that closed-back cabs are sealed. There's a cushion of air in there that compresses when the speakers move back and forth, preventing the speakers from traveling in the same manner as they would in an open-back cab. The cushion of air actually protects the speakers in a way- those old cabs with greenbacks can handle high wattage but if you try to play a 4X12 with greenbacks with the back off, you'll find that you blow the speakers pretty quickly.

4X12's are really directional, and Oranges more so than Marshalls even due to the heacier construction of the cab. If you're using a soundman and he/she complains that the guitar is too loud coming off the stage, make sure that you don't have your cab faced directly at him. I used to angle a 30" squyare piece of plexiglass (Perspex for you UK types) at a 45° angle in front of the cab to deflect the sound and keep more of it onstage- it turned out to be more like an open back in terms of keeping sound on-stage without killing people in the front...

Billy

[badger668]

I just got back from the studio then. we were doing a song with my ad30 through the orange 4X12 and the other guitar track with my vox ac30 and we ended up just using the mics on the back of the ac30...sounded Great! very different sound.

badge.