Magnepan McIntosh 5.2 System

[mgard]

Ian,
I didn't know you were a mad scientist along with being an Audiophile! Thank you for taking the time to give a detailed report. I share your excitement and it put a smile on my face too. Nice picture of your room. Keep safe in your travels and when you are ready to share some more details, we are all eyes.

~Mike

[bzr]

Ian, Inva Mula does sound good even if she was computer enhanced on The Fifth Element. Thanks for the write up & look forward to your further writings of your system.

[audiot servant]

Ian - Just one pair of 20.7s can launch a resonant planar wave that just about dissolves the fabric of space and time... hmmm 15 ribbons and two subs... that room would be so energized from top to bottom you could just about hurt yourself or at least experience a bit of weight loss. I find the experience of music with the big Maggies is as physical (and not just in the bottom end of the range) as it is emotional... looking forward to hearing some more.

Graham

[Ian]

Mike
Mad scientist! I like the sound of that

Kev
Was Inva's octave range enhanced or was she digitally modified visually?
I note from another thread that your new system is coming together. It looks terrific

Graham
I am looking forward to measuring the planar output of the Maggie's.
In the process of putting the ribbon tweeter assemblies in to the Magnepan 20.7's I measured the magnetic field across the approximate 6 mm air gap in the magnetic circuit (where the ribbon is suspended). It varied between 0.1 and 0.15 T (Tesla). This is very low and explains the low sensitivity of the Magnepans. I was initially rather worried that even the McIntosh MC601's might not be up to the task of driving them. However I find that the power requirements rarely exceed 100 W even when playing really loud music. I suspect that it is the inverse roll-off in sound power level with distance typical of ribbon speakers (rather than the inverse square roll-off of cone speakers) in the near field (which the 20.7's certainly are in my room given their height) which is effectively compensating for the low sensitivity.

Any way, when I return next week from my trip, I will be sure to measure and post the roll-off function for both the 20.7's and 3.7's.

Best, Ian

[mgard]

Huhhhh, what did he say????

Does that mean it sounds good in Lyman's terms.....


~Mike

[Ian]

Mike
Yes, its all very good

My comment to Graham had to do with planar speakers acting as a dipole in the near field.

Let me explain: For a ribbon speaker like a Maggie you are in the near field region when you are within about 5 to 6 times the height of the ribbon. So for a 2 m high 20.7 ribbon you are in the near field when you are within about 10 to 12 m (<40') of the speaker. As you move away from a regular cone based speaker the sound power "dies away" ("rolls-off") very rapidly (inverse square of distance). The beauty of Maggie's in the near field is that the sound power decreases much more slowly (inverse with distance) compared with a cone speaker. All of this assumes that you are in a room with no reflections (anechoic chamber) which is not true of most rooms.

So my point is that I thought it would be fun to measure the 20.7 and 3.7 roll-offs with distance to see in a "typical" room just how much more sound they produce at a certain distance when compared with regular cone speakers.

Bottom line: Maggie's rock

Best, Ian

[mgard]

Ahhhhhh, said the blind man to his deaf daughter as they stood facing each other back to back. Ian you must have an engineering back ground. Or maybe you are a phycis professor. Anyway it was very interesting reading about your tests. I'm glad you are here at AA. I think it's about time for Graham to give us another update on what his favorite tunes are sounding like. Rayooo's 20.7's should be showing up soon too.

~Mike

[bzr]

Well, according to google Inva's voice was enhanced

[GaryProtein]

Originally Posted by Ian

Mike
Yes, its all very good

My comment to Graham had to do with planar speakers acting as a dipole in the near field.

Let me explain: For a ribbon speaker like a Maggie you are in the near field region when you are within about 5 to 6 times the height of the ribbon. So for a 2 m high 20.7 ribbon you are in the near field when you are within about 10 to 12 m (<40') of the speaker. As you move away from a regular cone based speaker the sound level "dies away" ("rolls-off") very rapidly (inverse square of distance). The beauty of Maggie's in the near field is that the sound level decreases much more slowly (inverse with distance) compared with a cone speaker. All of this assumes that you are in a room with no reflections (anechoic chamber) which is not true of most rooms.

So my point is that I thought it would be fun to measure the 20.7 and 3.7 roll-offs with distance to see in a "typical" room just how much more sound they produce at a certain distance when compared with regular cone speakers.

Bottom line: Maggie's rock

Best, Ian

To simplify what the Mad Scientist said:

With a line source (ribbon), the sound level decreases proportionately with the distance, whereas with a point source (cone) the sound level decreases proportionate to the square of the distance.

In still other words, with a line source/ribbon, the sound decreases by 3 dB as you double the distance, whereas with a point source/cone, the sound decreases by 6 dB as you double the distance.

Oh, yeah, and Maggies rock.

[Hornet77]

Holy Smokes! Running 2 Sub1, the bass response will be insane on that because they go down to a 7hz response, i hope your walls and and flooring are sound proof or that the windows are re-enforced. I'd love to hear that system. In our store we have a similar system hooked up like, we will use 3.7s hooked up to either the MC601 or MC1.2Kw just as stereo but we use full McIntosh equipment for power conditioner, pre amp (tube) and cd player (MCD301). Where are you from?