Planar Speaker Asylum

Welcome! Need support, you got it. Or share your ideas and experiences.

Planar Speaker Asylum

RE: Choke differences.

76.161.241.115

In Reply to: RE: Choke differences. posted by Al Sekela on August 16, 2010 at 10:44:52

When I first read about this the suggestion was for the ribbon tweeter only.
Are you now recommending this treatment for each driver, whether 2 way or three way.
So it goes.........

Follow Ups:

FWIW - Dawnrazor 21:02:52 08/17/10 (4)
I have the 5502 on each driver on my mmgs. And I am using the capless crossover.

I noticed a big difference on the tweeter and a smaller difference when I did the bass driver. But a difference. There are alpha core inductors in both those low and high pass crossovers, and I still heard a difference.

I am through with passive crossovers but will keep the chokes and rc networks when I finally go active.

My 2 cents is that they are so cheap, just add them to the other drivers. If you dont dig them, then I bet you could easily sell them to another inmate.

No one here remembers the bending of our minds
- RE: FWIW - plus calling Davey - JBen 23:38:18 08/17/10 (3)
  That's why I ilked the chokes when I first read about them and tried shortly after. They did a lot of what the capless inductor was helping with (in terms of imaging).
  
  Which reminds me, D, I keep wanting to bring back that inductor into the equation again for testing. During the early days, when I tried the chokes along with the inductor, I had some interesting imaging presentation. I did not tweak for it, as I was already going to line-level filtering. So, the inductor left the scene. Yet....
  
  oh Daveyyyy...here is one I've been meaning to ask you about for a while:
  
  a. Right now, the tweeter already gets the signal already filtered, in 1st order, directly from the amp
  b. In the past, the "capless" tweak, required a resistor in series and the inductor in parallel to the tweeter, for a 1st order filter. The resistor burned tons of energy but it was required in series with the tweeter.
  c. What happens if I keep the line-level (1st order) but in addition add the inductor + resistor BOTH in parallel with the tweeter.
  
  In effect, I would get a 2nd order filter of some weird kind, I guess. More to the point of my question, would it be safe to move the resistor to that parallel position, in series with the inductor? At this spot, I suspect, it would still prevent a short without causing much of a drop.
  
  This twisted mind of mine thinks that, perhaps, the combo could serve a good purpose. I don't know the proper values yet, but as long as it is relatively safe, I'd like to try it with the parts that I already have.
  
  For inductor, I can use the .39mH/.20 DCR that I used for capless.
  
  A resistor value of 8 ohm would - I think - make this kick in at just under 3300hz, slighty below were the first filter would already have done the job. (Oh, yes, for the first 1st order filter at line level, assume a similar slope of a 2nd or current design MMG.) So, much less energy is left.
  
  The theoretical desirability of doing this kind of thing is probably well south of the sanity mark. I just need to know that I am not burning an amp by trying.
  
  Yes, I know...I'll take my pills later, promise.
  - RE: FWIW - plus calling Davey - Davey 07:13:50 08/18/10 (2)
    Well, if I understand your question correctly, adding an inductor + resistor (wired in series) in parallel with the tweeter probably won't have much effect. The impedance seen by the amplifier will be modified such that the amplifier will see a lower than driver impedance at low frequencies, but at higher frequencies it would be like the circuit wasn't even there.
    
    You're amplifier is functioning as a voltage source, ie, it's going to supply a voltage shaped by the line-level filter ahead of the amplifier. Anything wired just in shunt...without a companion series element...is not going to have a desired (or consistent) effect in the audio region. This is why the "capless" high-pass filter requires both elements (resistor and inductor) to work properly.
    
    Cheers,
    
    Dave.
    - RE: FWIW - plus calling Davey - JBen 08:15:14 08/18/10 (1)
      Tks! That's along the lines of what I could only speculate about.
      
      So, the minimum impedance that the amp would see is about 2.7ohms, depending on the frequency?
      - RE: FWIW - plus calling Davey - Davey 21:11:40 08/18/10 (0)
        
        In Reply to: RE: FWIW - plus calling Davey posted by JBen on August 18, 2010 at 08:15:14
        
        Yep, somewhere in that neighborhood.
        
        Also, your amplifier may have some sort of RC network internal on the speaker outputs anyway. Many do. These are included for stability purposes on many amplifiers so they don't see high resistance loads outside (higher) the audio frequency range.
        
        Cheers,
        
        Dave.
Theoretically, - Al Sekela 14:58:17 08/17/10 (1)
the chokes should help in any configuration where there is a direct HF path from a speaker driver element to the amplifier. I have not used them in series with my MG-20 tweaked crossover sections for midrange and bass panel because there are already inductors in series with the drivers. The chokes would only help if these inductors had such poor self-resonance that they would permit RF noise picked up from the drivers to flow freely into the amp. I can't rule this out because I've not done the experiment.

In setups with active crossovers, the amps are connected directly to the driver elements and should benefit from use of the chokes no matter what driver is involved.

Maggie drivers are good antennas and can allow RF noise in the local environment to get into the amplifiers.
- RE: Theoretically, - pictureguy 22:00:33 08/18/10 (0)
  And I live <1 mile from radio transmitter antennas.....big un's.
  Too much is never enough
RE: Choke differences. - JBen 20:26:00 08/16/10 (0)
Sorry, I missed this earlier. Yes, early last year I found out about the chokes because I "ventured" into a 3.6s discussion.
Upon reading about the sound improvements that the chokes caused in the upper Maggies, I had a haunch.
I was already getting something akin to these improvements, but in my MMGs. Not "ribbon" sound, mind you. But at least far better than I had before the "capless" tweeter mod that gave me these improvements. Given some drawbacks of going "capless", I wanted to move on to a line-level xover.
One little problem with that...early tests suggested that in simply going to line-level, I could lose a valued contribution of "capless".
This contribution was better imaging and 3D soundstaging. When I read that the chokes were doing this for some of the upper Maggies, I JUST HAD TO TRY!
I got the chokes and I also went to the line-level xover. It worked, grandly.
Around that time, other users picked up on the discussion of the chokes and tried it in their non-ribbon Maggies. Many reported solid results. Others could not hear much of a difference. All I can say is that, here, they have become key to enhancing the 3D imaging sound of my system.
Al Sekela is the originator of the chokes idea. If you search around for his inputs, you will find valuable details.
[Edit: I forgot to add that imaging attributes are not the only contribution of the chokes to my system. I consider them partly responsible for the cleaner-sounding upper registers in my tweeters. I had never expected the upper end to get this good because, indeed, that is "ribbon" territory. On SACDs, friends can't believe the extension and cleanliness that these cheap old MMGs can deliver. That does not happen if the chokes are off. It will only get better the day I can afford 3.6s]

Edits: 08/16/10

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.

This post is made possible by the generous support of people like you and our sponsors:

VH Audio