Ricci's Skram Subwoofer & Files

[dsl1]

5 Sheets of 18mm and 1 Sheet of 12mm was enough for TWO Skrams cnc'ed.

Sheet 1 - 18mm:

Sheet 2 - 18mm:

Sheet 3 - 18mm: Enough driver panels for 6 subs...

Sheet 4 - 12mm: 

 

[klipsch]

1 hour ago, chrapladm said:

Thanks. Its what I use also. Other wise I couldnt afford to build much. Arauco B/C and PL premium. Just building a pair of Skrams so I was curious how much ply I wold still need. Looks like 3 more sheets for sure.

I find that the made in USA southern US pine plywood is really nice stuff and is in most big box stores if you don't have access to a nice local lumber yard (usually about 30 bucks for a 7 ply and 36 bucks for a 9 ply 4x8) . It's a lot nicer from a rigidity and void/blemish perspective than the big box store birch plywood (especially when the birch is from China and not Canada). While classifications differ, I think the big box stores pine are BB/CP. 

Baltic birch plywood at A or B is another story. I wish I had the equipment and time to test resonance differences and such between the same cabs built in various materials. (looks not being a concern, just objective sound performance) 

[menace]

4 hours ago, klipsch said:

I find that the made in USA southern US pine plywood is really nice stuff and is in most big box stores if you don't have access to a nice local lumber yard (usually about 30 bucks for a 7 ply and 36 bucks for a 9 ply 4x8) . It's a lot nicer from a rigidity and void/blemish perspective than the big box store birch plywood (especially when the birch is from China and not Canada). While classifications differ, I think the big box stores pine are BB/CP. 

Baltic birch plywood at A or B is another story. I wish I had the equipment and time to test resonance differences and such between the same cabs built in various materials. (looks not being a concern, just objective sound performance) 

Baltic birch is the only option. Its so strong, I made a small sub box out of 12mm and once i put a few braces in it was easily strong enough.

[peniku8]

1 hour ago, menace said:

Baltic birch is the only option. Its so strong, I made a small sub box out of 12mm and once i put a few braces in it was easily strong enough.

I never understood why people use anything else. The price difference is not that big (here in Germany BB is twice the price of MDF). I built a car sub for a friend from MDF and I used MDF for a current project, which I only built the prototype of. Final cabs will be from BB. That was enough for me to know that even just working with MDF is a disgrace. Especially when your shop is a basement room and your dust collection system is undersized for the table saw.

The only pro for MDF, price aside, are the very clean cuts/routing results.

[menace]

47 minutes ago, peniku8 said:

I never understood why people use anything else. The price difference is not that big (here in Germany BB is twice the price of MDF). I built a car sub for a friend from MDF and I used MDF for a current project, which I only built the prototype of. Final cabs will be from BB. That was enough for me to know that even just working with MDF is a disgrace. Especially when your shop is a basement room and your dust collection system is undersized for the table saw.

The only pro for MDF, price aside, are the very clean cuts/routing results.

It has to be said that you Europeans are very lucky being so close to the baltic. The story in new zealand is very different, 18mm mdf 25 euro and 18mm BB ply 110 euro(2440x1220 sheets).

[chrapladm]

About the same price here in OZ. Hence why I use what I use.

[klipsch]

Birch here in the States is cheap in my area, but it is usually Chinese crap. The Canadian birch here can be decent. 13 ply Baltic birch in my area is 3x the price per sheet of good southern US pine but the Baltic is 5x5 VS 4x8 for the pine.  Would really love to see an objective comparison. More plies isn't always a better thing either, but I feel like this debate has been had in every wood forum countless times. 

I avoid MDF cutting on the cnc.  Not a fan at all. 

[peniku8]

12 hours ago, menace said:

It has to be said that you Europeans are very lucky being so close to the baltic. The story in new zealand is very different, 18mm mdf 25 euro and 18mm BB ply 110 euro(2440x1220 sheets).

I pay about 80€ for a sheet of 18mm BB (2500x1250), but why the hell is your MDF so cheap? I pay about 45€ for the same amount of MDF (19mm, 18mm MDF doesn't seem to exist)

[menace]

Pinus radiata plantations down her are big business and there is about four mdf plants largely for export and at least two are owned by the Japanese. I am though surprised that Europe buy economy of scale alone doesn't at least equal our prices....... Anyway going a bit too much off topic now I think. Sorry OP....

[geritass]

On 9/11/2019 at 1:08 PM, Ricci said:

DXF files uploaded to the first post...

Thank you Ricci, for your valious contribution and amazing cabinets.

