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I only mention the disconnected channel as something I noticed when connecting the speaker to a live amp with music playing and noticed the stereo effect kick in. I never tested or measured freq response with a channel disconnected. I will have to try a pan with the LR balance knob on the old style Yamaha amp. Nowadays such knobs are often missing on compact amps and one had to resort to pan within software if playing from a computer. Even an iPod has no easy to access LR pan.
One more thing of note: for grins I tried this matrix with a TPA3116D2 class D amp. I know that this amp has very idiot proof built in protection from direct shorting of speaker leads. Anyhow, I was surprised that it works! Albeit, only up to about 40% volume setting. Above that the self protection kicks in and it shuts down. This tells me that if you have two independent class D amps (for example if running bi-amps in vertically integrated mode), this may work. The nice thing with class D amps is the ability to make a low power consumption portable SSS for a MP3 player or iPod Dock.
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Hello and how do you do !
A few years ago I presented the theory and operation of matrixed single stereo loudspeaker
http://www.diyaudio.com/forums/multi-way/200040-stereophonic-sound-single-loudspeaker.html
Just recently I discovered that late Nagaoka has left us with a huge heritage of single stereo matrix loudspeakers
Basically he used two kind of matrixes. For 3 and for 4 elements.
The 4 element matrix looks like this:
Notice that this is MS matrix. The front elements sum acoustically to form L+R signal.
hkjunk0.web.fc2.com/hobby/audio/matrix_db/matrix02.jpg
And the 3 element matrix is like this:
We can see it is the famous x=0.5 matrix(Notice though the left amplifier channel negative terminal is left unconnected, possibly to avoid a ground loop?)
hkjunk0.web.fc2.com/hobby/audio/matrix_db/matrix03.jpg
{HIRO}'s Website!! - matrix_db1
(edit: those hkjunk images are pain to see online, just copy the link to an empty window)
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Maybe it's mentioned in this thread, but I can't find it... In the diagram for only three drivers,where does the negative side of the left speaker terminal go?
Thanks,
Mike
Mikej,
This is the circuit I am using:
The negative of the L driver (as well as the negative of the R) goes to the positive of the center channel. Choose R & C such that the highs that you don't want showing up on the center channel are bypassed (low-pass shunt filter) I am using 4 uF and 5 ohms.
This is the circuit I am using:
An externally hosted image should be here but it was not working when we last tested it.
The negative of the L driver (as well as the negative of the R) goes to the positive of the center channel. Choose R & C such that the highs that you don't want showing up on the center channel are bypassed (low-pass shunt filter) I am using 4 uF and 5 ohms.
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This has been quite an interesting thread and it's given me an idea. I have one old BLH that my father built in the 1960's. It has two eight inch JBL extended range speakers sitting side by side in it. They are wired up in mono right now, and crossed over to a horn tweeter at a little under 2khz. Do you think it would work if I ditched the horn tweeter, wired the two JBLs in stereo and used three small full rangers or large tweeters in a matrix setup for the top end? I could just build a small box and set it on top of the BLH.
I think you want the tweeters on the sides and the wire the woofers (low pass) on the front center. Maybe augment the tweeters with some side firing mids (500 Hz to 2 kHz)? Main thing is to have a banana plug "patch panel" and experiment. It is the side directed HF that gives the stereo image.
Hi X,
I didn't pay attention to it, but I looked it up just now and found the TPA3116D2 you use is internally bridged.
In a bridged amp, both of the output terminals are 'floating'. So I'm very curious how your system actually work -- you tie the negative side of both channels into one common, and the chip is still doing OK? Wow !
I didn't pay attention to it, but I looked it up just now and found the TPA3116D2 you use is internally bridged.
In a bridged amp, both of the output terminals are 'floating'. So I'm very curious how your system actually work -- you tie the negative side of both channels into one common, and the chip is still doing OK? Wow !
I knew this which is why I never tried this until I got a cheap class AB amp to play with. It works well with class AB amp. Anyhow, I happened to get a new 3116 amp one day and said what the heck? Why not just try it? I know that the 3116 is bullet proof so at worst it would just shut down. Anyhow it works but at very low volumes - somehow it does not short out right away. If works up to about 40% volume (music dependent - peaks shut it down sooner). I would not use it with a class D amp more than just to test for grins. But what I suspect is that it may work fine if you have dual class D amps (one for left and one for right)?
