Timon

That's a point we also don't like. We would build it in lightweight construction with carbon epoxy combination, so we think it will end up at approx 130kg, but still it's really heavy.
But at the end its not depending on the weight for us but on the sound.

Hi all!

we finish our second skram and in the meanwhile we are thinking to build some more. 
And then we saw the new Powersoft M Force EDM Sub Design.
Now we ask ourselfes if it makes more sense to build 2 more skrams and have 4 in total (28hz–100hz) or we give it a try and build the Powersoft EDM 2 x 30" (18hz–40hz, infra setup), so the skams just plays down to 40hz... 

My inner child skreams "build this robo subwoofer!" haha

Ricci and all the others, what do you think makes more sense?

PS_EDMSUB_RD.pdf

4 hours ago, Ricci said:

MomoTon,

The bracing should be fine. 

You can't reduce the width of the cabinet really. The 21.5" frame diameter of the drivers plus the wall thickness doesn't leave much to gain there. The depth could be reduced as well as the enclosure height but you will be reducing volume for the ported chamber and the ports. You will have to change the port size/length in order to maintain the same tunings and low bass efficiency will be reduced and vent velocity would go up most likely due to smaller vent area. 

I look forward to seeing your finished project with the CF. This sounds like an adventurous build. 

Hi again,

I'm working with MomoTon on the project. Our plan is not reducing the width but increasing it for more output. I think we made the parts +5cm in width for now. The question is if its worth it to let it 5cm broader to get more output. If its just +1dB that we'll gain, I wouldn't think it's necessary and we would make the skram with the original width..

We are also very excited about the build! There will be a few challenges... 

Thanks for the good advices!
I´ll be back with some testing results of the materials and maybe we try some cooling systems (not sure yet)
 

about 1200€
I just wrote an email to powersoft oem europe and described who we are.. then they answered that they support us with pleasure.
I don't know if its normal or if we are just lucky.

Yeah, I thought about asking for the price for the M-Force haha looks so cool.
 

Ipal on bluearan in uk and the mod from powersoft europe

We don't know if the temperature will be a problem, but if it does we will test some cooling systems (we thought of a water cooling.. )



 

Hey again!

We just found a cheap way to buy the 21ipal and a ipalmod for each skram, so we want to make the skram active.
In addition to that we will plan an active cooling system for the magnet (because we think that temperature will be the a limiting aspect(?)).
Now we are considering to optimize the skram cabinet, because if the temperature and power are not the limiting aspects it will be excursion again, right?
If it's like that, how would you change the cabinet? Maybe smaller, that there is more pressure? Or could be the half skhorn the better option?

Next topic will be the positioning of the pressure sensor of the ipalmod. In the picture there are the possibilities we are thinking of and another picture how 18sound made the positioning (the small hole between the speakers).
It's important that the distance between sensor and diaphragm is as little as possible and it has to measure the pressure difference between the environment in front of the speaker and the back.. 
Has someone experience with the module and the sensor?
Or how would you do it?


 

28 minutes ago, peniku8 said:

I would advise against the combination of hardwood and plywood, as both have a different CLTE. If you're really limited on weight, you may try to use Banova Ply. You could do the outside panels with regular BB ply and use the Banova for all inside panels (and be my guinea pig at the same time 😉)

7 minutes ago, Ricci said:

I don't see any issue with modifying the plans a bit for 15mm wood. It should still be strong enough. Banova ply for the interior bracing would be nice as we were just discussing it at AVS but it seems quite expensive. Carbon and epoxy bracing sounds interesting. What's the goal though? Weight savings?

 

before we start building the second skram we want to make oszillating tests with test pieces. These will be like 18mm birch, 12/15mm Banova with Epoxy(and carbon), the same with  poplar and birch. we are not sure zet, how the tests will look like, but we are sure to find a way  after that we will make the second skram out of the winner design and then compare it with the orig. skram.

36 minutes ago, peniku8 said:

Other than that, I'd personally prefer to keep the speaker count at 2 (i.e. one or multiples of the same sub playing from 20/30Hz to 60/100Hz depending on taste and a (line) array of the same capable tops). I had a quick look at the tops you're using and I don't see the need for a kick bin here. The dual 10" tops should capable enought to cross them over between 80 and 100Hz, and the Skrams are capable enough to be used in that configuration as well.

15 minutes ago, Ricci said:

I don't generally use kick bins. I like subs that can get up fairly high in frequency and big mains that can get low with power so I don't usually add a third set of cabs. I like to put the extra weight and size of the kick bins into the subs and or mains, and have one less amplifier channel and set of DSP settings to worry about. YMMV. A lot of other guys swear by the kick bin approach. If your preference is for kick bins the Martin 215mk3 design gets a lot of praise but it's bigger and heavier than a Skram so it better be good!

It'd be hard for me to pack a pair of those when I could add another <120Hz sub cab instead unless I was already running like 8+ subs. 

Ok, those are interesting advices, so we will try it without them first.  Is it a good idea to make i.e. per side one Top with both, the AMT with the Mids, and a second cab with only the Mids (eighter with the same tuning or again as a 4 way system?)

Another change in the plan is to use not the very expensive wavecore driver, but instead something like the http://www.precision-devices.com/Product-Details/PD103NR1.
Would you recommend a closed box or BR Design for a tuning around 100Hz? (And could you recommend a calculation tool for designing these?)

We want to use a FP10000Q for two skrams, another class A/B or D amp for the L/R mids and one for the L/R AMTs.
Do you prefer a single extern dsp for all amps or the build in dsp (with much more effort)?
 

Thanks a lot for your help, I think we are on a good way!

 

Hey guys,

my friends and I are totally fascinated of the Skram and for now we want to build two of them. 
At first we'll build it with the suggestion of 18mm birch ply and after we want to do some changes for the second pair.
We want to make it out of 15mm (birch ply and in the core of it one layer of poplar to make it lighter) in addition we would like to add some braces out of carbon and epoxy resin. It should be as stiff as 18mm birch ply.

Do you have any concerns with this plan so far? 
 

We are not sure which kickbass we want to use. Maybe some of you have another recommendation?

We are planing to build one Cubo Kick 12 per Skram with the 18sound 12ND830 and a little bigger cabinet, so it gets down to about 90hz and up to 200hz.

The other consideration is to build some sealed boxes as kicks but I worry if this will be very harmonic with the Skram. But it should be the purest and punshiest kick, isn't it?
There would be I guess 2 drivers per Skram (depends on the driver). 

What do you think? What would you do?

As Mid Tops (from 200hz with a bit different AMT) there will be one Mundorf AMT (with a horn in front of it and an active cooling system) and two Wavecore WF259PA01 per side.. Mostly we are playing Techno, etc. but the system should be able to let you enjoy all kinds of music...

It would be great if you guys could help us with your knowledge!

Thanks a lot,
Timon