[jk@home]

I'm waiting for someone to biamp a Mini plus double DWM setup, forgoing the factory crossover and use a DSP settup (active crossover or hybrid plus EQ). That's right, mod em! The potential should be there for improvement.

[stelo]

That's what I thought when I posted the question (under "Do you have a question for the Magnepan factory?") on 19 Oct 2011.  I posted something similar again on 5 Jan 2012 and called Wendell a few weeks later.  I posted a brief summary of our conversation as Reply 81 on 24 Jan 2012, hoping that Wendell would correct anything in the post that seemed incorrect.

I am not sure how the DWM is wired to operate when being fed on 1 channel or 2 channels, but I do not recall hearing any difference in volume levels and I hope that does not mean that I am going deaf.

Maybe I will try that setup again this weekend and use the Radio Shack sound pressure meter to record any volume differences when a DWM is fed 1 channel or 2 channels.

I looked at reply 81. This is what Wendell writes:
"The DWM woofer has two inputs that are not designated L+R channels. Each input feeds one half of the DWM.  The output of two DWM woofers partially fed is equivalent to a single DWM woofer fully fed."

From what I read here, if you connect 1 channel to a DWM, you will get 1/2 output compared to feeding it with 2 channels.

Stefano

[Robin Hood]

I looked at reply 81. This is what Wendell writes:
"The DWM woofer has two inputs that are not designated L+R channels. Each input feeds one half of the DWM.  The output of two DWM woofers partially fed is equivalent to a single DWM woofer fully fed."

From what I read here, if you connect 1 channel to a DWM, you will get 1/2 output compared to feeding it with 2 channels.

Stefano

I guess that is the correct interpretation and that's why if you want more bass and mid-bass you will add a 2nd DWM woofer and 2nd amp with volume control.

If you want smoother bass than a single DWM provides you will add a 2nd DWM woofer and just use the single amp.  However I believe by relocating the two DWM woofers to the parallel walls and floor you will get an increase in bass.  I assume two DWMs next to two parallel walls even with only one side powered provides slightly more bass than one centered DWM fully powered, but not as much bass as a 2nd DWM woofer fully powered by a 2nd amp.

I will test the bass volume levels this weekend for the different configurations and post the results.

[Robin Hood]

Test Results for Mini Maggies

I currently have my Mini Maggies in my upstairs living room on 36” high speaker stands, high enough to clear a 34” low wall that is 7” behind the Maggies.  There is a solid wall 52 inches behind the Maggies and another solid wall 150 inches in front of the Maggies.

I have the DWM woofers on the inside with 32” clear distance and 78” from the left DWM outside edge to the right DWM outside edge.  The satellites are angled slightly on the outside edges of the DWMs to give an overall edge to edge distance of 98” for the Mini Maggies.

I put on Track 5 of the Mapleshade Rives Audio Test CD, which is a 50Hz test tone, on automatic repeat in my Oppo player. I set the Radio Shack sound meter on a tripod with the opening of the meter exactly 36 inches from the face of the left DWM woofer and 40 inches high from the floor.  For the tests the sub was turned off. The reference measurement with 1 channel powered in both DWMs was 76dB.

After disconnecting the right DWM, the measurement of the left DWM, still with only one channel powered was 73dB.

Then connecting the right channel to the left DWM, so that both channels were powered, the measurement of the left DWM was 78.5dB.

Moving the left DWM to butt up against the side wall, with both channels still powered, the measurement of the left DWM was 85dB.

Disconnecting one of the channels from the left DWM, and keeping the left edge of the DWM  next to the side wall, the measurement of the left DWM was 78dB.

[stelo]

Test Results for Mini Maggies

I currently have my Mini Maggies in my upstairs living room on 36” high speaker stands, high enough to clear a 34” low wall that is 7” behind the Maggies.  There is a solid wall 52 inches behind the Maggies and another solid wall 150 inches in front of the Maggies.

I have the DWM woofers on the inside with 32” clear distance and 78” from the left DWM outside edge to the right DWM outside edge.  The satellites are angled slightly on the outside edges of the DWMs to give an overall edge to edge distance of 98” for the Mini Maggies.

I put on Track 5 of the Mapleshade Rives Audio Test CD, which is a 50Hz test tone, on automatic repeat in my Oppo player. I set the Radio Shack sound meter on a tripod with the opening of the meter exactly 36 inches from the face of the left DWM woofer and 40 inches high from the floor.  For the tests the sub was turned off. The reference measurement with 1 channel powered in both DWMs was 76dB.

After disconnecting the right DWM, the measurement of the left DWM, still with only one channel powered was 73dB.

Then connecting the right channel to the left DWM, so that both channels were powered, the measurement of the left DWM was 78.5dB.

Moving the left DWM to butt up against the side wall, with both channels still powered, the measurement of the left DWM was 85dB.

Disconnecting one of the channels from the left DWM, and keeping the left edge of the DWM  next to the side wall, the measurement of the left DWM was 78dB.

* only one channel powered, the measurement of the left DWM was 73dB
* both channels were powered, the measurement of the left DWM was 78.5dB

5.5dB more is quite a bit, right? ... the decibel scale is logarithmic (3dB represents a factor of two)

Stefano

[stelo]

I think I have something related to Robin Hood's Test recent results.

In my experimentation today I discovered that I can enhance significantly
the low frequencies from my single DWM if I lower the volume of one of the two
channels from the DAC.

Let me explain. While I listen to the Maggie+DWM, I turn down the volume of
the right or the left channel, and now I can hear the low frequency a lot
more. Initially I thought that when both channels are on, the satellites
are "masking" (or overpowering) the DWM, but I am not sure anymore.

