Hi guys,
I am not experienced at all at calculating enclosures for lows woofers, but I have given it a try down below.
I have a defective CLS-15S (both amp and driver), and I am looking to reusing the box for a "new" subwoofer. It is only going to be used for parties and assisting a couple of 15" 3-way speakers, where I would like some more punch. Both inside and outside.
The Monacor SPH-390TC seems to be a good candidate for that box, as far as I have been able to tell. If you have other suggestions, I am all ears!
I have inserted the 390TC parameters in WinISD and have come up with this response:
The CLS-15S is about 100 litres. I will do a more precise calculation later.
What I am unsure of, is how to tell if the woofer's XMAX is being pushed to the limit. And if that graph above seems to be correct and "functionel" for the needs I have. 🙂
I plan on running the Monacor with a second CLSC-12S board amplifier, which is claimed to deliver 350W RMS. I will parallel connect the 2x8ohm DVC 390TC into 4 ohm for the amplifier.
I know you get a lot of threads like this in here, but I hope you've got time to help me out, as well!
Thanks in advance. 🙂
I am not experienced at all at calculating enclosures for lows woofers, but I have given it a try down below.
I have a defective CLS-15S (both amp and driver), and I am looking to reusing the box for a "new" subwoofer. It is only going to be used for parties and assisting a couple of 15" 3-way speakers, where I would like some more punch. Both inside and outside.
The Monacor SPH-390TC seems to be a good candidate for that box, as far as I have been able to tell. If you have other suggestions, I am all ears!
I have inserted the 390TC parameters in WinISD and have come up with this response:
The CLS-15S is about 100 litres. I will do a more precise calculation later.
What I am unsure of, is how to tell if the woofer's XMAX is being pushed to the limit. And if that graph above seems to be correct and "functionel" for the needs I have. 🙂
I plan on running the Monacor with a second CLSC-12S board amplifier, which is claimed to deliver 350W RMS. I will parallel connect the 2x8ohm DVC 390TC into 4 ohm for the amplifier.
I know you get a lot of threads like this in here, but I hope you've got time to help me out, as well!
Thanks in advance. 🙂
In WinISD, where it says "Transfer Function Magnitude" above your graph, click on that and in the resulting dropdown select "Cone Excursion".
Then, at the bottom left, select the "Signal" option and input "33" in the box described as "Driver input voltage(each)".
That will show you how much cone excursion will happen if you were to input full power at every frequency, which is a worst case scenario.
Good Luck,
David.
Then, at the bottom left, select the "Signal" option and input "33" in the box described as "Driver input voltage(each)".
That will show you how much cone excursion will happen if you were to input full power at every frequency, which is a worst case scenario.
Good Luck,
David.
Ah, that's cool. Thanks!
I am not able to change the Driver Input Voltage (each), though. Am I missing some parameter in my setup?
These were all the parameters given by Monacor (afaik):
EDIT: The XMAX was also provided. I have entered this now. The resistance was given as 2x8ohm. Do I put 4ohm in Re, if I plan to run it in parallel?
EDIT2: So I put in 4ohm as my Re. I am now able to change the input voltage. This is the XMAX result:
So a bit too much excursion. Which means I need a smaller enclosure, right? 🙂
I am not able to change the Driver Input Voltage (each), though. Am I missing some parameter in my setup?
These were all the parameters given by Monacor (afaik):
EDIT: The XMAX was also provided. I have entered this now. The resistance was given as 2x8ohm. Do I put 4ohm in Re, if I plan to run it in parallel?
EDIT2: So I put in 4ohm as my Re. I am now able to change the input voltage. This is the XMAX result:
So a bit too much excursion. Which means I need a smaller enclosure, right? 🙂
Last edited:
I wouldn't worry about it going 0.5 mm over Xmax... 🙂
Remember, Xmax is the maximum LINEAR excursion. Most drivers designed for subwoofer duty are designed to allow the cone to exceed that, sometimes quite significantly (look at Dayton's neo-magnet PA drivers, for example). They will just produce more distortion when doing so. As for whether or not that distortion is audible, that depends on motor design, how far beyond Xmax the driver is being pushed, and how much that distortion is masked by what the rest of the system is producing.
