MemX Posted August 15, 2015 Report Share Posted August 15, 2015 1) I wonder how much usable content there is in modern movies... say below 12Hz. (that is where the sealed starts getting the advantage over the ported) in the WinISD sim...I really don't know.. never had a system that can reproduce these frequencies accurate and with serious spl.. Check out the google docs spreadsheet linked to in the first post of the Low Frequency Content thread: http://data-bass.ipbhost.com/index.php?/topic/12-the-low-frequency-content-thread-films-games-music-etc/page-1 Column C of the spreadsheet gives the extension in Hz, recorded as the -10dB point in the SpecLab measurements. For some reason it's not working for me at the moment, only giving me the first section and not letting me scroll down, but from what I can see, the first 38 films all extend well below 12Hz... I went from a ported SVS sub to a Sealed DIY setup and the 'tightness' of the bass is night-and-day different - drums have a real kick to them now and the subs integrate so well with the speakers that I now just listen to the music, rather than listening to music and being somehow aware of the ported sub. For the cost of a few sheets of MDF, why don't you make one simple sealed box for one of the drivers and then run it with the rest of the system. I reckon that you will like how it sounds (if EQd properly) so much that you'll happily build the rest sealed! And you will get a chance to experience that <12Hz stuff if your signal chain roll-off is shallow, so you'll get to know what you might miss if you go ported Link to comment Share on other sites More sharing options...
Leons Posted August 15, 2015 Author Report Share Posted August 15, 2015 Hello all, This is what WinISD sims: 1117L. ported vs 959L. sealed (959 liter is ideal for a sealed HS24 according to WinISD)the idea of building a sealed testmule is tempting..altough the difference in output in the 15 to 30 band is verry big.. see attachementbest regards,Leon SI HS24 ported vs sealed.pdf Link to comment Share on other sites More sharing options...
MemX Posted August 17, 2015 Report Share Posted August 17, 2015 Hello all, This is what WinISD sims: 1117L. ported vs 959L. sealed (959 liter is ideal for a sealed HS24 according to WinISD) the idea of building a sealed testmule is tempting.. altough the difference in output in the 15 to 30 band is verry big.. see attachement best regards, Leon Can you show the graphs with the SPL output rather than the output relative to 0? That will give you a better idea of in-room output. Don't forget you will probably get Room Gain below 30Hz, at something like +12dB per octave. You will not know for sure until you have the subs in-room and measured, but you can guesstimate the 'best case scenario' by adding 12dB per octave at the bottom end of the scale, <30Hz. For example: 30Hz = 0dB Room Gain 15Hz = 12dB Room Gain 7.5Hz = 24dB Room Gain 3.75Hz = 36dB Room Gain I think that's how it works. Bossobass has posted a graph of various people's in-room responses, which shows that Room Gain does generally seem to start about 30Hz in room. Link to comment Share on other sites More sharing options...
Leons Posted August 17, 2015 Author Report Share Posted August 17, 2015 Hello MemX, The last attachement contained 2 graphs... the second is the max spl output sim of WinISD Holy cow!! that room gain below 30 is massive! I did not account for that... In that way even the sealed cab will be plenty.. max spl wise... add another 12dB for four cabinets... Can't wait to get the system together and fire it up... Thanks! Leon Link to comment Share on other sites More sharing options...
SME Posted August 18, 2015 Report Share Posted August 18, 2015 I think room gain of 7 to 9 dB per octave is more realistic. It's still a lot. Add my vote to the tally for sealed. Link to comment Share on other sites More sharing options...
MemX Posted August 18, 2015 Report Share Posted August 18, 2015 I would agree with this! ^^^ Hello MemX,The last attachement contained 2 graphs... the second is the max spl output sim of WinISDHoly cow!! that room gain below 30 is massive! I did not account for that...In that way even the sealed cab will be plenty.. max spl wise... add another 12dB for four cabinets...Can't wait to get the system together and fire it up...Thanks!Leon haha, Reading Fail on my part 122dB-ish max output from one driver, with 106dB @ 10Hz, is pretty loud... Add 12dB and you will have 118dB @ 10Hz, potentially, without room gain! As I suggested before, I suggest you build one and then see how it runs - I think you'll like the 'tightness' that Sealed brings, and it will still kick arse below 20Hz! Link to comment Share on other sites More sharing options...
Infrasonic Posted August 19, 2015 Report Share Posted August 19, 2015 Like I mentioned earlier, sealed is the way to go with the HS24's and it looks like others agree. You have other bass systems that will do loud bass higher in frequency. Sealed is an easier build, smaller, better extension and no need for high pass filters. Link to comment Share on other sites More sharing options...
