Advice please on DIY Polkstands

bindibadgi

Hi

For the TL;DR version, just see the bottom paragraph!

I'm the happy new owner of a pair of Monitor 10Bs which I picked up from their original owner. I've been busily reading on the forums here, and with the advice I've found, I've already done some work on the speakers.

I did the JB Weld treatment (I didn't look too hard, but I couldn't find any of the other recommended adhesives locally - I'm in Australia), and although it was a tad messy, I think it turned out alright, and now I'm not concerned about magnets coming loose!

While I was in there, I rolled the baffling back up and secured it to the divider between the drivers.

I checked that everything was moving freely, and that the cabinet was nicely sealed (pressing the passive radiator in, the mids take several seconds to return to a neutral position so that's great).

I'm now very much enjoying the sound, but I'd like to get the most out of them, so I'm going to try my hand at making some stands (I'm not ready to leap into crossover mods or new tweeters yet).

I plan to use MDF and put spikes in, which I hope will be alright (they're on carpet with a concrete slab underneath), and I plan to fill them with some dried sand to deaden them and make them more stable, but I have a few questions for the experts if I may.

Firstly, will 16mm thick MDF be sufficient for stands? I can get 18mm but only in a huge size, and 25mm seems overly expensive. Secondly, what height is ideal for the Monitor 10? I've seen the plans which westmassguy posted, and I can follow those, but a few people have mentioned a taller set of stands. Is there any reason I should consider one height to be better than another? Thirdly, how do people prevent the speakers sliding backward on the slope (or is it a non-issue)?

TennMan

I'm no expert but... here is what I did to prevent sliding. Mine were made of 1/2" shelving boards - MDF covered with woodgrain vinyl.

mhardy6647

Even though there are a couple of Polkstands (genuine and ersatz) here, I can't answer most of the OP's questions.

I think 18 mm is a better choice, but 10s aren't that heavy, the stands are stout, and 16 mm is probably OK. I'd actually think plywood would be better for dimensional stability than MDF, but that's just an opinion.

The home-made (not by me) stands here are made of thinner plywood -- looks like 1/2 inch (a hair less than 13 mm) plywood with a 'frame' made of thicker stock. The latter enhances aesthetics and may make things a little stronger, too.

The early 7 and 10 used the same stands.

earlypolkfamilyportrait by Mark Hardy, on Flickr
(ca. 1977)

Later, 10s were observed on taller Polk stands -- they make me a little nervous on stands that tall, though

These look like the taller stands I remember (FWIW).



As to the angle of repose of those tall, heavy-ish boxes on the tilted- back stands -- the original Polkstands had four thin, very "grippy" rubber like pads attached to the top plate. These tended to "creep" backwards over time.
It would be a good idea, I think, to put some sort of anti-slip 'grippy' material on the stands, but truth be told, the angle is slight enough that most speakers sit on them pretty happily.

Still, for permanent use, I'd think some sort of anti-skid pads on the speakers and/or the stands would be a 'best practice'

Hope this is helpful -- lots of words for not much information (that's kind of my hallmark).

mhardy6647

TennMan wrote: »

I'm no expert but... here is what I did to prevent sliding. Mine were made of 1/2" shelving boards - MDF covered with woodgrain vinyl.

That is a beautiful stand -- seems like an excellent design to hold a Polk 10, IMO (and FWIW).

TennMan

mhardy6647 wrote: »

That is a beautiful stand -- seems like an excellent design to hold a Polk 10, IMO (and FWIW).

Thanks. They were built really strong. I weight about 275 and they would hold my weight. They were sold with my monitor 10s.

There is a cross brace between the uprights that couldn't be seen in the previous photo to give them lateral stability. The three covered screws on the sides are what holds the brace to the uprights.

Gerres26

TennMan wrote: »

I'm no expert but... here is what I did to prevent sliding. Mine were made of 1/2" shelving boards - MDF covered with woodgrain vinyl.

I copied these a couple years ago and made stands for my 7c's. They worked great.

bindibadgi

Thanks for the replies, that's some good info. Those do look like nice stands TennMan, and I think I will incorporate that piece at the back as a stop. It should add even more strength to it as well.

I guess if I build them with enough of a frame, then what everyone has said suggests that 16mm would be fine. That only leaves the question of the height I guess, and it looks like that's more a matter of preference. Would that seem right?

I mocked up some stands in a CAD package and I might post a picture when I'm home again. They aren't too different from TennMan's stands actually, except that it's a base, a top, and between them four vertical pieces that form a box. I intend to fill that box with sand (the current design is a tad over four litres, so more than a gallon).

tonyp063

from a thread long ago
http://forum.polkaudio.com/discussion/24335/polk-audio-monitor-series-stands-reference/p1

This might give you more ideas.

bindibadgi

Thanks tonyp063. That's a good thread!

Here are a couple of snaps from the CAD drawings I did. It should work out pretty well with a standard piece of 1200mm x 600mm x 16mm MDF.

Stand:


With 10B speaker:


Layout for cutting:

bindibadgi

I should mention:

• it's pretty much right on a six degree tilt;
• it will put the bottom of the front of the speaker at about 200mm (8") from the floor once there are spikes in it;
• everything will be glued and (predrilled and) screwed;
• I'll also be filling up the "box" part with sand, so I guess there will need to be a hole in the top to allow access for that;
• all the cuts are 3mm wide so I think it will work with this size of wood, but it's not critical anyway really; and
• offcuts are a lighter colour.

Also, you can't see it from the drawing, but the cuts between the front and back pieces (the rectangular 190mm x 155mm and 190mm x 135mm pieces) need to be with the blade at a six degree angle so that the pieces match up with the sides and make a smooth top for the top piece to be affixed to.

Please feel free to critique; that's what I'm here for!

TennMan

Looks great to me. Could your cad program easily convert the metric dimensions to inches? If so please post another photo of the drawings in inches. It might help members here on the forum that want to use your plans.

bindibadgi

Sure. I redrew it a bit so the dimensions work with what I think is your standard size of timber (3/4" x 2' x 4'), and so you don't have to work with 64ths of an inch or anything crazy. I can't accept responsibility if it doesn't work though!

Cuts are 1/8" wide.

TennMan

Thanks!

bindibadgi

It seems the standard size board is about 1/4" smaller than I thought in length and width, so you'd probably need to lose 1/8" from each top piece (the one with the "FRONT" sideways in the picture). You'd also probably need to lose 1/16" from each of the bits that make up the support box. Why can't standard sizes be standard sizes?