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Ricci's Skram Subwoofer & Files

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Installed behind screen. Hope to have them powered up this week. Unfortunately will have no time run any voltage to them this weekend¬†ūüėę

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Box 1 of 2 is almost complete. The lower vent section still needs to be attached properly.

Looking at amps currently.

The Powersoft LITEMOD 4HC with a Medium heatsink is looking pretty tasty if i go with a Plate amp, still need to get a price quote.

Otherwise I'm looking at a Powersoft K6 with upgrade Mods equivalent to a K10 with DSP is a little over 3,000$.

Powersoft K20 with DSP is closer to $4,000.

itech 12000hd is $5,000+

Lab Gruppen FP10000q is just over $3,000 but i hear Behringer purchased them and there are reports of dropping quality and reliability/experiences with poor service and support.

 

I figured I should brand the box so I laser engraved it 3/16" deep which will eventually be coated with Duratex black.

„Éč„É£„Éľ„Éč„É£„Éľ

MEOWMEOW

 

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14 minutes ago, jay michael said:

Looks great Tahoejmfc! I run 4 Skrams on a k10 and have been very pleased. 

Ive been looking at your system, love it, and nice furry hat! I would love to talk about your system on the phone. I am running B&C 21SW152's which are rated at 2000W, peak 4000, so I'm not sure what would be the best option. 530-three-eight-six-0649. I am in Lake Tahoe California right near Reno and the Playa. would love to chat.

-fellow furry hat collector (I've been to Mongolia several times so Ive ended up with 4 fox fur hats)

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Just spoke to my Powersoft connection and have been informed Powersoft has discontinued the K lineup of amps except the K20. They have existing stock of K6's that can be modified to K10 levels with DSp for 3250$ at discount

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That skram is looking good @Tahoejmfc! 

I've been listening to my pair  ... need to do some EQ'ing still and deciding whether to run the skrams with 2 ports plugged or wide open

Here is John Wick 1's club seen peaks ... sealed subs are low passed at at 33 and skrams are high passed at 31 both at LR 48db/octs ... both skrams have all 4 ports open ... this is at -10 db reference with sub preout running 3.5 db hot vs all channels which are crossed at 80hz

Anyone else crossing skrams with sealed for the ULF?  LR or BW or any recommendations?

johnwick.thumb.png.4d5bdbd7b48f03968044a9fedc256c51.png

 

Edit:  I guess I should also add that these skrams are just stupid ridiculous and I'm pretty sure I could fit at least 1 or 2 more behind the screen ...:rolleyes:

Thank you Ricci!

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I like seeing all of these builds. It is giving me motivation to finally finish off the prints for the slightly more compact sub.

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11 minutes ago, Ricci said:

I like seeing all of these builds. It is giving me motivation to finally finish off the prints for the slightly more compact sub.

6th order bandpasses seem to be very popular over the past couple of years. Any reasoning as to why that is? Seemed like tapped horn popularity came right before...

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9 minutes ago, klipsch said:

6th order bandpasses seem to be very popular over the past couple of years. Any reasoning as to why that is? Seemed like tapped horn popularity came right before...

Essentially, isn’t a tapped horn exactly that - a 6th order BP? 

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5 minutes ago, m_ms said:

Essentially, isn’t a tapped horn exactly that - a 6th order BP? 

I wouldn't argue... Ironically I believe danley has a patent on TH while bose has a patent on 6th order BP. 

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OH MY GAWD!! WELL WORTH THE BUILD. These things pound!!!! FUCKINEH

I will have my Powersoft K10 here next week and start to really set things up with tuning with a sound engineer friend from Meyer.

THANKS RICCI & Everyone else that has contributed !!!!!!!!!!!!!!!!!!!!!!!!

Notes from first build.

1. Don't rotate the mounting hole pattern, the handle will be in the way, making tightening 2 of the screws a slow process.

2. Don't install one of the side handles until the driver is mounted. Otherwise you end up hitting the inner part of the handle with a sledgehammer to make it fit because I used gorilla glue to put in the handles with and couldn't remove a handle..

3. Don't install the handles with Gorilla glue, its a mess and squeezes out on the frontside.

4. Have a friend there just incase when glueing and screwing the final piece on in, mine was the bottom with vents attached and I could have used a hand to hit it with a block and hammer from the front to seat it proper as my arms are not 4 feet long and I had to run the screw gun on the other side.

