Bass Panel Magnet Alignment Technical Query

[User211]

I was wondering why the bass panel magnet aligment is as it is on the ribbon speakers. It follows the straight vertical line of the panel. That seems counter-intuitive to me. Surely they'd be better being equi-distant between the diagonal(ish) and vertical edges, as the ribbon(ish) panel would be covered with a more even force in the place where it is capable of the most deflection?

Thoughts?

[Duetta86]

I asked the same question on the old boards. Essentially, it dosen't make any difference, and may cause more problems.
Honestly, the guys who designed the speakers were rocket scientists, I'll bet they tried all kinds of configurations and used the best ones.

[User211]

Duetta86 - do you have a link to the thread? I'd really like to read it.

[Graz]

DEFINITIVE and SYNERGY follow the slant/straights, in different ways...

Take care - Graz

[joseph]

Graz - That has got to be the most enigmatic sentence I've read in a long time! I would call that "trolling" so here goes - I'll bite. What on earth do you mean?

Joseph

[Duetta86]

Duetta86 - do you have a link to the thread? I'd really like to read it.

Sadly, no. It was several years ago, and would be rather tough to track down. If I remember right it was a member that was/is making his own version of a ribbon speaker.

[RedAlert]

How accurate the magnet alignment is? I took a look to my duettas (bass ribbon is not in place) and some magnets are few millimetres off the straight line (both vertical and horizontal). Is this someway effective to the sound? Should I correct this? BTW...about the kapton and aluminiumfoil...what should their thickness be? And when I looked the old damaged ribbon, it seems that kapton and aluminium are just glued together...perhaps some siliconebased glue...What about the tension on bass ribbon? (or are these "classified information" ). Thanks in advance if someone bothers to answer...

[Groove-T]

How accurate the magnet alignment is? I took a look to my duettas (bass ribbon is not in place) and some magnets are few millimetres off the straight line (both vertical and horizontal). Is this someway effective to the sound? Should I correct this? BTW...about the kapton and aluminiumfoil...what should their thickness be? And when I looked the old damaged ribbon, it seems that kapton and aluminium are just glued together...perhaps some siliconebased glue...What about the tension on bass ribbon? (or are these "classified information" ). Thanks in advance if someone bothers to answer...

Magnet alignment = Efficiency and Q. You can correct only when foil is removed, it is important.
Thickness ali = Impedance and power capability, Thickness Kapton = Tension = Power capability & Tuning
Alu/ Kapton is glued together. Do you have a better idea how to attach it to each other?
Glue = Secret, affect durability and sound
Tensioning = Tuning

[RedAlert]

Am I guessing it right...for kapton/aluminium...the thinner the better (=low mass)...?

[Groove-T]

Low mass is good for tweeters, not for woofers.
Low woofer mass is the best method to avoid deep bass reproduction.

Every woofer is a spring/ mass load system.
There is a math equation, between mass, suspension stiffness, and magnetic field strength.

Make the magnet small ( low power) and you have tons of bass, but no definition and control. ( have a look at the big Infinitys)
Make the mass low, the F res will raise and thus lesser bass extension.( Cabasse speakers for example)
Make the suspension stiff also raises the Fres. ( Full range electrostatics)
And so on.

Thats why we love Apo's.
Extrem good compromise. very well engineered.

[RedAlert]

Found some info: http://www.magnetostatic.com/membrane.html

He uses mylar to avoid kapton's rattling noise...is it called "buzzz..."? How about using mylar with apogee's bass ribbon, possible? Why kapton is used, it must have some advantages...?

He gives even specs:
Membrane material: Mylar Film 12 micrometers (0.012 mm)
Alu-foil: aprox. 12 micrometers (0.012 mm)
Total width: 0.024mm

And he uses 3M Super 77 as a glue...

[Graz]

Respectfully I try to discourage discussions in here about making home-made ribbons for genuine Apogee's - there are lots of places to go to chat about ribbon making theory for planar speakers that don't have the Apogee name on them. Truth is (absolute fact) it costs many times the cost of a brand new (today's rates) speaker to tool up for making ribbons properly, and that is assuming all facts and a full understanding of the task are in place and correct when making tools.

If you want your Apogee's to be real and sound as they are supposed to then the only decision would be to fit the proper parts using the proper methods. You will get the sound you want - and others who hear your speakers will not hear something with the APOGEE ACOUSTICS brand on that doesn't sound right!

I advise to seek out some 100% working Apogee's, preferably restored and experience them as they should sound. That way - you will know what can be achieved.

