Connecting subs to Integrated Amp

[highfigh]

Absolutely do not do that. First of all, it will not be quadraphonic, but four channel stereo which is a mess. More importantly it will blow up your integrated amp. That is because A & B speakers are not intended to be run at the same time. If you do then all speakers will be in parallel, and drop the load impedance low enough to blow your amp.

From what I remember of those speakers, and this is a long time ago, the bass was not well defined. Your ideal solution, but complicated, would be to put an electronic crossover in the preamp to amp loop and send the high pass to the JBLs and the low pass to the subs.

I am not really convinced that a cheap sub with no crossover is going to improve your listening experience and could make it worse.

Those JBL speakers actually go down pretty low. The issue is, that as I remember them the bass was far from the best quality.

As an historical note, your speakers go back to the old "West Coast/East coast" divide. JBL were East Coast and had the deeper 'tubbier" bass and Altec Lansing were the West Coast flag bearers with less deep bass, but tight as a drum literally.

Look at the area near the speaker terminals- it will show the minimum load if A are used and a higher load per speaker if A+B are used- that means two things- it WAS designed to operate with both sets and the speaker switch puts the speakers in parallel. Some were designed to put the speakers in series and if only one pair is connected with the speaker selector in the A+B setting, no sound is produced. The series switch was more common in the 1970s. Also, most speakers before the 1990s showed 8 Ohms as the load- the minimum was almost never mentioned, nor was phase angle.

When were JBL considered 'East Coast'? The Lansing Manufacturing Company was founded in Los Angeles, so it would be odd to use 'East Coast' to describe the sound.

I'm not arguing about East Coast vs West Coast sound- in the '70s and '80s, we used those as a guide for customers when describing the sound when they would ask about various brands like AR, KLH, or others that were actually designed and produced around the East Coast. We also mentioned British, German, Scandanavian and brands from other countries as having a particular sound.

This said, I wouldn't recommend connecting two pairs of speakers to one receiver or integrated amp with two pairs of terminals without knowing the impedance or at least measuring the DC resistance.

 

[ifsixwasnin9]

Quadraphonic is four discrete channels, deliberately recorded that way. Back in the day you needed a particular recording (vinyl or reel to reel) and special receiver/decoder, not just four speakers and 2ch gear. You can still get quad recordings via SACD, tho. Having two sets of speaker terminals are generally to have sound in two different rooms (with modern gear they do it via "zones").

OK, I understand it better now. You convinced me not to add another pair of speakers to my system.

More than any other speaker I can remember, convinced me to never ever own a speakers from a major speaker manufacturer. I never have, and never will.

You can't think of any speaker from any manufacturer that produces decent sound? You design your own speakers? That takes an awful lot of engineering, work and lots of testing equipment. How do you do that?

 

[TLS Guy]

Look at the area near the speaker terminals- it will show the minimum load if A are used and a higher load per speaker if A+B are used- that means two things- it WAS designed to operate with both sets and the speaker switch puts the speakers in parallel. Some were designed to put the speakers in series and if only one pair is connected with the speaker selector in the A+B setting, no sound is produced. The series switch was more common in the 1970s. Also, most speakers before the 1990s showed 8 Ohms as the load- the minimum was almost never mentioned, nor was phase angle.

When were JBL considered 'East Coast'? The Lansing Manufacturing Company was founded in Los Angeles, so it would be odd to use 'East Coast' to describe the sound.

I'm not arguing about East Coast vs West Coast sound- in the '70s and '80s, we used those as a guide for customers when describing the sound when they would ask about various brands like AR, KLH, or others that were actually designed and produced around the East Coast. We also mentioned British, German, Scandanavian and brands from other countries as having a particular sound.

This said, I wouldn't recommend connecting two pairs of speakers to one receiver or integrated amp with two pairs of terminals without knowing the impedance or at least measuring the DC resistance.

It came down to the fact, that basically most JBL bass drivers where high Q and Altec Lansing favored low Q. JBL did have pro drivers though, that were low Q.

 

[TLS Guy]

OK, I understand it better now. You convinced me not to add another pair of speakers to my system.

You can't think of any speaker from any manufacturer that produces decent sound? You design your own speakers? That takes an awful lot of engineering, work and lots of testing equipment. How do you do that?

I have just been doing it since I was seven years old. So I got quite a bit of practice in learning what not to do. Yes I have software, and test equipment. My first computer assisted design dates from 1984. Yes, commercial speakers have improved enormously over the last 20 years especially. So the competition is much stiffer. However, I still have a few tricks up my tool box, they don't have.

 

[lovinthehd]

OK, I understand it better now. You convinced me not to add another pair of speakers to my system.

You can't think of any speaker from any manufacturer that produces decent sound? You design your own speakers? That takes an awful lot of engineering, work and lots of testing equipment. How do you do that?

If you really want quad or surround sound, you can upgrade to a modern avr and put the speakers to use.

You might like this book if you want to get into speaker building https://www.audioholics.com/loudspeaker-design/loudspeaker-design-cookbook-8

You can also buy a kit speaker and put it together yourself, perhaps something like this https://forums.audioholics.com/forums/threads/parts-express-orian-3-way-high-output-bookshelf-speaker-kit-review.128276/