Playing my DS18 SELECT brand subwoofer in free-air at anything around 30 to 40hz its perfectly fine playing all day free air. coil barely warm to the touch if i pause the music and reach my finger in the pole piece venting and feel the coil. after playing at close to maximum excursion for 30 minutes straight
but if I play anything around 20hz it gets searing hot even though theres no distortion and i triple checked that. it gets so hot i can smell it a little bit.
and thats with it playing free air.
it doesnt bottom out its not even close to bottoming out.
but in the box its the complete opposite. it plays around 20hz or below fine all day long. no distortion. doesnt bottom out or anything. doesnt get hot at all. but around 30 to 40hz it gets hot and smells. Why does it behave opposite temperature wise when in the box vs free air at the same power. nothing else changed except it being in or out of the box.
it doesnt smell super strong bad. just a little bit. so I have to watch my volume and keep the gain set a little lower. depending on what frequency the bassline of the song is playing
but if I play anything around 20hz it gets searing hot even though theres no distortion and i triple checked that. it gets so hot i can smell it a little bit.
and thats with it playing free air.
it doesnt bottom out its not even close to bottoming out.
but in the box its the complete opposite. it plays around 20hz or below fine all day long. no distortion. doesnt bottom out or anything. doesnt get hot at all. but around 30 to 40hz it gets hot and smells. Why does it behave opposite temperature wise when in the box vs free air at the same power. nothing else changed except it being in or out of the box.
it doesnt smell super strong bad. just a little bit. so I have to watch my volume and keep the gain set a little lower. depending on what frequency the bassline of the song is playing
Last edited:
You often post about "observations" that defy common knowledge or Physics Laws, then let us try to explain them.
It would have been more believable if you had said that speaker works cooler inside the box at 30 to 40 Hz, which might be its resonance there, and same thing when tested in free air at 20Hz , its "free air resonance", because at resonance speaker impedance rises dramatically and it trakes less current from amplifier, so dissipating way less heat ... but the exact opposite as you claim is, to be polite, quite improbable.
It would have been more believable if you had said that speaker works cooler inside the box at 30 to 40 Hz, which might be its resonance there, and same thing when tested in free air at 20Hz , its "free air resonance", because at resonance speaker impedance rises dramatically and it trakes less current from amplifier, so dissipating way less heat ... but the exact opposite as you claim is, to be polite, quite improbable.
but thats what im experiencing. im not lying. the subwoofers FS free air is about 41hz from what the specs say.
inside the box its tuned to about 34hz
I dont know why it gets hotter when in the box rather than free air around the subwoofers FS. it barely gets warm free air around 30 to 40hz and hotter around 20hz but in the box it gets hot around 30 to 40hz and cooler around 20hz
thats just what its doing for me. the box is 1.8 cubic feet tuned to 34hz. i tested it sealed by stuffing the port with a thick dense blanket really well to make the box act like a sealed box instead of ported and then the problem becomes the opposite like its being played free air. so something to do with it being ported makes it act the opposite.
inside the box its tuned to about 34hz
I dont know why it gets hotter when in the box rather than free air around the subwoofers FS. it barely gets warm free air around 30 to 40hz and hotter around 20hz but in the box it gets hot around 30 to 40hz and cooler around 20hz
thats just what its doing for me. the box is 1.8 cubic feet tuned to 34hz. i tested it sealed by stuffing the port with a thick dense blanket really well to make the box act like a sealed box instead of ported and then the problem becomes the opposite like its being played free air. so something to do with it being ported makes it act the opposite.
Last edited:
In free air, its impedance around 20 Hz is low, if its Fs is at 41 Hz.
In the box, with an Fb around 34 Hz, its impedance will be lowest at that frequency, hence it will get hotter when driven near that frequency.
In the box, with an Fb around 34 Hz, its impedance will be lowest at that frequency, hence it will get hotter when driven near that frequency.
Port resonance provides a heavy mechanical load to the driver, so it has to work hard, more current - basically the driver is causing a lot more air movement (via the port), it feels more back pressure at the port resonance - the ported system is effectively changing the acoustic impedance.
Free air resonance doesn't have to work so hard against the air, and the resonance produces back-EMF that reduces the winding current. This is only true for lower efficiency speakers where the suspension dominates over the air pressure in free-air and the Q is high (which allows the back-EMF to be significant).
Free air resonance doesn't have to work so hard against the air, and the resonance produces back-EMF that reduces the winding current. This is only true for lower efficiency speakers where the suspension dominates over the air pressure in free-air and the Q is high (which allows the back-EMF to be significant).
Last edited:
so is my only option to have it be sealed and not play below 30hz? thats the only way I can play it at full power and not have it get hot. but then I lose some of the low end extension down to 22hz
yeah but they shouldn't start smelling a little bit like they do right? if I smell the port i can smell it a little bit. same with playing free air around 20hz cause the FS is so much higher above 20hz in free air that it draws alot more power and gets hot i can smell it a little if i smell around the magnet of the subwoofer. its not really bad but i can notice it so I have to be really careful not to play the wrong frequencies for too long so it doesnt get hot and start smelling.
