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The parts of my new Altecs

So is there a huge difference having the ports by the horns or cut in the cabinets next to the woofers?
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I'm not sure i'd call it a huge difference, but the ports are certainly the more scientifically refined method and would offer much more precise tuning.

I've wondered about the vents at the sides of the horn causing modulation effects in the HF, but this is probably negligable.

The ported baffle with solidly mounted horn just seems that it would lend itself to better overall structural integrity and be the more logical design.
 
You'd think after owning so many, I'd have it down pat.
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Naaaaaaaaaa, i have to have examples sitting here in front of me to keep it all straight usually.

Of course the other thing about vintage Altec is that there seems to be at least one exception to every rule.
 
That's something I have to work with too as my Milano's have the porting along side the horns. I'll eventually rebuild a new baffle for them if it's easy enough to get the old one out. Then, I'll port them next to the woofers like the Valencias and seal off the area around the horns or make a new baffle for them.

We'll have to measure the internal volume and give those #'s to Zilch or someone that can run them for optimum tuning. It will have to take into account the displacement for the horn and the woofer but he/they may alread know that part.
 
The software automatically deducts for the woofer volume (you even set whether it's front, flush, or rear mounted,) and we know Altec's published displacements of the horns and compression drivers, which are separately deducted.

Key to computing the internal volume precisely is that it is the sum of two different sections, the one behind the horn being of shallower depth, as the horn is recessed. Measure from the rear of the horn mounting flange, as the "ports" at the sides are not part of the internal volume.

We've already done this once for Valencia, but verifying it independently will serve to narrow down a precise determination in which we can all have confidence. You guys get your numbers, and then I'll link you to that previous work and the Altec specs for comparison. :yes:
 
spartanmanor said:
So if I go the ported baffle method what makes up the structure of the tube? and what is its width? and length?
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Manufacturers typically use cardboard tubes, like mailing tubes, and DIYers scrounge up everything from carpet roll cores to food, booze, and toilet-bowl cleaner cans. :p:

My recommended material is black ABS pipe, readily available inexpensively in short lengths (3 ft.) at Home Depot and simiilar in 2", 3" and 4" diameters. Standard hole saws matching the outside diameters of these are also available. For fine tuning the bass, you simply make several sets of the tubes of varying length, say, +/- 1/2" of the "guideline" value provided by the software. BB6P usually generates suggested lengths that result in tunings lower than the target, so it's just a matter of shortening the ducts to get spot on the target tuning.

An elegant way of installing the ports for those with the tools and skills to accomplish it is a hole the size of the inside diameter (the nominal 2, 3, or 4 inches) of the tube with a counterbore that of the outside diameter on the inside of the baffle into which the tube is inserted and ultimately secured, once the desired tuning is achieved.

Flared ducts and duct kits are available from Parts Express and others, but the calculations and lengths are a bit different for those. Generally speaking, I find them flimsy in comparison to the black ABS pipe. I guess I'm "old school" when it comes to ducted ports, and usually have a selection of lengths and diameters at the ready for whatever box tuning project might come along.... :thmbsp:
 
I've used 1/4" wall PVC in the past with good results, too. The main thing I did to the PVC was to give the inside edges a roundover to help control any noise coming off a flat edge...just in case.
 
Zilch said:
Manufacturers typically use cardboard tubes, like mailing tubes, and DIYers scrounge up everything from carpet roll cores to food, booze, and toilet-bowl cleaner cans. :p:

My recommended material is black ABS pipe, readily available inexpensively in short lengths (3 ft.) at Home Depot and simiilar in 2", 3" and 4" diameters. Standard hole saws matching the outside diameters of these are also available. For fine tuning the bass, you simply make several sets of the tubes of varying length, say, +/- 1/2" of the "guideline" value provided by the software. BB6P usually generates suggested lengths that result in tunings lower than the target, so it's just a matter of shortening the ducts to get spot on the target tuning.

An elegant way of installing the ports for those with the tools and skills to accomplish it is a hole the size of the inside diameter (the nominal 2, 3, or 4 inches) of the tube with a counterbore that of the outside diameter on the inside of the baffle into which the tube is inserted and ultimately secured, once the desired tuning is achieved.

Flared ducts and duct kits are available from Parts Express and others, but the calculations and lengths are different for those. Generally speaking, I find them flimsy in comparison to the black ABS pipe. I guess I'm "old school" when it comes to ducted ports, and usually have a selection of lengths and diameters at the ready for whatever box tuning project might come along.... :thmbsp:
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Good tips. The ones that were in there were made with Maxwell House coffee cans and loads of silicon caulk. PITA to remove.
 
avguytx said:
I've used 1/4" wall PVC in the past with good results, too. The main thing I did to the PVC was to give the inside edges a roundover to help control any noise coming off a flat edge...just in case.
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Yes, and the front opening can be radiused with a router, too. The counterbore in the rear installation method lends itself well to this, for those who have the requisite tools to add the flare.... :yes:
 
spartanmanor said:
Ok, I have one in front of me to take the measurements. Do I just open her up and measuer the height, width and depth?
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Yup, inside dimensions, but mind that the section behind the horn is shallower in depth.

Measure to the nearest 1/16", if possible.... :thmbsp:
 
Zilch said:
The software automatically deducts for the woofer volume (you even set whether it's front, flush, or rear mounted,) and we know Altec's published displacements of the horns and compression drivers, which are separately deducted.

Key to computing the internal volume precisely is that it is the sum of two different sections, the one behind the horn being of shallower depth, as the horn is recessed. Measure from the rear of the horn mounting flange, as the "ports" at the sides are not part of the internal volume.

We've already done this once for Valencia, but verifying it independently will serve to narrow down a precise determination in which we can all have confidence. You guys get your numbers, and then I'll link you to that previous work and the Altec specs for comparison. :yes:
Click to expand...

Internal dimensions of the Milano's are:

24 1/8" width
27 3/4" height
14 7/8" depth

Which comes out to 5.76 ft3 of air space less driver displacements and various little blocks, etc.
 
avguytx said:
Internal dimensions of the Milano's are:

24 1/8" width
27 3/4" height
14 7/8" depth

Which comes out to 5.76 ft3 of air space less driver displacements.
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Big boxes, huh?

I'll look up what we previously calculated for Valencias. I was reading that last night, but did the Zilchster bookmark it?

NOOOOOoooo.... :p:

Edit: Heh. Post #632, of course:

http://audioheritage.org/vbulletin/showthread.php?p=163004&#post163004

Measurements by LHF member VTUBE6 on the previous page, including factory stock 846B port dimensions.... :thmbsp:
 
avguytx said:
You would think that the internal volumes would be identical seeing as they are basically the same speakers overall.
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:lmao:

I'm gonna have to make a spreadsheet now.

We have three sets of dimensions plus the factory drawings and specs.

Somewhere between 5.25 and 5.75 cuft, looks like.

[Love this stuff.... ;) ]
 
It's giving you a woody, isn't it? :D

Hell, it does the same for me. Makes it tough when you work at home (when I'm not traveling) and I have all these "toys" in the house!

Ok. I'm out to the garage to cut some 1/4" MDF down to size for holding the new banana jacks I'm putting on the Milano's in place of those cheesy stock ones.
 
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