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Poplar ply - any good?

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Category: General
Forum Name: Advanced Discussion
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URL: https://forum.speakerplans.com/forum_posts.asp?TID=89014
Printed Date: 12 April 2021 at 2:32am
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Topic: Poplar ply - any good?
Posted By: stevie
Subject: Poplar ply - any good?
Date Posted: 10 October 2014 at 6:07pm
Does anyone have any practical experience of bass cabs made from poplar ply? Do any pro companies use this material for their boxes? The weight savings are attractive but I wonder how they perform in comparison with proper birch.



Replies:
Posted By: djyves
Date Posted: 10 October 2014 at 8:01pm
I've build a few cabs and cases out of poplar ply. It's much softer and more flexible.
So it will require more bracing, but it is a cheap alternative.

I sometimes use it for modular 19'' racks for amps, effects etc. works fine.


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"If brute force doesn't work, you're just not using enough!"


Posted By: TONY.A.S.S.
Date Posted: 10 October 2014 at 8:15pm
I've done some guitar and Bass guitar cabs out of it. Not sure about heavy subs. I'd probably double it up just to make it nice and heavy. If the end grain doesn't become a problem, it is certainly alright for non acoustic stuff.

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http://www.facebook.com/tony.rossell.3" rel="nofollow - http://www.facebook.com/tony.rossell.3


Posted By: MarjanM
Date Posted: 10 October 2014 at 8:44pm
Dynacord use poplar in lot of their boxes.

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Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: stevie
Date Posted: 12 October 2014 at 2:32pm
I was thinking of building a reflex cab using a single BMS 500W 15" driver. I don't think poplar is any cheaper than birch but it's much lighter - which is its attraction. I want to keep cabinet vibration to a minimum. Perhaps extra bracing might do the trick then.
I didn't know Dynacord used poplar. Interesting.


Posted By: RobinMatrix
Date Posted: 12 October 2014 at 6:10pm
We use a lot of poplar in our builds, both Italian and Spanish variants, it's more expensive than Birch, but it is light. If you brace it appropriately it is fine.  We have built several hundred poplar cabs the past year ...


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Matrix Pro Audio :: http://matrixproaudio.com/" rel="nofollow - http://matrixproaudio.com/"


Posted By: woody2
Date Posted: 13 October 2014 at 1:30am
burns well


Posted By: swan
Date Posted: 21 November 2014 at 6:12am
JBL use poplar ply wood in their PRX range. Very light.  

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Music is my adiction


Posted By: bitSmasher
Date Posted: 21 November 2014 at 8:13am
Not very poplar as it seems


Posted By: jazomir
Date Posted: 21 November 2014 at 9:16am
There are several pallets of the stuff  in the Peavey Auction that was highlighted in another thread. (It is referred to as 'popular' ply)

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Regards

Jazomir


Posted By: Dub Specialist Sound
Date Posted: 21 November 2014 at 12:11pm
I have used it before, you can get some good results , bit of extra bracing jobs a gud,un

above all wood burns well to my knowledge....no? , NO perhaps not!!!


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Musical Roots Reggae Vibration is Life! for music is sound...sound is vibration...vibration is energy... and energy begets life. Therein lies my passion!...MUSIC IS LIFE...


Posted By: KidCreole
Date Posted: 21 November 2014 at 12:13pm
No. Should never be used for speaker cabinets. Too light weight.

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Speakers don't pay bills


Posted By: MarjanM
Date Posted: 21 November 2014 at 12:21pm
I wonder what kind of cardboard wood is used in the JRX range.

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Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: Dub Specialist Sound
Date Posted: 21 November 2014 at 12:28pm
Better than chipboard no?

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Musical Roots Reggae Vibration is Life! for music is sound...sound is vibration...vibration is energy... and energy begets life. Therein lies my passion!...MUSIC IS LIFE...


Posted By: mini-mad
Date Posted: 21 November 2014 at 3:39pm
Originally posted by KidCreole KidCreole wrote:


No. Sthould never be used for speaker cabinets. Too light weight.

thats like saying titainium is to light for aircraft construction......

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If it sounds like a gorilla is trying to escape, turn it down.


Posted By: MarjanM
Date Posted: 21 November 2014 at 3:44pm
Poplar plywood is much softer then the birch. That is why it is lighter.

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Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: stevie
Date Posted: 21 November 2014 at 4:11pm
The information I'm able to glean on the web, which is not much, is that poplar plywood can be as stiff as birch. This one here: http://www.panguaneta.com/en/industrial-plywood/okoume-superior-plywood is faced with okoume to give it a harder exterior surface. Its bending strength is 40NM/m2, which is the same as birch plywood.

That doesn't seem to be the general consensus here though.


Posted By: KidCreole
Date Posted: 21 November 2014 at 4:45pm
Originally posted by mini-mad mini-mad wrote:

Originally posted by KidCreole KidCreole wrote:


No. Sthould never be used for speaker cabinets. Too light weight.

thats like saying titainium is to light for aircraft construction......
Poplar is balsa wood veneers. Good luck with building cabs from it. If you are going to then I would suggest carpeting like jbl does for their cheapo range

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Speakers don't pay bills


Posted By: bass*en*mass
Date Posted: 21 November 2014 at 4:51pm
guess it depends a lot which manufacturer as with many other things?

poplar is poplar, balsa is balsa, some might mix them up and sell as the wrong deal?
the sheets available from the peavey auction look quite well made, if they even have a hard outer layer as mentioned above why should they not be usable for small, light cabs, appropriate bracing provided?


