Acoustic Elegance AV12-X D2!

[John_E_Janowitz 10+ year member]

For those interested, I just got my ED 11Ov2's installed yesterday. They do not seem to exhibit the lack of upper frequency extension that the AV15 did. This is now 3 separate drivers that have not exhibited this problem in my vehicle. Perhaps it's time to stop blaming the user or the vehicle and start (rightfully) blaming the poorly performing drivers???
A comment from a friend who's not much of an audio person was simple 'wow, these things have WAY more range than that 15 you had did" >_>

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I think we have covered this a few times and I just don't know why you have such a hard time understanding. The 10 people who were here from the forum on saturday and heard the already damaged papermaker woofer STILL playing to 200hz. You can see the videos here as well as all the people here to witness.

http://www.caraudio.com/forum/showthread.php?t=418231

Thanks to Bumpin Buick for the videos.

Again I'll try to educate you, although I'm starting to feel like i'm talking to a rock. If you have no upper end response it is due to your setup, not the woofer. I spent some time measuring transfer functions in Bose301's Jimmy, my Audi S4, and my bravada. One of the things you will find out is that positioning has a HUGE effect on upper bass response. You have a time delay from the direct signal off the woofer and the reflected signal off the back of the vehicle. This delay causes a substantial notch in frequency. Below are the measurements in Bose301's Jimmy.

You can see that the red curve is smoothest and has the least amount of drop in the upper region. This is because the distance from the woofer to back of the vehicle is only a few inches. Any dip occurs well above 200hz and is not an issue. The closer the box is to the back of the vehicle, the better the upper response will be. If you have your box firing forward right behind the back seat this maximizes the time difference and you get the most significant dip at the lowest point in frequency. This is seen in the orange curve. The difference at 88hz between the 2 positions is 20dB. Output is lost everywhere from 57hz on up to over 100hz. Bose301's now stated he has much better upper end response from the same woofer just due to positioning. This of course makes perfect sense to most people.

As another example, here are the measurements from the 01 Audi S4. Again we see the same thing. Box at the back of the vehicle firing towards the back of the trunk gives the best results. Box firing forward at the back of the seat again is very poor. Box firing up actually causes even more loss lower in frequency.

In case this isn't becoming clear yet, here is one more set of measurements from the 02 Olds Bravada. Again from 65hz on up, there is much more upper bass with the box at the back firing back. This vehicle, which i drive all the time has another cancellation that I have to deal with. The dip at 65hz occurs only at the headrest position and is changed due to mic placement. It just so happens my head has to go in that spot where the dip is.

What we can see here is that over and over, you lose upper bass output due to positioning. The current measurements were with the subwoofer only from 10hz to 200hz. No front stage was brought in. The other thing that affects the upper bass response is the integration with the front stage. That will be a lesson for another time though.

John

 

[microhaxo 10+ year member]

Now i have graphical proof to show my friends why forward firing is not good in many applications. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[Parker G 10+ year member]

All I want to know is whats up with some passive radiators??????

 

[ciaonzo 5,000+ posts]

All I want to know is whats up with some passive radiators??????

Indeed.

Good one ParkerG. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Parker G 10+ year member]

Indeed.
Good one ParkerG. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

I was only saying that because I want John to answer my question about PR's

And you can call me Parker lol

 

[Koon 10+ year member]

microhaxo, hows the AV holding up after a few weeks of use? any differrence in performance? Do you think the AV could handle constant rap songs with lots and lots of bass? thx so much

 

[microhaxo 10+ year member]

Works just as good as the day i got it. I dont abuse the sub though and i know how to setup a system properly.

It handles constant rap songs every day from me.

 

[bose301s 5,000+ posts]

Can't wait to get mine, will be picking it up from John in the next week or 2! //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[AudioAnonymous 10+ year member]

John you should let me borrow 4 15 or 4 18s and I'll see how it stacks up against some of the best SPL subs. I live 10 minutes away from your shop. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Papermaker85 5,000+ posts]

Works just as good as the day i got it. I dont abuse the sub though and i know how to setup a system properly.
It handles constant rap songs every day from me.

i hope your not seriously trying to say that we didn't correctly install the woofer, if anything you have a fart box thats WAY to large.. so your claims and oponions are completely invalid...

for you other idiots kenny isn't comparing output, he is comparing frequency response...

