- Thread Starter
- #31
I know it can take the power, thats not the issue. 10 posts later, you still don't seem to grasp what my issue/question is, so I'm not going to bother trying to explain it to you anymore.
I know it can take the power, thats not the issue. 10 posts later, you still don't seem to grasp what my issue/question is, so I'm not going to bother trying to explain it to you anymore.
i know what you want..i told you your box isnt right..get it reconed, give it 1400, youll be happy..you want tight high end(you want it to be hard to breathe)..bigger box isnt the answer..go 3.5 cu ft tune it to 30hz
are you really helping here? i dont see you telling him anything he doesnt already know..
kenny, here's what i would do, you say you dont have enoguh time to build a box? do you have a enough time to cut the port off of your current box and reduce the size/sealed it up? if so give that a go, you will lose output and a bit of bottom end but it should boost the upper frequencys, i would not go with the TD driver, it's not a car audio driver, it has lower xmas and can't take as much power as the AV also, if you want to go PR do it with the AV you have now rather than getting the TD, i think john has an AV with a PR as his setup? either way i would try a few things before getting a TD (well i wouldn't get one)
- Thread Starter
- #34
Actually, the TD will take tons more power than the AV (it'll take 2500 rms all day long on music according to John), and even with the lower xmax, being it's a larger diameter, it'll displace roughly the same amount of air.
yea i was trying to help..sry for offending you
he must of done an upgrade on them or something? last i read they did 500wrms (this was the 15" though)
just had a look at the t/s params for it, it has a higher FS than the AV, and it looks very effecient, it might do farely well in a car with a PR, i always thought they had a much lower FS than that.
i would just try the AV sealed, if you dont like it there's no harm in upgrading to a better driver..
well just my input..my av is in a sealed box, and i love it..its a very solid punch..2.5cu ft
- Thread Starter
- #38
The 18 is a completely different driver, new design from the ground-up. Same basic principles, but still a completely new driver.
yeah i see that, looks much more impressive than the other models, bet they cost alot more though, i would imagine they have a nicer punch than the AV, due to the higher FS and being tighter, if you put one in a sealed box with a PR to help on the lows im sure it would sound amazing, if you decide to go with this keep me informed on how it sounds
Hi everyone. Sorry I'm late here, but I thought some of these things had been cleared up in the past but apparently they were not. Regarding the original question. The AV15H and TD18H+ have almost equal displacement capability down low. The AV15 has 23mm Xmax but smaller Sd and the TD18 has 14mm Xmax but larger Sd. Both have 2.5" coil with the full copper sleeve next to them. Power handling is almost identical. We have prosound customers running the TD18H+ with 2500W on a nightly basis. Elite Audio is able to get output in the range of 145dB at the stage for live events with their stack of them. They abuse them quite a bit with no issues. I will have a single TD18H+ in the truck when I bring it up to Michigan Tech. Bose301's can give you his thoughts after the 18th.
Now regarding the current situation. Lets look at a few things. The AV15X is about 90.5dB 1w efficiency or 94.3dB 2.83V sensitivity. The AV15X is flat to over 2KHz where it then has a really nasty cone breakup. The output you have up high is not determined by the enclosure but only the woofer and power applied. Also cabin gain is pretty much non-existent above 70hz or so. Regardless if you apply 1000W you are gaining 30dB over the 1W efficiency no matter what woofer you apply it to. That doesn't take into account any losses due to power compression though which could be a few dB if the coil temperature goes way up after continual use. Regardless that is the rage of 120dB. This is significantly higher than most any front stage is going to get. The best Scan Speak, Seas Excel, etc will get you around 110dB max at full input power. Nearly all dome tweeters regardless of silk, alum, titanium dome, etc are going to be limited to much less output than that. This means with no cabin gain at those high frequencies you have significantly more output than almost any front stage could ever match. Obviously there are some extreme options out there which can exceed those levels but for the most part that gives you an idea.