Your speaker is overheating with the volume you want, so get a better driver - or build a second speaker to share the load.
We have no information on the actual driver you have, or the power you are using, or the cabinet design, so you cant really expect everyone to guess what is happening in any detail.
We have no information on the actual driver you have, or the power you are using, or the cabinet design, so you cant really expect everyone to guess what is happening in any detail.
+1
Surprising to see some replies to OP with imaginative theories rather than scepticism.
B.
WHAT extension "down to 22Hz" are you talking about?
I very much doubt your speakers reach down that low, by any means.
PLEASE post your cabinet design, and what speakers are you using.
Impossible to answer your vague doubts otherwise.
We-need-real-facts.
Last edited:
There's less than 3dB between smell and silence.
You need more or better drivers, or to simply accept that there are limitations.
Chris
Stop playing sine waves and enjoy the music. 😀
If you are talking about music the whole discussion makes no sense to me as music has harmonics so never is only 20 or 30Hz coming out of the system; most power will be in the higher frequencies.
If your sub woofer gets hot you are at it's power handling limits, the more heat the shorter it will work. It should not smell.
If you are talking about music the whole discussion makes no sense to me as music has harmonics so never is only 20 or 30Hz coming out of the system; most power will be in the higher frequencies.
If your sub woofer gets hot you are at it's power handling limits, the more heat the shorter it will work. It should not smell.
Lyrics are NSFW, but some music does have sine waves: YouTube
IIRC, the LF peak-to-average ratio is about 2dB, which is more compressed than a sine wave. Most of the power is at 36Hz.
Chris
the song bass i love you has frequencies below 16hz
and the bass will destroy you has bass frequencies below 20hz
and this song makes the windows in my bathroom across the hallway vibrate visibly
YouTube
the box is 1.8 cubic feet per subwoofer tuned to 34hz and i have two subwoofers hooked up in it its a dual separate chamber subwoofer box so I can run just one subwoofer if I want to.
and the bass will destroy you has bass frequencies below 20hz
and this song makes the windows in my bathroom across the hallway vibrate visibly
YouTube
the box is 1.8 cubic feet per subwoofer tuned to 34hz and i have two subwoofers hooked up in it its a dual separate chamber subwoofer box so I can run just one subwoofer if I want to.
Thanks.
Now we need to know your cabinet design and what speakers are you using, so fellow Forum members can simulate your design and how well it reproduces 16 and 20Hz , as well as its impedance at
and
which are the frequencies you are asking about.
its just a simple MDF carpet ported box. supposedly a simplified T-line
Amazon.com: DS18 SLC12S Car Subwoofer Audio Speaker - 12" in. Paper Glass Fiber Cone, Black Steel Basket, Single Voice Coil 4 Ohm Impedance, 500W MAX Power and Foam Surround for Vehicle Stereo Sound System: Car Electronics
is the subwoofer. and so far it sounds great and hits hard and clean.
Amazon.com: ASC Dual 12" Subwoofer Universal Slot Vented Port Sub Box Speaker Enclosure: Cell Phones & Accessories
box and the chambers have a wall between them they are separate chambers.
and I confirmed my playing different tones and stepping through them one by one its really tuned to 34hz. the subwoofer moves the least at 34hz
and it moves the most at 19hz but its fine its not even close to bottoming out and i can hear clean bass down to 20hz thats where it starts to drop off. but it still sounds good.
Amazon.com: DS18 SLC12S Car Subwoofer Audio Speaker - 12" in. Paper Glass Fiber Cone, Black Steel Basket, Single Voice Coil 4 Ohm Impedance, 500W MAX Power and Foam Surround for Vehicle Stereo Sound System: Car Electronics
is the subwoofer. and so far it sounds great and hits hard and clean.
Amazon.com: ASC Dual 12" Subwoofer Universal Slot Vented Port Sub Box Speaker Enclosure: Cell Phones & Accessories
box and the chambers have a wall between them they are separate chambers.
and I confirmed my playing different tones and stepping through them one by one its really tuned to 34hz. the subwoofer moves the least at 34hz
and it moves the most at 19hz but its fine its not even close to bottoming out and i can hear clean bass down to 20hz thats where it starts to drop off. but it still sounds good.
Ok, since we don´t know woofer parameters, nobody measured it, cabinet is generic "one size fits all", we know little about it either, you are using it in the wrong environment: a room which is , say, 30 times larger than the car that speaker is designed for, all adds up that it´s really hard to impossible to answer your doubts.
And you are in the wrong Forum section: both speaker and cabinet type and music program choice belong in the "Car Audio" area.
Specially because here people tend to work with hard data and accurate models and Math, while in the Car Audio World, gut feeling seems to be more important.
Literally, as in how much a Bass track turns your gut inside out.
And you are in the wrong Forum section: both speaker and cabinet type and music program choice belong in the "Car Audio" area.
Specially because here people tend to work with hard data and accurate models and Math, while in the Car Audio World, gut feeling seems to be more important.
Literally, as in how much a Bass track turns your gut inside out.
- Status
- Not open for further replies.