Settings for commercial theater speakers

[Maverick1776]

Ye, the correct ones. You can not use any old crossover. The ones you are using now will destroy the compression drivers in the horns.

You need the original Altec passive crossovers, or bi-amp with the Shure SR 106 electronic crossovers. NOTHING else will do.

Hmm, it's a noob question, but how do I connect RCA plugs from the pre-outs on the onkyo to the shure sr 106 unit ? I run regular 14awg speaker wire from the speakers out.

I appreciate your help by the way. I knew something was missing. These speakers had more umph when they were running from my 35mm projector. Like literally you can watch a movie with just center channel on and get incredible sound.

Can I add my altec Lansing a324a tube amplifier to the mix you think? Or will there be some distortion.

 

[TLS Guy]

Ye, the correct ones. You can not use any old crossover. The ones you are using now will destroy the compression drivers in the horns.

You need the original Altec passive crossovers, or bi-amp with the Shure SR 106 electronic crossovers. NOTHING else will do.

You will need to use the preouts on the receiver.

You will need an SR 106 for each speaker and two external power amps for each speaker. The amps should have level controls or pots inserted between the SR 106 and the power amps at least for the HF amps. Or add trimpots to the SR 106 units.

The SR 106 can be used balanced or unbalanced.

You connect to the Onkyo with RCA plugs to the respective preouts, and connect with a 1/4 mono phone jack to input of each SR 106. Then you take the low pass output of each SR 106 to each bass amp. The you take the high pass output of each SR 106 to each HF amp.

You connect the bass amps to the woofer, and HF amps to the horns.

Now the SR 106 is able to be customized easily. You can easily change the circuits to alter the crossover points and order.

However I know from working with those Altecs over the years setting the crossover to 800 Hz and trimming the levels works perfectly.

There are quite a few of those units still coming up on eBay.

Now I do have a number of those units from days of dealing with these sort of systems and halls and theaters.

If you really are interested in restoring a vintage system for a true 70s sound in your home theater you need: -

New or rebuilt horn compression drivers from Great Plains Audio.

I think you said you have three of these speakers, so you will need three Shure SR 106 crossovers.

You will need six power amps preferably with level/gain controls.

Failing that I can add trim output pots to your SR 106 crossovers.

You have to realize that you have a scarce interesting and limited vintage resource. You have already vandalized it by loosing the original crossovers.

Owning equipment like this carries responsibilities to future generations and collectors.

If you really are serious about optimizing this system and making it a show piece then I am prepared to help you and will consider making the crossovers available.

First you will have to convince me you are going to be responsible with this project and will not be an idiot. You will also have to convince me you have the financial resources to complete the project.

If you don't think you are up to this, then you need to sell and make the equipment available to a serious and experienced collector/restorer.

 

[lsiberian]

This project is not one where I advise simply blindly following TLS or anyone else's advice. You need to understand what a crossover is, how it works, the different types, you need to fully research your options and come to your own conclusion about how you want to proceed based on your own informed position.

The last thing you want is to be dependent on someone for troubleshooting issues.

Check out the resource below for a good starting point.
http://sound.westhost.com/index2.html

 

[TLS Guy]

This project is not one where I advise simply blindly following TLS or anyone else's advice. You need to understand what a crossover is, how it works, the different types, you need to fully research your options and come to your own conclusion about how you want to proceed based on your own informed position.

The last thing you want is to be dependent on someone for troubleshooting issues.

Check out the resource below for a good starting point.
http://sound.westhost.com/index2.html

I could not agree with you more.

The Shure SR 106 was designed for the Shure PA line, of Vocal Master and especially the Pro Master series..

Here is a picture of a Pro Master.

They wisely made a selector on the back to make it compatible with the major horn systems in use, which basically meant Altec Lansing and J.B Lansing. Electrovoice had their own electronics.

This is a typical 70s Altec Voice of the Theater smaller cabinet.

This is a typical Voice of the Theater speaker for larger Cinemas, with the woofer horn loaded back and front.

A couple of 10 to 15 watt tube amps on each speaker would fill a large cinema and then some!

 

[Maverick1776]

Yikes, this can get pricey very quick. Is there another solution I can do in the meantime and still get decent sound ?
The way I have the passive crossovers right now is 2K hz to the woofers, and 2.5K to the tweeters.
The boards I have allow for 2K, 2.5K and 4K.
By the way, the horns pictured in the 2nd photo are exactly the ones I have.

I could buy 800hz 2way passive crossovers for now.

 

[TLS Guy]

Yikes, this can get pricey very quick. Is there another solution I can do in the meantime and still get decent sound ?
The way I have the passive crossovers right now is 2K hz to the woofers, and 2.5K to the tweeters.
The boards I have allow for 2K, 2.5K and 4K.
By the way, the horns pictured in the 2nd photo are exactly the ones I have.

I could buy 800hz 2way passive crossovers for now.

That will not do the trick, as you have to level trim. It is not just frequency also.

What speakers are those. The circuit will be available.

Bi-amping is by far the best for those speakers, but in the interim building the exact passive crossovers is the best solution.

 

[TLS Guy]

The crossovers that originally came with these speakers had solder points on them. They were from altec lansing as well. They were enclosed boxes, very good build quality. I stopped using them a long time ago, and no longer have them. Here is one on ebay http://www.ebay.com/itm/Altec-N-800-D-Crossover-16-ohms-800Hz-/231889151575?hash=item35fdaba657:g:Tj0AAOSwLpdW9DLh

Is there a crossover you can suggest ?

The circuit for that Altec crossover is attached.

You are some one else can build them. It has the correct attenuation circuit. It is 16 ohm which it should be, and is a now unusual series circuit and not the now universal parallel circuit.

Those series circuits were common back in the day, and give a steeper roll off.

You will damage those speakers if you don't use the correct crossovers.