Open back cab question

[scottcw]

When using an open back cab, how much of the sound is projected from the front compared to the back... ie, what is the front/back ratio - 50/50? 60/40? 75/25?

 

[bosstone]

I would guess more like 75/25 but at that it is still louder than it would be if it was closed backed.

 

[mrt]

open back cabs are great for filling a room with sound.

closed backs are great for low end, and micing.

 

[jamison162]

Depends on the design of the cab and the back panels. Look at the THD, it's rather small and only has a 2" slot between the panels.

 

[scottcw]

Anyone else?

 

[scottlr]

I could be wrong, but I always heard that open backs fill the "stage", while closed back projects forward better. Not sure the ratio on open back.

 

[Oldtone]

So, a combination of open back ( combo) plus a single closed back cab should give you the best of both worlds? Like a Peavey Classic 30 and the 112E cab.
I recently considered enclosing one speaker in a 2x12 half open back cab, leaving one half open, to see what it sounds like.

 

[Guitar Dave T]

When using an open back cab, how much of the sound is projected from the front compared to the back... ie, what is the front/back ratio - 50/50? 60/40? 75/25?

"Enough projects out the back for the drummer to constantly piss and moan about guitar volume while he's still the loudest thing on stage."

 

[Guitar Dave T]

I could be wrong, but I always heard that open backs fill the "stage", while closed back projects forward better. Not sure the ratio on open back.

It has been my experience that open back combos project the sound out the front like a flood light; closed back cabs project more like a spotlight.

Or you can use the shotgun/rifle analogy if you're feelin' ornery.

 

[Guitar Dave T]

So, a combination of open back ( combo) plus a single closed back cab should give you the best of both worlds? Like a Peavey Classic 30 and the 112E cab.
I recently considered enclosing one speaker in a 2x12 half open back cab, leaving one half open, to see what it sounds like.

I just built a deep closed back 1x12 to use with my 1x12 open combo. Sounds nice at home. I'll let you know this weekend after gigging with it.

 

[mrt]

I could be wrong, but I always heard that open backs fill the "stage", while closed back projects forward better. Not sure the ratio on open back.

HAHA!! ^

I really dont think anyone will know 100% of the ratio...

 

[scottcw]

Depends on the design of the cab and the back panels. Look at the THD, it's rather small and only has a 2" slot between the panels.

I'm using an open back 2-12" similar to Vox AC30 dimensions.

 

[bosstone]

I just built a deep closed back 1x12 to use with my 1x12 open combo. Sounds nice at home. I'll let you know this weekend after gigging with it.

In the 80s I used to use a Boogie MKIIC+, single EVM combo with either a single 12" or single 15" EVM equipped Thiele cab. That was an awesome setup especially with the 15". It was good with ripping distortion and in clean, with a good chorus, flange or echo was extremely thick sounding for a mono rig.

 

[fr8_trane]

"Enough projects out the back for the drummer to constantly piss and moan about guitar volume while he's still the loudest thing on stage."

Its funny 'cause its true.

I much prefer open back cabs/combos for live gigs. I have had a hard time hearing myself with closed back cabs due to the beaminess. That said an openback closed back combination would be a great compromise.

 

[Jujo]

I'd say it's about 75/25. I've used open back cabs for years and I strongly prefer them. I also have a vertical halfback, and having the open top surely lets the sound spread around on stage.

 

[Miles]

open back cabs are great for filling a room with sound.

closed backs are great for low end, and micing.

For this exact reason I use a 1x12 open back combo with a 2x12 closed back cab for many gigs. Closed back is great for the mic and gives the tone a little whoomph on stage, and the open combo really projects.

My Genz Benz Black Pearl actually acts like a hybrid of both. It really has the low end and mic friendliness of a closed back but with the room filling qualities and upper midrange sweetness of the open back that it is in just about any room we play in.

