Quebec winter temperature goes down to -30 CELCIUS in january/feb and got up to 30 Celcius in summer. The sub would see a lot of temperature variance. would the surround eventually break from that.
I'm usually warming it a little in winter before getting it going. Never had any problem with car audio subs
You sure about that?? I turned the xover up on mine as far as it would go and it made no difference. Mine had little to no output in the upper frequency range. Compared to another driver in the same vehicle, my little Orion XTR 12 off 1/3 the power has more output above 50 Hz.
You sure about that?? I turned the xover up on mine as far as it would go and it made no difference. Mine had little to no output in the upper frequency range. Compared to another driver in the same vehicle, my little Orion XTR 12 off 1/3 the power has more output above 50 Hz.
I think we have covered this MANY times now but you clearly still do not understand. If you didn't have any upper bass it is from not setting it up properly. I spent literally HOURS trying to explain this to you in the past, but if you continually ignore everything I say there is nothing I can do to help you.
A big dip in response at the top end of the bass is due to positioning and/or cancellation between the sub and front stage playing the same frequency range. When two drivers are playing the same frequency range but are out of phase, they will cancel each other over a certain narrow band. The way to correct this is to have proper time alignment between the drivers. Also positioning the sub appropriately so it is in phase with the front stage at the upper bass region or adjusting the phase knob if you have one will correct the issue.
Keep in mind that phase will be different from woofer to woofer. Phase is directly derived from the frequency response which is affected by the driver's impedance curve. Quite simply if drivers do not have the same inductance, they will react differently. You may get lucky and throw a driver in where everything works just great and as a shot in the dark everything just happens to line up perfectly where you put the box with no adjustment. This doesn't happen too often though. If you stick a different woofer with drastically higher or lower inductance in that same position the phase will not be the same and it will be out of alignment. There are reasons there are 0-180degree phase adjustments on many subwoofer amps. This is the most simple adjustment to get the drivers in phase and remove this cancellation. You don't have to worry about moving the position of the enclosure or having processing with time alignment, although time alignment is the ideal way to go.
The AV woofers extremely flat impedance and response up to over 1KHz, so there are absolutely no issues with playing to 100Hz. This is well documented in many places. We pulled 129.3dB on the TermLab at 72hz where there is virtually no cabin gain in BumpinBuick's 4Runner. The majority of all front stage components out there will never come anywhere near this kind of level to keep up. Below are response and impedance curves from the AV12X. You can clearly see how high they play and how flat the impedance curve is.
As a measured example of how placement affects phase and then response, here are the measurments from Bose301's Magv4 in his blazer. The light blue curve was the original placement. There is a huge peak at just under 50hz followed by a large dip at about 88hz. The difference in magnitude between these two points is 45dB! This will make it sound like the woofer is not even playing at all as many people experience. The dark blue curve is the flattest placement. This is simply changing the same woofer in the same box to firing upwards. A lot of the bump below 70hz was decreased and the bump at 88hz came up significantly.
There is still a large amount of extra low end, but the apparent difference is now only 18dB vs 45dB. All that was done was to change the position of the box in the vehicle.
If an amplifier has a 0-180 phase adjustment knob you can play test tones to hear if you are getting any of this cancellation or null. If you hear a point where there is a big null, you can then turn the phase adjustment until you get to the point where the level comes back up in this region. In some cases you won't get perfectly in alignment anywhere in this 0-180degree range. You can then flip the polarity on your woofer. This would then allow you to be going from 180-360degrees. A simple 0/180 switch only gives you 2 options. One way may be better than the other.
You sure about that?? I turned the xover up on mine as far as it would go and it made no difference. Mine had little to no output in the upper frequency range. Compared to another driver in the same vehicle, my little Orion XTR 12 off 1/3 the power has more output above 50 Hz.
Could be wrong, but with an inductance that low (it rivals some 6" drivers) it should be able to play cleanly way above that. If you don't like it, then you don't like it no biggy.
John, you have yet to come up with any explaination of why such a 'lesser' driver with 1/3 the power can do what yours wasn't doing. In the same position, in the same vehicle.
:edit:
As usual, I skimmed past most of your post, because reading the same thing and seeing the same graphs over and over again with no other explaination gets boring. My woofer is ancient, I have no idea what the impedance curve of it looks like. If I can ever get an enclosure built for the 11Ov2's, we'll see if they exhibit the same problem as your driver did. FWIW, yours, and the DIYMA12, are the only drivers I've ever owned that experienced this phenominon.
Quebec winter temperature goes down to -30 CELCIUS in january/feb and got up to 30 Celcius in summer. The sub would see a lot of temperature variance. would the surround eventually break from that.
I'm usually warming it a little in winter before getting it going. Never had any problem with car audio subs
We can occasionally get that cold here in Wisconsin also, although not too often. I remember one year when I was at Michigan Tech up in Houghton when Lake Superior completely froze over. We'd have temps in that range for several days at a time.
The colder the temperature, the better most electronics work. Heat is the big thing that affects amps. Likewise in a woofer, heat raises the resistance of the VC wire so the warmer it is, the less power you can deliver. The colder the better as far as getting power to the woofer. The only thing typically to worry about in a woofer is that the surround will stiffen up in the cold. We specifically picked santoprene for the surround. It has the lowest brittle point of any rubbers out there. It was designed for use in gromets and rubber boots in vehicles that would be subjected to these kind of extreme temperatures. It's brittle point is -65F or about -54 Celsius. It should have no issues with cracking or breaking, although these extreme temperatures will raise the Q of the driver significantly. It should work with no issues, but in any very cold weather situation I would play any woofer at moderate levels until the inside of the cabin warms up.