Bossobass Dave Posted August 21, 2015 Report Share Posted August 21, 2015 Sealed is an easier build, smaller, better extension and no need for high pass filters. This is true with most drivers, not just the HS-24. Also, when modeling a ported sub, have a look at the Rythmik, PB-13, Cap 1400, RA 15" ported sub, or any other ported sub test and you'll discover a thing called port compression. There will be 5.5 to 8dB of compression at tune. That's the approximate difference in output advantage in the model going ported vs sealed. By contrast, the HS series sealed sub tests show 2 to 2.5dB of compression below the knee. Link to comment Share on other sites More sharing options...
SME Posted August 21, 2015 Report Share Posted August 21, 2015 Also, when modeling a ported sub, have a look at the Rythmik, PB-13, Cap 1400, RA 15" ported sub, or any other ported sub test and you'll discover a thing called port compression. There will be 5.5 to 8dB of compression at tune. That's the approximate difference in output advantage in the model going ported vs sealed. This is mostly true. The amount of port compression depends on the design. Port compression can be reduced or eliminated by making the ports large enough in diameter. However, when you make the ports larger in diameter, you also have to make them longer and the box bigger in order to maintain the same response. The subs named here are already quite large and would be impractical if made large enough to eliminate port compression. As you can imagine such subs would not sell very well. The HS-24 needs a *huge* box to make a low tune practical even with port compression, so imagine multiplying that box in size again in order to have low tune without compression. At that rate, you might as well go for an infinite baffle design with ports in the walls. Or just stick with sealed. Link to comment Share on other sites More sharing options...
Electrodynamic Posted August 21, 2015 Report Share Posted August 21, 2015 This is mostly true. The amount of port compression depends on the design. Port compression can be reduced or eliminated by making the ports large enough in diameter. However, when you make the ports larger in diameter, you also have to make them longer and the box bigger in order to maintain the same response. The subs named here are already quite large and would be impractical if made large enough to eliminate port compression. As you can imagine such subs would not sell very well. The HS-24 needs a *huge* box to make a low tune practical even with port compression, so imagine multiplying that box in size again in order to have low tune without compression. At that rate, you might as well go for an infinite baffle design with ports in the walls. Or just stick with sealed. Or you have the room for ported and can grab your cahones and build the appropriate volume enclosure(s). And yes, you want to make sure you have enough port surface area...not an inadequate amount of port surface area. Link to comment Share on other sites More sharing options...
Infrasonic Posted August 21, 2015 Report Share Posted August 21, 2015 This is true with most drivers, not just the HS-24. Also, when modeling a ported sub, have a look at the Rythmik, PB-13, Cap 1400, RA 15" ported sub, or any other ported sub test and you'll discover a thing called port compression. There will be 5.5 to 8dB of compression at tune. That's the approximate difference in output advantage in the model going ported vs sealed. By contrast, the HS series sealed sub tests show 2 to 2.5dB of compression below the knee. Well... depends on what kind of drivers you're looking at but yes, most of the time this is true. I'm glad you just posted this because this seems to be ignored by everybody who compares a sealed to a vented system and goes, "hey! Look at ALL that extra SPL. Yeah, it's in one spot but look!" Yeah... well... guess what? Max out that system and all that extra SPL is for nothing because you are now overloading your port system and it is compressing. Measure it now. How's all that extension doing now? Link to comment Share on other sites More sharing options...
BeastAudio Posted August 21, 2015 Report Share Posted August 21, 2015 Oh boy.... if nyt saw this post ^^^^^ Link to comment Share on other sites More sharing options...
Infrasonic Posted August 21, 2015 Report Share Posted August 21, 2015 He is in a more exclusive position because he has EIGHT uber woofer subs in large vented boxes. Whether he listens loud or not does not mean he may approach levels where his system will compress at all. I'm sure he extremely happy with his system and I would too but that doesn't mean his are immune to these things. All resonant systems will reach a point where they compress. As do passive radiator systems. So do sealed systems. Link to comment Share on other sites More sharing options...