 

[Guitar Dave T]

Quote:
Originally Posted by Guitar Dave T
I just built a deep closed back 1x12 to use with my 1x12 open combo. Sounds nice at home. I'll let you know this weekend after gigging with it.

In the 80s I used to use a Boogie MKIIC+, single EVM combo with either a single 12" or single 15" EVM equipped Thiele cab. That was an awesome setup especially with the 15". It was good with ripping distortion and in clean, with a good chorus, flange or echo was extremely thick sounding for a mono rig.

I remember a local player in the 80's who ran his MkIIC+ with an open combo 12" EVM and a closed cab JBL D120. He walked a fine line between harsh/bright and beautiful sounding with that rig.

UPDATE: I went home for lunch - wife and kid at school/work - and dragged the amp and extension cab into the "great room" and lined up a handful of pedals and a couple guitars. I got to CRANK it for about 20 minutes.

Here's what it is: The combo is a '92 Fender Blues Deluxe with a Celestion V30. The V30 works well with this amp - very smooth with a hint of bright and nice bottom. The closed back extension cab is solid pine with a 1/2" birch ply baffle and back, width and heigth dimensions the same as the Blues Deluxe, only deeper. The speaker is a Celestion G12H-30.

With the Les Paul, I had to make more adjustments from the high to low notes - the G12H-30 was very bright for the high notes, though the V30 balanced it out. Noticeably more bottom end thump with the closed back, a strong hint of the vibe I used to get with my 4x12, at a much more manageable volume.

With the CS-336, less adjustments were necessary. Both speakers seemed to work well together, with more distinct highs than the single V30 equipped combo. Still got some nicely defined bottom end thump, without being too boomy.

With the '61 SG RI, tonal Heaven. Great balance, could go from warm and sweet Freddie King tones, to Eric Johnson, 400-lb violin, depending on pedals. The variety of speakers and enclosures created a wide tonal spectrum.

I ran out of time before getting to plug the Strat in. I suspect I will have to make some treble and midrange adjustments on the amp, but will find out soon enough.

 

[bosstone]

Quote:
Originally Posted by Guitar Dave T
I just built a deep closed back 1x12 to use with my 1x12 open combo. Sounds nice at home. I'll let you know this weekend after gigging with it.




I remember a local player in the 80's who ran his MkIIC+ with an open combo 12" EVM and a closed cab JBL D120. He walked a fine line between harsh/bright and beautiful sounding with that rig.

UPDATE: I went home for lunch - wife and kid at school/work - and dragged the amp and extension cab into the "great room" and lined up a handful of pedals and a couple guitars. I got to CRANK it for about 20 minutes.

Here's what it is: The combo is a '92 Fender Blues Deluxe with a Celestion V30. The V30 works well with this amp - very smooth with a hint of bright and nice bottom. The closed back extension cab is solid pine with a 1/2" birch ply baffle and back, width and heigth dimensions the same as the Blues Deluxe, only deeper. The speaker is a Celestion G12H-30.

With the Les Paul, I had to make more adjustments from the high to low notes - the G12H-30 was very bright for the high notes, though the V30 balanced it out. Noticeably more bottom end thump with the closed back, a strong hint of the vibe I used to get with my 4x12, at a much more manageable volume.

With the CS-336, less adjustments were necessary. Both speakers seemed to work well together, with more distinct highs than the single V30 equipped combo. Still got some nicely defined bottom end thump, without being too boomy.

With the '61 SG RI, tonal Heaven. Great balance, could go from warm and sweet Freddie King tones, to Eric Johnson, 400-lb violin, depending on pedals. The variety of speakers and enclosures created a wide tonal spectrum.

I ran out of time before getting to plug the Strat in. I suspect I will have to make some treble and midrange adjustments on the amp, but will find out soon enough.

JBLs are very bright speakers.

 

[scottcw]

Now back to the original poster's question...

 

[Guitar Dave T]

Now back to the original poster's question...

Pardon the excursion through tangentville.

Actually, it seems like you could get a good idea of percentages with a Db meter, right?