Bergantino offset speaker placement

[Justybuddy]

Hey guys,

I remember reading a thread while ago about the reasoning behind the offset speaker placement in Bergantino cabs, and its advantage over traditional cabs with their parallel and perpendicular speakers.

I haven't been able to find the thread...does anybody know where that would be, or the reasoning for the Bergantino design? Thanks!

[Mr. Foxen]

Offset means they fit in a different shaped cab. Being off the centerline gives a better dispersion pattern

[Justybuddy]

Do you know where any stats on the subject could be found?

[Mr. Foxen]

Look up 'baffle step'.

[Justybuddy]

There is a lot of interesting information to be found on the subject of the baffle step, which I would like to familiarize myself with, but I'm still not finding what I'm looking for. There was a specific article or conversation that I had read, which I believe was written by Jim Bergantio describing his reasons for the speaker offset which is found in all of his cabinets, with the exception of the 410...as far as I know. The article was talking about the 'classic' cab designs such as the 410, 610 and 810 and how the design was sonically flawed...for some reason...and the reasons why speakers being off the center line solves that sonic...irregularity of sorts.

[Forrrest]

any multiple driver system will result in comb filtering caused by phase cancellation (a ratio of distance between speakers to frequency half cycles). the trick is to not to re-enforce these holes by layering the same combs (ie using the same speaker distances between each speaker). So ANY symmetrical speaker layout (NV412 is guilty too, but less i guess) emphasizes the flaw. Wouldn't the ideal speaker layout be one where no speaker distances are ever equal?


Edit for fun, i wrote this out, so might as well post it:

4X12 in square formation
|AB|
|CD|
AB center cone distance 12"
AC center cone distance 12"
AD center cone distance 17"
BC center cone distance 17"
BD center cone distance 12"
CD center cone distance 12"
4X comb caused by 12" distance
2X comb caused by 17" distance


4X12 in offset formation (like the berg 4X12)
|A |
| B|
|C |
| D|
AB center cone distance 12"
AC center cone distance 14"
AD center cone distance 23"
BC center cone distance 12"
BD center cone distance 14"
CD center cone distance 12"
3X comb caused by 12" distance
2X comb caused by 14" distance
1X comb caused by 23" distance

i do not know of this post Jim made, but i'd like to read it as well.

[kringle77]

In practical use, the only advantage of the staggar is to get the drivers closer to your ear. In any meaningful way, other than that, there is no advantage. I've owned all the berg staggard cabs except 2 and MANY 4x10's. There is no real difference. When all drivers are in a vertical columb, you will hear a difference. There have been several threads on this.

[Forrrest]

yeah vertical cabs are probably the worse because the combs will overlap due to the equal ratio of the distances

|A|
|B|
|C|
|D|
AB center cone distance 12"
AC center cone distance 24"
AD center cone distance 36"
BC center cone distance 12"
BD center cone distance 24"
CD center cone distance 12"
3X comb caused by 12" distance
2X comb caused by 24" distance
1X comb caused by 36" distance

[KJung]

I think the offset helps just a little with beaming in that relatively small slice of upper midrange up until the tweeter kicks in (basically half way between 'side by side' and 'pure vertical), and allows for a VERY nice form factor... wide enough for a full size head, and very shallow front to back.

The upper midrange beaming, IMO is quite overstated on this site (once you get to 'audience distance' from the cab, the beam has spread quite a bit, if you look at the plots... mostly a near field issue anyway, at least with bass guitar). Jim's vertical offset 212's and 210's sound good and even both straight on and moderately off axis (given his lower than typical tweeter crossover). Zero issue for me.

Very nice boxes. Since EVERY speaker design is a compromise, I view Jim's form factor and voicing as close to the best balance of great tone, size, form factor and acoustical science.

[Bass_Pounder]

Originally Posted by Forrrest

yeah vertical cabs are probably the worse because the combs will overlap due to the equal ratio of the distances

Nope............

Why do you think all the best modern PA's are vertical arrays.

[Forrrest]

The modern vertical PA's line arrays use speakers designed for poor vertical dispersion. They also use phase compensation technology. This isn't technology in the realm of the passive bass cabs that we're talking about here.

[Bass_Pounder]

Originally Posted by Forrrest

The modern vertical PA's line arrays use speakers designed for poor vertical dispersion. They also use phase compensation technology. This isn't technology in the realm of the passive bass cabs that we're talking about here.

Really.........

Then why do all the speaker builders and engineers recommend a vertical bass stack for LESS comb filtering and better dispersion ?

[Arjank]

Originally Posted by Bass_Pounder

Really.........

Then why do all the speaker builders and engineers recommend a vertical bass stack for LESS comb filtering and better dispersion ?

E.g. when stacking two regular 210's vertically instead of horizontal you get less comb filtering in the horizontal plane, but the system starts to act(from a certain frequency on) as a line array in the vertical plane (thus more comb filtering in the vertical plane).

[JimmyM]

Originally Posted by Forrrest

The modern vertical PA's line arrays use speakers designed for poor vertical dispersion. They also use phase compensation technology. This isn't technology in the realm of the passive bass cabs that we're talking about here.

They don't use phase compensation to give PA's better dispersion. They use it to combat phasing issues. Sorry, but you are completely wrong about vertical arrays not being better for dispersion of highs and mids. I've heard it with my own ears. It's better dispersion every time.

Now, to change the subject and belabor Ken's point, is dispersion of highs all that important? To some it is, and that's cool. To me, not so much. Not a big treble guy, and any time I don't have a PA for bass, my rig sounds exactly like what I want it to sound like in the house. I have a double 210 vertical stack that has pretty good dispersion, but when I run a cab rig where the dispersion up high gets reduced due to beaming, it still has plenty of treble for my tastes and no problem with the high mids. So I don't sweat beaming.

[JimmyM]

Originally Posted by Arjank

E.g. when stacking two regular 210's vertically instead of horizontal you get less comb filtering in the horizontal plane, but the system starts to act(from a certain frequency on) as a line array in the vertical plane (thus more comb filtering in the vertical plane).

Guess you better not climb ladders when you're listening to a concert

[mystic38]

a vertical array allows for the best possible horizontal dispersion.. vertical however is another matter..

[JimmyM]

But my little joke above your post was a way of saying that vertical comb filtering isn't near as annoying as horizontal since most of us aren't climbing ladders during a show.

[chadds]

Originally Posted by JimmyM

But my little joke above your post was a way of saying that vertical comb filtering isn't near as annoying as horizontal since most of us aren't climbing ladders during a show.