Plate Reverb pre EQ Issue

[Sounddesign84]

Another type of corner gusset for reinforcement - used in building available at any hardware:
View attachment 146258

Ooo, thank you for these, I wanted to ask about them, I was wondering about it.

 

[RoadrunnerOZ]

Would you by any change happen to know how many meters I would need very rougly approximately for the construction without the dampers?

For the 2000 x 1000 you need to add the length of a half extended turnbuckle you choose and your chosen spring plus 2 hookbolts to each dimension - say your spring is 65mm, your turnbuckle is 150mm half opened (this allows a bit of leeway) and each hookbolt adds 50mm then
your long sides will be 50+65+2000+150+50 = 2315 x 2 = 4630
Your short sides will be 50+65+1000+150+50 = 1315 x 2 = 2630
Total for this example = 7260 so an 8 meter length would be perfect. You need to source your turnbuckles, springs and hookbolts first - measure those also making sure the hookbolt will fit through the spring end loop and the turnbuckle ring (as these are closed rings). Turnbuckles usually are hook and ring - the hook end can go through the holes in the plate corners which must be close enough to the edge to allow the spring to fit.
The hookbolts are to mount the springs and turnbuckles to the four corners - they only require a hole to be drilled and need to be long enough to pass through the steel box - they will need a washer on the outside face inside the nut and if the threads are long enough you can put a nut and washer on the inside as well to lock the hooks in place.
Turnbuckle:

Hookbolt:

 

[RoadrunnerOZ]

You can get quite small turnbuckles for fence wire tensioning or yachting stay tensioners.

 

[Sounddesign84]

For the 2000 x 1000 you need to add the length of a half extended turnbuckle you choose and your chosen spring plus 2 hookbolts to each dimension - say your spring is 65mm, your turnbuckle is 150mm half opened (this allows a bit of leeway) and each hookbolt adds 50mm then
your long sides will be 50+65+2000+150+50 = 2315 x 2 = 4630
Your short sides will be 50+65+1000+150+50 = 1315 x 2 = 2630
Total for this example = 7260 so an 8 meter length would be perfect. You need to source your turnbuckles, springs and hookbolts first - measure those also making sure the hookbolt will fit through the spring end loop and the turnbuckle ring (as these are closed rings). Turnbuckles usually are hook and ring - the hook end can go through the holes in the plate corners which must be close enough to the edge to allow the spring to fit.
The hookbolts are to mount the springs and turnbuckles to the four corners - they only require a hole to be drilled and need to be long enough to pass through the steel box - they will need a washer on the outside face inside the nut and if the threads are long enough you can put a nut and washer on the inside as well to lock the hooks in place.
Turnbuckle:
View attachment 146260
Hookbolt:
View attachment 146261

THANKS! =)

 

[RoadrunnerOZ]

The other supplier is telling me he can get 0,6 mm thickness and is asking me what quality I need in cold and in stainless, what is suitable for the application? He is talking about the M-12-O that kind of thing.

The standard size for stainless sheet for what you need is either 24 gauge - 0.64mm or 25 gauge - 0.56mm (not sure which one they call 0.6mm but whatever they have around that size is fine) and for stainless 304 grade is best and cheapest - 316 tends to be more weather resistant but is more expensive and much harder to drill and cut so avoid that.

 

[Sounddesign84]

304 yes. And for cold rolled do you recommend it and if so what kind?

 

[Sounddesign84]

This is the sickest demo of plate I heared on youtube. The mic needs credit too! If you listen shortley after 2:31 when she says ... cathedral tiled in gold .. thats crazy.

 

[Sounddesign84]

She is talking about line level vs balanced at 5:19, what does that mean?

 

[RoadrunnerOZ]

304 yes. And for cold rolled do you recommend it and if so what kind?

Not sure about the grades but they normally use it for car panel repairs as it is easy to weld. You need to ask the supplier what they supply normally in 0.6mm
Example here:
https://handysteel.com.au/sheet-metal-bright-sheet

 

[RoadrunnerOZ]

She is talking about line level vs balanced at 5:19, what does that mean?

That’s actually not really making sense - what she said earlier is ok but line level signals can be balanced or unbalanced. Domestic audio line level is -10dBV unbalanced, Pro audio line level is +4dBu balanced - a much hotter signal so input sensitivity is reduced as well.
Ecoplate I, the early version had 2 balanced inputs and 1 unbalanced out, the Ecoplate II was unbalanced in and out which meant that for long cable runs it would be more prone to noise on the input.
Balanced circuitry allow long cable runs with very little noise due to the fact that it employs two input connections and amplifies only the difference between the inputs without reference to ground - the grounded cable shield does not carry signal - so any interference picked up is the same on each input leg and therefore does not get amplified - which is why microphone inputs are balanced as the signal level is so low that with the high input gain required this would amplify any noise which for long cable runs unbalanced would be considerable as the cable shield in unbalanced is part of the signal path and is open to external interference.
With line level signals unbalanced runs are obviously less prone to noise than mic level as the signal to noise ratio is much higher. In most mixing consoles effect sends are unbalanced so it’s desirable to have the equipment close by to reduce interference. With big plate reverbs they need to be mounted in an area well away from the monitor speakers and people walking around causing thumps and talking spilling into the plate as the plate is an acoustic receiver - so in an isolated room some distance away unbalanced I/O can be a problem with noise. In one of the studios I worked in with plate reverbs we had them in a room on another floor - to make adjustments the assistant engineer would be in the plate room with headphones and a talkback mic.