5. Do apply liberal amounts of Sake to the process.

6. Bondo works great, so does the Gorilla glue, I used 2" screws on the perimeter, 1.75" on interior work, and a few 1.25" here and there. 

 

Don't know why I cant attach photos over .41 mb?

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18 hours ago, Tahoejmfc said:

OH MY GAWD!! WELL WORTH THE BUILD. These things pound!!!! FUCKINEH

I will have my Powersoft K10 here next week and start to really set things up with tuning with a sound engineer friend from Meyer.

THANKS RICCI & Everyone else that has contributed !!!!!!!!!!!!!!!!!!!!!!!!

Notes from first build.

2. Don't install one of the side handles until the driver is mounted. Otherwise you end up hitting the inner part of the handle with a sledgehammer to make it fit because I used gorilla glue to put in the handles with and couldn't remove a handle..

3. Don't install the handles with Gorilla glue, its a mess and squeezes out on the frontside.

5. Do apply liberal amounts of Sake to the process.

Don't know why I cant attach photos over .41 mb?

Thanks for giving a quick review.

Good set of notes.

Sorry I thought I mentioned leaving the handles off on this page! It is recommended to leave the side handles off until the driver is installed. It helps a lot. Extra space and access to the screws. I always use gasket tape on the handles so they can be easily removed. Gorilla glue!?

#5 is DB approved.

Not sure about the photo limit. I'll ask about it. 

 

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On 2/2/2020 at 10:45 AM, klipsch said:

6th order bandpasses seem to be very popular over the past couple of years. Any reasoning as to why that is? Seemed like tapped horn popularity came right before...

The newer drivers with higher xmax and lower Qts lend themselves to compact 6th orders better than the drivers of old. IMHO. At least that's how I ended up on these during the MAUL design process back in late 2014.

I'd like to think I had a hand in popularizing this type of 6th order among the DIY crowd and perhaps even the pro market (In this case it's probably a result of form following function). Among the DIY scene they sure seem to have exploded in the last year. 

There's always been 6th order variations going back decades though. Too many variations to count. There really isn't anything new in audio. Just different spins on the tradeoffs and design choices. The only thing I did different was slot load the drivers and shrink the slot or horn greatly compared to the old pro audio designs. The old pro designs used the volume in front of the driver for huge gain in the >60Hz range but the chamber for the "low end" was basically an afterthought and greatly overpowered by the higher tuned section. HIL is always in effect. I also planned to have multiple tuning options for the low section from the get go, which you don't see on the pro 6th orders. I try to get a reasonably smooth and extended response while still picking up a bit of broadband sensitivity vs direct radiating. I also try to keep the resonances under control and bury the driver noises a bit. A lot of the old 6th order designs were notoriously bad and labeled as 1 note, or boomy so I spend most of the effort making sure it will sound good first and then worry about loud second. I did the same with the Othorn TH back in the day. You have to sacrifice some loudness for bandwidth and smoothness. 

As far as why 6th's seem to be popular and TH's seem to be less so these days, I'd say it is due to the fact that 6th orders can be smaller than a TH to cover the same bandwidth. TH's are also more tricky to design well and build. Especially once you start attempting to tune them much below 30Hz. A good 6th order system can also be tricky to get right though. 

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Great details and response as usual. I appreciate the write-up.

I need to work on integration more, but these skrams are awesome. Finally getting the chest pressure with kick drums I was lacking. I need to try things with 3 blocked ports. If that works well, I am wondering if I just sell the sealed boxes and go all skrams... 

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4 hours ago, Ricci said:

Thanks for giving a quick review.

Good set of notes.

Sorry I thought I mentioned leaving the handles off on this page! It is recommended to leave the side handles off until the driver is installed. It helps a lot. Extra space and access to the screws. I always use gasket tape on the handles so they can be easily removed. Gorilla glue!?

#5 is DB approved.

Not sure about the photo limit. I'll ask about it. 

 

What kind of gasket tape?

Yah, Gorilla glue, Im not a wood worker, but more of a mechanical engineer so I don't really know what is the correct method for assembling wood, it was a learning experience....

- sent from my vibrating keyboard with occasional shit falling off the walls of my garage

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11 hours ago, klipsch said:

Great details and response as usual. I appreciate the write-up.

I need to work on integration more, but these skrams are awesome. Finally getting the chest pressure with kick drums I was lacking. I need to try things with 3 blocked ports. If that works well, I am wondering if I just sell the sealed boxes and go all skrams... 

