Altec 414

[Barossi]

Hi,

i would like to build a "new" Altec speaker.
I would like to use 2*Altec 414-16 Ohm in parallel for each side.

I am not sure about the right enclosure for that. I will use my Klipsch K-horn for the lower bass (<60 Hz)
So it is not nessesary to build a enclosure for the 414 which is very big and goes down to 40 Hz!

What will be the best enclosure for 2*414 for each side?
IMHO Klein+Hummel build an enclosure (called OZ ???) for 2*414.

I will use the 806a or the 288 K as high frequency driver.....

Greetings Barossi

[Carl Bill]

http://www.thomas-schick.com/Kleinhummel.htm

Is this the enclosure you were refering to?

[Barossi]

Hi,

i found a data sheet of the OZ at:

http://www.klein-hummel.de/produkte/...ml/oz/oz_g.htm

or:

http://www.klein-hummel.de/produkte/...ente/oz/oz.pdf

The enclosure volume is 250 L = 8.83 cubic-foot

IMHO that is way too much. What is your opinion?
I don't need the lowest octave.... 60Hz is enough...

Greetings Barossi

[GM]

Greets!

Hmm, this design will require you to sit at least 40-50 ft away for the sound to 'gell', so not a good design for the home.

Since you use SET amps, what't the output impedance for the one that will drive the 414s as it affects Qts, ergo the 'optimum' cab alignment.

GM

[Barossi]

Hi,
i will drive the Altec 2-way system with a 300B single ended amp. I think the output impedance is ~ 1 ohm.

I will stack the system like on the following photos:







I hope the photos explains my project.
I will build two enclosures for the 414-16 which should be flexible. So i could adjust the angle of the upper enclosure. The driver + horn should added between the enclosures. (D'appolito)

My question is: How small could i build the enclosures for the 414 that they can reach about 60 Hz?

I would like to build sealed enclosures.
The crossover point should be 1000Hz 6-12 dB.
As i wrote before, i will use a Klipsch K-horn for the lowest frequencys <60 Hz. I use an active subwoofer module.

Any suggestions?

Greetings Barossi

[Barossi]

Hi,

yes, exactly, that is the enclosure!
But what could be the volume of the Klein & Hummel OZ?

Greetings Barossi

[Carl Bill]

I would think that you will loose some of the acustic coupling by putting the 414 drivers in two cabinets and separating them with the horn. It may look "cool", but acustically will not be helpfull.

[GM]

Greets!

That's very low for a 300B SET, typically they are ~2.5-4 ohms. 1 ohm on an 8 ohm tap means a damping factor (DF) = 8, so if this doesn't agree with published specs then calc OPR = DF/tap rating, or 8 ohms assuming they will be wired in parallel.

Anyway, if it is accurate, then using measured specs I get a sealed 1.35 ft^3 net/~60 Hz F6 cab without exceeding Xmax, so no real need for a hi-pass filter if a ~60 Hz/2nd order low pass is used.

WRT your layout, for best coherence the 414 cabs will need to be right up against the 511's flange and the drivers right at the edge of the cabs. This puts the horn too low unless spaced up so you'll lose most of the floor boundary gain if it's not ~solid, which will tend to make the finished system look bottom heavy.

GM

[Barossi]

Hi,

yes, you are right. 1 Ohm is way to low. The damping factor should be 3 or less, that means more than 2 Ohms.
I will build an 6 dB filter using a lower couple capacitor between the two stages in my 300B amp.
I will tune the filter to 30-40 Hz (-3dB) IMHO that will give a nice roll off.

Greetings Barossi

[GM]

Greets!

Oops! Wrote the formula backwards: OPR = tap rating/DF, so 8/3 = 2.66 ohms. This increases Vb to 1.85 ft^3/44 Hz F6.

GM