Complete Altec Setup - Help Please

[bowtie427ss]

Is there a crossover network?

I suspect there may be an absence of one which means the HF horn is probably playing some 15db louder than the LF.

 

[Houston]

Un

Is there a crossover network?

I suspect there may be an absence of one which means the HF horn is probably playing some 15db louder than the LF.

Unfortunately there is not a crossover. #1, Do you have any suggestions for one with this setup? #2, if I ran the Low horn at 4ohm and the high horn and 16ohm, then the lower resistance to low horn would mean higher output. I know it works that way in car audio. Maybe not with this mono vintage amplifier. Oh. Thank you for responding and helping.

 

[bowtie427ss]

The 2 immediate issues are this:

a) The HF horn and driver have a sensitivity that is at least 15 db above the woofer, without attenuation the system will never be balanced.

b) The HF signal needs to be high pass filtered to protect the diaphragm from over-excursion. Playing an un-filtered full range signal thru them is going to damage them.

A 12db/octave 500hz network would have been the standard from Altec.

 

[bowtie427ss]

But why would the high horn sound great but the low horn barely has any output?

Because of the difference in sensitivity between the drivers.

Without the attenuation section of a crossover network, you will have to feed the LF section 10 times the power of the HF section to get close to an equivalent acoustic output.

The crossover network provides a finely tunable attenuator to allow system balance, and a high pass filter section to prevent damaging low frequency information from reaching the HF elements.

There's a bit more going on in the network. But, the above is the basis.

 

[Houston]

The 2 immediate issues are this:

a) The HF horn and driver have a sensitivity that is at least 15 db above the woofer, without attenuation the system will never be balanced.

b) The HF signal needs to be high pass filtered to protect the diaphragm from over-excursion. Playing an un-filtered full range signal thru them is going to damage them.

A 12db/octave 500hz network would have been the standard from Altec.

Thank you for the break down. Would something like this be what I need to purchase and install? It looks to be of the same age and look as the amplifier I have.

 

[Houston]

Thank you for the break down. Would something like this be what I need to purchase and install? It looks to be of the same age and look as the amplifier I have.

You know what. I’m sorry for double guessing you. Your a very smart individual. I’ll take your advice and get what you told me. You have been very helpful by blessing me with your time and knowledge. I’ll contact you later and let you know the progress. Have a day day. Thanks.

 

[bowtie427ss]

You're actually going to need a network that has been modified to work with your drivers, or perhaps a scratch build.

The filter sections must have appropriate component values to match your drivers in terms of impedance in order to arrive at the target crossover frequency.

While i can get you squarely pointed in the right direction, there are others here who are far more seasoned in crossover building. Some tremendously fine folks in fact. I know a couple of them are following along, hopefully they will chime in. Hint @EarlK

 

[bowtie427ss]

I’ll take your advice and get what you told me.

Ease into this so we get it right the first time around.

Wait for the real crossover experts to come along, they will. Parts are not inexpensive, and folks here can help you choose wisely the first time around.

This is worth doing right.

 

[Houston]

Ease into this so we get it right the first time around.

Wait for the real crossover experts to come along, they will. Parts are not inexpensive, and folks here can help you choose wisely the first time around.

This is worth doing right.

Yep. I agree. Thanks. I’ll contact your friend. I saw that the crossover you recommended was 8 ohm and my drivers are 16 ohm. I wondered. But still. You must be a history major. You have a good night. Thanks. Crossover necessary.

 

[bowtie427ss]

For some reason i was letting the 4 ohm tap confuse me, thinking the HF was actually a 4 ohm driver.

With both drivers being 16 ohm this becomes a bit less complicated, and can be done with factory networks.

What is needed is a version of the N500 network which will be designed around 16 ohm components.

Have you verified with DMM that the DCR of the drivers is appropriate for a 16 ohm driver?

it is possible for various impedance diaphragms to be installed over time and use.

Most Altec 16 ohm voice coils will show a DC resistance of around 11 or 12 ohms.

 

[Houston]

I’ll brea

For some reason i was letting the 4 ohm tap confuse me, thinking the HF was actually a 4 ohm driver.

With both drivers being 16 ohm this becomes a bit less complicated, and can be done with factory networks.

What is needed is a version of the N500 network which will be designed around 16 ohm components.

Have you verified with DMM that the DCR of the drivers is appropriate for a 16 ohm driver?

it is possible for various impedance diaphragms to be installed over time and use.

Most Altec 16 ohm voice coils will show a DC resistance of around 11 or 12 ohms.

I’ll break out my equipment and test again to make sure. Just like cabinets. Measure twice, cut once. ;-)

 

[bowtie427ss]

I’ll brea

I’ll break out my equipment and test again to make sure. Just like cabinets. Measure twice, cut once. ;-)

When i have a bad day, it's more like "i've cut this off 3 times, and it's still too short!"

 

[elitopus]

Unless your friend wants to play around with a big horn setup, I would consider selling the Altec gear and buying him a more plug and play system.
I mean, you have a couple grand worth of Altec drivers and horns there. It could buy some newer gear that would be less finicky to setup.
Or even some Altec Valencia’s or something similar if you wanted to stay with Altec.

Don’t get me wrong, I love Altec. It would be awesome to get this setup for free, but it’s not for everyone.

You didn’t mention what your friends audio experience is and what type of music he would be listening to through this system.

 

[EarlK]

I think this is a mono setup ( applicable as a flown center cluster for reinforcing voices at a distance ).

I'm struggling to understand what the recipient will do with it now that it's landed back on earth and is non-flyable ( since I believe it's meant for re-use by a church in some capacity ).

I guess one could make a copy of the N500G as a crossover ( while substituting a variable 16 ohm LPad in place of the "multi-tapped 100 watt resistor + then switched" LPad , that's seen in the following pic ).

 

[elitopus]

I couldn’t tell if it was for the church or for a friend at the church for personal use.

So does the OP have a single 515C and a single Hollywood 515? He mentioned the 20ohm Hollywood 515 but also shows a pic of a 515C.

 

[EarlK]

I couldn’t tell if it was for the church or for a friend at the church for personal use.

So does the OP have a single 515C and a single Hollywood 515? He mentioned the 20ohm Hollywood 515 but also shows a pic of a 515C.

Right, it's nary impossible to give meaningful advice when such ambiguity exists.

 

[bowtie427ss]

Mayday! Mayday!

We've lost contact with Houston.

 

[elitopus]

Why does this always happen?

Hopefully both of his HF diaphragms are still intact at this point.

 

[Houston]

I’m so sorry. I’m still here. Both diaphragms are still intact. 3 kids and full time job keep me on the run. It was nice to have these components gifted to me since I’m a cabinet maker. Before I give to my church I just wanted to get it operational. They will play some music. Not to shake the walls but I think a majority of the time they will be speaking to be heard. I know that these old systems were made with dependability and if they wanted to sell it in the future for a upgrade, then that would fund the upgrade.

 

[Houston]

I’m so sorry. I’m still here. Both diaphragms are still intact. 3 kids and full time job keep me on the run. It was nice to have these components gifted to me since I’m a cabinet maker. Before I give to my church I just wanted to get it operational. They will play some music. Not to shake the walls but I think a majority of the time they will be speaking to be heard. I know that these old systems were made with dependability and if they wanted to sell it in the future for a upgrade, then that would fund the upgrade.

this is a crossover that is more available. It doesn’t match the Altec name. But still looks like it follows the same guidelines. I homes the lf driver at 12.36ohms thought even though it says 16ohms. I could hide it in the top box so it wouldnt stand out like a sour thumb. Functional, no?