# Open back VS Closed back cabs.



## greco (Jul 15, 2007)

I just tried a closed back cab (1 X 12") for the first time and am very impressed. The cab is ported and is converted from some type of cab that once had a horn, etc. in it (I think). 

Thanks again to Riff Wrath as he did the original conversion. He can provide more detail about what the cabs had in them originally.
. 
I like the tightness, "fullness" and "projection" of the closed back cab. 

I'm just interested in what others have to say about their preference for open back VS closed back cabs.

Does your preference depend on what and/or where (i.e., specific situations) you are playing?

Cheers

Dave


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## Geek (Jun 5, 2007)

I like semi-open backs :smile:
(I guess that counts as "closed" on the poll)


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## Budda (May 29, 2007)

im all about closedback cabs


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## Stevo (Apr 3, 2008)

I like the open back cabs myself for gigging. I find the closed back cabs very directional and unless you have some serious space between yourself and the cab, it is hard to hear yourself. Closed backs sure have a nice thump though....


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## Guest (Oct 13, 2008)

I like them both for differnt reasons but in my Rivera rig I've got both. If you check out the pic I posted in the rig pics thread you can see the ext. cab has little nylon pull slips at the bottom to remove the grill. The amp is semi-open and the ext. cab is closed. It's a sweet combination.


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## mcgriff420 (Sep 30, 2008)

greco said:


> Does your prefernece depend on what and/or where (i.e., specific situations) you are playing?
> 
> Cheers
> 
> Dave



I'm with Yoda and Stevo, different situations call for different gear. For my Country/Rock gig I use a combo -which is open back and sometimes a 112 matchless cab -also open back. In that situation I'm not playing 'clean' but i don't need alot of bass or any chuga chuga thump/tightness, just an uncompressed open/airy sound.

For a Rock gig I have a head that I use with an oversized closed back 212. It's tighter with more thump, but it's more directional and requires more space ie. nearer to the back of the stage pointing out directly at the crowd.


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## mhammer (Nov 30, 2007)

I think it was SMF, but I may be remembering it wrong. In any event, "they" produced an amp a couple years ago that had an adjustable back so that you could have it fully open, fully closed, or in between.

Pignose users will also remember that the instructions directed you to adjust the tone via the extent to which the cabinet was open or closed.


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## Metal#J# (Jan 1, 2007)

How about both............


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## guitarman2 (Aug 25, 2006)

Stevo said:


> I like the open back cabs myself for gigging. I find the closed back cabs very directional and unless you have some serious space between yourself and the cab, it is hard to hear yourself. Closed backs sure have a nice thump though....



My Dr Z Maz 38 head with 2X12 closed back was an amazing tone. Lots of bottom end and Marshall crunch. As you say I liked stages where I could get it atleast 19 feet behind me. Which was almost never. It was very beamy and projected alot of sound to the back of the room and never on stage. I put in beam blockers and although that helped with driving it right out front it was still a hard beast to tame. I now only use open back on stage and with my Dr Z stangray head I still have a lot of thumb.


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## Lemmy Hangslong (May 11, 2006)

I like them both for different tones... I play closed back more though.


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## greco (Jul 15, 2007)

Thanks for all the responses.

Two further questions...

1) Do the commercial closed back cabs typically have some sort of enclosure sound dampening/lining material on the inner walls?

2) Are the commercial closed back cabs usually ported?


Thanks

Dave


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## mcgriff420 (Sep 30, 2008)

The Bogner OS212 has insulation, but the Mesa recto 212 didn't, neither did the Koch 212. However, I played through an old BF Fender 212 that did have insulation, but at that age i'm not sure whether or not it was original spec.

I like insulation in closed back cabs, I installed some in the mesa recto i refer to above and it helped remove some of the boxiness -it still didn't hold a candle to the Bogner though.

I've never played through a true ported cab.


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## screamingdaisy (Oct 14, 2008)

Open back for cleans.

Closed back for dirt.


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## greco (Jul 15, 2007)

Geek said:


> I like semi-open backs :smile:
> (I guess that counts as "closed" on the poll)


Gregg..Is there a specific method for determining the amount of opening in the back of the cab (apart from trial and error) that is usually considered "best" ?

I have looked at websites that go into a lot of detail about port diameters, lengths, placement, etc but I haven't seen anywhere that discusses semi-open back cabs. Any links that you know of ? I'd just like to educate myself. 

Thanks

Dave


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## Budda (May 29, 2007)

no porting or insuluation on a peavey XXX cab, i can tell ya that much.

and Jason, was that reeeeeally necessary?


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## greco (Jul 15, 2007)

Budda said:


> no porting or insuluation on a peavey XXX cab, i can tell ya that much.
> 
> and Jason, was that reeeeeally necessary?


Who is Jason?


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## Geek (Jun 5, 2007)

greco said:


> Gregg..Is there a specific method for determining the amount of opening in the back of the cab (apart from trial and error) that is usually considered "best" ?
> 
> I have looked at websites that go into a lot of detail about port diameters, lengths, placement, etc but I haven't seen anywhere that discusses semi-open back cabs. Any links that you know of ? I'd just like to educate myself.
> 
> ...


