Crossover recommendation 411s & 802s??

[robertbartsch]

OK, I'm trying to build a system comprised of 15" 411s woofers and 1" 802 HF drivers and I need some guidanace on suitible passive crossovers.

I'n not sure I will eventually use the 511 cast aluminum horns which are kinda physicially too wide for my preference but they would probably be the best accustic choice; right? Would the smaller 811s work too?

Anyway, I have a pair of original Altec 800hz crossovers but (i) I'm not sure they are the right x-over frequency for this system, and (ii) they may need new caps.

So which would be the better choice?

1. Use my current Altec 800hz x-over and replace the old caps
2. Buy the correct 500hz Altec x-over and replace the old caps
3. Use a new commerical crossover alternative in 500hz from a speaker vendor
4. Build something from components (e.g., caps and chokes, etc.)


The sensativity of the two drivers is not equal so I will need some from of attenuation; right?

Thx.

[GM]

All the answers are here: 9846-8A

GM

[robertbartsch]

Thx GM:

So you would use the 511 horns and 500hz crossovers and not the 811 horns and 800hz crossovers?

[Panomaniac]

The 9846-8 is a is a proven design, so a shortcut to good sound. Shortcut meaning time and money.... GM really knows his Altec, so he's pointing you in a good direction.

But if you don't want the 511 horns (they are big) then you should be able to use the 811 horns circa 800Hz no big deal. I've done it and it worked well.

Whatever you do, you'll be much better off with a custom crossover than something off the shelf. If you are not up to the task of designing it yourself, many here are.

[GM]

Thx GM:

So you would use the 511 horns and 500hz crossovers and not the 811 horns and 800hz crossovers?

It's why I pointed you to it. Frankly, 250-300 Hz would be my choice with a wide BW single driver in a large conical waveguide (WG). At 800 Hz, the 411 doesn't have enough overlapping BW for the 811 IMO and judging by how poorly the Santiago did in the marketplace, apparently I'm not the only one who was underwhelmed by their performance. Note that you'll need an 800 Hz version of the 9846's contour filter also if you don't design the XO from scratch.

GM

[Art J.]

If you want the most out of a system using a 411, you must deal with
these factors, listed in order of importance.

1 Damping Factor, The 411 with its 4 inch voice coil produces unusually high amount of
Back EMF which must be handled by an amplifier with a high Damping Factor.

2 Crossover no higher than 500hz, second order.

3 Correct size sealed box.

Dealing with number 1, a passive crossover blocks the ability of the amplifier to damp the back-EMF.
In the case of the 411, its critical, it will sound muffled and you will see visible cone bounce.
The subject is dealt with in detail with the link below. Mr. Elliott sure knows how to write.
After reading this, the trade with Marty might seem good, or, Its not really that bad.....................

Active Crossovers Vs. Passive Crossovers

[Brek]

It's why I pointed you to it. Frankly, 250-300 Hz would be my choice with a wide BW single driver in a large conical waveguide (WG). At 800 Hz, the 411 doesn't have enough overlapping BW for the 811 IMO and judging by how poorly the Santiago did in the marketplace, apparently I'm not the only one who was underwhelmed by their performance. Note that you'll need an 800 Hz version of the 9846's contour filter also if you don't design the XO from scratch.

GM

I've been reading for years how poorly the Santiagos play. I bought mine new in 1973 and still enjoy them to this day.Quality electronics is the key. Bad amp will give you harsh sound. Good amp will give you nirvana.

My Dalquists DQ10s usually sit idle while I enjoy the Altecs.

I tryed them at 500 hz crossover active, and ended up going back to 800. The 411 and 811 are best at 800hz. IMO

[Old Guy]

Didn't GM post some info about the 411 in a ported box a ways back?


Anywhoo....I have a set of 411's sitting around...and a pair of 311-90

One of the things I considered was using them with the BMS Neo 4594

Overview

My history of completing projects lately hasn't been good though....and I am not sure I wanna drill holes in a nice pair of 311's