if my subwoofer is getting 21v RMS AC and its bridged. what wattage RMS is it getting?
if my amp is seeing a 2ohm load when its bridged do I use 2ohms as a calculation even if the speaker is 4ohms?
because that makes the wattage RMS be about 220W RMS approximately
but if I use 4ohms for the calculation I get 110W RMS approximately
and that doesnt seem right because my subwoofers seem very stressed at max volume at just 21v AC
they look like they are reaching very close to their limits in power handling and close to suspension limits.
dustcap gets slightly warm but no smell from the subwoofer ports. unless I go up to 24v AC RMS when measuring across the bridged subwoofer terminals then they start to smell slightly if i play for about 30 seconds its not strong but noticable so i turned it back down to 21v AC RMS
Which is correct? 2ohms for the calculation since its bridged? or do i still use 4ohms because the subwoofer is 4ohms?
if my amp is seeing a 2ohm load when its bridged do I use 2ohms as a calculation even if the speaker is 4ohms?
because that makes the wattage RMS be about 220W RMS approximately
but if I use 4ohms for the calculation I get 110W RMS approximately
and that doesnt seem right because my subwoofers seem very stressed at max volume at just 21v AC
they look like they are reaching very close to their limits in power handling and close to suspension limits.
dustcap gets slightly warm but no smell from the subwoofer ports. unless I go up to 24v AC RMS when measuring across the bridged subwoofer terminals then they start to smell slightly if i play for about 30 seconds its not strong but noticable so i turned it back down to 21v AC RMS
Which is correct? 2ohms for the calculation since its bridged? or do i still use 4ohms because the subwoofer is 4ohms?
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No expert on this but surely the bridging of the amp has nothing to do with the load of the speaker.
If you amp puts out 220w rms bridged in to 2ohm
And 110w rms bridged in to 4ohm
And you have a 4ohm single voice coil speaker. The your amp is seeing 4ohm and gives a max of 110w period.
Forget voltage as is irrelevant really on what your wanting to know.
There are many other reasons why your sub may be reaching its limit. Usually a box that’s too big. Or it may seem like it if there is amp distortion as your past the amps limit
If you amp puts out 220w rms bridged in to 2ohm
And 110w rms bridged in to 4ohm
And you have a 4ohm single voice coil speaker. The your amp is seeing 4ohm and gives a max of 110w period.
Forget voltage as is irrelevant really on what your wanting to know.
There are many other reasons why your sub may be reaching its limit. Usually a box that’s too big. Or it may seem like it if there is amp distortion as your past the amps limit
My amp puts out 220W RMS bridged at 4ohms. not 2ohms
and its a 4-channel amp. each channel can be bridged at 4ohms load and outputs 220W RMS (not peak! actual RMS) when bridged with a 4ohm load
and it puts out 80W RMS NOT bridged at 4ohms per channel or 120W RMS per channel NOT bridged at 2ohms. it cant handle 2ohm bridged load.
so with two 4ohm subwoofers bridged it outputs 440W RMS total power (Someone measured it on the amplifier dyno and it actually put out 250W RMS clean power into a 4ohm load when bridged into 2 channels)
subwoofer is not reaching its limits except for under 16hz
it's not clipping. i know its clean output. even up to 26v RMS
The subwoofers are reaching THERMAL limit not mechanical limit
they still have plenty of mechanical travel left at 21v RMS and they arent bottoming out at 26v RMS either but they get too hot at 26v RMS so i have to lower it back down to 21V RMS
they look like they are reaching optimal mechanical excursion for maximum safe output at 21v RMS but 26v they look stressed but arent bottoming out. and they get too hot. so reaching thermal limit before mechanical limit
I have tried running them free air at maximum volume and they do not bottom out from mechanical limits. they get hot before they bottom out. so i know they arent going to reach mechanical limits in any box at full safe power.
I have two 12" subwoofers they are rated for 250W RMS max
and they seem to work great in the box I got. plays loud low and deep. 34hz tuning and 1.8 cubic feet per subwoofer
and its a 4-channel amp. each channel can be bridged at 4ohms load and outputs 220W RMS (not peak! actual RMS) when bridged with a 4ohm load
and it puts out 80W RMS NOT bridged at 4ohms per channel or 120W RMS per channel NOT bridged at 2ohms. it cant handle 2ohm bridged load.
so with two 4ohm subwoofers bridged it outputs 440W RMS total power (Someone measured it on the amplifier dyno and it actually put out 250W RMS clean power into a 4ohm load when bridged into 2 channels)
subwoofer is not reaching its limits except for under 16hz
it's not clipping. i know its clean output. even up to 26v RMS
The subwoofers are reaching THERMAL limit not mechanical limit
they still have plenty of mechanical travel left at 21v RMS and they arent bottoming out at 26v RMS either but they get too hot at 26v RMS so i have to lower it back down to 21V RMS
they look like they are reaching optimal mechanical excursion for maximum safe output at 21v RMS but 26v they look stressed but arent bottoming out. and they get too hot. so reaching thermal limit before mechanical limit
I have tried running them free air at maximum volume and they do not bottom out from mechanical limits. they get hot before they bottom out. so i know they arent going to reach mechanical limits in any box at full safe power.
