[Elizabeth]

no longer available

[I.Greyhound Fan]

I use  Duelund 1.2ohm graphite-silvers resistor in my 1.6's.  They smooth out the high frequency without removing too much and sound much better than the Magnepan resistors.  Also tried Mills 1.2 ohm 12watt resistors.  They give a slightly darker and warmer sound but the sound stage seems just a bit smaller compared to the Duelunds.

http://www.partsconnexion.com/resistors_duelund_cast.html

http://www.partsconnexion.com/resistors_mills_mra12.html

Can you use the chokes in the 1.6/1.7's?

[Elizabeth]

no longer available

[rollo]

   If one uses a resistor check out Duelund. Like the choke method check out Speltz Cable. Also if unhappy with tweeter being too hot try toeing in and or out your speakers. Reflections can cause a altered top. Have fun ya'all.


charles

[I.Greyhound Fan]

I do not know if one can use the tweak in 1.6 or 1.7
The easiest way would be if they had the extra Maggies gizmo ports for a resistor.
Otherwise it could be added in line with the speaker cable.

(I took off the midrange one. just to dull) back to straight through for the midrange.

The 1.6/1.7's do have the tweeter jumpers and come with the El-cheapo sand resistors to tone down the tweeters if needed.  For that matter so do the MMG's.  That is where I have my Duelund Resistors which dial back the tweeters by a little more than 3 db. I believe.

The Duelunds are expensive, but well worth the money.

[GregDunn]

Do we actually know what inserting an inductor into the circuit does to the speaker response? (Incidentally, a 10 µH inductor is not an RF 'choke' - that would be pretty much the same as an open circuit at audio frequencies.)  Clearly it is going to alter the amount of overlap between low and high frequency drivers, but it might also cause a dip or peak due to phase issues at the crossover point.  Has anyone measured the result?  I wouldn't mess with the crossover unless there was an improvement in measurable transient or frequency response; the midrange is an area where the ear is very susceptible to small changes and it might be perceived as an improvement when in fact it's causing unwanted changes in a different frequency band.

[Elizabeth]

no longer available

[Davey]

A 10uH inductor is not "open at audio frequencies."  C'mon folks, the misunderstanding regarding this "choke tweak" just grows through the years.

A 10uH inductor connected to a 4 ohm load forms a simple low-pass filter with a turnover point around 60khz.  A 10uH inductor is actually a short circuit at audio frequencies into a Magnepan load.

Dave.

[Elizabeth]

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[Davey]

Or you just do not understand where the choke is placed?

You're kidding, right?

And no, I don't like tweaks.  Especially when they're misunderstood by those formulating them and those applying them.

Dave.

[Elizabeth]

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[Davey]

Correcting misstatements and outlining the basic filter function of this tweak is troll behavior? 

BTW, this is not "your" thread and I will respond to whatever thread I darn well please.  If silly accusations are all you have to offer in reply, maybe the real troll is looking at you in the mirror?

Dave.

[SteveFord]

If you have something constructive to add please do so without the insults.

[Pryso]

Hi Elizabeth,

Sorry but another curiosity question.  Didn't modifying (adding the choke) your new speakers jeopardize the warranty?  I would think after your problem with the first pair you would want coverage for at least several months to complete a full break in.  I'm not familiar with the 20.7 so if that was a simple plug-in then disregard my question.

That aside, nice to hear you are now so pleased with them. 

[josh358]

Hi Elizabeth,

Sorry but another curiosity question.  Didn't modifying (adding the choke) your new speakers jeopardize the warranty?  I would think after your problem with the first pair you would want coverage for at least several months to complete a full break in.  I'm not familiar with the 20.7 so if that was a simple plug-in then disregard my question.

That aside, nice to hear you are now so pleased with them. 

I wouldn't worry about it. The choke isn't being added inside the speaker, it's just being placed in series using the external resistor jumpers. So there's no modification or harm. It's just an RF filter that supposedly keeps RFI from getting back into the amp through the Zoebel network. Al believed that Maggies acted as antennas!

If this is indeed an issue, it would presumably be a variable one, as it would depend on the strength, direction, polarization, and frequency of RFI in your neighborhood (and for that matter the behavior of your amplifer). Worst case I think would be vertically polarized, edge-on, wavelength twice the voice coil wire spacing -- ouch! Then you have a nicely-tuned multi-element antenna. OTOH, you have the perforated pole piece right next to it, which would tend to act as a ground plane, even though not grounded.

I didn't follow the original discussion so don't know if Al actually did any measurements to check for RFI. I'm personally skeptical, but others have pointed out to me that the standard Zoebel network isn't as effective as an RF filter as I'd believed.

Bottom line I think is that if it sounds good, go for it, it won't do any harm! There are other things a choke might be doing -- forex, I've wondered about the possibility of high frequency aliasing or noise shaping intermodulating in the ribbon tweeter and getting into the audible range. Nobody knows what the high end of these ribbons is, because the mic Magnepan used to test them had an upper limit of only 40 kHz! But dynamic tweeters can get to 40 kHz, and a ribbon is less massive, so . . .

[Elizabeth]

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