As you turn the volume up for the channel that was low, the low frequencies
slowly disappear. Anyone has an explanation?

[Doublej]

I think I have something related to Robin Hood's Test recent results.

In my experimentation today I discovered that I can enhance significantly
the low frequencies from my single DWM if I lower the volume of one of the two
channels from the DAC.

Let me explain. While I listen to the Maggie+DWM, I turn down the volume of
the right or the left channel, and now I can hear the low frequency a lot
more. Initially I thought that when both channels are on, the satellites
are "masking" (or overpowering) the DWM, but I am not sure anymore.

As you turn the volume up for the channel that was low, the low frequencies
slowly disappear. Anyone has an explanation?

The speakers are out of phase in the bass region? Thus when you turn the second speaker up it cancels the output from the other speaker.

[stelo]

The speakers are out of phase in the bass region? Thus when you turn the second speaker up it cancels the output from the other speaker.

Something is really strange/wrong with the DWM. I tried to disconnect the satellites from the DWM,
so now only the DWM is powered by the Wadia 151 (the polarity is correct + with +, - with - from
the AMP to the DWM). If both channels are powered, the output from the DWM is really minimal
(it seems that the two channel are "cancelling" each other).

If I disconnect one channel, the DWM is working again. Should I talk to Magnepan?
(incidentally, I just noticed that the serial number of my DWM is #000666  )

[SteveFord]

Connect the speaker wire from the amplifier to the amplifier input on the DWM, observing polarity. Connect the "small" Magneplanar to the output of the DWM, observing polarity. (Note- There are no left or right inputs or outputs on the DWM Bass Panel.)

If 2 Bass Panels are used for a 2-channel setup, one set of connections is used for each Bass Panel.

----------------------
It's been a while since I had a DMW here but I only used one set of connections when I ran the DMW by itself.

[Doublej]

I this useful? There is also a wiring document on their site.

http://www.magnepan.com/usingDWMwithMMG

[stelo]

Connect the speaker wire from the amplifier to the amplifier input on the DWM, observing polarity. Connect the "small" Magneplanar to the output of the DWM, observing polarity. (Note- There are no left or right inputs or outputs on the DWM Bass Panel.)

If 2 Bass Panels are used for a 2-channel setup, one set of connections is used for each Bass Panel.

----------------------
It's been a while since I had a DMW here but I only used one set of connections when I ran the DMW by itself.

Thanks for these advices, but I was following these instructions.

I ended-up calling Magnepan this morning and spoke to Mark. He was puzzled, but he said that the only
explanation he had was the two channels where out of phase on the DWM. He advised me to switch the polarity for
one of the two channels of of the amp (instead of "observing" the polarity doing the opposite) and the DWM came back
to life using both channels. I asked him whether it is possible that inside the DWM the polarity was
switched -- he said "very unlikely, but possible".

[SwamisCat]

One of the two store sample DWMs that my dealer lent me to try at home was wired out of phase. It took me most of two weeks to figure it out, partly because not all the effects are negative.

The two which I later bought were both wired with correct polarity.

I love the bass improvement I get with to my 3a's. However, the quest to integrate everything is never ending. It isn't just a matter of adjusting the woofer panels, but also the mains, the listening seat, and the room treatment. With the DWMs I can get flat response to upper 20s, but this then leads to issues with timing and bass decay and power imbalance within the room.

BTW, doesn't this mean then that if I connect a separate speaker wire and connect it in parallel from the first speaker input and to the second that I will effectively double the output of each DWm? This would probably make a tough load for an amp which already is driving a full range Maggie, but wouldnt this work?

[stelo]

One of the two store sample DWMs that my dealer lent me to try at home was wired out of phase. It took me most of two weeks to figure it out, partly because not all the effects are negative.

It took me two weeks to figure it out too.
In fact, the experience has been so frustrating that I asked my dealer if I can return
the Minis and the DWM and "upgrade" to the 1.7

[clang]

What does "each input feeds one half of the DWM" mean? That there are 2 panels in one DWM, each fed by one of the 2 inputs?

[SwamisCat]

My understanding is that their are two overlapping internal panels, each driven by a separate input.

Steve, could you ask Magnepan if it is productive to ever "daisy chain" a panel to get both internal  panels driving rather than one? Is this a way to get even more output? (God forbid, as the things put out a lot already)

I have DWMs and am worried about trying it as an experiment. I don't want to blow anything up.

By the way, my learning experience with integrating the panels with full range three series could be converted into a book. In the end I got it to work, but it took tens, probably a hundred hours. The things are fascinating, but frustrating.

I finally have them dialed in though. I can no longer imagine going without them.

[SteveFord]

What does "each input feeds one half of the DWM" mean?

From Wendell:

That there are 2 panels in one DWM, each fed by one of the 2 inputs.  There are two voice grids which drive the same diaphragm.

[SteveFord]

Anything for SwamisCat.

Daisy chain is not a good idea since two crossovers would be in series. You could drive with separate amps, however. But, there is a limit on the output of the Bass Panel when driven too hard.

Let's hear about this DMW undertaking of yours, please.

[MarvinTheMartian]

From Wendell:
That there are 2 panels in one DWM, each fed by one of the 2 inputs.
There are two voice grids which drive the same diaphragm.

So with two mono DWM's ie. left and right,  that means only half the potential output?
No comprehend.

Shawn

[SwamisCat]

Thanks, Steve. I will not daisy chain mine.

Should I write up my experience with integrating the DWMs and start a new thread?

[SteveFord]

A new thread would be good.

Wendell's swamped, he's been on vacation which I think is pretty nervy of the guy.