Welcome! Need support, you got it. Or share your ideas and experiences.
In Reply to: RE: Danny Richie of GR Research VS Magnepan posted by TitaniumTroy on December 30, 2020 at 18:01:54
I had seen this on YouTube a few days ago and was interested.
When you say..."He wasn't a fan of the changes made..." has your friend tried the modification/new x-over?
Or is this based on Danny's description, which is light on information.
Okay as and example he didn't like the flattening out of the bass hump, because Magnepan designed that to compensate for the speaker being open baffle. Hence bass frequencies cancel each other out when the back wave meets the front wave.
How is it that Danny "flattened out the bass hump" by just altering the crossover configuration?????? I don't know what you're referring to there.
That bass hump is inherent.....and can't be flattened out without electronic equalization and/or some very large value passive parts.
Davey, DR explains what he did in the video. It's pretty simple, not many parts. He changes the tweeter high-pass filter slope from 1st-order to 2nd, which he claims lowers the sense of "strain" the driver exhibits when pushed. I don't remember how he brings the lower and higher frequencies into more even response, I'll have to watch the video again.
He also suggests discarding the rear plate and the speaker binding "posts" (suggesting his Tube Connectors for use in their place) and fuse parts (they contain numerous ferrous elements), and making a new plate out of perhaps MDF. He sells the Mod Kit for a couple hundred bucks (per pair) iirc, but not using the Tube Connectors (some Maggie owners have installed Cardas binding posts in place of the stock) will save you $59/pr.
I watched the video. He doesn't explain anything regarding the bottom end of the speaker. Which would be very difficult to address anyway....as I said.
Nor whether he changed the crossover from series to parallel....which I assume he did.
There's a lot of hand-waving in Danny's video's, but very little specific information. I don't understand what some folks see in them, but he appears to be impressing the beginner type audiophiles.
I just rewatched the video. DR states he brought the low end down with an inductor on the bass/midrange driver. I don't know how anyone could miss that ;-) .
The 1.6 comes from the factory with a parallel x/o, the 1.7 with a series, correct? DR says the 1.7 has two elements in parallel on the tweeter---sort of a dual voice coil, he says---with a resulting 1.9 ohms impedance at high frequencies. To raise that impedance, he suggests rewiring the two elements in series.
I know some prefer the 3.6 to the 3.7 because the .6 Maggies have a parallel x/o, which allows bi-amping with an electronic x/o, unlike the series x/o .7 Maggies. Given the price of the 1.6, that may not be as common with them.
His plots don't show the "low end." (Everything is 200Hz and above.)
The only way to bring the low end down would be to use an inductor with much increased DCR. If he did that, I don't see the wisdom in that approach. The system is already very low in efficiency.
Also, in my opinion, the top end of the stock 1.7 is actually a bit too bright without the resistor in. I think Danny's hearing might be going if wonders where the highs are. :)
I'm well aware of how the 1.7 tweeter is wired and works. But Danny chose to reconfigure it. It's actually very easy to do by clipping one leg of the 10uF capacitor. But he made it sound like a complicated process and probably confused some folks. :)
The pair of 1.7's I heard didn't sound bright, but they did sound somewhat "wispy": thin, un-fleshed out, no color or body to instruments.
I'm not aware of a general consensus that the 1.7 sounds bright. in fact, quite the opposite: soft. Davey, you found the ET LFT-8b to be bright too, choosing to use the lowest output tap on the tweeter. Perhaps you are more sensitive to very high frequencies (the LFT-8b tweeter high-pass filter is at 10kHz) than average?
Brightness in a loudspeaker is located at a far lower frequency than 10kHz of course, but the LFT-8b tweeter filter is 1st-order, so that driver is still putting out a lot of sound at 5kHz (6dB down relative to 10k), even 2.5kHz (12dB down).
I'd still like to know how Danny "brought the low end down" on these speakers without using an inductor with significant DCR. That info is not in his video.
If you can explain that one to me (without speculating) it would be appreciated.
If you look at the plots, the 1.7 bass is down by @ 3dB @ 200Hz and @ 5dB @ 300Hz, but the rolloff at 65Hz is still @ 2.5KHz suggesting the bass panel's slope rolloff is shallower after the mod.
Is it possible he also changed the bass panel's XO ?
Tim, in the video DR states he left the bass/midrange driver filter slope stock. A call to him may answer every question one has.
Like everyone else here, I know only what's in the video. Anyone who buys DR's mod kit for the 1.6 and 1.7 will get a pair inductors, and be free to provide it's value to any interested party, assuming DR doesn't remove any value designation on the part, as do many other modifiers. For that same reason, a call to DR asking for that value may have his request denied. ;-)
Here are the plots from the video. I would have to watch it again, but I think the first 2 are the 1.6 before and after and the second 2 are the 1.7 before and after.
He did say he put the 1.7 tweeters in series.
He also said he raised the impedence on the Maggies so they didn't dip so low. I didn't grab those plots, but you can scan the video for them.
It looks like he lowered the 1.7 hump by @ 5dB. Part comes from the faster tweeter rolloff.
Would like to see what the rest of the plot below 200Hz looks like both before and after.
Danny never posts measurements below 200Hz.
He doesn't have the facility to effectively do that, I guess. And certainly not with a large/dipole speaker like a Magnepan.
Where dipoles exhibit cancellation is at either side of the loudspeaker/sub. The back wave meeting the front wave CAN create out-of-phase cancellation, but also in-phase reinforcement. That is true for all dipoles. It is a function of frequency and the distance of the dipole from the wall behind it, so designing in a "bass hump" to combat that phenomenon is not possible unless a mandatory dipole/wall distance is specified by the designer.
And you know, Danny Richie designs dipole loudspeakers and subs (though not in a manner that satisfies Davey---see above), and is well aware of all the above. DR has not found the skewed bass response exhibited by the MG1.6 and 1.7 in other dipoles he has tested (not to mention designed).
FWIW, Danny said he measured them (using a CLIO system) out in the room and not near field because they are large panels.
That being said, he didn't give the dimensions of his room, nor how far the speakers were from the walls, nor the gating settings so we don't know the specifics of his room's influence on the measurements.
I had 1.6's a long time ago, but never took measurements of them when I had them.
All true Tim, and valid points. But DR has measured many other dipoles in exactly the same manner, and not found the frequency response "problems" exhibited by the MG1.6 and 1.7.
I have heard the 1.7 (at the same dealer in Portland who demoed the 30.7, but in a different room), and didn't care for it. I much prefer the Eminent Technology LFT-8b, and the various Tympani's (I've owned three pair: T-I, T-ID, and my current T-IVa.). Still gotta hear the 3.7!
Post a Message!
This post is made possible by the generous support of people like you and our sponsors: