Note.: I also have one Inuke 3000 that i was using in bridge with my two T18, but AB amp for subs looks more warm and better, from what i ready and read tests results looks like the difference is mainly regarding the capacitor bench it give the AB more SPL at LF. In terms of electricity I'd say that the energy storage on the capacitor helps to sustain better the voltage on the driver. But this comparison between class AB and D amp are complex and very long and i'm not prepared enough to argue about.
Additionally the class D are more fragile regarding the AC supply, so this is other reason i replace it for AB.
Unfortunately I lost some headroom because AB is less efficient and i'm limited by AC supply.
Note 2: Some enthusiasts like to use bridge mode so supply subwoofer because the capacitor bench will be added, so it means more sustain even if you compare with the same output voltage for a parallel mode
Additionally the class D are more fragile regarding the AC supply, so this is other reason i replace it for AB.
Unfortunately I lost some headroom because AB is less efficient and i'm limited by AC supply.
Note 2: Some enthusiasts like to use bridge mode so supply subwoofer because the capacitor bench will be added, so it means more sustain even if you compare with the same output voltage for a parallel mode
Last edited:
1200 watts referenced to 5 ohms is 77.46 volts.
2000 watts referenced to 5 ohms is 100 volts, so you were showing the power with almost 2000 watts, not 1200 watts.
EDIT - just in case it's not clear, the driver Re in the sim inputs you posted is 5 ohms, not 8 ohms, so when calculating Eg reference watts to 5 ohms, not 8 in the sim. And you should do this for EACH driver, as each driver will have a different Re - if you show everything at 2.83V or referenced to 8 ohms this is not even close to accurate.
Last edited:
understood.
Unfortunately in this case the software traps me.
The Re i set on the T/S parameters but regarding the Eg the software calculates the voltage value once you choose the target Watts and indicates the drive's impedance. For sure if i indicate Re value to the software calculate the Eg it will be lower but Re is parts of the impedance the Le is the other part and it will varies regarding the frequency, so it just sound strange.
Regarding the high displacement, any thoughts?
Unfortunately in this case the software traps me.
The Re i set on the T/S parameters but regarding the Eg the software calculates the voltage value once you choose the target Watts and indicates the drive's impedance. For sure if i indicate Re value to the software calculate the Eg it will be lower but Re is parts of the impedance the Le is the other part and it will varies regarding the frequency, so it just sound strange.
Regarding the high displacement, any thoughts?
Yes of course I have thoughts, I already told you that you are simulating with almost 2000 watts.
I'm sorry that you felt trapped by the software but I recreated you sim exactly and I didn't feel trapped, in fact I used the software to confirm that you are simulating at upwards of 1900 watts.
Top left - input screen, copied exactly from your posted inputs
Top right - impedance, note the minimum impedance in the passband is what you reference to your input voltage, it's 5 ohms, just like I said
Bottom left - this is displacement based on the almost 2000 watts you input by setting Eg = 97.98V
Bottom right - this is Hornresp's driver power screen explicitly telling you that when Eg = 97.98V the driver is going to consume upwards of 1900 watts
Of course impedance and inductance vary with frequency, that's why the driver power curve swing wildly back and forth between 100 watts and 1900 watts. But the fact that they vary with frequency has nothing at all to do with setting power in the Eg input box. Like I told you, set voltage in reference to driver Re, not nominal impedance. Or grab the minimum impedance right off the impedance graph, that should be close to Re in most cases (with these undersized horns).
An externally hosted image should be here but it was not working when we last tested it.
i forgot to post the new simulation yesterday but nothing change as I said, the driver are no able to deliver max output power with current parameter :/
Simulation corrected for 1200W over 5 ohm
The 18LW2400's sheet indicates 9,5 as Xmax so to guarantee this value the maximum output power would be 750W.
Simulation corrected for 1200W over 5 ohm
An externally hosted image should be here but it was not working when we last tested it.
The 18LW2400's sheet indicates 9,5 as Xmax so to guarantee this value the maximum output power would be 750W.
An externally hosted image should be here but it was not working when we last tested it.
Then choose a better driver. The B&C 18tbw100 has 12 mm xmax and 14 mm Xvar, it's probably going to work fine in that horn.
Anyway, the driver in that sim is a terrible choice, as I already said, when you see that specific curve shape it means the enclosure is too small for the driver. You don't want to see a big hump at 50 hz in this design. Add a few ohms extra resistance to simulate heavy power compression and you will see how bad this 18LW2400 driver looks in this design. It's not a bad driver per se, it's just not a good match for this design.
Also like I said, you should be simulating the max spl results with the appropriate high pass filter in place. This won't make a huge difference inside the passband for the tapped horns but it will make a big difference for the front loaded horns. Since you are simulating all kinds of different alignments, it's best to show them all at max spl (excursion or power limited) with high pass filters in place. That's the only way to compare them fairly.
What me it sound strange the fact that this driver is the ONE Xoc1 chosen for the TH18 project and you know, a lot of forum member put effort together to develop this project and the results was good enough to compete with Danley TH118.
How came they worked since 2011 on it and didn't saw that? I'm more oriented to accept some error from my side for a while. But it looks strange.
take a look:
http://www.diyaudio.com/forums/subwoofers/190635-th-18-flat-35hz-xoc1s-design.html
How came they worked since 2011 on it and didn't saw that? I'm more oriented to accept some error from my side for a while. But it looks strange.
take a look:
http://www.diyaudio.com/forums/subwoofers/190635-th-18-flat-35hz-xoc1s-design.html
I saw that, but when I run the sim with your inputs (x4 cabs) I don't get the same result that he shows in that post. Close, but not the same and definitely way past xmax.