I'll copy a lot of this from the CAF post that went through most of this and the issues before.
As far as box design goes, you can put the woofers in really any size sealed box, vented box, or PR box you wish. The woofer honestly does not care what box it is in. You get different shape curves with various tunings and box sizes. The AVH is intended more for high tuned SPL applications OR for smaller sealed or PR enclosures. The AVX is more for everyday use and can be used in mid to large size sealed or vented boxes. Below are various curves I have modeled for people.
Here are 3 suggested sealed enclosures for the AV12H
AV12H vs IDQ 1cf sealed comparison. Yellow is the AV12H
AV12X vs IDQ 1cf sealed comparison. green is the AV12X
AV15H suggested sealed enclosures
AV15H vs DD9515G in an the DD suggested SPL Tune. AV15H is the dark blue
Single AV15X with various tunings
Of course it is important to match the output to your cabin gain. The first thing I do in any install is get an idea of the cabin gain. Here are a few transfer functions measured so you can see how much gain there is:
Ford Escort transfer function mid/late 90's:
Comparison between buick regal and toyota camry response
The regal and camry are quite similar as they are both 4 door vehicles with similar cabin size. If you wish to see a few other curves to see what happens with windows up or down and mic position from driver head to apex of dash, feel free to check out the page. Keep i mind this is like 8 yrs old now:
http://www.aespeakers.com/basszone/deonspace/cabin.html
Kenny mentions that with the current amp that the AV15 "makes the wipers dance off the windshield with lil john" and makes "my spoiler look like it's about to rip itself to shreds." Clearly the woofer is doing it's job, moving air. Looking at the cabin gain though you can see why there is so much less output up high. You have as much as 30dB on the low end of cabin gain in his vehicle. This is equivalent of having 1000X the power at those frequencies! Yes, one thousand times the power. 10 log 1000 = 30dB gain with 1000W input power. If you have 1000x the power at one frequency than you do at another, you will likely barely notice the other frequency being played.
When bass is overpowering at the low frequencies there are 2 options. One is to go sealed. This will restrict the excursion of the driver rolling off the output. However you now need as much as 10x the power to get the same amount of output as you did in the vented box. This means much more distortion from thermal issues and flux modulation issues based on the current in the coil. Using much more power down low also means your amplifier has nowhere near as much headroom available. The other option is to use EQ to pull down the output on the low end. Where you would need 100W to get a given level at 30hz in the sealed enclosure you now may need only 10-20W. Much less thermal related distortion. Your amplifier now has much more headroom for the higher bass frequencies where you do need the power as there is no cabin gain.
This is the same concept that is used with compression drivers for every pro audio system out there. The horn makes the lower frequencies of the compression driver very efficient. The output is then EQ'd back flat and in the end the gain is cutting distortion by 10-20x and greatly increasing the overall output capability.
Here is a typical response curve from a compression driver. This is an 18sound ND1075 on their XT1086 horn.
You can see the intentionally rising response as you go lower in frequency which when EQ'd flat gives a much lower distortion system.
Now let's apply that to the car subwoofer world. The following graph shows the vented AV15 tuned to 28hz in orange vs the sealed in light blue. Then we apply the escort transfer function to both. Yellow is the response of the vented vs the sealed in green.
Now you will notice a few things here. The yellow curve is actually +/- 2dB from 16hz to 50hz. The green curve does clearly have less output from 20-50hz but it is still very overpowering in that range. The issue is also that you are still using the same amount of amplifier power so you haven't saved any headroom on the amp.
The ideal solution would be to use a notch filter to pull down the 16-50hz range. You have about a 24dB slope at both ends. A notch filter with 24dB bessel slopes to pull down that region about 18dB would would be ideal to flatten out the response. Implementing that filter would give you a response +/- 2dB from 12hz to 100hz. You'd also have tons of headroom and amp power available. Midbass would be proportional to the low bass output. Distortion is extremely low this way as well. You'll be capable of the same overall SPL levels at the low end, just everything will be in proper proportion.