Leons Posted August 22, 2015 Author Report Share Posted August 22, 2015 Hello all, You got me convinced that sealed is the way to go... sounds "tighter" and "digs lower" at the expense of some extra spl...Since I build 4 + the extra room gain down low... I dont expect a shortage of spl.Thanks for getting me in the sealed direction..When I enter the HS24 driver (sealed) in WinISD it will automatically come up with a 959 liter cabinet? Does this mean that 959liter is the "ideal" volume for this driver in a sealed cabinet? Making the cabinet bigger indeed gives very little improvement...959 liter (internal demension) is actually smaller than I planned per cabinet..best regards, Leon Link to comment Share on other sites More sharing options...
SME Posted August 22, 2015 Report Share Posted August 22, 2015 Hi Leon, The answer depends a lot. The "ideal" cabinet proposed by WinISD is probably one with a Q of 0.707 (1/2 the square-root of 2). This only ideal in the sense that it provides a maximally flat pass-band (the part above the resonance frequency) for the sub. On the other hand, if you use any kind of signal shaping or EQ, you can modify the response to whatever shape you like, within the capabilities of the equipment. Generally speaking, the larger the sealed cabinet, the less power you need to hit frequencies well below resonance, to a point of diminishing returns. This point is called infinite baffle (IB) because it's essentially the same as mounting the driver on a wall of infinite extent with infinite volume behind it. Depending on the driver, even a modest size box may perform almost the same as IB. With that said, the driver excursion required to hit the lowest frequencies is the same regardless of box size. This means that in a larger cabinet or IB it takes less power to push the driver too far and cause damage. In this case, it is more important to ensure that the amp power is limited to prevent damage. The larger cabinet will also have less output in the vicinity of the resonance frequency, but if you are aiming for maximum extension, this probably isn't a very important consideration. Link to comment Share on other sites More sharing options...
d_c Posted September 5, 2015 Report Share Posted September 5, 2015 Good news Leon - LMS Ultras are on clearance at PE, so you can have 4 GHorns with your 4 sealed hs24! Do it. Link to comment Share on other sites More sharing options...
Leons Posted September 5, 2015 Author Report Share Posted September 5, 2015 Hey d_c I have 4 LABhorns that take me down to 35...The HS24's will do everything below 35...No need for Ghorns anymore.. I will post my HS24 cabinet design this week.With a little luck tomorrow... met de vriendelijke groeten,Leon Link to comment Share on other sites More sharing options...
MemX Posted September 6, 2015 Report Share Posted September 6, 2015 Excellent work, we will look forward to some pics! Link to comment Share on other sites More sharing options...
Leons Posted September 6, 2015 Author Report Share Posted September 6, 2015 Hello all,Since I have to buy a lot of wood and make sawdust anyway.. and I have the space, I decided to go for a Big Hybrid.Via mounting a panel I can change from ported to sealed in minutes... see attachementI will countersink a permanent rubber gasket in the cabinet for an airtight seal.. The panel will be aluminum so it will even look cool when sealed..Let me know what you think.. any comment is welcome.I intend to start building in 2 weeksbest regards,Leon BigHybrid.pdf Link to comment Share on other sites More sharing options...
MemX Posted September 9, 2015 Report Share Posted September 9, 2015 I think you might struggle to seal the vents with what I assume is just going to be a screw-in panel over the front of them - the 24 can move some serious air so I'm not sure what it would need to seal the vents completely.. It looks like you are over XMax under 15Hz in sealed mode with that much power to each, though, which could be risky... Link to comment Share on other sites More sharing options...
Leons Posted September 11, 2015 Author Report Share Posted September 11, 2015 Hi MemXAs mentioned im my post: I wil countersink a rubber gasket in the cabinet (around the ports), then use a 18mm aluminium plate to seal them off.This will seal the vents completely... The aluminium plate can be bolted into the cabinet. The frontplate of the cabinet is 1,65" thick baltic birch-ply (double 21mm plates) That thickness provides enough "meat" for a serious attachment of the aluminium plate to the cabinet. Nick sent me a quick update of my four monsters in the making ... see attachment. Link to comment Share on other sites More sharing options...
Leons Posted September 12, 2015 Author Report Share Posted September 12, 2015 and a few more... Link to comment Share on other sites More sharing options...
Electrodynamic Posted September 13, 2015 Report Share Posted September 13, 2015 The picture of all four drivers ended up pretty cool looking. I should have all four drivers finished by the middle of this coming week. More pictures to come. Link to comment Share on other sites More sharing options...
MemX Posted September 15, 2015 Report Share Posted September 15, 2015 They look like they've landed from space lol Link to comment Share on other sites More sharing options...
Leons Posted September 15, 2015 Author Report Share Posted September 15, 2015 Seems Nick is on steam!... Link to comment Share on other sites More sharing options...
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