 

[Papermaker85 5,000+ posts]

Can't wait to get mine, will be picking it up from John in the next week or 2! //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

you getting a 12 or 15?

 

[microhaxo 10+ year member]

I never claimed anything other than that i installed and used the sub properly.

Anyone who is looking to get this sub, all i can say is that it sounds great and you will be very happy.

This sub is a quality sub and should be treated as such. (not abused)

 

[bose301s 5,000+ posts]

you getting a 12 or 15?

I will get a 12, don't want to give up the space for a 15.

 

[bumpin buick 5,000+ posts]

John you should let me borrow 4 15 or 4 18s and I'll see how it stacks up against some of the best SPL subs. I live 10 minutes away from your shop. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

We are doing a direct swap out as soon as the 3" coil drivers are complete. This way we can test the apples to apples, as far as a sub made for getting loud and both having a 3" coil now. Hughes went up to the shop and checked it out as well. We may try to swap out his two 10"s I think it would be interesting to see a direct drop-in test in the street A application.

 

[microhaxo 10+ year member]

Hmm, sounds like john is pretty close to some 3" prototypes eh? lol

If he can get those up and running i think that would appeal to a lot of the SPL'RS around here.

 

[Koon 10+ year member]

Works just as good as the day i got it. I dont abuse the sub though and i know how to setup a system properly.
It handles constant rap songs every day from me.

that's what I like to hear. I'm very interested in these 3" coils but I'm only gonna have like 1200 RMS to work with.

 

[bumpin buick 5,000+ posts]

that's what I like to hear. I'm very interested in these 3" coils but I'm only gonna have like 1200 RMS to work with.

I dont want to speak to much for John but a pair of prototypes should be together very soon, and some drop-in testing will be done on my vehilce to see how they compare.

 

[T3mpest 10+ year member]

that's what I like to hear. I'm very interested in these 3" coils but I'm only gonna have like 1200 RMS to work with.

the 2.5 will take that all day anyway. Judging by the heatsinking capabilities of his 2.5 you'd need 2000+watts to start to really push the 3inch coils, that's just a guess tho.

 

[Koon 10+ year member]

the 2.5 will take that all day anyway. Judging by the heatsinking capabilities of his 2.5 you'd need 2000+watts to start to really push the 3inch coils, that's just a guess tho.

I was thinking the same :/

 

[John_E_Janowitz 10+ year member]

I think it's important to again emphasize the difference between thermal power handling and the amount of power it will take to get to the physical limits of the driver. Thermally the AV series 2.5" coil can take a large amount of power. When we hooked one up to the wall socket that gives about 4800W to the driver and the already damaged woofer still went for about 30sec with that kind of continuous power. Thermally 1200W or so as stated above is no issue for the AV woofers.

Mechanically it is a much different story. A modeling program can give you a fairly good indication of how much excursion you have in a given box with a given amount of power at each frequency. In a vented box it is especially important to have a subsonic filter to protect the driver from over excursion below tuning. Below the tuning frequency the port unloads and you are easily able to push the driver to high excursions. You are also doing so at frequencies that will be below the limits of audibility due to the rolloff. There really is no point to attempt to play these frequencies. A highpass filter (subsonic, infrasonic are the common names) protects the driver from over excursion and also gives back some headroom as the amplifier is not producing power for frequencies the woofer can't even play.

The ideal situation is to setup the system so that both the thermal and physical limits are reached approximately at the same time. That way neither of these factors are greatly limiting the output.

The 3" coil driver will be able to handle more power than the 2.5" coil thermally. It will also have more mass and more motor strength. As a result it will be more efficient than the 2.5" coil requiring less power for a given SPL while being able to take more power overall as well. The same things will apply in terms of mechanical limitations of the driver though as they apply to every/all drivers made.

John