Hi Dave,

Yes there is, sorta - use a HiFi speaker program and tailor the cab dimensions as per the T/S parameters of the speaker (which for guitars isn't published most times, so you have to find it out for yourself and each speaker can vary bigtime!). But this tends to tailor only the bottom, as the mids are pretty complex and can vary tremendously with the type of wood and finish used. So it's a crummy route to go other than for bass.

But I just as soon make a test box with variable opening rear and adjust until it sounds right. Then you measure the area of the opening and you can make it in any shape you want for the final product :smile:

I've found no links myself for semi-open backs. If you find one, I'd like to see it too :wink:

Cheers!


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## Budda (May 29, 2007)

greco said:


> Who is Jason?


the guy with the 612 closed/open cab - or he at least posted that pic hehe.


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## greco (Jul 15, 2007)

Geek said:


> Hi Dave,
> 
> Yes there is, sorta - use a HiFi speaker program and tailor the cab dimensions as per the T/S parameters of the speaker (which for guitars isn't published most times, so you have to find it out for yourself and each speaker can vary bigtime!). But this tends to tailor only the bottom, as the mids are pretty complex and can vary tremendously with the type of wood and finish used. So it's a crummy route to go other than for bass.
> 
> ...


Thanks Gregg...I'm so impresed with my new (used) closed back cab that I want to try "your" concept of semi-open with my pine cab (also.... it has he Weber AlNiCo in it....smooth and warm ....like a good single malt Scotch)

Cheers

Dave


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## RIFF WRATH (Jan 22, 2007)

The closed back cabinet Greco (Dave) is referring to originally held 5 small plastic tweeter horns across the top and one large horn in the center. It was initially designed to have a flat bottom and top, with the sides tapering from front to the back, with a bowed top edge and bottom edge. We tipped it on its side which gives the cab a tilt back (and of course) the top is tilted back. This gives the speaker it's own unique look and gives the visual impression of "projection". the cab was ported with a port from another older sterio speaker, giving the option of using as a 1X12 bass bin.......the cab itself is 3/4" thick , what I call "sawdust board", covered with a black felt like material. After reading a bunch of stuff about building sterio speakers, yellow, 1" insulation was stapled on the inside sides, top & bottom.....Perforated black painted steel is used for the front and is "bowed" from top to bottom to follow the cab's bow...3/8 rough ply for the baffle...Dave, what speaker did you put in it...........still haven't finished the other "matching" 1X12.........
cheers
Gerry


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## greco (Jul 15, 2007)

Thanks for all the info Gerry...you did a great job in converting the cab.:bow:

I have tried 2 speakers in the cab...both are Fender replacement speakers (made by Eminence for Fender..so I am informed). At present, it has the ceramic version in it. This speaker is an old one that is well broken in.

I have been comparing the cab in both the "upright" (speaker is angled up by 15 degrees) and "long side down" (speaker is not at an angle) ...I tend to like the tone from the non-angled position (plus my BandMaster head sits nicely across the top)

There certainly is no shortage of bass from the cab!!

I wanted to ask you what type of insulation material you used and where you bought it (QComponents ??)

Cheers 

Dave

PS The sweetgrass is still fragrant


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## Milkman (Feb 2, 2006)

As a player I prefer closed backs.

As a sound man I prefer them even more.


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## RIFF WRATH (Jan 22, 2007)

Hey Milkman (Mike)........that 4X12 I got from you was closed back, and insulated ...........I currently have one set of 2X12's and two single 1X12's installed.........I put a 4"x4" open grille in the back, under the insulation, hasn't seen much use but in my opinion, I prefer the closed back sound.........I think that having extra cubic volume of space is important though...It's running G25's & vintage 30's
cheers
Gerry


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## Milkman (Feb 2, 2006)

RIFF WRATH said:


> Hey Milkman (Mike)........that 4X12 I got from you was closed back, and insulated ...........I currently have one set of 2X12's and two single 1X12's installed.........I put a 4"x4" open grille in the back, under the insulation, hasn't seen much use but in my opinion, I prefer the closed back sound.........I think that having extra cubic volume of space is important though...It's running G25's & vintage 30's
> cheers
> Gerry


Glad it's being used. It was collecting dust at my place.

I like the tighter bottom end response with closed back cabs and also the fact that the sound is more controlled. That's why I said I prefer them even more as a soundman. Open backed amps shoot sound everywhere and are a little more of a problem in terms of bleeding into other mics for that reason. If you're not mic'ing them I suppose it's nice to have the extra dispersion.


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## Buzz (May 15, 2008)

I've got an awesome JBL d130f 15" speaker that I have in a smallish closed back, homemade cabinet with no port holes. Should I put holes in the front? 

I've tried this speaker in an open back Garnet combo and it was very good, but I think I'd like to keep it in a closed back cab.