Take care - Graz

[RedAlert]

My purpose wasn't to step anybody's toes, especially Yours Graz. I know this is a business to You, long time developed business secrets in case. Surely You don't tell one novice how to do it .But there is first time for everyone, including You also, like it's now to me. We finns are people who don't believe before first trying ourselves. The more I study this the more I'm interested. The price is not the main priority, challenge to do it myself is. You say You want to help, helping others not to do the same mistakes You might have done in the early years (that's fine and I'm very grateful for all help). But isn't it so that by doing the mistakes you're learning the most? It's not very helpful if You say don't bother even try (it will fail almost certain). I'm pretty sure that even You would publish the facts, only very few people (like myself) would try to make the ribbons to their Apogees. No masses of people rushing to do those themselves, no customer escape to You. And I don't believe that it will require expensive devices do it properly (lots of skills & knowhow no doubt), at least not before I've tried. Surely I can be very wrong. But I will continue asking questions (perhaps this is not the right forum)...collect information a piece by piece...from here and there...make mistakes and try it again...not because it is easy but because it is hard (who said that in the past ) My humbliest apologies if I did something wrong by asking "wrong"questions...but any help is still always welcome:) A true Apogee sound, that's my goal...even though it might not be the original and genuine...

[Prisma]

.

[Graz]

At the end of the day there are those who require parts to repair their Apogee's, or new Apogee speakers and that is my professional function. If getting the right quality is a priority I can solve it, and already have. If money is tight then that is the most predictable path. If you are on a budget tooling up to do what I have tooled up to do (properly) involves investment way, way beyond the costs of making several pairs of speakers.

Others have different ideas in mind. I am not here to teach others to manufacture, or to skill rivals. Though many who email me or who post feel I should do just that, for their benefit. And some from the most unlikely sources, or so I thought...


Take care - Graz

[Prisma]

Hi Graz,

But there are also a lot of people who like to build speakers themselves. If you supply the parts they like to make the wood. These people are not even on a budget it is just a hobby.
But I do understand that asking how to build the ribbons here is of limits because people might use the knowledge to manufacture the ribbons.
However I see a huge market for people that could build the hybrids from scratch! Using Graz ribbons, building the original filters, buying the wood and using all kind of techniques to finish it. In the end they will have something that sounds like the original if there would be plans around that they could use.
Just wanted to point out that like me some people just like to build speakers and my question about the solder was off limits too I suspect

[RedAlert]

Hi Graz,

But there are also a lot of people who like to build speakers themselves. If you supply the parts they like to make the wood. These people are not even on a budget it is just a hobby.
But I do understand that asking how to build the ribbons here is of limits because people might use the knowledge to manufacture the ribbons.
However I see a huge market for people that could build the hybrids from scratch! Using Graz ribbons, building the original filters, buying the wood and using all kind of techniques to finish it. In the end they will have something that sounds like the original if there would be plans around that they could use.
Just wanted to point out that like me some people just like to build speakers and my question about the solder was off limits too I suspect

I could not agree more...

[RedAlert]

I checked the magnets in my Duetta's and there are some misplacements indeed. Should I concern, if there are 1-2mm misalignments (both horizontally and vertically)? And how can one get those magnets loosened without breaking them if planning realignment? What kind of glue was used originally and what kind of glue should I use?

[User211]

Whilst I appreciate that many want to adopt a DIY approach to full range Apogees, it must be appreciated that they aren't a good candidate for DIY. They are much harder than conventional speakers to work on. And for obvious reasons.

For the best results I really do think people should concede that a professional is the best option. Just thought I'd make the point here.

[artm]

I disagree...if Graz says his installers detest this magnet alignment procedure, then why not allow the owner to do it, provided he's given the right info and tools? If I can do it in double the time and save some money then I'd do it.

We're not talking about potentially damaging a fragile item here, so it's the perfect job for a "knowledgable", DIY enthusiast.

[User211]

Well then just go ahead and do it. But don't expect free advice and time from someone who does it professionally.

[Graz]

Art - at the end of the day supplying somebody with alignment protractors, installation hardware, array specifications,and training somebody to use them would cost more than the Installers I have trained in the procedure or myself doing the task for them at the capped rate. We already have the tools I designed for assessing and correcting the classic Apogee's, and they will see few uses even so. Simple as that. Such information is also harmful to our brand if in the hands of a person who would use the information in bad faith - as one (trusted) individual has recently done, at my expense. The line between good for the client's fun, and harmful for the brand has already been well and truly crossed, believe me. I am not a teacher - I am a manufacturer.

Red Alert - I have given you telephone support, assistance and a means of solving your problem properly. Asking for mfr information like this is getting a tad irritating. I wonder if Ferrari would give you a wing former so you could beat out some plate into body parts? Nah...

Probably time to leave this one guys, methinks.

[artm]

I got the impression that all that was required was the protractor, glue and basic tools to reinstall. I suppose if that was the case then an installer wouldn't bitch about the job.

Let's move on...

[RedAlert]

Graz - Ok, I understand your point of view, sincerely...it was not purpose to step on your toes, sorry about that. And I'm very grateful for all your advices you've kindly given to me, thanks Restoring my Duetta's...I'll try to solve any problems possible coming ahead by myself with the old style - try, make an error and learn from it...

[EldRick]

Brain surgery is not for do-it-yourselfers.

Neither is remanufacturing Apogee speakers.