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Posts posted by peniku8

  1. 34 minutes ago, klipsch said:

    Give those PA a try :)

    I was thinking with 2 ports blocked on the skrams that there should be good response in to the 20s. Maybe try running the 3 dual sealed from 5 to 30ish and skrams from 30ish to 100ish. There is a dual front firing pair of 18s too behind the first row of seats (they're good for tactile).  I'll need to play around and see how things work out. The 18s are the original stereo integrity ht18s so nothing bad, nothing great. 

    I'll watch movies around reference, usually 5db below. I enjoy music as well and hoping these skrams bring some more fun to that arena. 


    My PA mains are 85lbs each, I don't particularly like hauling them around. Plus I'd need the dsp amp with me for the EQ profiles. Not fun. These are line-array elements with a 12" lf driver and a compression driver (both B&C) with a 90x30° coverage. They sound horrid without the system EQ.

    Either way I will be building high quality mains soon. A tri-amped design with ribbon tweets. Highest fidelity 😉

  2. That's gotta be the cutest thing I've seen all day! The smell in the shop must be horrible thou 😅

    Making small scale models would require using a tiny router bit. That laser surely is a handy thing.

    If you now put a 6" (???) driver inside and made a working cab you would make my day!

    • Haha 1
  3. Using PA speakers for HT seems to be pretty popular. I should maybe try my PA tops for the HT as well... But if I like it, the price for the upgrade would be outrageous lol.

    Where are you planning to cross the skrams to the sealed subs? You could also use some shaping to have the sealed subs play along with the Skrams in the mid-bass region, to even out room modes. Tune the Skrams to 25Hz, HPF them at 40Hz and you will have the phase swap out of the way. Or measure them outside and feed the impulse response to a convolution plugin. If you have good drivers in your sealed subs, 6 of them should be able to keep up with the Skrams in an HT. Unless plan on watching movies at 140db inside. Which I'm almost doing (115db peaks in the bass; add bass management => ~125db peaks; plus a rising house curve that ends up at +15db at 20Hz, but I usually watch between -10MV and -5MV).

    It's just sad that my favourite movies/genre are the Marvel movies. Even with BEQ the bass is lacklustre.

  4. 5 hours ago, klipsch said:

    Sorry for the confusion. I was suggesting the use of melamine sheets to use for the vacuum housing box.  Phenolic lined sheets can be used too if they're cheaper in France.  Both are usually particleboard middles with lining of both materials on the outside (veneered like you mentioned). The melamine surface is well sealed to keep the multi-vacuum vac box chamber air tight.  However, making a box is not necessary. Some just hook 1 vac per zone.  The cost of mdf VS melamine in my area is the same. Making a vac box out of melamine saves time and money to seal the vac box if it is made of a porous material like mdf  or wood. Metal would work just as well (maybe better) if you have access to fabricate that cheaper. 

    I used 3/4 mdf for the vacuum board and have used regular mdf and umdf for spoilboards. The ultralight mdf may have been slightly better for these motors. I just had a free mdf sheet on hand once I went through the last spoilboard. Each spoilboard has always started out as 3/4".

    PS There are full phenolic sheets (no particleboard, but full phenolic throughout). Those sheets are several hundred each here in the States. High-end cnc machines use those as the vacboards. They just carve the pattern and need zero sealing due to the phenolic properties. MDF will expand and change with temperature and humidity, but phenolic supposedly does not. 

    I'd rather weld a steel box with a bunch of connections for PVC tubing to take care of the airflow and house all that inside an MDF box to keep the noise inside. This airtight case doesn't seem like a reliable idea to me.

    Do you think bolting down the spoilboard with 4 screws at the corners would be sufficient? If I seal the sides, the vac should suck the spoilboard to the vac board so I would be able to prepare the spoilboard.

    I found this material called Iberpan 400, which is ultra light MDF with a density of 400kg/m³. That's a little less than 2/3 of the usual MDF density. I just don't know a price since it seems that it's only available for commercial customers, plus the wood supplier where my company is registered doesn't seem to have it.

    I thought about making the entire vac bed from aluminum, but the cost would be outrageous.

    btw, @Ricci, I'm sorry for now completely derailing your Skram thread! Maybe we should start a dedicated CNC thread somewhere?

