Magnepan DWM amp & crossover

[Audiobill]

When adding the DWM to larger Maggies, Magnepan suggests adding a 1.4mh inductor and/or resistors to tailor the response of the DWM. The inductor will roll off higher frequencies at about 200 hz, too high imo. Since these parts effectively serve to alter the crossover, I decided to try this
Dayton crossover / amp to tailor the response much more effectively to my specific room and speaker placement:

https://www.parts-express.com/dayto...MImdqNuaGA5gIVCZ2zCh1rpwnYEAAYASAAEgIrbPD_BwE

Works like a charm!!

Benefits:

Stereo
Adjustable hf rolloff frequency (I settled on about 70hz)
Adjustable level (and remote included to get it perfect from listening position)
More than adequate power into very low impedance
No need to interfere with main speaker outputs to drive dwm
Line level outputs to drive other components if needed
Very low price (less than $200)

Very happy with results!

Bill

 

[Blue Shadow]

Great that you are pleased with the system, but could you let us know what it is other than the Magneplanar DWM? A friend is thinking about DWMs

 

[Audiobill]

 

[Audiobill]

Current lineup:

Conrad Johnson ET-5 preamplifier
Conrad Johnson Premier 140 amps (two), wired as 280 watt monoblocks
Conrad Johnson MV-60SE amp
Custom VTA SP-14 preamplifier (two)
PS Audio Directstream DAC
Thorens TD-316 TT
Grado Silver Cartridge
Emotiva XPS-1 phono preamp
Sennheiser HD-600 Headphones
Dynaudio Gemini speakers
PBN Montana EPS speakers
Magnepan 3.6/R speakers
Magnepan DWM bass module
Mac Mini as server

 

[Blue Shadow]

It does seem that Magnepans want to run full range and that subs should be rolled off fairly early to get the best integration. That does look like an inexpensive way to get the DWM to work with lots of option to duplicate that with wallet emptying gear on par with the rest of the rig.

The owner of the Tympani IVs I'm using right now is looking at sub options and that includes the DMW. Your 3.6 are down 3dB at 34 Hz and the DWM is rated as a 40-200 Hz but Magnepan says they work fine for the 20.7, too so they must have some oomph down below 50 and even an octave lower.

You mention 1.4mH and the article on Magnepan's site says 1400mH. Just mentioning that.

Glad that sub amp works for you.

 

[Audiobill]

Thank You.

With my main amps off, I can hear, and feel, the contribution the DWM is making down low.

As for the inductor value, I believe the 1400 mh value you cite from a user review is in error.

From Magnepan's actual DWM manual:

"If the Bass Panel is adding too much output in the lower midrange or upper bass, a 1.4 mh inductor (with low DCR) can be installed in the Attenuation terminals for a faster roll-off rate. Inductors are available from Magnepan."

Also, here's an extract from an lcr resonance table to support this:

Speaker Impedance
2 Ohms 4 Ohms 8 Ohms
Frequency L1 C1 L1 C1 L1 C1
80 Hz 4.1 mH 1000 uF 8.2 mH 500 uF 16 mH 250 uF
100 Hz 3.1 mH 800 uF 6.2 mH 400 uF 12 mH 200 uF
130 Hz 2.4 mH 600 uF 4.7 mH 300 uF 10 mH 150 uF
200 Hz 1.6 mH 400 uF 3.3 mH 200 uF 6.8 mH 100 uF
260 Hz 1.2 mH 300 uF 2.4 mH 150 uF 4.7 mH 75 uF
400 Hz 0.8 mH 200 uF 1.6 mH 100 uF 3.3 mH 50 uF
600 Hz 0.5 mH 136 uF 1 mH 68 uF 2 mH 33 uF

From these values, you can see that a 1.4 mh value will roll off the 4 ohm DWM's bass at above 400 hz. Even used in parallel with main speakers (2 ohms!), 200 hz is still too high to integrate well with the larger maggies like my 3.6/R. Without an inductor at all, the dwm goes all the way up to 2 Khz.

I think the extra panel area of the dwm is responsible tor the added "oomph". Not necessarily lower, but louder down there.

A "poor man's" way to get even more panel area with the 3.6/rs than the 20.7's offer, at a huge savings to upgrading the actual speakers. I'll probably even add anothar dwm in my 40' l x 20' w by 18'h , 14,400 cubic foot listening room.

Since the Dayton sub amp is stereo, very easy to do.

Best,

Bill

 

[Blue Shadow]

I'm using 0.5mH coils on my IIIas so that 1400 struck me as not quite right but it is on the Magnepan site.