There are some class D amps like the IRS2092 MOSFET driver that probably will work because each channel is independent and not bridge tied.
I am not sure if it will work but the negative output of each amp to the other and one amp is right and other is left. Just one channel of each amp is used. The remaining channels can be used for the sub.
Class D amplifiers are something that should have been left uninvented
You see, people don't even know how to use them
.
Please elaborate.
lol. I've had mixed results. but i was clipping a 3w 3110 chip amp on piano. Sounded like TIM distortion. But unclipped, it was excellent, especially Lyle Lovett "Joshua, Judges, Ruth" cd. It could be that specific chip and it wasn't a digital 50 watter (chip driving mosfets). But my crest amp (with way too much gain) could pick up noise and buzz/modulated through the sub when input pot set to minimum.
Were you driving a SSS matrix speaker with the 3110 amp? I really like that amp too by the way. Sounds like a little brother of the 3116 and for most applications even up to 12 watts is possible when driven by 19v supply.
nope. It was the 3110. It was run bi-amp 4ohm woof (93db 8" silver flute) and an 8ohm compression driver (110db). I didn't get to try a higher supply, but 8xAA's sounded better than a 12v car battery or a 12v power cord for a laptop. Maybe I'll try more double AA's some day to get a few more volts (up to 19 according to the specs). Better output inductors would help as should installing non electrolytics in the signal path (everywhere there are .22uF's).
2x8W at 4 Ohm TPA3110 Class-D Audio Amplifier Board Only
Voice was magical, clarity (people coughing in the background) was awesome.
2x8W at 4 Ohm TPA3110 Class-D Audio Amplifier Board Only
Voice was magical, clarity (people coughing in the background) was awesome.
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I know you are not supposed to connect them together - but I did it anyway to see what happens. It works at low volume but shorts at higher volumes so technically doesn't work. I have not tried connecting negatives of two separate class D amps together - so don't know if that doesn't work.
It's a bit more than "not supposed to".
It's stereo, so the L and R signals are different. Output Lout- is trying to put out a different voltage/current than output Rout-. Both amps are "fighting" to put a different voltage/current to the same node.
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It's the same as if you tried to connect the L and R channels of a normal amp to get mono. You'd need some "sharing" resistors of 0.2 ohm.
I commend your DIY spirit!
I don't want you to release the magic smoke so you can keep doing wacky experiments and posting for us here! Just use "test" amps and speakers, never your good ones ...
It's stereo, so the L and R signals are different. Output Lout- is trying to put out a different voltage/current than output Rout-. Both amps are "fighting" to put a different voltage/current to the same node.
.................... .....It's the same as if you tried to connect the L and R channels of a normal amp to get mono. You'd need some "sharing" resistors of 0.2 ohm.
I commend your DIY spirit!
I don't want you to release the magic smoke so you can keep doing wacky experiments and posting for us here!
Just use "test" amps and speakers, never your good ones ...
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Ahh but I do have "sharing" resistors of nominal 6.3 ohms resistance in the L and R channels before the signals get summed. I did not have to worry about releasing the magic smoke because 1. The TPA3116 is idiot proofed with auto shutoff in case of shorted leads, 2. The amps cost $13 to $20 so no worries. I will stick with my $5 class AB lunch money chip amp for this when away from the console amp.
of nominal 6.3 ohms resistance in the L and R channels before the signals get summed. I did not have to worry about releasing the magic smoke because 1. The TPA3116 is idiot proofed with auto shutoff in case of shorted leads, 2. The amps cost $13 to $20 so no worries. I will stick with my $5 class AB lunch money chip amp for this when away from the console amp.I'm having trouble visualising how the cabinet volume and bass reflex port should be calculated for a 4 driver matrix sharing one cabinet. Working on the assumption that low bass is often shared evenly between the L and R channels, in this situation the main L and R drivers will be moving equally so no (bass) signal will be present across the two difference channels. Looking at it this way you have two drivers working in parallel into one enclosure with two passive radiators with the same parameters as the main drivers (I'm not sure how you'd calculate the load on the passive radiator voicecoils).
Am I on the right track? Can anyone help me understand how I should calculate the box and port?
Am I on the right track? Can anyone help me understand how I should calculate the box and port?