    And btw, Happy New Year, y'all!

  5. @Ricci These cabs will be used for live gigs and rentals, so a durable coating is preferred. I rounded over all edges which come into contact with the environment with a quarter inch roundover bit, to prevent the coating from breaking too easily there. The 8lbs of Warnex I have should be more than enough for one cab at least. I will spray the cabs inside, with the windows open for some fresh air to breathe (although I think the low viscosity of the paint prevents it from evaporating to some extend). Gonna get some plastic wrap to cover the surroundings. I wanna keep the room as white as it is. I don't remember reading anything about diluting Warnex.

    @klipsch I might be able to do 3 rectangular regions, depending on how flexible I am with mounting the T-Nut bed beneath.
    I'm unsure what you mean by Melamine table. If I search that term online, I only find veneered MDF or plywood sheets. Making everything from MDF seems like a more simple solution to me. I can seal the bottom layer and use the same sheet of MDF for the top layer. Which thickness would you recommend?

  6. 9 hours ago, klipsch said:

    Haha about avsforum. I can relate - there may be 8 18" drivers in the room where the 2 skrams are going... 😯

    I also have an extra b&c 8ohm 152 that needs a home. Build another skram? Buy another 152 and try a skhorn? 1st world problems... 

    What type of clone Amp did you go with? I'm thinking of trying one for the 2 skrams. 

    Maybe I should not have, but I suggested 3 vac motors as that is what I think I should have done. That is awesome that you and your Dad are working together. Congrats on his upcoming retirement. Right now, I have 4 vac motors. Can run either 2 at once or 4 at once. 2 is what I run 90% fof the time. 2 works for full 4x8 sheets. I've run 4 on large warped boards, but that was for material I ran for a few customers. Also run 4 for carving and cutting smaller pieces.  For your smaller work area, 2 would probably be great, but for when you upgrade or cut smaller pieces, 3 would probably be a good option. 

    I've never sprayed Warnex, but I've sprayed duratex before. It was not the spray version of the duratex. I watered it down a bit and it sprayed well with a cheap Warner sprayer (maybe it was 5 to 1 mixture). However, I ran a thick nap roller on the sprayed surface after the spray to get the texture look. 

    I simmed the 152 in my cab and it somehow starts rolling off almost 5Hz earlier. While it has the same headroom than the DS, EQ'ing up the roll-off would probably introduce too much ringing for my taste. EQ'ing down that 70Hz spike which the DS produces is much more convenient. I don't even know the the SW starts rolling off sooner.

    I got a Sanway FP13000 maybe 6-7 years ago. The old version that is. The newer ones are more stable into low impedance loads and can output more sustained power. Mine outputs enough power to dim the lights on a 230V circuit... Bad installation in this house here in France. I also have their 10k dsp amp with touch screen which I'd never buy again. The dsp clips long before you can reach maximum output power and is so unflexible that you can't find a workaround (there is no input gain, and the output gain can only be negative). Many on AVS seem to be happy with the Sinbosen 20k 4 channel amp. It outputs 8KW sustained total to 4 channels iirc. Nowadays I'd rather spend about twice the money and get a used name brand amp. For HT use these amps are phenomenal thou.

    I'm planning to make a table with 2 vacuum sections. A smaller one about 1.5' x 2' and an L-shaped section around it to expand to the whole table.
    I'll have a look at shipping costs of the Lighthouse motors, as I can't seem to find anything similar here. If I save alot buying multiples I'll go for 3 motors right away (using three in a 3 phase configuration would be pretty cool).
    Are you masking the table when doing smaller parts?

    I wasn't aware that there was a 'spray' version of Duratex, but as for Warnex it's all the same. And it actually seems that you only get proper texture when spraying.

  7. 20 hours ago, klipsch said:


    A diy vac with 3 lighthouse motors will run around 700 bucks for melamine box (melamine makes sealing easy), pvc, mdf, pvc glue, circuit breaker, etc. I have two layers of mdf (one is the spoilboard). I made something similar to the below. It is based off of a Gary Campbell design: 


    The two skrams will be going behind a screen in our basement. Probably only to be heard and never to be seen again. 