 

[dmp]

This is the sickest demo of plate I heared on youtube.

Nice sound - pretty typical for a plate I think. You can hear the low frequency flutter, which I think is due to the plate being slightly out of tune. I personally really like that warble in a vocal track. The Ecoplate II does not have the Length/width=2 relationship, looks more like 1.6 (minor 6th). Does not have the simple octave described by @Rob Flinn for the EMT.
Here are the ecoplate tuning instructions, which have you push with a constant force and check that the long deflection is half the short deflection.

 

[Rob Flinn]

Nice sound - pretty typical for a plate I think. You can hear the low frequency flutter, which I think is due to the plate being slightly out of tune. I personally really like that warble in a vocal track. The Ecoplate II does not have the Length/width=2 relationship, looks more like 1.6 (minor 6th). Does not have the simple octave described by @Rob Flinn for the EMT.
Here are the ecoplate tuning instructions, which have you push with a constant force and check that the long deflection is half the short deflection.

That depends on the particular ecoplate. The version I owned had a bigger case than the EMT 140, but the plate was 2m x 1m.

Jim Cunningham used to sell a gauge to tune the plate which was a kind of plunger thing with a spring. As you say you had to get it so that the plunger moved half the ampunt on the long edge compared to the short edge. A friend of mine bought one, but I found it was pretty crude to use & I found it easier tuning by ear.

 

[dmp]

That depends on the particular ecoplate.

I wrote Ecoplate II (TWO) - which was the particular Ecoplate in the above video. The Ecoplate I (ONE) is indeed 2mx1m. I found pictures of a Ecoplate II to estimate the aspect ratio, because it is obviously not a 2:1 ratio.

 

[Sounddesign84]

Here are the ecoplate tuning instructions, which have you push with a constant force and check that the long deflection is half the short deflection.

Only looking inside of it with the Emmet Brown layout style is an adventure in itself!

 

[dmp]

She is talking about line level vs balanced at 5:19, what does that mean?

Yes, you want it line level in and out. Balanced is more convenient in a studio I think.
But the piezo pickups will be the major offender - I have to shut off the room LED lights to kill a little buzz in the recordings.

You need driver electronics and pickup electronics. I made new boards last year based on the Ecoplate schematics - they work great. Only thing I would do differently is the EQ on the driver. I don't use it. I pre-EQ at the desk where I am listening, because the plate is in another room (as is typical). I would probably keep the Sallen-Key HPF and not have the rest. For sparse songs I don't EQ at all.
I would like to build a damper remote.

 

[Sounddesign84]

Nice sound - pretty typical for a plate I think. You can hear the low frequency flutter, which I think is due to the plate being slightly out of tune. I personally really like that warble in a vocal track. The Ecoplate II does not have the Length/width=2 relationship, looks more like 1.6 (minor 6th). Does not have the simple octave described by @Rob Flinn for the EMT.
Here are the ecoplate tuning instructions, which have you push with a constant force and check that the long deflection is half the short deflection.

@dmp You wrote earlier that "stainless steel sounds a little bit 'shinier' than cold rolled when I heard them side by side"

I would say this is an example of a warmer tone so if I like the tone here I should go with cold rolled?

 

[dmp]

Ecoplates used stainless steel - that video is an example of stainless. (EMT used cold rolled)
The difference is subtle!

 

[RoadrunnerOZ]

That one in the video was smaller than the Ecoplate I which like the EMT had a cold rolled steel plate and was 2000 x 1000 - they made the 2 as a smaller unit with I believe a thinner plate and suspect it to be stainless - the smaller the plate dimensions the thinner the plate material needs to be but the more air resistance damping comes into play. The larger unit had 0.024” (0.6096mm) steel thickness. Best bet is to build one and see how it sounds and then you’ll know if you need to change plate material or thickness etc. There’s also the driver to consider - the Ecoplate had a unique driver but the idea of using a speaker and fastening the voice coil to the plate is pretty close to how the Ecoplate driver works - if you cut off the cone and used the voice coil still centred by the spider to drive the plate you’d need to attach it so that it will pull as well as push the plate.

What I mentioned before about tuning can be done using a feeler gauge between the coils of the springs to obtain equal gapping - if each spring is identical then the extension under stretch being the same should equate to equal tension (spring physics).
The accuracy of lateral pressure on the plate to measure tension using the gauge would be less than measuring spring extension gapping - the gauge can’t tell you which direction needs tightening - vertical or lateral, also the Ecoplate did not use springs for tensioning so as it seems you’re planning on using springs you’ll need pretty heavy duty ones to get enough plate tension like the ones shown in the construction video you posted.
The gauge in the tuning instructions - best of luck finding one although alternatives are available. You can do it by ear - there are some articles on this concerning the EMT140.
Having used the EMT reverbs in the past I found that they have a character like no other reverb - mechanical or digital and also no two sound exactly the same - my first experience with one of those was in the late ‘70s.

 

[dmp]

That one in the video was smaller than the Ecoplate I which like the EMT had a cold rolled steel plate

Ecoplates had stainless. If you think Ecoplates had cold rolled steel please post a source.

 

[Sounddesign84]

@RoadrunnerOZ "the thinner the plate material needs to be but the more air resistance damping comes into play." What does it mean?

"so as it seems you’re planning on using springs" I must say that I have not.