Non-identical speakers in parallel

On a sunny day (Thu, 10 Dec 2009 09:21:39 -0800 (PST)) it happened mkr5000 wrote in :

Well, eh, each speaker its own amp with each a nice opamp filter? (ducking for flying pies).

It will be driven by the same amplifier.

On a sunny day (Thu, 10 Dec 2009 09:45:11 -0800 (PST)) it happened mkr5000 wrote in :

Some woofers can be just connected in parallel, but maybe you should ask in an audio group? No telling without knowing your audiophile status and lots of other details about the speakers, cabinet, your supernatural hearing capabilities, room acoustics, type of voodoo dolls your have, what planet you are on, how much gold is in the speaker cables, if it contains oxygen, if your power outlets are gold plated, all things we need to know.

Well, the biggest issue will be the sensitivity of the two speakers, i.e. how loud the speakers will play given the applied signal.

You can certainly hook them in parallel and the net result will provide sound. But, due to the sensitivity differences in the speakers, you're going to most likely have one speaker play louder than the other. Not sure if the full range speaker is a coaxial or not, but it will probably dominate and be the louder of the two.

The parallel combination won't be as coherent and balanced as say a two way system with a crossover that's designed to accomodate not only the frequency ranges of the individual component speakers, but they're sensitivities. A crossover sorta dials in the individual speaker components to try and get them working more coherently and blended better with one another, especially at the crossover point.

Experiment and see what you find. You certainly aren't going to harm anything at low power levels. 1-5W of power would be plenty of juice for some decent listening levels to test, and it's not gonna be a heavy burden on a power amplifier even if the load impedence of the combined two is relatively low, 2ohms or less.

You need to watch your phase. You can check proper phase by momentarily putting a 9V battery on the terminals, positive on the battery to positive on the speaker. You should see and feel the cone of the speaker come outwards. Make sure that when you hook up both in parallel, they both move outwards together. You can kinda see and certainly hear what would happen if you got one reversed. And, just because the terminal is marked positive or is red, doesn't always mean that... there are sometimes, many times, mistakes in manfacturing of speaker components.

Anyway, hope this helps... have fun!

Dan Charette {dan_at_thesonicfrogFUZZ-dot-com} Remove the "FUZZ" and replace the underscores and such from my e-mail address to contact me.

"I may not always be right, but I'm never wrong."

Another thing I forgot to mention is that the only crossover will be a simple series cap to the tweeter. The full range will be in parallel with the woofer -- I'm aware of the impedance and sensitivity issues.

There will be times when the full range is operating and the woofer isn't because of the woofer's cutoff.

Odd question I know but it's an odd configuration.

By the way Jan-- some of the most intelligent answers on audio are in this group. (Although posts are rare).

I won't mention his name but a world renowned speaker designer (and author) has posted answers here before.

On a sunny day (Thu, 10 Dec 2009 11:57:11 -0800 (PST)) it happened mkr5000 wrote in :

I am wondering about the purpose of your question. And now a tweeter was added too. I wonder who that speaker designer is?

Oh, I did not want to say it, but you could go mono, and use each halve of the stereo amp for a speaker, and do the filter with low level electronics. Then you can go stereo later again if you have money for a new amp. After all, the woofer should be mono anyways.. This makes me wonder, maybe the sound can be encoded so the woofer is between channels and the other speakers each on a channel. Oh, and I should patent that,

Had enough yet? We can bring in an FPGA and ADC DAC, go 24 bit, or just buy a drum set and go for it. Play air gitar? I dunno.

Hope this helps, but I have no expectations.

BTW I am happy with my Chinese speakers and Chinese amp designed in Germany. And I have NEVER played that at full volume, anyways it was only 67 Euro or so.

So this is what you could try: Mid range speakers normally connected to output left and right. Tweeters via capacitors to midrange speakers. 1 woofer connected between left and rigth output of the amp.

Now at the input, if the midrange starts for example at 250 Hz, filter each channel steep into a 250 Hz - 30 kHz band, called 'left high', and 'right high',

Add the left and right channel, filter it so you have 15 Hz - 250 Hz mono, a signal called 'low'. Now make 2 special networks, Feed the 'low' through one that creates a +90 degrees phase shift from 15 Hz to

250 Hz, signal ' left low shift'. Feed the 'low' through one that creates a -90 degrees phase shift from 15 Hz to 250 Hz. signal 'right low shift'.

Add the ' left high' and ' left low shift' and feed it to the left input of the amp. Add the 'right high' and 'right low shift' and feed it to the right input of the amp.

Now you have, by simply controlling the signals ' left low', ' left high', and 'low', full control over the audio...

Need to patent this really.... hehe

"Jan Panteltje"

** You need to build one first - pal !!!

Those constant 90 degree filters will be VERY hard to make.

For the idea to work, all you really need do is invert the low band in one channel.

..... Phil

On a sunny day (Fri, 11 Dec 2009 11:54:23 +1100) it happened "Phil Allison" wrote in :

Yes Phil, you are right about that, thought of that after I posted that, here is an alternative setup: ftp://panteltje.com/pub/new_woofer_driver_img_1681.jpg There are actually a few interesting points: If he has 2 boxes with 2 woofers, then he can put those in parallel, The woofers are between the outputs, so get double the voltage, and also in parallel, makes 8 x the power. So we need to drive at about .35 x the voltage, that is why the bass pot. That lower voltage also means the midrange speakers see very little signal below

250 Hz or whatever cutoff!

Build it? But Phil, my Chinese amp and boxes work fine, and my woofer is mounted to the floor, driven by this one:

It is a wooden floor, tables start jumping when you turn it up full. Na, I do not need to build more audio, and I have PC speakers too. Most incredible sound on the original star wars movie... amazed me. Anyways, for a patent, even those perpetual motion machines did not need a prototype?

But seriously, I think this system is a cool idea :-) :-)

Also it was a nice complicated answer to a simple question don't you think? :-)