    There is no such thing as too many clamps :)

    Your cabs look great. Really nice job with the design and cnc work. Very clean. Looks like you and Kregg have been really busy too! I hope your design gets you that flat 30hz you're looking for in a transportable form. I'll find your avsforum post when you get to it. I am hoping to have these cabs done and running in the next 3 weeks. Doing some traveling... 

    It's always the same. I spend 2 weeks on AVS and am convinced that I need at least two 21's on a clone amp (that's what I have now with the SKHorn in my living room).
    I talked to my dad today (who will retire in a few months and is very interested in this whole CNC thing, especially since the machine sits in his basement 😅) and it took me about half an hour to convince him that we need a vacuum table. We agreed to split the cost 50:50, so the budget for the 4.5' by 3' table is about 1 grand now. It's decided. Gotta finish the two 21" cabs and also two 12" cabs for live gigs first, but after that I'll allocate some free time for this project. Doing the final assembly of the second cab today showed me that those parts seemed to have moved even more on the table, which made me want to get the vacuum table asap.

    Anyways, I'll probably pester you with some questions about your build soon. I've looked into making the air grid from aluminum but that's darn expensive.

    The reason why you're using 3 vacs is for the big surface area I guess? To my understanding, the increased air throughput also increases the vacuum strength.

    2 Skrams in the basement sounds like a fun party room/home theater/both.

    My next step is to coat the cabs in Duratex (called Warnex here in Europe). I'm planning to spray it for the most part, to achieve the pro look. Have never worked with this paint before, so I'd be glad if anybody has some tips for me. The Warnex PDF made me a little more confident already and I'll try on a scrap piece first.

  8. 5 hours ago, klipsch said:

    Vacuum hold down will change everything :).  These cheap vac motors will take 1/2" warped sheets down flat. 3/4" warp sheets will go flat as well, but only if the warp is slight. If these cheap vac motors were replaced with a much more expensive regen vac motor, then there isn't much that wouldn't be flattened. Servos are very nice. Steppers work just fine too.

    This HSD air cooled spindle is not loud at all. I can hold normal conversations with just the spindle on. The cutting of the material is far louder than the spindle motor and the vacuum motors. However, all of that is no where near as loud as the dust collection system. Water cooled spindles are quiet, but do have more things to do for maintenance and operation. 

    In my experience, for wood, typically I'll use climbing for first pass and conventional for final pass. For dados/grooves/joints, I'll do full axial path in climb and leave a bit on radial. Then do full axial and radial conventional path to remove the remaining radial stock material. For profiles, I'll do climb and leave 0.04" axial and typically 0.02" radial. Then do the final pass with conventional for remaining. This usually yields good results regardless of grain direction. Climb can be less forgiving against the grain. Higher RPM can combat that, but then an increase in IPM is usually needed, etc. 

    The wife wanted me to stain these like the other sub cabinets we have.  Current plan is to sand lightly and poly them. No duratex on these two. 

    I really like your joints. They look nice for fit and great for final assembly. Long ago I used to glue and use brad nails, but have just been "gluing" with Pl premium 3x and clamping for years now.  With CNC cutting (assuming joints or similar like yours), screwing and nailing has not been needed for me or others. Heck, I've seen people use Pl premium and painters tape instead of clamps with joints like yours. The tape was enough to hold everything in place while the adhesive expands and cures. I've had 4 DO 18" sealed subs running for 6+ years with no issues with the Pl premium and clamp method.

    I do use kregg's pocket jig and screws for things cut on a table or miter saw, even with that square headed bit :)

    Some clamping action:


    Have any pictures or models of the inside of that cab? 


    How much would a DIY vaccum table cost all in all? As far as I've read, it's basically just like 3 layers of MDF, of which the top layer is low density MDF to allow more air to flow through. Seems pretty simple with like 4 sections for a table. Add some PVC tubing and a motor or maybe several?

    My dust collection system is pretty quiet, but I'll be getting a new one soon. Need better air flow also for the table saw.



    So your wife wanted them to be stained huh.. that almost sounds like these will be an addition to your living room system?!

    You got quite a lot of clamps there.. I guess I need to get some of those quick lock clamps as well. Mine are super heavy and the old school threaded system is a nuisance to work with.

