Bracing planar speakers

[aechmea]

I have tall thin speakers. When you give them a slight push they wobble. This is because of their height (centre of gravity) and the way that the feet attach to the speaker proper.

I know that the theory is to have them as rigid as possible and to couple them to the concrete floor. I have spikes but I don't like using them much as they seem to turn the speakers into a teetering tower ready to fall at the slightest touch.

I am thinking about getting granite slabs (like Stump), bolting the speaker feet to the slab (stability and to add more weight at the bottom), spikes under the slab thru the carpet to the concrete (rigidity), and some sort of triangular braces from the speaker's rear feet to the top edge of the speakers for rigidity in the front/back plane.

The granite is quite expensive and I would have to get someone to make the 'braces' since I am completely non-handy, but maybe its money well spent.

Has anyone done this sort of thing with their tall thin speakers?
Did you notice a change in sound quality?
Was the change profound or is it marginal?
Was it all worth the effort?

[Nigel]

Hi Peter,
I reckon the bracing of the base to the uprights is more important.
I don't see how the weight of the base is so important, unlike conventional box speakers driving a 12" loudly.
The metal brackets don't look super strong so there may be some flex. ??? Can you detect movement ?
Be careful as the woodwork on your maggies looks really nice.

[JA]

Hello Aechema,

For your Magnepans I was going to suggest you build heavy steel stands with a rear strut/s reaching up behind or even to the top of the speaker, but it's already been done....

ps_audio_ces_2010.jpg

Attachment 14703


Note the use of a building brick for increased mass in one of the later images
https://myesound.com/Gallery.html



https://myesound.com/Home_Page.html

You could probably get them custom built in Oz for a few hundred dollars, even using solid steel bar.

Best
JA


A DIY proto..

panstand5.jpg

[aechmea]

Haaaaa! Look at that!

Thanks JA.

Yes thats exactly what I was thinking of. Maybe I'm not a complete idiot after all.

I pictured the struts coming off the back of the rear feet up to the top; even envisaged a sort of G-clamp arrangement so as not to mar the wood finish.

I also like the brick (weight) at the bottom to lower the centre of gravity. My equipment rack is made from granite slabs and bricks, so a matching granite speaker base would fit in well and keep the spikes well grounded.

So looks like its worthwhile pursuing at that price, just got to find a tame metal worker.

Anyone else with experience/knowledge of braced maggies or electrostatics?

Thanks
Peter

[Nigel]

Hah, hi peter, yes i've done it to mine but it's nothing to write home about.
I'm sure you could do better.
Also, you mention running the brace to the top, I think the brace is strongest at 45o, but I'm no expert.

Before you do it, do you have an idea of how much movement/loss is occuring ?
I'm thinking your bass (which is likely to suffer the most) is right at the bottom where there is minimal movement.
You may go to alot of trouble to achieve little, perhaps...

[andyr]

I have tall thin speakers. When you give them a slight push they wobble. This is because of their height (centre of gravity) and the way that the feet attach to the speaker proper.

Has anyone done this sort of thing with their tall thin speakers?
Did you notice a change in sound quality?
Was the change profound or is it marginal?
Was it all worth the effort?

One poster implied you have Maggies. If you do:
a) you might like to PM me with your email address and I'll send you some pics of 2 different versions of braced stands that I have had made up for my IIIas, and
b) I suggest you sign up to the Planar Asylum, where you will find lots of posts on this subject. In particular, Mye stands are available from Canada (but shipping them here will cost quite a lot, which is why I had some made up here ).

You get a significant increase in sound quality with Maggies, when you throw away those ridiculous pissy little feet and install braced stands. Better bass and better dynamics (which are Maggie's only weakness! ).

Regards,

Andy

[andyr]

I'm thinking your bass (which is likely to suffer the most) is right at the bottom where there is minimal movement.

Maggie bass runs the full height. In my case (with IIIas), this means a wire-on-mylar driver which is about 250mm x 1,500mm.

Regards,

Andy

[aechmea]

Better bass and better dynamics

My bass is a little "spongey and hollow" for me a the moment. Probably due in part to the previous 25 years with fullrange electrostatics with little bass; I'm just not used to bass.

Anyway I expect that adding vertical rigidity to the maggies and coupling them through the carpet to the concrete floor with spikes will improve things considerably.

[andyr]

Better bass and better dynamics

My bass is a little "spongey and hollow" for me a the moment. Probably due in part to the previous 25 years with fullrange electrostatics with little bass; I'm just not used to bass.

Anyway I expect that adding vertical rigidity to the maggies and coupling them through the carpet to the concrete floor with spikes will improve things considerably.

Hi Peter,

You need to do 4 things to extract all the bass that Maggies are capable of delivering:

1. Braced, spiked stands in place of the ridiculous stock feet.

2. Throw away the external passive XO box (bass LP/mid HP) and use an active XO instead (and a second power amp). You need a ss amp directly attached to the bass driver (with no series inductors "in the way") to best control the bass panel.

3. You need an "appropriate" - and IMO ss - amp. This would be at least 100w into 8ohms/200w into 4ohms (ie. have a good PS) with a low output impedance.

4. Hardwood frames in place of the stock MDF frames. This mod also uses a better way of securing the big bass/mid driver assembly to the frame ... the staples which Magnepan use (in MDF) are pathetic.

Good luck,

Andy

[aechmea]

do you have an idea of how much movement/loss is occuring ?

At the moment with no spikes there is next to no resistance to a slight push with a finger. Then they oscillate slightly before settling. Gotta be able to do better than that.

With spikes its more rigid but they tend to teeter and I suspect that the thin metal strip that forms the feet bends under the weight.

The Doppler Effect (wavelength/frequency changes resulting from a moving source = red shift/blue shift) happens at all frequencies so maybe the highs might snap into place as well. Here's hoping.

[aechmea]

Hi Andy

I have done items 2 and 3 and I am now starting on your item 1, so in the fullness of time they will be showing their full potential; not that they aren't already a great speaker!

[I think that a bit more effort with my room will be the next project after maggiebraces.]

[andyr]

do you have an idea of how much movement/loss is occuring ?

At the moment with no spikes there is next to no resistance to a slight push with a finger. Then they oscillate slightly before settling. Gotta be able to do better than that.

With spikes its more rigid but they tend to teeter and I suspect that the thin metal strip that forms the feet bends under the weight.

The Doppler Effect (wavelength/frequency changes resulting from a moving source = red shift/blue shift) happens at all frequencies so maybe the highs might snap into place as well. Here's hoping.

As you say, Peter, a slight push with the finger, and the panels oscillate. Newton's third Law comes into play - so if the bass panel moves back because it's trying to push out a bass note ... that bass note is not going to be as good as if the panel was unable to move at all!
How much movement is involved - I guess staggeringly little, in a physical sense ... but it makes an amazing difference when you remove even this small amount of movement. Case in point, as I said, the bass/mid driver assembly is fixed into the MDF frame by staples (which, as you might guess, don't hold that well in MDF! ). Before I replaced the MDF frame with a hardwood frame (and screwed the bass/mid asembly to this hardwood frame), I replaced all the staples in my MDF frame with a L-shaped steel angles which were bolted through the frame, with the small side of the 'L' clamping down against the back of the driver assembly. This produced an amazing improvement in dynamics ... yet, how much would you think the driver assembly was able to move with the staples? 0.1mm??

Regards,

Andy

[Dr Good Vibe]

Frames are very important as suggested by andyr, I use steel sand filled that work a treat with delrin feet but I think the ultimate for me would be a turn buckle setup using floor and ceiling joist and beams and then tension and tune.