Adding mid-bass drivers to 1.6 magnepan to handle 150-50hz range with active XO

[icenoir]

Looking to increase movies action sequence thump, I am add stereo 8 inch subs (Dayton hf) to Maggie's to handle the mid-bass, I believe similar to how Martin Logan ESL do. I have a 15 inch sub for the lower frequencies.
Anyone do something similar?

 

[studiotech]

Do some searching here and at the Audiocircles forum in the planar section. Plenty of people do it. For it to be most beneficial, you need to cut those same frequencies from the Maggie, since that's the region where it struggles most with distortion and output capability.

 

[icenoir]

Yes. The Maggie's are actively crossed as well.

I saw one post with a wall of subs crossed at 400 hz to 3.6 panels. That's far beyond what I have..

 

[EdGr]

I measured the MG1.6 bass panel resonance at 47Hz. The MG1.6 should be good down to 42Hz.

If you want more mid-bass, you may want to try attenuating the tweeter. I use 0.39 ohm resistors to reduce the tweeter level by 1dB. This makes the MG1.6 even more coherent by narrowing the gap at the crossover.
Ed

 

[icenoir]

Thanks.. I have an active crossover and dirac. Should I drop the gain on the tweeter 1db?

I know the panels can run deep, I just don't feel they have a lot of thumb for home theater.
I will cross the bass panels at 150hz which may or may sound better. Will see...

 

[EdGr]

Yes, try 1dB of tweeter attenuation. How closely does the active crossover replicate the stock crossover? The stock crossover was designed with a gap between the high-pass and low-pass sections.
Ed

 

[icenoir]

It should be exactly the same a passive, at. 600 hz 12 db I believe .
I can program it to anything.. not aware of a gap?

 

[EdGr]

The low-pass section is 12dB/octave. The high-pass section is 6dB/octave. The crossover is at 600Hz but -9dB.
Ed

 

[icenoir]

Thank you. I will check what I have it at..

 

[BeardyWan]

I built a stereo pair of a similar thing to a Linkwitz ripole and used it with some satisfaction with a pair of 1.6QR Maggies. I have since moved on to a GR Research pair of Hiframes using a pair of 12 inch active corrected drivers. It works well. Whatever you do I think it is important to try to use a open baffel type sub to get a good match with the maggies.

 

[icenoir]

The low-pass section is 12dB/octave. The high-pass section is 6dB/octave. The crossover is at 600Hz but -9dB.
Ed

I had all that except the -9 db for the tweeter... Thanks
I'm guessing Dirac fixed it?

 

[EdGr]

I don't know about Dirac.

Does the active crossover allow setting the low-pass and high-pass frequencies independently (to match the response of the stock crossover)?
Ed

 

[icenoir]

Yes, many options including delay and peq as well. Amazing machine. Xilica 4080.

 

[EdGr]

Okay. I suggest starting with the response of the stock crossover so that you know what the MG1.6 sounds like in stock form.

You have the hardware to do better dipole compensation than the stock speaker (which uses the crossover and bass panel resonances). The stock MG1.6 has a lot of boost in the mid-bass.
Ed

 

[icenoir]

Yes, familiar with the xo. I have been using the DSP for years, just now adding an mbm for mid-bass now...

 

[icenoir]

Regarding mid-bass boost on 1.6 panels. I did not see that on the dirac graph...

 

[EdGr]

That's at normal distance, right?

Here is my measurement at 1m. It includes the room. Hum is visible at 60Hz and 120Hz.
Ed

 

[icenoir]

Thanks. Also saw a similar graph from the 1999 sterophile review. Next time I run Dirac I will try to capture the graph, although I think it shows all the channels combined.
Do you know what(if any) delay should be applied to the tweeter?

 

[EdGr]

Yes, my measurement has the same general shape as Stereophile's measurement.

Delays should not matter. The significance is in the peaks. The valleys should be ignored - they are due to cancellation at that particular placement of the microphone.
Ed

 

[Speedysteve7]

I like reading about these projects.
Improving on a commercial system that was left less than perfect (for whatever reason).

It's like the veteran / classic race cars that are run today by enthusiasts and are far better developed than they were when competing back in the day.

You could explore getting your Mags and the added mid bass drivers phase aligned, and the sub phase aligned with the mid bass.
I only speak from horn loaded experience though..