    Here are two pics of the inside of my cab. The second cab is mirrored. I will make a thread about those on AVS soon, if you want more info I'm happy to answer any questions via PM as I don't wanna discuss that in the thread dedicated to a different cabinet ;)

    The essence of the cab was getting flat response down to 30Hz in the smallest package possible while avoiding a direct radiator design. They'll be around 120lbs with the driver, which was the goal (easily movable with two people, possible to flip them onto the wheels alone).




  9. @klipsch I'll seriously consider a vacuum bed when I'm done with the next project and am still having problems with accuracy even with more tabs and a thicker waste board (thicker than 8mm of MDF to screw into). Of course I would also need some free time to take care of all that...

    How does your table handle warped sheets?

    I have yet to find the limits of my machine. The 2.5HP spindle should be able to handle it just fine, but my machine is outfitted with stepper motors. And instead of upgrading those to servos I'd rather buy a bigger machine. I'd love to have a water cooled spindle. This one is pretty noisy.

    When working with metal, it is generally advised to use climb cutting only when you're removing less than half the bit's diameter. I found climb cutting to yield a slightly worse surface finish compared to conventional cutting. Do you see much of a difference?

    Did you stain the cab to use less Duratex or will you leave it as is?

    I assembled both my cabinets over the past few days and already have many changes I'll make in the CAD model for aid the assembly. Namely: more joints.

    Do you glue and clamp? I used Kreg screws for this project for the first time and while I like the system itself, I hate the head. The bit is not grippy at all. Plus those push the boards outwards, which I had to find a workaround for (pic below).



    I currently don't have any pics of an assembled cab, so here is the dry assembly:


    Can't wait to get those finished and do some measurements!

  10. On 12/27/2019 at 2:21 AM, klipsch said:

    I ran a while without a vacuum hold down.  There are motors here in the US for about $160 that last about 1200 to 1500 hours. 2 or 3 of them with 2 sheets of melamine for a housing will get you over 5 hg if that is something you choose to pursue.  Not sure what you have available in your part of the world. 

    Prior to the vacuum hold down, I would make tabs of .25" wide and .0625" thick.  They worked well, but took work when finishing like you've mentioned.  I then went to onion skinning from tabs and had much better results.  Using a down cut bit helped keep the material on the table without a vacuum, but meant any plunge cuts were not too clean (more of a burn than a cut).  To work around the plunge cut issues, ramps were used where they could be.  A compression bit gave me the ability to do plunge cuts cleanly and still have decent down pushing pressure on the material without a vacuum and using tabs.  Is the straight bit causing some "chatter"?

    20,000 RPM at 150ipm for a single flute bit should produce a chipload around .008.  Is that about what you are making?  I only ask as when I was first starting out, I was running too high of RPM which made more heat and dulled my bits (was also using cheap bits).  When that happened, the onion skinning and tabs both suffered as the wood was being pushed more than cut.

    Sounds like you made the table yourself? Guess you had fun drilling hundreds of holes! There is a vacuum bed for my CNC but it's 2.5 grand...

    The straight bit I have was 20$ and it did all parts nicely; it's a double flute bit. There are some high performance bits for 30$ to 40$ which I might consider in the future. I just recently spent 400$ on bits, so I'm good for now. I got the CNC just a few months ago. I never CNC'd wood before, but I've got some experience in milling various metals. CNC'ing aluminum essentially uses very similar feed rates and speeds (if the machine is sturdy enough). There was an audible high pitched screetching while doing the cuts; I'll try lower RPM next time! Nothing burned and the chips produced were small, but definitely not dust.

    This picture shows a part straight from the machine. All cuts parallel to the grain are pristine and those against the grain have some slight edge shatter, but nothing grave.


  11. 2 hours ago, klipsch said:

    Hey peniku.  Yes, that is my cnc.  I added, what may be, extra detail which made this a longer reply.  Hopefully adding some detail helps to better answer your questions.

    For each of the sheets, no holding tabs were used.  Instead, about 5 hg of vacuum hold down was used.  For a few of the pieces requiring 2 sided work, the vacuum hold down was bumped up to 10 hg.  Onion skinning can work better for rigidity and finish in my experience vs tabs when working with quality plywood sheets.  What are your experiences?