 

I'm using the SKHorn in 1 port mode in my HT. I get no usable output below 18Hz (chuffing related), which is fine because I'm sitting on a tiled basement floor. Only TR I can get is from my mini riser.

9 hours ago, Tahoejmfc said:

What kind of gasket tape?

Yah, Gorilla glue, Im not a wood worker, but more of a mechanical engineer so I don't really know what is the correct method for assembling wood, it was a learning experience....

- sent from my vibrating keyboard with occasional shit falling off the walls of my garage

Use regular oval-head screws. I use those black ones commonly used for sheet metal, which work great on plywood too. There are gaskets for the handles which are less than a dollar (penn elcom) but you can also use 20x2mm gasket tape like I did. I like the screws, they make for a clean look.

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17 hours ago, klipsch said:

Great details and response as usual. I appreciate the write-up.

I need to work on integration more, but these skrams are awesome. Finally getting the chest pressure with kick drums I was lacking. I need to try things with 3 blocked ports. If that works well, I am wondering if I just sell the sealed boxes and go all skrams... 

 

Give it a shot. Tuning should be in the 15Hz range. Your sealed will probably only have an advantage below that point. If you went to 4 of them for extra headroom with the lowest tuning I don't think the sealed will have any advantage until very low in frequency. Likely below 13Hz or so. Depending on your room it may be more reasonable to use a tactile transducer setup for the really low stuff rather than throwing piles of sealed subs at it. 

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@RicciI have some closed cell foam. Would that work to block the ports? I only made a 2 port block out of wood and would need something else for that duty.  Guessing a High pass LR48 @ 14hz for the 3 port test? 

I have 2 HT18s nearfield in a front firing sealed box behind the MLP for full tactile. However, even though I'm on a concrete slab, the 6 other HT18s behind the screen in 3 DO sealed boxes do give tactile feel in the seats, but I would not give up the nearfields at this point. And the sealed never gave me as much chest compression like skrams either. Maybe that's on me with the previous positioning and calibration. 

 

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I use big chunks of mattress foam to block ports all the time. It works just fine. Yes it is a little bit leaky. No you will not be able to hear or tell a difference. Just make sure it's over sized and stuff it in there. Make sure the general shape is the same as the vent. The pieces I use are about 8" thick. 

I'd go with a 3rd or 4th order high pass at about 13 or 14Hz. Your electronics chain and amps will add a 1st or second order high pass at around 8Hz to begin with. 48dB is a little excessive but IMO but it won't hurt to try it. 

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Well i got scammed pretty hard on the K10 amp. Sold to me as a lightly used amp with very low hours....  I pulled the amp out of the box and within 2 seconds knew the guy that sold me the amp was full of sh....... in his lightly used statement.

It looked like it had been on tour for 10 years, never once cleaned and covered in RUST, GRIME and had a bent case as well. The dust screen was full of grime and had never been cleaned. I didn't even want to have a look at the circuit board as I knew from my electronics experience that it was going to look like a crusty 5 day old dead hooker on the side of route 66.

Any thoughts on the QSC PL 380 for driving a B&C 21SW152 4 ohm?

or recommendations for another amp choice in the under 3000$ range?

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6 hours ago, Tahoejmfc said:

Well i got scammed pretty hard on the K10 amp. Sold to me as a lightly used amp with very low hours....  I pulled the amp out of the box and within 2 seconds knew the guy that sold me the amp was full of sh....... in his lightly used statement.

It looked like it had been on tour for 10 years, never once cleaned and covered in RUST, GRIME and had a bent case as well. The dust screen was full of grime and had never been cleaned. I didn't even want to have a look at the circuit board as I knew from my electronics experience that it was going to look like a crusty 5 day old dead hooker on the side of route 66.

Any thoughts on the QSC PL 380 for driving a B&C 21SW152 4 ohm?

or recommendations for another amp choice in the under 3000$ range?

I was looking at the 380 as well. It was well regarded in the forums I came across. I was convinced to try a clone though. So I ended up buying a sinbosen 20000q. 

I know many of us understand the circuit board experience, but I think many of us are interested in the route 66 dead hooker story. :)

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Haven't EQ'D the skrams yet, but do have levels and time/phase lined up (I think) in the room with the other drivers in the room. Still running the skrams wide open. These skrams with the NSW are visceral, clean, and dynamic. I'm not an audio review guy, so I apologize for my remedial description. My ears and chest are highly enjoying the skrams. Thank you again Josh! 

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