Now you may not want to pull that range down the full amount. Your own desires may want a slightly rising response, bump in the 30-45hz range where the lowest stuff in most rap music is centered. You can adjust it to whatever your own tastes are.
John
Now regarding the current situation. Lets look at a few things. The AV15X is about 90.5dB 1w efficiency or 94.3dB 2.83V sensitivity. The AV15X is flat to over 2KHz where it then has a really nasty cone breakup. The output you have up high is not determined by the enclosure but only the woofer and power applied. Also cabin gain is pretty much non-existent above 70hz or so. Regardless if you apply 1000W you are gaining 30dB over the 1W efficiency no matter what woofer you apply it to. That doesn't take into account any losses due to power compression though which could be a few dB if the coil temperature goes way up after continual use. Regardless that is the rage of 120dB. This is significantly higher than most any front stage is going to get. The best Scan Speak, Seas Excel, etc will get you around 110dB max at full input power. Nearly all dome tweeters regardless of silk, alum, titanium dome, etc are going to be limited to much less output than that. This means with no cabin gain at those high frequencies you have significantly more output than almost any front stage could ever match. Obviously there are some extreme options out there which can exceed those levels but for the most part that gives you an idea.
I'll copy a lot of this from the CAF post that went through most of this and the issues before.
As far as box design goes, you can put the woofers in really any size sealed box, vented box, or PR box you wish. The woofer honestly does not care what box it is in. You get different shape curves with various tunings and box sizes. The AVH is intended more for high tuned SPL applications OR for smaller sealed or PR enclosures. The AVX is more for everyday use and can be used in mid to large size sealed or vented boxes. Below are various curves I have modeled for people.
Here are 3 suggested sealed enclosures for the AV12H
AV12H vs IDQ 1cf sealed comparison. Yellow is the AV12H
AV12X vs IDQ 1cf sealed comparison. green is the AV12X
AV15H suggested sealed enclosures
AV15H vs DD9515G in an the DD suggested SPL Tune. AV15H is the dark blue
Single AV15X with various tunings
Of course it is important to match the output to your cabin gain. The first thing I do in any install is get an idea of the cabin gain. Here are a few transfer functions measured so you can see how much gain there is:
Ford Escort transfer function mid/late 90's:
Comparison between buick regal and toyota camry response
The regal and camry are quite similar as they are both 4 door vehicles with similar cabin size. If you wish to see a few other curves to see what happens with windows up or down and mic position from driver head to apex of dash, feel free to check out the page. Keep i mind this is like 8 yrs old now:
http://www.aespeakers.com/basszone/deonspace/cabin.html
Kenny mentions that with the current amp that the AV15 "makes the wipers dance off the windshield with lil john" and makes "my spoiler look like it's about to rip itself to shreds." Clearly the woofer is doing it's job, moving air. Looking at the cabin gain though you can see why there is so much less output up high. You have as much as 30dB on the low end of cabin gain in his vehicle. This is equivalent of having 1000X the power at those frequencies! Yes, one thousand times the power. 10 log 1000 = 30dB gain with 1000W input power. If you have 1000x the power at one frequency than you do at another, you will likely barely notice the other frequency being played.
When bass is overpowering at the low frequencies there are 2 options. One is to go sealed. This will restrict the excursion of the driver rolling off the output. However you now need as much as 10x the power to get the same amount of output as you did in the vented box. This means much more distortion from thermal issues and flux modulation issues based on the current in the coil. Using much more power down low also means your amplifier has nowhere near as much headroom available. The other option is to use EQ to pull down the output on the low end. Where you would need 100W to get a given level at 30hz in the sealed enclosure you now may need only 10-20W. Much less thermal related distortion. Your amplifier now has much more headroom for the higher bass frequencies where you do need the power as there is no cabin gain.