    Your eyes are good.  A 1/4 inch 2 flute compression bit was used throughout at about 250 ipm and ~12k rpm.  Single climbing passes were used for all pocket/groove/slot/recess cuts.  Two passes were used for the inside and outside profile cuts:  one climbing pass at about 98% depth and 1 conventional pass at 100% depth.  Those settings worked well throughout and I do not plan to change them for the 2nd skram.  I thought about using a 3/8 inch bit for most of the cutting to be able to run > 450 ipm, but that used a little bit more material and would need a slightly different layout. Since I'm not mass producing these for profit, I stuck with the cheaper 1/4 inch bit.

    Looking back at my rough notes and machine logs, the following should be approximate cutting times for 1 skram:

    • 12 mm baltic birch sheet:
      • ~18 minutes
    • 18 mm baltic birch sheet1 with the left and right side...:
      • ~40 minutes
    • 18 mm baltic birch sheet2 with hatch, bottom, top..:
      • ~20 minutes
    • 18 mm baltic birch sheet3 with single driver cutout:
      • ~2 minutes

    Each second side cutting for the parts that have handle recesses took less than 5 minutes total for set up and cutting for each.  There are 4 parts with 6 handle recesses, so I think a conservative estimate of 20 minutes total is accurate-ish (5 minutes x 4 parts).

    The second side cutting for the back part which fits the hatch part took less than 10 minutes for set up and cutting.

    Total time with setting up the sheets, parts, tooling, machine, and cutting for one skram is probably around 2 hours and 10 minutes with the 1/4 inch bit.

    How long did it take you to cut one?

    Thanks for your very detailed response! My CNC is quite a bit smaller and I have to cut a sheet of plywood (2.5m x 1.25m) into three pieces to fit them on the table, but the total machining time for a pair of my subs (a little smaller than the Skrams but also with dados and multiple handles etc) would be ~4 hours. I'm using an 8mm bit for all operations at 150ipm and 20k rpm because I don't want to change tools (I have a tool length sensor but no automatic tool changer). Maximum cut depth was half the total depth (2x9.5mm).

    Here is a pic for one of the 9 sheets. Machining time for this one is 34 minutes.


    Onion skinning on a vacuum table sounds like a great solution. I have a T-Nut table thou... I have tried onion skinning with the frame screwed to the waste board with little success. Aluminum does that, but not wood.

    It looks like my holding tabs were too small because some parts are not perfect. Edges are not always 100% straight and some measurements are a little off (but max 2/100th of an inch). I used conventional passes throughout because those gave me a better surface finish. I used a simple straight bit; cuts against the grain do require some sanding, but nothing critical. Removing tabs from all the parts took me maybe 2 hours at most, but I prefer having the parts ready to be glued together straight out of the CNC.

    I am thinking of selling those cabs (not the ones I made, just generally producing subs for customers), which overall process-optimization would make a lot of sense for of course.

    My tabs were 3mm thick, 8mm long and were placed every 120mm. For the next project I'll try thicker tabs every 90mm and will also use a thicker waste board.

    You can see the un-sanded surface in this photo.


  12. The 2 channel 6000D is a bridged version of the 4 channel amp. One channel will output a little more than 2KW bursts into 4R but seems to be able to sustain like 1.5KW (according to notnyt's tests on AVS). If you hook up the 2nd channel as well, those numbers drop by about 25%. The SKHorn is fairly efficient and you said that your priority is not SPL, so I think the Behringer should be a good start for you.

    The amount of cabs Ricci stated is not a 'requirement' for SPL, but rather to even out room response and have higher flexibility I'd guess. Even one SKHorn should be enough to exceed 130db in the room size you mentioned. That's a tiny room for so much sub. But more is always better for sure!

    I'd say build two SKHorns and use it with the NX6000 at first to save some money. If you want to upgrade to an amp with more power in the future, you'll have to spend a lot more money compared to the Behringer. There is quite a big price gap in that market if you don't count the China clones. Maybe you're lucky and you can snatch a K10 for under 2 grand used.

  13. You can love any brand to death, but I personally wouldn't touch an 8" driver for anything "sub" related. If I read the data sheet correctly, it actually is an 8" driver.

    I own an 8" powered sub and I regret buying it. It's good for an 8" subwoofer, but it's not good for being a 1000$ sub.