I don't know what inputs he used, I don't know how much power he used, I don't know if he thought it was ok to exceed xmax by a few mm. And I don't really care. If you want to know more about the sim in that first post maybe ask the guy that posted it, or Xoc1, or anyone else in that thread.
From the sim I can tell you that if the inputs are right the 18 Sound driver is a bad choice for this horn.
An externally hosted image should be here but it was not working when we last tested it.
I don't know what inputs he used, I don't know how much power he used, I don't know if he thought it was ok to exceed xmax by a few mm. And I don't really care. If you want to know more about the sim in that first post maybe ask the guy that posted it, or Xoc1, or anyone else in that thread.
From the sim I can tell you that if the inputs are right the 18 Sound driver is a bad choice for this horn.
I can use the same input as mine and will reach the same output. I read all 200 pages on the thread.
I will see two different output 1W or 1200W, so you also can check both.
I will see two different output 1W or 1200W, so you also can check both.
An externally hosted image should be here but it was not working when we last tested it.
The keystone model presents less discrepancy.
Regarding the original driver (B&C 18SW115) the maximum power (1700W) also exceed the Xmax, but reducing the power till 1500W was enough to bring Xmax for safe place. Maybe they are designing with compression factor in mind in some way.
Regarding the original driver (B&C 18SW115) the maximum power (1700W) also exceed the Xmax, but reducing the power till 1500W was enough to bring Xmax for safe place. Maybe they are designing with compression factor in mind in some way.
An externally hosted image should be here but it was not working when we last tested it.
In this image Scoop: https://s12.postimg.org/3xklmf3ot/P_20161009_153907.jpg
In the link Scoop box image what is the advantage by inverting the Subwoofer than regular?
In the link Scoop box image what is the advantage by inverting the Subwoofer than regular?
I'm not the must specialized guy to answer you but one of the advantages is regarding the thermal things, once your driver get heat you will see compression effect, so this position helps the heat transfer if you compare with FLH with rear chamber.
More ventilated your driver is better for your sound quality.
More ventilated your driver is better for your sound quality.
Xvar for the 18sw115 is 16 mm so it looks safe at 1700 watts.
B&C I believe spec xmax as geometric while Xvar is a more conservative limit. There's no problem using Xvar in sims.
Interesting.
Thanks to share.
Will be hard to find appropriate driver for this design at my market, but in case none of the TH works i will shift to FLH with rear chamber as the 1850/186 design that the Xmax is not so important but i will need to forget about 40Hz once FLH are bigger them TH.
Thanks to share.
Will be hard to find appropriate driver for this design at my market, but in case none of the TH works i will shift to FLH with rear chamber as the 1850/186 design that the Xmax is not so important but i will need to forget about 40Hz once FLH are bigger them TH.
B&C Speakers Brasil
BRAZIL
Comércio de Equipamentos de Áudio LTDA
Sérgio Jungblut Dieterich, 1011, Dep.3
São João – Porto Alegre
91060-410 RS
Tel./Fax 0055 51 3348 1632
Mob. 0055 51 8464 4684
info.br@bcspeakers.com
B&C Speakers
Xmax is always important. FLH can have a low frequency low knee with no problem. Labhorn has a low knee lower than 40 hz. And I just showed you a flh design with a 22 hz low knee. FLH doesn't always have to be bigger than TH.
B&C is an Italian company so it is imported and the current ratio is not helping
I said that the Xmax is not so important for FLH due to the data a collected and they look more reasonable.
Pecision-Drive PD186 = 9mm
RCF L18P300 = 7,8mm (very apreciated on the forums)
Eminence Omega Pro 18A = 4,8mm (this is really small)
B&C 18TBX100 = 9mm
18Eighteen 18TBX100 = 7mm
The original simulation for TH18 they were using the 18eighteen 18LW2400 which Xmax is 9,5mm it was part of my input data with incoerent cone displacement, maybe they shift to B&C.
Take a look at some models comparison.
Keystone and TH18 are the main option if i find drive to well fit them
1850/186 are still an option, less LF but more 3dB compared to the previous ones
WSX, it start to became too heavy (~100kg/cab)
Labhorn no chance
I was thinking about band pass 6th order but the major people complain about it, it sounds like one note cab and I'm looking for more HiFi stuff.
I said that the Xmax is not so important for FLH due to the data a collected and they look more reasonable.
Pecision-Drive PD186 = 9mm
RCF L18P300 = 7,8mm (very apreciated on the forums)
Eminence Omega Pro 18A = 4,8mm (this is really small)
B&C 18TBX100 = 9mm
18Eighteen 18TBX100 = 7mm
The original simulation for TH18 they were using the 18eighteen 18LW2400 which Xmax is 9,5mm it was part of my input data with incoerent cone displacement, maybe they shift to B&C.
Take a look at some models comparison.
Keystone and TH18 are the main option if i find drive to well fit them
1850/186 are still an option, less LF but more 3dB compared to the previous ones
WSX, it start to became too heavy (~100kg/cab)
Labhorn no chance
I was thinking about band pass 6th order but the major people complain about it, it sounds like one note cab and I'm looking for more HiFi stuff.
An externally hosted image should be here but it was not working when we last tested it.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.