As far as the top end of the heat spectrum, santoprene is good to nearly 280F before it begins to drastically soften. It is thermoformed at about 320F. In any woofer the thermal power handling will go down in extreme heat situations. Amps will heat up easier and clip easier as well. Anytime the ambient temperature of the vehicle is higher, a woofer or amp can't dissipate heat as easily as if it were colder.
Could be wrong, but with an inductance that low (it rivals some 6" drivers) it should be able to play cleanly way above that. If you don't like it, then you don't like it no biggy.
What about cone breakup and nodes of the cone deflecting at resonance //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif..inductance is cool and all...
Just because a Mercury 2.5 EFI drag boat engine will turn 14,000rpm during a 1/4 mile pass doesn't mean it should do that all the time right?
John, you have yet to come up with any explaination of why such a 'lesser' driver with 1/3 the power can do what yours wasn't doing. In the same position, in the same vehicle.
Once again you prove my point that no matter what I have stated you ignore it. Re-read the third paragraph in post #25 above. It's quite simple. Your sub to main stage is a crossover point, the same as any other crossover point in any speaker. For it to sound right and have a properly summed response the phase needs to be right.
Then other way to test for this is to actually listen for the null. Flip the polarity of the woofer and adjust until the bass really disappears at the xover point. Then flip polarity back. Sometimes it is easier to listen for the most cancellation than the most summation.
Here is an example of a 3way system. You can see the yellow curve is quite flat response with drivers all in phase. When the polarity of the mid is flipped 180degrees you have 2 very deep nulls at the crossover points. This shows that the phase was correct when the mid is wired with normal polarity.
What about cone breakup and nodes of the cone deflecting at resonance //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif..inductance is cool and all...
Just because a Mercury 2.5 EFI drag boat engine will turn 14,000rpm during a 1/4 mile pass doesn't mean it should do that all the time right?
If you take a look at the impedance curve you can see the 2 breakups. The dust has a breakup at almost exactly 1KHz and is quite minor in magnitude. The cone on the 12" has a breakup about 2.4KHz which is more significant. Even if crossing at only 12dB as high as 100hz you'd be over 40dB down by the time you got to the first minor breakup from the dustcap and over 50dB down by the cone breakup. For any subwoofer application the breakup is not even remotely an issue.
If you plan to use the drivers up to 500hz or so in a 3way home speaker then you'd need to take a little more care. You'd want to have a 24dB slope to keep these breakups suppressed. These drivers actually will reproduce the lower vocal region as well or better than most good midrange drivers. I doubt anyone on this forum needs to worry about it though. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
What about cone breakup and nodes of the cone deflecting at resonance //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif..inductance is cool and all...
Just because a Mercury 2.5 EFI drag boat engine will turn 14,000rpm during a 1/4 mile pass doesn't mean it should do that all the time right?
Point taken, however when you look at the measure response of the driver in question, IMO the most significant break up with just over 2kHz, that is a good 4.5 octaves above where I would cross over at, so really it isn't an issue.
Anyone who says this driver has no output past 60hz is wrong, it has more output than the Fi Q hands down in that area, the quality of this driver is amazing.
If you take a look at the impedance curve you can see the 2 breakups. The dust has a breakup at almost exactly 1KHz and is quite minor in magnitude. The cone on the 12" has a breakup about 2.4KHz which is more significant. Even if crossing at only 12dB as high as 100hz you'd be over 40dB down by the time you got to the first minor breakup from the dustcap and over 50dB down by the cone breakup. For any subwoofer application the breakup is not even remotely an issue.
If you plan to use the drivers up to 500hz or so in a 3way home speaker then you'd need to take a little more care. You'd want to have a 24dB slope to keep these breakups suppressed. These drivers actually will reproduce the lower vocal region as well or better than most good midrange drivers. I doubt anyone on this forum needs to worry about it though. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
Graphs and everything is great...theory is great as well.
But what does it actually sound like at 500Hz..1000Hz etc. In a real world either Home or Car scenario?
There is something about something being that big re-producing those frequencies that simply do not sound 'right' to the ear. Especially with aluminum...which is why you see all of the great pro sound people using ultra light paper cones and edge wound coils with 11" diameter motors.
Also I am not talking about impedance breakups. I'm talking about actually putting the cone, on a shaker table, mounting accelerometers on it, exciting it from 1-4000Hz and recording the data and running through a dac program like MATLAB. This actually tells you where the cone has acoustic excitation and where it is dead. With nothing else coming into play, just the cone itself. Mat lab and accelerometer graphing gives you a great deal of information that is very useful...if you know how to use it. I did some stuff for Boeing a while back on some panel vibration stuff..very cool...learned a great deal about aluminum //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
Anyone who says this driver has no output past 60hz is wrong, it has more output than the Fi Q hands down in that area, the quality of this driver is amazing.
How could something with less linear excursion have more output in a lower octave where it takes 4 times as much displacement to be within the same output of say a nominal 100dBa?
It's very probably that a single spider more efficient floppy suspension would appear to have 'more output' on the bottom end because it is much easier to move on a per watt basis. But there are costs to this...one is durability and idiot factor of not knowing what a subsonic filter is on something that has a long coil and capable of a lot of excursion.
But laws of physics say otherwise...it could work better in a given scenario. Which is very probable. Outside of that something that moves more on a lower frequency will always have more output in a A vs. B swap, all things constant.