Hi there,
Driver is 5,5 C 1,5 CP 8+8Ω coax.
https://sica.it/wp-content/uploads/2023/12/Z002810.pdf
According to specification it is 120W AES and 240W Continuous Program Power speaker combo. AES is measured with 6dB crest factor as per manufacturer info.
Crossover:
If I do use VirtuixCAD Power dissipation tool with 240W on 8Ohm with "Flat" settings, I get so ridiculous results, that there seem to be no such resistors in the market. 25-40W of power dissipation for single component seems too much for a 5 inch woofer and 1 inch dome tweeter. But If I use "M-noise" setting - everything seems the other way around - too little power going through components.
Now the speaker in on the active crossover and powered by the Class D TPA3250 ~40W/8Ohm per channel amp, so 40W for woofer and 40W for tweeter (24V 4A power supply). The exact numbers are not important and probably not correct anyway, but lets assume it has at least 30W per channel.
So, the thing is - I cannot fully crank volume signal, it seems that this small amp can melt this speaker on the spot(~-2dB attenuation on PC global, with 100% volume, Presonus 26c as soundcard/preamp, max gain on mechanical gain knob). It is not 240W or even 120W driver. NO WAY!
The question is: which settings should I use for simulations on VirtuixCAD?
On the normal listening conditions I would use 5W resistors and call it a day, but I now I have doubts...
R4 is ~26W on 900Hz, R5 is ~41W on 20kHz(!). My guts say that 20W for R4 and the same 20W for R5 is more than enough. Right?
Screenshots attached
Driver is 5,5 C 1,5 CP 8+8Ω coax.
https://sica.it/wp-content/uploads/2023/12/Z002810.pdf
According to specification it is 120W AES and 240W Continuous Program Power speaker combo. AES is measured with 6dB crest factor as per manufacturer info.
Crossover:
If I do use VirtuixCAD Power dissipation tool with 240W on 8Ohm with "Flat" settings, I get so ridiculous results, that there seem to be no such resistors in the market. 25-40W of power dissipation for single component seems too much for a 5 inch woofer and 1 inch dome tweeter. But If I use "M-noise" setting - everything seems the other way around - too little power going through components.
Now the speaker in on the active crossover and powered by the Class D TPA3250 ~40W/8Ohm per channel amp, so 40W for woofer and 40W for tweeter (24V 4A power supply). The exact numbers are not important and probably not correct anyway, but lets assume it has at least 30W per channel.
So, the thing is - I cannot fully crank volume signal, it seems that this small amp can melt this speaker on the spot(~-2dB attenuation on PC global, with 100% volume, Presonus 26c as soundcard/preamp, max gain on mechanical gain knob). It is not 240W or even 120W driver. NO WAY!
The question is: which settings should I use for simulations on VirtuixCAD?
On the normal listening conditions I would use 5W resistors and call it a day, but I now I have doubts...
R4 is ~26W on 900Hz, R5 is ~41W on 20kHz(!). My guts say that 20W for R4 and the same 20W for R5 is more than enough. Right?
Screenshots attached
Last edited:
Are you conducting an experiment, how many seconds will my loudspeakers perform until they get toasted? 🙂
Nope, I just hope not to toast them at all, and the question is should I stay with "classic" 5W or go 20W resistors?
I really started to like VirtuixCAD tools, and getting better with them, this part of the sim is not known to me still
Program power according to manufacturer is 120W, AES1 conditions. Voice coil is 38 mm.
Seas specifies 80W of program power for a similar vc. I would trust a more conservative rating.
So about 70W to bassmid and 10W of input power to tweeter. These are values to be fed to a
simulator.
Seas specifies 80W of program power for a similar vc. I would trust a more conservative rating.
So about 70W to bassmid and 10W of input power to tweeter. These are values to be fed to a
simulator.
From VCad manual "Pink noise represents effective RMS spectrum of music signal. Initial corner frequency is 2 kHz. Significant variation exists between music genres and recordings".
Consider that is not realistic to apply 200W to a speaker like that (flat option) and that above xo FR the power applied to the midwoofer is much lower.
EDIT: image disappeared...
Consider that is not realistic to apply 200W to a speaker like that (flat option) and that above xo FR the power applied to the midwoofer is much lower.
EDIT: image disappeared...
Last edited:
For that crossover, there is inline resistor for tweeter and parallel to the woofer - what W resistors would you choose?
I cannot add to that sim separate W ratings, but I more or less agree that powewr split at ~2.6-2.8kHz crossover would be very close to what you described. But I somehow doubt, that 5W is enough
Have you used VirtuixCAD tool? If not, which simulator would you suggest?
Manufacturers would install typically a 10W value in such a product. There is no harm
if you double that value for whatever reason, but this is beside the point and the point
is to not overload them.
VituixCAD is alright a simulator. Just do not let it calculate with too large an initial power rating value.
if you double that value for whatever reason, but this is beside the point and the point
is to not overload them.
VituixCAD is alright a simulator. Just do not let it calculate with too large an initial power rating value.
Maybe 5W is the more obvious manufacturer choice: https://www.diyaudio.com/community/...eakers-2010-2015-yr-model.388989/post-7866839
I start to think that the only negative to put 20W instead of 5W is a bit bigger dimensions, because price is 0.1EUR different or similar. Nothing in DIY.
I used what manufacturer stated. That is fair starting point.