In this case, going by your sim above, I think it should sound fine.
Remember, Xmax is the maximum LINEAR excursion. Most drivers designed for subwoofer duty are designed to allow the cone to exceed that, sometimes quite significantly (look at Dayton's neo-magnet PA drivers, for example). They will just produce more distortion when doing so. As for whether or not that distortion is audible, that depends on motor design, how far beyond Xmax the driver is being pushed, and how much that distortion is masked by what the rest of the system is producing.
In this case, going by your sim above, I think it should sound fine.
About entering the TS parameters, WinISD is happiest if you leave out as many of the first group at the top of the pages as you can; it prefers you to input the second block instead. It shouldn't make a big difference, but it's a habit I've always kept.
Monacor do provide Re, it's 6 Ohms per voice coil, you can enter that and then tell WinISD that it's a dual voice coil driver towards the bottom left of the Driver Parameters window, or you can just enter 3 Ohms for Re if you expect to always run the voice coils in parallel.
Don't worry about that being lower then the nominal 4 Ohms the amp may be rated for, this is perfectly normal and the impedance variations across the frequency spectrum mean the realistic average load seen by the amp will be higher than 3 Ohms in real world use anyway.
Monacor do provide Re, it's 6 Ohms per voice coil, you can enter that and then tell WinISD that it's a dual voice coil driver towards the bottom left of the Driver Parameters window, or you can just enter 3 Ohms for Re if you expect to always run the voice coils in parallel.
Don't worry about that being lower then the nominal 4 Ohms the amp may be rated for, this is perfectly normal and the impedance variations across the frequency spectrum mean the realistic average load seen by the amp will be higher than 3 Ohms in real world use anyway.
T/S max flat alignment is 20*Vas*Qts'^3.3 = ~73.654 L net, so looking good mathematically as it's easy to 'shrink' a box. 😉
[Qts']: [Qts] + any added series resistance [Rs]: Calculate new Qts with Series Resistor
[Rs] = 0.5 ohm minimum for wiring, so may be higher if a super small gauge is used as a series resistor plus any added resistance from an XO/whatever.
Definitely easier to shrink a box than enlargen it. 🙂 Would you recommend making the box 73 L instead of the ~100 L? To me the response looks pretty flat with the simulation with 100 L.
I had no idea how those parameters worked. Thanks a lot. I will change these to the correct values. Maybe I should read up on the different parameters, too ... 🙂
No, I'm old school, so BIB rules! [bigger is better] 😉
That said, T/S alignments pares off any excess 'fat' of the pioneer's way of tuning since over the decades of electronics design, driver manufacturing improvements, has negated the need for box efficiency plus there's the issue of signal bandwidth [BW] and electronic music, so unless you're like me and only listen to 'golden oldies' and/or talk radio, best to stick with the ~73 L and EQ as required since I imagine you'll have plenty of power on tap.
That said, T/S alignments pares off any excess 'fat' of the pioneer's way of tuning since over the decades of electronics design, driver manufacturing improvements, has negated the need for box efficiency plus there's the issue of signal bandwidth [BW] and electronic music, so unless you're like me and only listen to 'golden oldies' and/or talk radio, best to stick with the ~73 L and EQ as required since I imagine you'll have plenty of power on tap.
I'll primarily be using it for electronic music, I'm afraid. 🙂
How is the driver looking btw (SPH-390TC)? I don't have a lot of experience DIY'ing speakers, but I heard that this was a fine budget driver.
How is the driver looking btw (SPH-390TC)? I don't have a lot of experience DIY'ing speakers, but I heard that this was a fine budget driver.
No clue WRT foreign products beyond haven't read anything negative about Monacor products and the fact that high efficiency [HE] drivers in general and specifically powerful motor [low Qes/Qts] drivers implies a very fine product indeed and the sort I've historically used/recommended.