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

---

[ Follow Ups ] [ Post Followup ] Thread: [ Display  All  Email ] [ Planar Speaker Asylum ]

---

[ Alert Moderator ]

---

RE: Neolith has posted Excel Spread Sheet for magnepan speakers

Posted by ghost4man (A) on April 25, 2017 at 18:50:59

In Reply to: RE: Neolith has posted Excel Spread Sheet for magnepan speakers posted by Satie on April 25, 2017 at 08:12:05:

Hi Satie,

During the testing phase with my other 3 amplifiers I actually blew the true ribbon in the 3 way active set up.

At that point I pulled the pin on doing any additional testing until I could source an amplifier that was capable.

It was at that point that I accidentally stumbled across the Lexicon.

One of the good things about it is its claimed stability into a 2 ohm load. Now being stable AND being musical dont necessarily mean the same thing.

Thus far the testing with the Lexicon has been really really impressive.

In the absence of the true ribbon I have been going 2 way active with the Lexicon dealing with the bass duties and tweeter duties.

I havent gone for anything extravagant in terms of XO. By this I mean I have retained the intrinsic XO point at 1100Hz with a 6dB first order slope.

Now one of the bigger differences has been the complete elimination of ALL the PEQs that I had in place from previous testing. In other words they have been bypassed. I have gone for the minimalist approach at the advice of some colleagues.

Results thus far have been very very good.

By comparison, the previous setup with the other 3 amps were dreadful. So much so I reverted back to the passive setup.

This has been a big wake up call to me as to the importance of having an amplifier which isnt just sufficient in terms of brute strength but more importantly can deal with 2 ohm loads.

To my mind there is no point having a 10k amplifier that has all the bells and whistles and is stable into a 4 ohm load but bleeds out when presented with a consistent 2 ohm load.

When you say:

"The power demands for the tweeter are not that great so the Lexicon is well built and well designed and should do well."

I am not so confident about that. There is still a lot of territory that the Lexicon has to deal with in terms of frequencies from 1100Hz and above.

Dont forget my other amplifier only had to deal with the true ribbon from 3-4k and that resulted in a bad outcome.

I have looked at the Theta Dreadnaught which seems to be a weapon of an amp in its own right whether for musical listening or HT.

I dont quite understand your comment about the bass panels.

In the active state they are linked in series which means the amplifier will a single speaker with an impedance of 8.5 ohms.

If I go down the path of keeping the passive option I can either retain the series setup or go parallel. The latter gives me an impedance rating of just over 2 ohms which in itself is another problem because that would mean in the existing setup that I would have the existing tweeter sitting on 2 ohms as well as 2 bass panels presenting a 2 ohm load.

So when you say:

"wiring the bass panels in series you would not be able to make a single amping option with a simple crossover. ?

Can you explain what you mean here because that is precisely what was done.

Just remember the original setup for the T1Ds was 2 way with a first order 6dB slope cutting off at 1100Hz.

If you maintain the intention of keeping the cutoff at 1100 as well as a first order slope then would it not be the case that you adjust your cap an inductor to suit? Or does it get more complicated?

Now if I decide to add the TR into the mix its a game to see at what point I cut off the existing tweeter.

Right now my gut is telling me that 5k would seem appropriate.

I have had a look at the historical values and it seems the earlier versions were kicking into gear around the 3k mark. My understanding is that the 3 series maggies all used the later TR and were still cutting off at 3k??

So in a 3 way active setup I would be looking at those cutoffs. Thats my gut feeling at the moment. I am building a Holton Precision Audio amplifier here in Australia which is rated at 800wpc into 4 ohms with unconditional stability into a 2 ohm load. I could use it and the Lexicon for the drivers and feel very confident about their ability to handle the lower impedances.

Ideally I want the option of passive and active especially for resale purposes. Not everyone is inclined to want to buy a set of speakers which would require 6 channels of amplification.

I am looking at contacting a guy over here is Oz who is highly regarded and has worked on ESLs a lot. I've been told he may have similar experience with maggies but I will have to speak to him to find out. More importantly he has the reputation of being very astute in terms of XO design.

Have to wait and see though. I am finally starting to get some decent results. Its been 12 months of getting constantly pushed back with one drama after the other.

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

Kimber Kable

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---