I have two 12" subwoofers they are rated for 250W RMS max
and they seem to work great in the box I got. plays loud low and deep. 34hz tuning and 1.8 cubic feet per subwoofer
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AC RMS multimeter. why?
I measured right at the terminals of the amplifier before the wires that go out to the subwoofers
and my amp actually can put out 240W RMS of clean power at 4ohms bridged. so it having 4 channels bridged to 2 channels I'm powering two separate 4ohm subwoofers with the amplifier bridged to each subwoofer. so in total about 480W RMS total output from the amplifier. at max volume
and the amp is seeing 2ohms since its bridged with a 4ohm load so at 21v AC it should be giving out somewhat over 200W RMS of power at full volume? or will it still only give out 100W RMS or so because the subwoofer is 4ohms even though the amplifier is seeing a 2ohm load when its bridged?
cause if I try to apply 26v RMS in a calculator that would be still under 200W RMS at 4ohms so my subwoofer shouldn't be overheating but it IS overheating
but if I do the same calculation at 2ohms the subwoofer would be seeing over 300W and would overheat.
but its fine at 21v RMS because that would be just over 200W if the amplifier is seeing a 2ohm load because the amplifier is bridged even if the subwoofer is only 4ohms and the subwoofer can handle up to 250W RMS without a problem
I measured right at the terminals of the amplifier before the wires that go out to the subwoofers
and my amp actually can put out 240W RMS of clean power at 4ohms bridged. so it having 4 channels bridged to 2 channels I'm powering two separate 4ohm subwoofers with the amplifier bridged to each subwoofer. so in total about 480W RMS total output from the amplifier. at max volume
and the amp is seeing 2ohms since its bridged with a 4ohm load so at 21v AC it should be giving out somewhat over 200W RMS of power at full volume? or will it still only give out 100W RMS or so because the subwoofer is 4ohms even though the amplifier is seeing a 2ohm load when its bridged?
cause if I try to apply 26v RMS in a calculator that would be still under 200W RMS at 4ohms so my subwoofer shouldn't be overheating but it IS overheating
but if I do the same calculation at 2ohms the subwoofer would be seeing over 300W and would overheat.
but its fine at 21v RMS because that would be just over 200W if the amplifier is seeing a 2ohm load because the amplifier is bridged even if the subwoofer is only 4ohms and the subwoofer can handle up to 250W RMS without a problem
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most meters are only accurate in a narrow band around 60 hz so results above or below 60 may be questionable
rms is fine for ballpark or average but you are ignoring "peak" potentials
i may be wrong but i don't think it works that way.
what pretell are your sub cabs? if bass reflex or vented it may well be a condition of uncontrolled excursion causing the excess heating.
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You forgot that voltage on inverted side will fall as much positive will rise.
So, your RMS voltage on speaker terminal will be double of the one amplifier out.
chris661 determined well your error in measuring,
When calculate, you should use 42V RMS value which is on both speaker terminal. (I am assuming that you measured at one pole to the ground)
Regards,
So, your RMS voltage on speaker terminal will be double of the one amplifier out.
chris661 determined well your error in measuring,
When calculate, you should use 42V RMS value which is on both speaker terminal. (I am assuming that you measured at one pole to the ground)
Regards,
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I measured right across the speaker wires where they go into the amplifier from positive to negative where its actually bridged in the amplifier.
I just wire the subwoofer from right negative to left positive (channel 1 positive and channel 2 negative) and it becomes bridged on that channel.
so i measured it the same way and i measured 21v RMS AC across the speaker wires where they go into the amplifier bridged.
my subwoofers only start moving below 25hz and dont start "flexing" until the frequency they are playing is down to about 10hz to 16hz.
and they dont overheat below 25hz even at 26v AC RMS but around 30hz and up they are barely moving even a millimeter and start to overheat if i play them too long at 30hz and 26v AC RMS.
between 30-ish hertz to 45hz is the range where they overheat. but they start moving a little bit more around 50 to 60hz and stop overheating there and the excursion is not a problem until below 16hz but they still dont bottom out or have overexcursion problems even at 10 to 14hz where they flex the hardest.
at 21v its fine at all frequencies no overheating and plenty of excursion at 20hz and below.
