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Posts posted by radulescu_paul_mircea

  1. Welcome Moar!! Thanks for the link, it is a very useful tool. I needed that in my life ;)

    Playing with it I've been getting very interesting results, some of them really incredible. Even from a single enclosure, the Directivity starts to go forward even at very low frequencies like 40 Hz.

    This made me go out in a parking lot with 4 single 18 subs and to take directivity measurements.


  2. That M-Drive is a true beast, the way it can swing volts and amps is exactly what a driver like M-Force needs. It is not exactly double the IPal though.


    ,What do you mean, will you get your hands on one? That would be great, to see what it's capable of. 

    The DPC sensor was firstly made to be installed into the driver dustcap, but the added complexity wasn't worth it on those wavelengths. But still, for it to be able to truly function, it needs to be as close as possible to the acoustic radiator. It can be defeated if the feedback gain is set at -100 dB in Power Control Manager, so if you want to use the amps only on Virtual Transducer without DPC, you can. I haven't tried to use it without connecting the sensor.

    @awedio I have tested the IPal module. I own one and I'll add 3 more soon . But go pro audio use

  3. I've managed to get this sensitivity curve when I simulated the acoustic load of the air around the enclosure, as if it would be another waveguide with a very rapid expansion, but acting on the enclosure . In fact that, coupled with some acoustic resistance in the enclosure, higher losses through friction, increased viscosity in the port and enclosure gave me the most similar response. 

  4. I'll recommend you to use a single module for both drivers in series. It is more than enough for them. It will exceed the nominal excursion of the drivers at 25 mm at about 20 hz with all losses and nonlinearities accounted for. Also ,the DPC sensor needs to be extremely close to the acoustic center and that's why I think that enclosure is not best suited for this application. You would better use a manifolded enclosure, this way your acoustic center is very close to both diaphragms and the feedback loop gets more accurate. Having 2 modules in this tiny box is a huge waste.

    Also ,the M-Drive modules are not available without the motor and this system is hard to get and to implement.

  5. Is there a way of explaining how is it possible that the sensitivity of the speaker to be 107 dB at 100 watts/ 10 meters at 100 hz? I've tried everything to get that sensitivity in Hornresp and Akabak but with no results.i usually get a play response from 40 to 120 hz at about 102 dB. The rising response is not present in any simulations, except if I take into account the directivity increase at higher frequencies , but even with that, I can't seem to duplicate the results. 

  6. I think the noise we are hearing is a form of mechanical non harmonic noise. At the end of the stroke, in a well designed driver, the suspension has to stop the voice coil or any other part to hit another part of the driver. It is doing this by getting harder and harder to stretch until it stops completely. Before it does, some  mechanical clipping noise can be heard but it's not really a square wave because the diaphragm is bending a little also at those displacements.

    In the image one can see what one Powersoft X8 channel can do to a pair of 18TBX100 drivers in an 340 BR enclosure where the maximum excursion allowed was 1.5 mm more than the maximum Klippel recommended protection of 15.4 mm, which is already 4.4 mm over XVar (50% KMS) and where the people using it completely neglected that powerful noise


    • Sad 1
  7. 4 hours ago, chrapladm said:

    Will be interesting to see what your results are. I do like the IPAL but havent been able to make a design that warrants the extra cost yet.

    Oh, but they warrant the cost on their own. In anything you put them, that has increased performances. But only with the right amp. There's in fact the problem. Here we only have Powersoft amps that handle very low impedance and high reactivity subwoofers. SpeakerPower amps would be the others, but I can't really get my hands on them easily. Probably some Crests are also good and stable and also Crown amps. But not as good.

  8. No, I missed a punctuation mark. They are using the 18SW115-4 driver in the original TH118. I will build 2 identical enclosures to the TH118 , that are now easily found on the web.in those enclosures I will try the ID and IPal drivers to see what are the differencies and if it worths the cost difference. In my sims, the IPal version should go flat to 33 Hz instead of 37 and it should keep the same max SPL because it has more excursion and long term power handling than the SW115. 