[Ricci]

On 9/18/2019 at 7:53 AM, menace said:

 Anyway going a bit too much off topic now I think. Sorry OP....

Don't worry about it. It's kind of on topic anyway. 

Personally I am not a fan of MDF. I don't like working with it and it doesn't hold screws well. Also it hates moisture.

I'd rather use a cheap Arauco ply or similar if the 13ply void free stuff is too expensive. I've done a number of cabs out of cheaper ply materials and they've turned out fine. 

[menace]

On 9/18/2019 at 11:49 AM, klipsch said:

Birch here in the States is cheap in my area, but it is usually Chinese crap. The Canadian birch here can be decent. 13 ply Baltic birch in my area is 3x the price per sheet of good southern US pine but the Baltic is 5x5 VS 4x8 for the pine.  Would really love to see an objective comparison. More plies isn't always a better thing either, but I feel like this debate has been had in every wood forum countless times.

I would though say that less plies will almost always be worse!

As for Baltic vs other birch, this should be an important distinguishing factor and having not seen the other birch ply i would imagine they should not be compared. Wikipedia list 50+ species with in the genus and imagine there will be chalk and cheese like differences among them. Growth rate according to geographic location and the correct species will mean everything!

[peniku8]

8 hours ago, menace said:

I would though say that less plies will almost always be worse!

As for Baltic vs other birch, this should be an important distinguishing factor and having not seen the other birch ply i would imagine they should not be compared. Wikipedia list 50+ species with in the genus and imagine there will be chalk and cheese like differences among them. Growth rate according to geographic location and the correct species will mean everything!

All I know about plywood is that it seems that there is no low quality plywood on the German market, since whatever I buy, it's always void free etc. There are some occasional surface patches but these are really just a visual impairment. I'm currently only interested in trying out Banova ply, but the supplier I'm working with discontinued these and I haven't found any other supplier in my immediate area, which I could get a sample piece from. Still dreaming about the 100lbs SKHorn.

[klipsch]

11 hours ago, menace said:

I would though say that less plies will almost always be worse!
 

I would have said the same thing! 

What I've observed is that it depends on species, glues used, and where it was made. I've seen Chinese 9 ply birch that was no where near as good as US 5 ply pine (Chinese was flimsy, warped, etc.) The Chinese ply had 1/120th veneer and the US had 1/40th (as measured with calipers). The birch Chinese plywood also looked like it was made with Douglas fir as the cores that had birch veneer on each face. 

I'm just going by my own experience of people bringing me material to cut here in the north east of the States. These may not be issues in your experiences and locale. 

Been traveling a bit lately. Hoping to get home and make some skram saw dust. 

 

[Droogne]

On 9/14/2019 at 1:26 PM, Droogne said:

I did yes. Didnt use the "lossy Le" option.

Here is the difference:

2 port configuration:

@Ricci Does this look more like it? 

[klipsch]

Price drop on the 152s 4 ohms at amazon. $500 each

https://www.amazon.com/21SW152-4-21-Inch-Ohm-Neodymium-Subwoofer/dp/B00HJK24GC

[menace]

Not that I can see. At least not any more. If it's true I trust you only reported after purchasing....

[dsl1]

13 minutes ago, menace said:

Not that I can see. At least not any more. If it's true I trust you only reported after purchasing....

It happens, they were down to $422 April 2018 on Amazon and I bought them. The price immediately went back up after I purchased the couple that were available.

[peniku8]

Price difference between SW and DS seems heavily in favour of the DS considering that the drivers are basically just a bit different. I mean, you won't gain any notable headroom by choosing one over the other. SW is 520$ if you buy 4 or more, DS is 420$ for 2 or more from where I can get them. I guess the prices are similar in the states when on discount?

I've seen the LaVoce for 380$ on PE, so that's anyother even cheaper alternative. And the LaVoce models a bit differently, which can be great depending on the cab you're using. It doesn't show the bump in the 60-70Hz region which I sometimes see from the DS.

[Jedi940]

I've never found the 4 ohm DS in the states for less than $600. 420 would be a steal. Is there some secret site I'm missing?

[Droogne]

2 hours ago, peniku8 said:

I've seen the LaVoce for 380$ on PE, so that's anyother even cheaper alternative. And the LaVoce models a bit differently, which can be great depending on the cab you're using. It doesn't show the bump in the 60-70Hz region which I sometimes see from the DS.

Lavoces here in Europe also go for a lot less. I was modelling them vs the SW152 drivers and I see around a 3-4dB difference (from 30hz and up) at full RMS input, so justifying the costs of the B&C. However, the Lavoce has an Xmax of 15,5mm (instead of 15mm) and a max power rating of 1700W (instead of 2000W), so I figured the SW152 might hit that 15mm Xmax sooner. 