I just wire the subwoofer from right negative to left positive (channel 1 positive and channel 2 negative) and it becomes bridged on that channel.
so i measured it the same way and i measured 21v RMS AC across the speaker wires where they go into the amplifier bridged.
my subwoofers only start moving below 25hz and dont start "flexing" until the frequency they are playing is down to about 10hz to 16hz.
and they dont overheat below 25hz even at 26v AC RMS but around 30hz and up they are barely moving even a millimeter and start to overheat if i play them too long at 30hz and 26v AC RMS.
between 30-ish hertz to 45hz is the range where they overheat. but they start moving a little bit more around 50 to 60hz and stop overheating there and the excursion is not a problem until below 16hz but they still dont bottom out or have overexcursion problems even at 10 to 14hz where they flex the hardest.
at 21v its fine at all frequencies no overheating and plenty of excursion at 20hz and below.
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How else am i supposed to hook up the subwoofer then?
I cant just leave the - wire for the subwoofer unplugged.
the speaker outputs have + and - on them where the wires go.
I put the wires in the right way to bridge the amplifier to the subwoofer so the subwoofers get more watts than just hooking them into one channel since the amp is bridgeable and has 4 channels
I can bridge the 4 channels down to 2 channels and hook up 2 subwoofers. one subwoofer per bridged channel
I cant just leave the - wire for the subwoofer unplugged.
the speaker outputs have + and - on them where the wires go.
I put the wires in the right way to bridge the amplifier to the subwoofer so the subwoofers get more watts than just hooking them into one channel since the amp is bridgeable and has 4 channels
I can bridge the 4 channels down to 2 channels and hook up 2 subwoofers. one subwoofer per bridged channel
V^2 / impedance
IF speaker is 4 ohms, amplifier sees 4 ohms, period.
It will NOT see 2 ohms, where are you pulling that from?
No, it won´t.
21V*21V/4r=110W
which you should.
That´s irrelevant.
You asked about power, you got your answer.
Irrelevant.
You asked about power, you got your answer.
You have already posted about your Smell-O-Meter many times.
Please stick to voltage and impedance Math, your nose is not NIST calibrated so can´t be used in any Tech , Physics or Engineering related discussion.
Of course, you can send it to:
Calibrations | NIST
and after paying the relevant fees they *may* send you a Calibration sheet, if physically possible.
Who cares whether it´s bridged or not?
You just use voltage across speaker terminals and speaker impedance.
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As you state that you are measuring a constant voltage and then state the excursion at differing frequencies it suggests you are using test tones to evaluate the system. This is never a good idea as even highly compressed music will still have a dynamic range that means that the average power that the speaker needs to dissipate is a fraction of the rated power.
Try to understand what 110w continuous is. How long can you hold a 100w light bulb before it burns you. Modern music systems often employ amplifiers that can deliver many kilowatts of power for very short transients.These allow speakers to have a wide dynamic range. The continuous rating is a fraction of the dynamic peak rating. Otherwise the speakers would bust into flames!
Try to understand what 110w continuous is. How long can you hold a 100w light bulb before it burns you. Modern music systems often employ amplifiers that can deliver many kilowatts of power for very short transients.These allow speakers to have a wide dynamic range. The continuous rating is a fraction of the dynamic peak rating. Otherwise the speakers would bust into flames!
its NOT distortion. I can confirm its a clean sinewave output I hooked a few resistors up in line with a cable and 3.5mm jack (10ohm and 10k 1W resistors to make a voltage divider. hooked to a laptop line-in and read the sinewave in real-time and it looks perfectly clean)
so it reads the sinewave just about as good as any oscilloscope. and i can definitely say its clean. recording a sample and playing it back through headphones i hear no clipping or distortion at all. even when 26v AC RMS is going to my subwoofers when they are getting too hot.
My amplifiers power rating is 2x240W RMS bridged at 4ohms (4 channels bridged to 2 channels rated at 4ohms bridged) but ive seen it tested to do up to 250W RMS clean power under 1% THD with high quality cables and power supply at 14.8v
The sound coming from the subwoofers is perfectly clean no audible distortion at 26v RMS bridged with both subwoofers hooked up to each bridged channel
so it reads the sinewave just about as good as any oscilloscope. and i can definitely say its clean. recording a sample and playing it back through headphones i hear no clipping or distortion at all. even when 26v AC RMS is going to my subwoofers when they are getting too hot.
My amplifiers power rating is 2x240W RMS bridged at 4ohms (4 channels bridged to 2 channels rated at 4ohms bridged) but ive seen it tested to do up to 250W RMS clean power under 1% THD with high quality cables and power supply at 14.8v
The sound coming from the subwoofers is perfectly clean no audible distortion at 26v RMS bridged with both subwoofers hooked up to each bridged channel
I think the reason why it’s overheating is that you are playing 20hz and under tones that stress the sub to death physically and thermally.