    But now you have the driver already, so it's up to you to decide if you wanna make a fun project with it or if you want to build something bigger instead. Without knowing the T/S parameters of the driver it's basically impossible for us to tell you what to build. They don't seem to sell drivers separately, so it'll be hard to get those unless you can measure them.

  14. I've been wondering... What if one took like 5 Movers and attached them to a piece of plywood (one at each corner and one in the center). Then mount this to an infinite baffle construction and seal off the gap with a rubber surround...

    The surface area of a 2.5m x 1.25m sheet is equal to about 20 21" drivers (if you add half of a decently sized surround) with an Xmax of 15mm.
    Even if the entire thing would probably not be able to widthstand acceleration forces to get maximum excursion at say 40Hz, this should be a pretty efficient solution for single digit extension in any home theater.

    5 movers have a total peak force of 4.5KN, which translates into an acceleration of 180m/s² of a 25kg mass (estimated weight of a 12mm thick sheet of BB ply).

    With an acceleration of 180m/s² you could move an object 15mm (Xmax) within ~0,013s. Since you need to do that 4 times to get a full sine wave cycle, that would result in a frequency of about 19Hz. And that only with 5KW if I'm interpreting their data sheet correctly. You could make an entire wall your cone area with enough movers...

  15. 14 hours ago, radulescu_paul_mircea said:

    This is not M-Force , it’s a chinese A&D audio driver. Neo motor and 8” coil.

    I heard the M-Force more than once and it is absolutely amazing. Unfortunately the users had some unlucky situations with them but they indeed perform extremely well!

    that Funktion one sub is the  loudest sub out there !period ! and it digs deep enough to be extremely impressive. It goes louder under 50 hz than 2 SKhorns XL loaded with Ipal and used with other  subs from 60 hz up they will have enough headroom. There are a few companies who have 6 and 8 of them in use constantly with great results.


    The picture of a similar driver in this thread got me confused then, thought it was some custom design!

    It's surprising that one of these subs is louder than 2 of your subs, the stats would tell a different story. According to hornresp, 4 IPALs should exceed 140db playing at their AES wattage from 30 (tuning frequency of my design) to 200Hz. Total volume being less than 1000L; 135db at 25Hz (excursion limited).

    Josh please get an F132 and do some CEA tests ❤️

  16. 1 hour ago, Ricci said:

    I need to hear one of these M-force systems at some point! 

    I would also love to. The Funktion One horn's stats are not all that impressive when you look at the humongous size of the thing. iirc it's over 1000L and like 300kg, but if you look at it as what it is (a single driver subwoofer), it's ridiculous.

    I would also love to experience the Mover. The motor is similar to the M-Force in design. It generates enough force to lift my entire body. I don't know how many motors are that capable 😅

  17. Well the power distribution I have for live shows is 32A three phase, which is plenty for the sound system. The supply line gets split up into 6 single phase 16A circuits which are on breakers with C characteristics. That allows for like 10KW for a few seconds before it trips. Would love to test the Hoellstern's sustained power. My loadbank is only 4x4Ohm sadly, so I wouldn't even be able to test something like 4x1Ohm. That would require 64 of the 16 Ohm heating elements I use 😅

    Quotes from the website:
    The total power of all four channels is at practical burst signals typically 20 kW (40 kW for a short time).

    1.6 ohm (only for information – 2 ohm minus 20 %)

    @Ricci It says minus 20%. Looks like they're only trying to say that the amp is stable into loads like these, but don't want to comit to a specific number of power output.

    With the super high maximum current of 125A on one of the amps, you would reach the rail voltage before the current limit even at a 1.6 Ohm load.

    Has anybody here tested/used Powersoft's DigiMod 3000? I might want to use it for my single 21" cab. It's fairly cheap (total looks to be under 1 grand with the dsp chip) and the figures look like a great match bridged into an 8 Ohm driver.

