Guitar speaker cabinets can either be open back (where a section/ panel of the back is removed), or closed back (where the back of the cab is solid). This changes the sound of the amp. Sometimes closed back cabs are more suitable, and sometimes open back cabs are the better option.
In this article I’ll explain the differences between open and closed back cabs, and their pros and cons so you can decide which is the best type for you.
Here’s the quick answer.
Open back cabinets sound more mellow and fill the room more because sound comes out of the front and back of the cab. Closed back cabinets on the other hand sound more tight and focused, and have more bass response making them popular for genres like metal.
Open back cabinets sound more natural and open compared to closed back cabinets which sound tighter and more focused.
- Open back cabinets sound more crisp, present and aggressive
- Closed back cabinets sound more mellow and loose
Check out this YouTube video to hear a comparison of open and closed back cabs.
More or Less Bass?
Speakers work by pushing air out to create sound waves. In order to push air out, the speaker must first pull air in. With a closed back cabinet, the speaker cannot pull as much air in, and consequently can’t push as much air out. With an open back cabinet, there is much more air available for the speaker to pull in (and then push out).
This would suggest that open back cabinets have more low-end, however this is not the whole story and in fact it’s open back cabinets which have more bass response.
This is because open back cabinets result in phase cancellation, where the sound waves coming out of the front and back of the cabinet mingle and cancel out some of the bass response. With closed back cabs, this phase cancellation doesn’t occur.
Music Style Suitability
It probably goes without saying that tone is a personal preference, and there aren’t any hard and fast rules here. However, there are general trends that I think are worth pointing out.
- Closed back cabinets are often preferred for rock and metal because they have a tight and focused sound
- Open back cabinets are often preferred for blues as they have a more natural and warmer sound
The reason that closed back cabinets are preferred for metal in particular is because they sound much tighter, so you don’t get any flabby low-end detracting from the aggressive tone. You also don’t get any of that phase cancellation that I mentioned in the section above, so you get more bass response.
On the other hand, open back cabinets do sound much more natural which is preferred for a lot of genres including blues and rock ‘n’ roll.
Best for Gigging?
When playing with a live band, open back cabinet it’s hard to control the sound dispersion and it varies considerably depending on how far the cab is from the wall and the drummer. The sound from the guitar amp can spill into the drummer’s microphone, making it hard for the sound engineer to control.
With a closed back cabinet, the sound is more directional because it can’t bleed out of the back of the cabinet. This makes it much easier to control the volume and means it will all be focused towards the crowd.
Even with that said, some guitarists prefer the sound of an open back cabinet in a live setting as it can fill the room more, and makes it easier for the drummer to hear them.
The drawback of a closed back cab in a live setting is that it can actually be too focused, and can sound different if you’re stood in different areas of the crowd.
Benefit of Open Back Cabinets
The first guitar cabinets had open backs because they were combo amps and there needed to be ventilation for the tubes inside the amp, otherwise they risked overheating. This is why pretty much every tube (valve) combo amp on the market has an open back cabinet.
With solid state combo amps this isn’t as much of a concern as there is less risk of overheating, so you will see many more closed back cabinets.
Check out my comparison between 1×12 and 2×2 cabinets.