  9. You are right about the average power. I was referring at that power into both.I didn't get that number from somewhere specific, all I did was to take the TruPower limiter setting for my BC18SW 115 in my Xoc 1 TH18 subs and double them. Off course, my gain strategy is to engage those limiters only on occasions when needed not to keep them engaged constantly.so the average power these get is a bit over half of that.

    Regarding the content, I was speaking from experience, when in a comparison of my 2 TH18 vs 2  BR with dual 18TBX100 tuned to 36 Hz, those 2 were louder than mine on average because even though the max clean SPL  was the same on paper and on measurements, on tehno music, long term the 2 were taking more voltage with less heat, so the limiters were not engaging on them.

    The kind of music I was referring to was techno,dance, minimal etc.. that music is much more focused in that passband but it doesnt mean there is no content outside of it.

  10. Bigger, for sure!! :)

    Now let's think why. the main thing with this is from the fact that putting a horn in front of the speaker, the general sensitivity in the pass band will be increased, and also the efficiency. 


    Grey Bass Reflex 522 L, Black SKHorn 522 L, SPL at 145 V,  same tuning frequency



    The main issue appears when using more than one and using a specific type of music material. Techno music is most of the time centered around 45-80 hz .there is right where this sub has its impedance minimum. If it is to be chosen between this SKHorn and 2 dual 21DS115-8 in very small enclosures, like 310 litters net each, with similarly big ports as the SKHorn, those would be better equipped to withstand a whole night of using them to their limit. Why? because of the content type.

    Most of the energy being centered in that band, the RMS limiters for an SKHorn would engage to keep the average thermal power into the sub at under 2-2.2 Kw (which IMO is very  risky, given the fact that the excursion is lower exactly where the power input is higher so the cooling is poorer) so even though the peak SPL capability of this sub would be within 2 dB of that couple, in use, those 2 would be much louder than this one because the RMS limiters would not engage if set to the same threshold. also the power compression would be higher on the SKHorn, and extremely low on the 2 dual BR because most of the time the drivers in the BR would see under 1 KW in the 40-75 HZ range and in that range more power will leave the voice coil firstly because the excursion would be higher, so better cooling and secondly the power conversion efficiency would be higher so more energy would be converted into sound instead of heat.


    In Grey is 2 dual 21 BCDS115-8 310 L net BR Efficiency


    In Grey is 2 dual BCDS115-8 310 L net BR input power 145V on 2 series Ipal, 160 V 2 drivers paralel, 2 subs parallel


    In Grey is 2 dual BCDS115-8 310 L net BR Max SPL 145V on series Ipal, 160V on 2 drivers paralel, 2 subs parallel

    So yes, the two would be heavier, a bit larger, more expensive to make, but would require far less power from the wall and will give more long term output than a single SKHorn. So for people who would carry these around from a gig to another, using them mostly on EDM and Techno, it would be a better solution. it wouldnt sound as clean as the horn, having the driver in front. and also it wouldn't be anything spectacular, but it would be useful for this sort of app which is the most commonly used

    So here comes the conclusion. Making it bigger would also make it more efficient. increasing the horn side would gain efficiency higher in frequency, increasing the back chamber and/or increasing the tuning frequency a bit  would gain efficiency in the lower parts. 

    Off course, making a sub tuned exactly for that genre would be even better, like a Danley DBH 218 horn which keeps the efficiency very high but also it keeps the excursion low for a clean sound, but high enough from the high pass crossover to help the drivers cool down.


  11. The DBH218 sounds very nice, but it's more of a 40 hz horn. This year at Pro Light and Sound they had 4 of them with a J3-96 each side of a stage but I wasn't there so IDK how they sounded. Last year they had 2 BC218 with 4 DBH at the ends of the stage with 2 SH96HO. Those BC are crushing but these M-Force horns are over them

  12. So I heard these for the first time.

    They are more than wonderful. That system goes down to 27hz clean and immensely powerful.they are so loud I was shocked. I heard the Danley BC218 last year but these are in another league. The cabinets are rock solid, even the back wheels inspire quality. The amp is clamped on in the back but they didn't make a personalized case for it



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