When I model it to limit the output to their respective Xmax (at 40hz) it looks like the Lavoce can take more power (80V instead of 60V) which translated into only 3dB loss instead of 6dB, so a relative '3dB gain' for the Lavoce which effectively bridges the 3-4dB gap I modelled at their respective full power. So Xmax limited the Lavoce results in only slightly less output instead of a very relevant 3-4dB. 

Please correct me if I make wrong assumptions or modellings, I'm pretty new to this. 

[Droogne]

Also sorry, to be someone else wondering about the CNC files, but I cant seem to figure out how to send this to my CNC operator in a way that he can effectively work with this. I downloaded the 3 files listed here above, but I cant seem to work out an 'easy' way to appoint the correct measurements, so my CNC guy can get to work. 

 

Greetings

[jay michael]

26 minutes ago, Droogne said:

Also sorry, to be someone else wondering about the CNC files, but I cant seem to figure out how to send this to my CNC operator in a way that he can effectively work with this. I downloaded the 3 files listed here above, but I cant seem to work out an 'easy' way to appoint the correct measurements, so my CNC guy can get to work. 

 

Greetings

From my understanding cnc machines often use slightly different software programs so there really isn't a one size fits all cnc file that will work with all machines.  Its likely the dxf files on the first post will require some tweaking by the operator anyways.  My cnc guy just converted the original pdf files to a format that works with his machine, added 50 bucks to labor price to do the conversion. 

 

Prices on the DS and SW are stupid up here in Canada.  The best street price I have found for an SW was about 950 Canadian (about 720 US dollars).  Thankfully I have a buddy who works for PK Sound here in Calgary, I've been buying mine through them for about 550 US dollars shipped.  Only bummer is they have to come right from Italy so it has in the past taken between a month to two months to get here.

 

On that note, I've started building another pair of cabinets so I can keep a pair in my livingroom at home.    I'm weighing the pro's and con's of staying with the 21sw152's that I've used in the previous 4 cabs vs saving a bit of money and trying a pair of the DS drivers instead.  It will be likely that occasionally Ill run all 6 together so maybe sticking with the same driver is my best move.... but it seems they do provide fairly similar performance.  What do you guys think? Should I just stick with the same drivers to match the others? A final consideration is ill be using a lesser quality amp to run the ones Ill keep in my house, a crest prolite 7.5 vs the k10 I use for my others.  Maybe the DS will work a bit better on the lesser amp?

[Droogne]

2 hours ago, Droogne said:

Lavoces here in Europe also go for a lot less. I was modelling them vs the SW152 drivers and I see around a 3-4dB difference (from 30hz and up) at full RMS input, so justifying the costs of the B&C. However, the Lavoce has an Xmax of 15,5mm (instead of 15mm) and a max power rating of 1700W (instead of 2000W), so I figured the SW152 might hit that 15mm Xmax sooner. 

When I model it to limit the output to their respective Xmax (at 40hz) it looks like the Lavoce can take more power (80V instead of 60V) which translated into only 3dB loss instead of 6dB, so a relative '3dB gain' for the Lavoce which effectively bridges the 3-4dB gap I modelled at their respective full power. So Xmax limited the Lavoce results in only slightly less output instead of a very relevant 3-4dB. 

Please correct me if I make wrong assumptions or modellings, I'm pretty new to this. 

Also, if I model the IPAL 21 I get similar results, though still massively favoring the IPAL (even when considering costs). First of all, consider the current marketprices over here (Belgium):

Lavoce 21 SAN: 358 euro

B&C SW152: 519

IPAL 21: 650 euro

When modelled to never exceed Xmax we get these results (2pi, 2 port configuration):

                                   20hz   30hz   40hz   50hz   60hz   70hz   80hz  amount of volts needed to reach Xmax   DB lost due to Xmax limiting   Price

Lavoce 21 SAN       117    123      125     125     125     127     128     80                                                                    3dB                                              358

B&C SW152             118    122      125     126     126     127     129     60                                                                    6dB                                              519

B&C IPAL 21            125    127      129     132     133     134     135     55                                                                    8dB                                              650

=> it looks like the IPAL suffers the most from limiting its output to Xmax, but it still kicks ass (especially in the low end), AND it needs LESS power to get there. 

Should I jump on the IPALs and get a pair before prices go up again?

 

[SME]

Hey @jay michael.  If using the same amp when running everything together, definitely get the same drivers.  Otherwise, it's not nearly as important.