There isn’t much context in music down that low anyway and what is there would not be held for a constant period of time .unless it’s competition stuff that you don’t want to listen to anyway.
And if you were listening to context that had 16hz continuously which caused sub overheating, then you need to do a few things.
1. Evaluate your music taste. Because it’s questionable
2. Buy a better amp and/or sub that can deal with that punishment better.
Likely distortion from amp and putting sub through constant low frequencies that is unrealistic that’s causing the overheating issue.
Just set the levels and enjoy the music. That’s what I say.
Oh and all the talk above about voltages and different wiring is really over the top
If it’s a 4ohm speaker. Look in the manual of what it puts out bridged and that’s it.
Oh and by the way, don’t be upset if your driver is overheating using the above methods before it’s rated RMS wattage. Because it’s rated RMs wattage is not calculated for the way you are using the woofer.
There isn’t much context in music down that low anyway and what is there would not be held for a constant period of time .unless it’s competition stuff that you don’t want to listen to anyway.
And if you were listening to context that had 16hz continuously which caused sub overheating, then you need to do a few things.
1. Evaluate your music taste. Because it’s questionable
2. Buy a better amp and/or sub that can deal with that punishment better.
Likely distortion from amp and putting sub through constant low frequencies that is unrealistic that’s causing the overheating issue.
Just set the levels and enjoy the music. That’s what I say.
Oh and all the talk above about voltages and different wiring is really over the top
If it’s a 4ohm speaker. Look in the manual of what it puts out bridged and that’s it.
Oh and by the way, don’t be upset if your driver is overheating using the above methods before it’s rated RMS wattage. Because it’s rated RMs wattage is not calculated for the way you are using the woofer.
Playing under 25hz does NOT heat up my subwoofers.
Ive played it at 10hz to 20hz for 10 minutes and the dustcaps were cool and no smell.
they ONLY get hot around 30hz to 45hz at 26v RMS
they have no problems playing 20hz or below. they dont reach mechanical or thermal limits below 20hz.
The amp is not the problem.
there is no distortion period. i dont know where your getting the idea that my subwoofer is getting distorted power but i know for a fact its clean power for sure because ive measured the sinewave and seen it in realtime for visual proof that its clean.
you also didnt read my message or understand what I wrote because I already said that it only gets hot between 30hz to 45hz and NOT below 25hz and only at 26v but not 21v
The subwoofer is single voice coil 4ohms and rated for 250W RMS
the amplifier outputs 2x 240W RMS bridged with two SVC 4-ohm subwoofers hooked up to the amplifier (rated 240W RMS but actual measured maximum clean output is 250W RMS so its slightly under-rated)
and theres no way my subwoofers should be overheating getting under their rated power when other brand of subwoofers can get their rated power just fine and not even get warm.
either the subs are overrated or my calculation of watts RMS going to my subwoofers is off somehow.
I like to listen to a lot of bass boosted music and a lot of tracks that have subsonic frequencies to make my subwoofers have a lot of excursion.
and I dont mean the horribly distorted kind of "bass boosted" music. I mean CLEAN bass boosted music with no distortion.
but I also watch movies that have a lot of subsonic frequencies or deep bass in intense scenes so I really wanna have my subwoofers playing to their fullest.
Ive played it at 10hz to 20hz for 10 minutes and the dustcaps were cool and no smell.
they ONLY get hot around 30hz to 45hz at 26v RMS
they have no problems playing 20hz or below. they dont reach mechanical or thermal limits below 20hz.
The amp is not the problem.
there is no distortion period. i dont know where your getting the idea that my subwoofer is getting distorted power but i know for a fact its clean power for sure because ive measured the sinewave and seen it in realtime for visual proof that its clean.
you also didnt read my message or understand what I wrote because I already said that it only gets hot between 30hz to 45hz and NOT below 25hz and only at 26v but not 21v
The subwoofer is single voice coil 4ohms and rated for 250W RMS
the amplifier outputs 2x 240W RMS bridged with two SVC 4-ohm subwoofers hooked up to the amplifier (rated 240W RMS but actual measured maximum clean output is 250W RMS so its slightly under-rated)
and theres no way my subwoofers should be overheating getting under their rated power when other brand of subwoofers can get their rated power just fine and not even get warm.
either the subs are overrated or my calculation of watts RMS going to my subwoofers is off somehow.
I like to listen to a lot of bass boosted music and a lot of tracks that have subsonic frequencies to make my subwoofers have a lot of excursion.
and I dont mean the horribly distorted kind of "bass boosted" music. I mean CLEAN bass boosted music with no distortion.
but I also watch movies that have a lot of subsonic frequencies or deep bass in intense scenes so I really wanna have my subwoofers playing to their fullest.
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