What would you do with a pairs of 416 ?

Hello everybody !

I m Corsican and English is not my langage but i try to be better.

I m passionate by Altec sound.

I have one pair of Altec 416-8C and a pair of GPA 416-8B. I would like to leasten to all 4 in the same time.

But i dont Know the best Way for.

Actually i use just one pair in 2 little Onken. With 2 Altec 902-8T and 2 tweeter Fostex T90A.
All drive by a Mcintosh mc275v6 and a McIntosh D100 preamp/dac (numeric music).

In your opinion, in what can i put my 4 416 for use it in optimal conditions ?
2 little onken more ? 817 ? 4 big onken ? Others ? I dont know every possibilities
..

Thank you for reading,

Amicaly

Hi Karlanza,

Welcome to the Lansing Heritage. Here are some quick thoughts.

The Altec 416-8C is described as a 16" with 16"frame, while the GPA 416-8B is said to be a 15" but has a 16" frame measurement, and the baffle opening is the same for both...

The two pairs of woofers are not the same. So unlikely you could mix them optimally in the same cabinet with their different parameters.

I think you need two pairs of boxes according to each type. The boxes could be one pair for horn loading and the other pair being vented box, or both vented, but not both horn loaded.

The 416-8C was specified by Altec for horn loading in the 817 and others, however i have not seen GPA specifing the 416-8B for horn loading, in fact the examples they give are vented box. Moreover, the Qts parameter of the GPA driver is notably higher than one usually sees in horn loading cabs. All this assuming your woofers are correct.

So to play all four at the same time with "comparable" response or sound you'd need to go with four vented boxes. But its tempting to also suggest why not going with a pair of horns (816A single woofer, cabs may be stacked if need be) and a pair of vented cabs to have diversity at your disposal.

The horn cabs would have the lower power rating driver (416-8C) but the higher efficiency/sensitivity, and the vented boxes would house the GPA woofers with their higher power handling. These two types won't sound the same, then its your call to decide if you prefer having more of the same or similar vs variety in LF sound...

Richard

Thank you si much Richard.

Please can you give me examples of « horn loadîng » and « vented box » ?

because i m not really sure i understand.

You Said if i understand, for exemple, i can put the 416-8C in a 816 or a box with horn ? And the 416-8B in a box without Horn like my Onken ?

thank you again !

Pierre

Ok, lets make this simple for you.

Altec 816A and 817A/B are front horn loaded cabinets. To explain this simply think of some sort of a megaphone at the front of the box: the curved sides along with the top and bottom make a horn. Another way of seeing this: when you put your hands around your mouth to scream someone's name at a far distance you're basically making a primitive horn with your hands. This reduces mouth sound dispersion in order to get increased distance or reach. As a result directivity is increased (more focused sound) as well as sensitivity.

Look at the attached Altec 817 tech sheet this is a horn loaded box, but this one also having a vented box aspect (vent) for lower frequencies. So here woofer cone front wave is horn loaded while the back wave of cone is treated as a vented box to get somewhat deeper bass.

I cannot show the Altec 816A horn loaded tech sheet here because file size i have is too large (almost 3 MB) to post on this site. If you need it give me an e-mail address and i'll send you the 816A document.

A vented box is a sealed box with one or more hole(s) in it (the vent) that tunes the cabinet to a specific frequency.

RE i can put the 416-8C in a 816 or a box with horn ?

Yes you can put the 8C in a 816A cab because it is SPECIFIED by Altec, NOT just in any box with a horn.

RE And the 416-8B in a box without Horn

A box without horn is too vague, it can be anything: vented, sealed, transmission line, etc. I suggest, like the GPA examples, a vented box, i.e. one with a vent, for its higher efficiency and lower distortion. One GPA e.g. is 6 cu.ft., tuned to 29 hz.

Richard

Attachment 90444


JBL L100 Century pic, example top right on the picture is the vent hole to tune the cab

Attachment 90445

Thank you again Richard,

Ok i think i understand.

I have a friend who have 2 box Altec 816 i will try with when i will be in my New home.

My box for GPA will be this : https://enceintesetmusiques.com/foru...t-comment-9710

If you think is not good can you give me a good example of good box ? And if i understand you say than 4 box 816 will be ok too ?

Thanks !!

http://www.audioheritage.org/vbullet...4-5321328f8c79

Pierre,

RE And if i understand you say than 4 box 816 will be ok too ?

NO, you don't have the drivers to make 4 X 816 boxes. Only the 416-8C pair can go in the 816 cabinets. The GPA 416-8B pair, not mentioned for horn use, is more suitable for vented (or even sealed) boxes loading.

There's some issues i see with the box plans you refer to following my quick look.

With the 25mm particle board the box weight is given at 92 kg, that's over 200 LBS! good luck to move this around

There is no sideways or front to back braces seen for a box this size its somewhat too optimistic re cab vibrations

Moreover the 35 mm wide braces, possibly pine as indicated, is not enough. I don't know in Europe but in Canada pine is not a harwood, in fact its one of the softess lumber available, it doesn't have high density or rigidity.

Your plans show long and narrow slot vents. These should be avoided since they don't behave like round or rectangular vents for example. Vent proportions are key here and those don't seem to meet Altec requirements: maximum 5 to 1 ratio (length vs width).

JBL has a similar note that slot vents should not have extreme proportions. Weems explains why: "A narrow slot can have a different tuning frequency from a round or square port of the same area and length, so such extreme variations should be avoided..." (P.53) Then he mentions an adjustment to the port length (to compensate)

Personnaly i would not use the cabinet plans you show even if it looks appealing.

For the GPA driver you might want to use the Altec 612 vented box plans or similar. I calculated your plan box internal volume at 6.4 cu. ft. and the Altec 612 is given at 6.5 cu.ft. net so pretty much the same box volume.

Using 19 mm 7-ply fir plywood would be sufficient with proper bracing, and make a lighter cabinet to move at about half the weight (based on Altec number).

Richard

Thank you Richard,

i will work on it and search 612 or ébénist 😅