Oversized cabs

[MichaelDean]

I had a thought after something Zilla posted on their socials - a massive 212 that is the size of an 810. Looks impressive, but I have found my bass fatboy loud enough for everything I've thrown at it so far.

 

I know that you want to have a big enclosure for bass speakers. I was just curious if there was a point at which an enclosure is too big?

 

https://www.instagram.com/p/DD9Sf6VIGzo/?img_index=1

[Bill Fitzmaurice]

Not necessarily too big, but there is a point of diminishing returns. Where a 2x12 is concerned they went well past it.

Edited January 3 by Bill Fitzmaurice

[ossyrocks]

I’ve had a couple of the old silverface Fender Bandmaster 2x12 cabs. Ridiculous things really, like a wardrobe onstage,  looked impressive, but sounded a bit meh.

[Bill Fitzmaurice]

I remember when those came out. They were considerably larger than the original Bandmaster and Bassman 2x12 cabs, nearly large enough to have housed four twelves. They were crap, but so were the smaller ones, because the stock drivers they used were cheap generic electric instrument drivers. Loaded with Altecs or JBLs they were pretty good.

[Dan Dare]

On 03/01/2025 at 13:00, Bill Fitzmaurice said:

I remember when those came out. They were considerably larger than the original Bandmaster and Bassman 2x12 cabs, nearly large enough to have housed four twelves. They were crap, but so were the smaller ones, because the stock drivers they used were cheap generic electric instrument drivers. Loaded with Altecs or JBLs they were pretty good.

 

In similar vein, I had the 2x15 Bassman cab back in the day. Awful stock drivers - flimsy pressed steel chassis, tiny magnets and seamed cones made of what looked like recycled greetings cards painted grey. I replaced them with Peavey Black Widows (which were the best I could get in the UK at the time) and it sounded great. Didn't know anything about matching cab volume to drivers, etc, but I must  have got lucky as it worked really well.

[Bill Fitzmaurice]

Back in Leo's day his stock drivers were whichever he could get the best price on, so they changed from year to year, if not more often. He used the same in both guitar and bass cabs. That didn't change when CBS took over. You had to pay extra for JBL to get decent results. Peavey's upscale Black Widows, which were similar to JBL,were pretty good. 

[BogeyBass]

Too big would depend on the Speaker. Flattest Delay or Critical damping for a live sound speaker can become incredible large.

Rarely used for live sound equipment. Musicians want small boxes and high SPL.

High SPL it is typical to reach distortion faster in too large of box.

Critically damping boxes rarely seen even in home HiFi use. But high sensitivity systems for home use is likely a more logical use for them.

 

Looks like the form factor of that speaker is tall and wide. So size appears Massive

Less depth, depends on the driver. Might not be too big technically for what is in there.

 

It sits higher to ear level and has a little slant. Good for hearing things on stage. When it is typical for " portable" sizes

to sit to low on stage. 

Agree though somewhat for high SPL and a tall form factor, might as well be 4x12.

Includes typical trade offs though of boxes too small for the speaker.

Wider baffle can have its benefit in a world of little guys, and endless EQ to fix itsy bitsy baffle responses.

Edited January 12 by BogeyBass

[Bill Fitzmaurice]

A critically damped sealed box, which is to say Qtc of 0.5, is going to be very large. But as it's a sealed speaker it's not going to have high sensitivity at low frequencies, which explains why they're seldom used even in home theater.

[Phil Starr]

Without going into the maths the bigger the box the more bass you get from any given speaker. This isn't just offset by the additional problem of transporting something big and heavy; the 'wrong' sized box brings problems withgettinga flat response. Typically an over large box gives a droop in the bass response and is difficult to make flat, a too small from ideal cab will have a much higher resonance and less deep bassbut will give some bass boost around this raised resonant frequency. This happens with all cone speakers and in both reflex (ported) cabs and sealed cabs though the details differ.

 

These are the calculated bass responses of a 10" bass driver in a 40l cab (blue) 20l cab (green) and a 5l cab (red). The medium sized cab in green gives the flattest response and a practical size. The red cab is way too small and -3db (the lower dotted line ) is 150Hz ish way to high to be useful. The large cab in blue has the response gradually falling from 500Hz and clearly isn't flat but crosses the -3db line way lower than the smaller cabs.

 

Generally speaking cheap speakers with weaker magnets work better in huge boxes. A lot of old cabs tend to be large because speaker magnets in the day were weaker and powerful magnet systems were extremely expensive. Cheaper manufacture and better manetic materials have allowed box sizes to be reduced but big old boxes can still be fun and have a sound of their own.

 

[bremen]

8 hours ago, Phil Starr said:

Without going into the maths the bigger the box the more bass you get from any given speaker. This isn't just offset by the additional problem of transporting something big and heavy; the 'wrong' sized box brings problems withgettinga flat response. Typically an over large box gives a droop in the bass response and is difficult to make flat, a too small from ideal cab will have a much higher resonance and less deep bassbut will give some bass boost around this raised resonant frequency. This happens with all cone speakers and in both reflex (ported) cabs and sealed cabs though the details differ.

 

These are the calculated bass responses of a 10" bass driver in a 40l cab (blue) 20l cab (green) and a 5l cab (red). The medium sized cab in green gives the flattest response and a practical size. The red cab is way too small and -3db (the lower dotted line ) is 150Hz ish way to high to be useful. The large cab in blue has the response gradually falling from 500Hz and clearly isn't flat but crosses the -3db line way lower than the smaller cabs.

 

Generally speaking cheap speakers with weaker magnets work better in huge boxes. A lot of old cabs tend to be large because speaker magnets in the day were weaker and powerful magnet systems were extremely expensive. Cheaper manufacture and better manetic materials have allowed box sizes to be reduced but big old boxes can still be fun and have a sound of their own.

 

Let's see the cone excursion vs frequency of those three examples.  I predict the 40 litre box will have less usable bass than the 20 as the driver begins to tear itself apart around 80Hz ...

[Phil Starr]

6 hours ago, bremen said:

Let's see the cone excursion vs frequency of those three examples.  I predict the 40 litre box will have less usable bass than the 20 as the driver begins to tear itself apart around 80Hz ...

I didn't save the simulations but you are of course correct, excursion is greater in a larger cab, directly in proportion to the extra bass.

 

I think 'tears itself apart' might be a little too strong The power handling is reduced might be a bit fairer and of course this is true universally for all speakers in over-sized cabs. The thermal power ratings remain the same of course and since we haven't specified an amp or what the signal looks like the speaker might be perfectly happy. The actual reduction in power handling is dependent upon the mechanics of the speaker itself too and may or may not be significant. I was aiming for something simple to understand without saying anything that wasn't misleading. The truth but not the whole truth maybe

Edited January 13 by Phil Starr