Altec 828/825 cabinet

[hifiapart]

Hi,

Could anybody provide some information on the size of the ports/vents on the 828 or 825 boxes. When I run WinISD (pro version) with the Thiele parameters for the 416-8a or for the 515b and use in that was the port size on the official plans it gives some strange results.

The ports on the 828/825 are big, guidance will be appreciated.

[Goodwill_HiFi]

I've heard 75 square inches works well.

[spkrman57]

But the VOTT cabs were horn loaded to 160hz and reflex loaded to 50hz at BEST!

The cabinet/system is a hybrid of a bass reflex/front horn-loaded that would be approx 6db down at the horn flare frequency.

I would say the A-7/VOTT cabs were down -6db @ 120hz and were most efficient in the midrange/lower midrange as designed for Cinema use behind perforated screeens.

Later versions were EQ'd, but these speaker systems were excellent at what they were desiged for in the 1st place, which was theater sound reproduction, mainly in the vocal range.

My 2 cents worth!

Regards, Ron

[Marc]

Does anyone have some accurate 828/plans? I have a few versions but there seems to be some descepencies in all of them.

Some have Datto joints some don't

There also seems to be a 1/4 inch difference in external sizing. as well as 1/32 of inch in horn radious. as well as Joint construction and bracing.

Looking for some Printable accurate blueprints if possible

I have one set that had the top mounted over the sides and the bottom with the sides over the bottom.

thanks