Looking for opinions on my setup

[leeclayton]

Hi all, I'm currently running 807 8A's with 811b horns and 416 8b woofers with the n501 8a crossover. After doing some research I've discovered that this is sort of a mismatched system. I was thinking of either buying 511 horns to better suit the crossover or seeking out a higher crossover to better suit the 811s and probably drivers as well. Any opinion on this or suggestions? Thanks

[gdmoore28]

Hi Lee,

What you've read is correct. The 811B horns are rated for a lower cutoff of 800Hz. The 511B is rated for 500Hz. So, the only problem you have in your system is the crossover point.

I'm sure you've also run across the quite common opinion that the two horns actually sound best when crossed even higher, with the 811B crossed at 1200Hz and the 511B crossed at 800Hz. The late, great Zilch (who was very well respected in his technical research and opinions) believed this was the case.

Regardless, if you decide to reconcile the matter, you have the choice of either finding some Altec crossovers rated for 800Hz or higher, or building your own. Considering the age of the Altec crossovers, many folks simply build their own, as replicating the said Altec versions with new components is quite easy. Schematics are readily available.

I would be remiss if I didn't mention the crossover choices that could make dramatic improvements in your speaker systems. The simplest suggestion would be to add the Altec 30923 network after your new crossover. This is a very simple network consisting of three resistors and a capacitor, but the improvement it makes in sound of Altec drivers/horns is remarkable. Simply put, all it does is attenuate the midrange frequencies and in the process makes the UHF response more apparent. It's good stuff.

The second suggestion would be to build and utilize the crossover network used in the Altec Model 19, or its equivalent, the (Zilch) Z19. This network accomplishes the same thing as the 30923 network, but with the addition of lots of adjustment for mid and high frequency response.

Personally, I would simply find the schematic for your choice of crossover points (let us know if you need help in finding one), replicate it with new components, and add the 30923 network between the new crossover and your HF driver.

Hope this helps. If I've neglected something, I'm sure Elitopus or 427 or one of the other guys will be along to comment.

GeeDeeEmm

[leeclayton]

Hey thanks for the reply. I'm pretty much a layperson when it comes to electronics so ideally I would like to buy a crossover. What do you think of the Eminence PXB2:800 crossover from Parts Express? And thanks for the tip about the 30923 network, something else I will have to consider.

[gdmoore28]

The Eminence crossover will work just fine. It's a step up from the Altec in that it provides 18dB slope for the horn instead of the Altec's 12dB. That simply means that fewer frequencies under 800Hz will enter the horn driver, but it provides a bit more protection and a sharper cutoff between highs and lows. And, you get the benefit of a bulb to handle any overloads.

That crossover followed by the Altec 30923 network (and an 8 ohm L-pad) will provide a very nice sounding system. So the order of installation will be the Eminence crossover, followed by the 30923 network, followed by the L-pad. (And you will need the L-pad regardless of whether you use the 30923 network or not. The horn driver is much more efficient - louder - than the woofer and will need to be dialed back a bit in order to achieve good balance between the two.)

Let us know how it works out.

GeeDeeEmm

[leeclayton]

What do you think about getting aluminum diaphragms from GPA to replace the current ones in my 807s?

[gdmoore28]

What do you think about getting aluminum diaphragms from GPA to replace the current ones in my 807s?



Lee,

Your 807-8A driver originally came equipped with the Altec 34726 Symbiotik diaphragm, which was designed to withstand more power in public address situations. The Symbiotiks are no longer manufactured. GPA recommends using the aluminum replacement diaphragm #34647-8 for critical-listening in a home environment.

If your drivers are original, I think there would be little doubt that you would benefit in replacing them with the new 34726, especially in the form of greater high frequency extension.

GeeDeeEmm

[leeclayton]

Great, I will get the aluminum diaphragms then. What do you think of a 1600 hz crossover for my components? I see that parts express doesn't have a 1200 hz one. I was also thinking of mounting my 416-8b in custom 614 cabinets, do you think that would be suitable? Thanks for all your help and feedback, much appreciated.

[gdmoore28]

Personal opinion is that going to 1600Hz crossover point would be pushing it a bit and may run into "beaming" from the 416. Altec used 1200Hz in the Model 19 and had spectacular results, of course. I just think you would be staying in the safe zone by sticking with the 800Hz crossover. That's a tried and trued setting. (PE used to carry the Eminence crossovers in 500, 800, 1200, and 1600 increments. I understand dropping the 500, but the 1200 is a very popular Xover point. Seems odd they would drop it, huh?)

I'd hate to comment on using the 416 in a 614 cabinet, because I'm not exactly a whiz when it comes to calculating cabinet volume/tuning/TS parameters, etc. Looks like the 614 offers roughly 4 cubic feet of volume, and that is banging on the door of the smallest cab recommendations. Of course, thousands of 604/605s were loaded in 614 cabs and used in studios for many years, so . . .

Short answer on using the 614 - I'm not sure.

I wish 427 or Elitopus and some of the other guys would weigh in here and give their opinions. It'd be good to have their expertise at play here.

GeeDeeEmm

[leeclayton]

Just to update, I recently acquired some 511s which I think sound better with what I currently have. Also there are some 809-8a crossovoers for sale near me, any opinion on those? After doing a bit of research I think I'm gonna get 612 cabinets built instead.