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## greco (Jul 15, 2007)

Buzz said:


> I've got an awesome JBL d130f 15" speaker that I have in a smallish closed back, homemade cabinet with no port holes. Should I put holes in the front?
> 
> I've tried this speaker in an open back Garnet combo and it was very good, but I think I'd like to keep it in a closed back cab.


I hope someone responds to this, as I'm curious as to what will be suggested.

The port in my cab is actually a plastic tube with a flange on the front. At a rough guess, the inside of the tube is about 3 inches in diameter and the tube is about 4 or 5 inches long.

Cheers

Dave


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## Geek (Jun 5, 2007)

Hi,

Closed backs work best when they are BIG. Especially for a 15" speaker.

Tuning a small closed back tends to make it sound like a HiFi speaker :-\

Cheers!


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## ssdeluxe (Mar 29, 2007)

its an interesting poll, for me not one is better than the other, open backs are gr8t for spreading the sound, and a closed marsh. 4x12 has its own tone that cannot be duplicated and equally as cool. depends on application.

good canadian answer.:smilie_flagge17:

ohh...the 15 thing, I think that would be way too thumpy for closed back, maybe for bass would be cool (ala ampeg b15)
but having a carr 1x15 open back blackface style amp (slant 6v), that thing sounded unreal good,,, for gtr, I would recommend a 1x15 in an oversized open back cab.


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## Bevo (Nov 24, 2006)

To the porting question..

You need to find the specs of the speaker or talk to the manufacture. The speaker is made to fit in a certain size cab, think of the cone moving back and not enough air to compress..wont move right..too loose and no control..
Ports are the same, the length and size are adjusted to a Tuned freq, depending on the speaker and cab..

So lots of info, do a bit of work on the net and see what you come up with.. If its a home made cab have some fun, buy a 3 inch PVC tube about a foot long and stick it in. Keep cutting it down till it sounds good, if you go to far its a cheap fix..

Have fun
Bev


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## Buzz (May 15, 2008)

Thanks for the tip Bevo. I think I'm going to build myself a new cab. The homeade cab for the JBL is probably too small. That speaker packs alot of :sport-smiley-002:.


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## Bevo (Nov 24, 2006)

Found this site that helps size the box once you have the speaker specs, more car audio related but still applys.

http://www.bcae1.com/spboxnew2.htm

http://www.gear-vault.com/understanding-speaker-cabinet-designs/
Good read..

Bev


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## Wild Bill (May 3, 2006)

Just thought I'd toss in a couple of points.

First off, there's a lot of talk about ports and port area with different speakers, along with cabinet volume. It's important to understand that this means diddley with regular guitar speakers!

T/S, cone resonance, etc. is all about extending the bottom end of a speaker system, which consists of a speaker in a box. A regular guitar has a bottom point of about 100 hz. At that frequency and higher pretty well any speaker you're going to use will handle the range just fine. The cab is just a frame to hold the speaker(s). It will make a difference whether it's got an open or closed back but that's about it.

Bass cabs, hifi cabs and PA cabs are different. They are asked to deliver at bass frequencies much lower than that of a guitar. Ports, ducts and stuff are methods of extending that lower range smoothly. If you google up some hifi DIY speaker sites you will find the formulae for calculating port area. Most speaker manufacturers like Eminence will give you the necessary speaker specs. 

High frequencies are never a problem. Any guitar speaker will cover the entire range of a guitar by itself. Hifi and PA can mount some horns. The wavelengths involved are so much shorter that you don't need any porting. Bass guitars don't need horns at all but some manufacturers put them in as "mojo" appeal. They make you feel better, I guess.

Last, it's important to remember that not every speaker will work fine in both open and closed back cabs! One of my customers put an Eminence speaker in an open back combo and it literally shredded, despite being over-rated for power! He had chosen a model specifically designed for closed back applications ONLY! With no back pressure, that poor cone was driven back far harder than it could take. It ended up like a flag that had been left on the flag pole all winter. The info was right there in the Eminence catalogue and on the website. Next time he'll look!

As the computer geeks say, "RTM!" (Read the Manual!)

:food-smiley-004:


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## Bevo (Nov 24, 2006)

Bill

That was great, thanks for the info. I was always told to size the speaker to the cab , guitar or other. The movement and frequency response obviously was not taken into account.

Question, why does a sealed smaller enclosure sound tighter than a larger closed back..same gear driving it?
I would say speaker dampening.

Thanks
Bev


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## mcgriff420 (Sep 30, 2008)

If a live sound guy has any trouble running your sound because you have a open vs. a closed back cab there are one of three things happening..

1) Your playing so loud onstage the ambient sound is blasting through the club too much to be controled by the FOH

2) The 'sound guy' is actualy a frustrated guitar player (who probably spends too much time on gear forums) and insist's on the guitar being front row center.

3) He/She has decided that an in ear monitor/amps off the stage approach is the best 'easiest' way to mix sound..(just cause the networks do it doesn't mean it's good..)


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