This is the same concept that is used with compression drivers for every pro audio system out there. The horn makes the lower frequencies of the compression driver very efficient. The output is then EQ'd back flat and in the end the gain is cutting distortion by 10-20x and greatly increasing the overall output capability.
Here is a typical response curve from a compression driver. This is an 18sound ND1075 on their XT1086 horn.
You can see the intentionally rising response as you go lower in frequency which when EQ'd flat gives a much lower distortion system.
Now let's apply that to the car subwoofer world. The following graph shows the vented AV15 tuned to 28hz in orange vs the sealed in light blue. Then we apply the escort transfer function to both. Yellow is the response of the vented vs the sealed in green.
Now you will notice a few things here. The yellow curve is actually +/- 2dB from 16hz to 50hz. The green curve does clearly have less output from 20-50hz but it is still very overpowering in that range. The issue is also that you are still using the same amount of amplifier power so you haven't saved any headroom on the amp.
The ideal solution would be to use a notch filter to pull down the 16-50hz range. You have about a 24dB slope at both ends. A notch filter with 24dB bessel slopes to pull down that region about 18dB would would be ideal to flatten out the response. Implementing that filter would give you a response +/- 2dB from 12hz to 100hz. You'd also have tons of headroom and amp power available. Midbass would be proportional to the low bass output. Distortion is extremely low this way as well. You'll be capable of the same overall SPL levels at the low end, just everything will be in proper proportion.
Now you may not want to pull that range down the full amount. Your own desires may want a slightly rising response, bump in the 30-45hz range where the lowest stuff in most rap music is centered. You can adjust it to whatever your own tastes are.
John
very good post as always John, now back to kenny, i think buying an EQ may be your best option, should be cheaper than your other options too
Things you can do to determine what is going on. Measure voltage and current going to the woofer. You want RMS values. Power applied = V*I. I can give you some test tones to burn on a cd or even send you a cd. Play a 30hz sine wave and measure, 50hz, 70hz, 90hz, etc. Ideally you want an oscilloscope to be able to see when the amp is clipping, but you can basically rely on doing it by ear. With a 0dB recorded sine wave you'll hear when the amp clips. Measuring this will tell you what kind of power your amp is applying at that measured frequency. The woofer is electrically nearly flat up to 2Kz(2000hz) so it should be applying the same power at all frequencies. If you measure less power at the higher frequencies, that is because of the lowpass filter and you need to raise it more.
Also at these higher frequencies you can end up with a lot of cancellation between the subwoofer and front stage if you don't have them properly time aligned, and phase coherent. Turning the phase adjustment knob on your amplifier from 0, gradually up to 180degrees will make a different if this is a case. If you don't have one on the amp, flip the polarity on the woofer. This changes it 180degrees. Sometimes you get a big difference, sometimes none. You may be 90 degrees out of phase and flipping polarity ends you up being 90 out of phase just in the other direction with no real apparent change.
John
Also at these higher frequencies you can end up with a lot of cancellation between the subwoofer and front stage if you don't have them properly time aligned, and phase coherent. Turning the phase adjustment knob on your amplifier from 0, gradually up to 180degrees will make a different if this is a case. If you don't have one on the amp, flip the polarity on the woofer. This changes it 180degrees. Sometimes you get a big difference, sometimes none. You may be 90 degrees out of phase and flipping polarity ends you up being 90 out of phase just in the other direction with no real apparent change.
John
- Thread Starter
- #43
OK, fine. After I demo it sealed at ~2.5 cubes for a few days, and I compare that to the single sealed Pioneer 12 I have in my closet, I'll find a way to cut a few inches out of the port and get the tuning into the 30's.
- Thread Starter
- #44
Does anybody know if there are still any Orion XTR 12's in existance anywhere?? I'd like 4 or 6 of them.
- Thread Starter
- #45
Just sold the AV15.
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