  18. 12 hours ago, Ricci said:

    I've heard of them but never seen one over here in the states. They seem to have a pretty good reputation among the live sound guys. Not sure these would drive 8 ipals that well. The specs list a couple of things that stand out. 1.6 ohm 10kw rating per channel has a note about calculated as 2ohm + 20%? I didn't see mention of if the power ratings are with all channels driven or not or the duration or signal type. The big spec that jumped out at me is the long term power limit is 16A, so I don't expect it will do very well in a sustained power test. The K20 and K10 allow for settings of up to 32A for example. How useful truly sustained power into low impedances is is up for debate. A lot of people seem to get excellent results out of the modern "stun gun" amplifiers. Seems like this is a good competitor for the X4 and X8. 

    Also check out the Linea research amps. Not necessarily for driving 1 or 2ohm loads but otherwise I've heard a lot of good things about these. 

    I've looked at the Linea lineup some time ago when I saw @radulescu_paul_mircea talking about them; the amps look feature-rich and seem to have a good dsp for a reasonable price as well. In the end I'd have a much more detailed look at the dsp or even test it before I'd make a call. I've also seen a similar Dynacord amp, dunno if it's new. 

    When I'm seriously ready to consider buying an amp of that caliber, there might be more options. First on the list are some l-acoustics system amps to get rid of the Sanway-workaround anyways.

    I'm unsure if the K20/K10 can really make use of a 230V/32A connection. According to the data sheet, the X4's maximum current draw in single phase operation is 15A, while being like 5A on 3 phases. It looks like the 30A connection is meant for 120V operation and not fully a feature for 230V. I might not interpret the manual correctly, but 230V 3 phase operation should allow for some serious long term output.

    32A single phase connectors are very uncommon in Europe too. Most of the time it's 16A single phase or three phase 32/63/125A. Or w/e multiphase 300A powerlock for the distribution.

    Did your K20 ever trip a 16A breaker on 240V operation?

  19. Just found this beast of an amp by a German company called Hoellstern:


    The data sheet reads >10KW per channel (4) into 1.6 Ohms and one of their amps is rated for 1.6 Ohm bridged (!?) operation, this looks like something that will make IPAL owners happy.

    I don't know the price of the DSP amps, but the non-dsp 20.4 is about 6 grand, which is actually pretty cheap for an amp with this much power, considering that the 8 Ohm and 4 Ohm performance per channel pretty much matches a Lab 14K (similar rail voltage), but the Hoellstern can output higher currents of up to 115A (FP14k@90A), which makes it stronger in the low impedance department.

    Powersoft's X4L is a bridged amp, so it won't be very useful with the 2 Ohm loads you get with IPALs (2 in series if you have the "regular" IPALs), which would make this one of the best available IPAL amps that I'm aware of.

    The single phase 16A/230V input would limit long term output to about 400W per driver if you connected 8 drivers to the amp. 4KW bursts per IPAL seem like a good match to me thou.
    There is a 2 channel amp with even higher current figures (125A, similar to K20) for about 3.5 grand, if you want more sustained power.

    Edit: after taking about 2 hours to write this (afk'ing in between and getting distracted), I even forgot the main question:

    What do you guys think about these? Ever came across Hoellstern before?

  20. I did a small test which might be interesting to some here, since the Tool album has been discussed here earlier (for the great dynamics with the Skram).
    Not entirely bass-related, but I just got my new measurement mic and placed it 1m away from my drumkit to get an impression of the crest factor of actual drumming.
    I hit some hard rimshots, which peaked at 143db(Z), but the RMS maximum in the measurement sat at 116db. That's a crest factor of 27db!
    That aside, I would never like to listen to recorded drums at the same volume as I am playing at. I always rehearse with ear-protection since the cymbals are just way too overkill, especially if you have high quality cymbals with lots of overtones and sustain.

  21. 8 minutes ago, Ricci said:

    It depends. The K20 will run stereo at 2 ohms, but it will limit long bass notes into low impedances considerably. Buss pumping can be a problem. The exact impedance and phase of the load and the bass content used will determine how well it does. I really recommend bridging the K20 or K10. They perform better with heavy duty signals into low impedances when fully bridged. 

    The plan would be a symmetric load anyways (8 drivers total), so bus pumping shouldn't be much of an issue. 4 drivers per channel on a K20 sounds like a good match to me. If that's not enough, doubling both would be the alternative. 16 of these drivers should be plenty for a lot of situations... X4L surely looks nice for that application, but since it's so new you hardly find it used anywhere.

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