Posted By: MarjanM
Date Posted: 21 November 2014 at 4:59pm
They are used. No one says it can not be used. But it is not as strong as birch.
Many Dynacord boxes are poplar plywood.


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Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: KidCreole
Date Posted: 21 November 2014 at 5:01pm
I have seen it with birch outer veneers. Made in china. It was about 1/3 the price of birch
 
poplar ply is not always poplar. What I have seen was always mixed. Soft core rubbish


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Speakers don't pay bills


Posted By: KidCreole
Date Posted: 21 November 2014 at 5:02pm
You can have string and stiff but if its light it will go walkabout
 
I like bass bins to stay where they are


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Speakers don't pay bills


Posted By: nickyburnell
Date Posted: 21 November 2014 at 8:45pm
Originally posted by MarjanM MarjanM wrote:

I wonder what kind of cardboard wood is used in the JRX range.


Have some here, made from MDF, screwed together OK, wood screws holding drivers in, although I have seen VERY high end cabs do that in the past.
As I mentioned before, worst I've seen is OSB in EV cabs of old, apart from chipboard of course.


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It's everything, not everythink!


Posted By: snowflake
Date Posted: 17 February 2021 at 1:15pm
anyone looking for poplar ply I think I have FINALLY found somewhere that will deliver small quantities for a reasonable price. And they have a cutting service.

https://www.atlantictimber.co.uk/efficency_ply_int_18mm.html" rel="nofollow - https://www.atlantictimber.co.uk/efficency_ply_int_18mm.html

commenting on the above thread:

poplar surface is not as hard as birch but is better than spruce or pine. hard surface can be achieved with high quality resin/paint/liner/fibreglass. poplar takes paint very well.

poplar is not quite as stiff as birch but it is 40% lighter. If you want really stiff panels then use 24mm poplar instead of 18mm birch - it will be lighter and twice as stiff. If you want heavy cabs then replace some of the wood weight with bigger drivers!

poplar machines very well and reduces tool wear.


Posted By: infrasound
Date Posted: 17 February 2021 at 6:13pm
Thanks for the link snowflake! Just what I'm after.


Stiffness is determined by the bracing primarily, thickness second.

With proper bracing, "just" 9mm of poplar ply can exceed the stiffness of 24mm birch plywood in cabinet.

Add a CF/GF skin to that and you're fixing that wear resistanceParty


Nb. 'Proper bracing' involves multiple rounds in FEM analysis & isn't a walk in the park. With guessing the bracing, you can go surprisingly far though.





Posted By: VECTORDJ
Date Posted: 17 February 2021 at 9:05pm
Why send all the time and work to make custom speaker cabs and use cheapie ply??? The best I have found is "Finland" 3/4" 4 x 8 foot 100 % birch exterior...........Like a Rock....


Posted By: snowflake
Date Posted: 17 February 2021 at 9:19pm
Originally posted by VECTORDJ VECTORDJ wrote:

Why send all the time and work to make custom speaker cabs and use cheapie ply??? The best I have found is "Finland" 3/4" 4 x 8 foot 100 % birch exterior...........Like a Rock....


the good poplar isn't cheap - if anything it's more expensive than birch.


Posted By: VECTORDJ
Date Posted: 18 February 2021 at 8:02pm
I am basing My choice of Finland 4 x 8 sheets as to what is stocked in Maine USA. The Poplar cored ply here has very thin Birch outer layers and is not water proof. Sort of soft too.  Go Finland. Like a Rock.


Posted By: stevie
Date Posted: 04 March 2021 at 1:08pm
Originally posted by infrasound infrasound wrote:


Stiffness is determined by the bracing primarily, thickness second.

With proper bracing, "just" 9mm of poplar ply can exceed the stiffness of 24mm birch plywood in cabinet.


How exactly did you reach that conclusion?


Posted By: snowflake
Date Posted: 05 March 2021 at 12:16pm
Originally posted by stevie stevie wrote:

Originally posted by infrasound infrasound wrote:


Stiffness is determined by the bracing primarily, thickness second.

With proper bracing, "just" 9mm of poplar ply can exceed the stiffness of 24mm birch plywood in cabinet.


How exactly did you reach that conclusion?

deflection of a panel is proportional to the width^3 and inversely proportional to the thickness^3.


Posted By: infrasound
Date Posted: 05 March 2021 at 1:48pm
Originally posted by stevie stevie wrote:

Originally posted by infrasound infrasound wrote:


Stiffness is determined by the bracing primarily, thickness second.

With proper bracing, "just" 9mm of poplar ply can exceed the stiffness of 24mm birch plywood in cabinet.


How exactly did you reach that conclusion?
]

FEA and some physical validation Smile


Posted By: stevie
Date Posted: 05 March 2021 at 2:27pm
And did all this FEA and physical validation result in a commercial product?


Posted By: infrasound
Date Posted: 05 March 2021 at 3:04pm
Nope, only for personal toys

IMO it would be hard to commercialise, specifically due to the cost, assembly complexity, tolerance, wear and definitely overall strength.

I'm happy to manage these personally, but wouldn't scale well upwards from there



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