[DrWho]

For what it's worth, the AV15 is a very good driver. However, it sounds like something is wrong with your particular unit and no amount of electronics is going to change that behavior. I also think choosing to go with a different driver is a premature solution. Do you buy a new engine when the tire goes flat, or buy a new car when it runs out of gas?

Is it possible that you have over-driven the sub due to some unfortunate modes in your listening room? The only reason I ask is that if you feel the model tells you that you should be getting more sound, then what's to say that the next sub isn't going to suffer the same problems?

 

[hawkmoon77]

When all of the problems happened, I did a lot more research (rather than messing with the driver itself). I came upon a few threads in some car-audio forums that had less than good things to say about the driver. There were reports of near 100% failure rates. I took it with a grain of salt considering that car guys tend to run things a bit differently than I do. But with the problems I was having, I eventually considered it a lost cause.

Your comments are making me re-think my testing process. If indeed the driver was more power hungry than the test sub I switched it for, it could have been the amp clipping. It never hit very hard at all, sounded a bit like if you dropped a penny on a metal cone from about 2 inches. Not a hard sound, just noticible when you are running a 30hz tone.

I did try it with the Behringer amp, but never with actual real-life audio, just test tones through a laptop. I wonder if perhaps the laptop output was too high, which might cause some clipping. Additionally, To access the speaker, I had to remove the plate amp that was in the back, meaning there was a gaping hole in the enclosure, so I guess I was running it free-air... which would certainly explain the low output coupled with the clicking sound.

I'll try sealing the back of the enclosure, and running it with the behringer with test tones AND some actual music and movies. I may have a different experience. Thanks for encouraging me to work with it again.

If it does, I still don't know what I'll do. I eventually want two subs, and even if this one did "pull-through" I'd feel reluctant to double down on my investment.

That being said, I did some modeling last night and found that the three recommended drivers would all work pretty well in an 8 cubic foot enclosure tuned to 19 or 20hz. If that's the case, I would feel better using the AE driver I have knowing that if it failed, I could swap it out for another driver without having to rebuild the enclosure. I doubt I'd notice the 1 or 2 db difference here and there.

I also took Blaser's advice, which was great - discuss the enclosure size with my wife. I showed her winisd, explained what the lines meant. I showed her what -3db sounded like on our 8 inch sub, and let her play with the box sizes in winisd to compare the results. It wasn't long before she was taking the tape measure and playing with the dimensions in our TV room. After seeing the compromises to be made in winisd, she thought that 8 cubic feet would produce a good effect while still being workable space-wise.

I'll let you guys know how the AE driver checks out with the Behringer in a proper enclosure.

 

[Ricci]

Contact John and see what he says. They are a nice driver, but they aren't an excursion monster. A bridged EP2500 would be too much for one driver. They are supposed to soft bottom.

 

[spanish68]

I agree with Ricci, your EP2500/4000 amp is probably good enough to drive two AV15H drivers. I have a AV15X driver that was bottoming during heavy bass scenes in a PR's box and also burned a coil during heavy low bass testing with test tones at 20hz. Anyways, I sent the driver back to AE just over two weeks ago and John is almost done repairing it.

 

[exojam]

Hawk,

I would most definitely talk to John and see if you can send it back and have him take a look at it. I have two AV15-H in sealed cabinets that are a little smaller than yours and can pound them all day with no issues. I am running each one off of a channel of a EP2500.

I was doing some testing on them awhile ago and had my PR-SC885 at -5 on the master volume while playing the U571 depth charge part and had no clipping on the amp or any weird sounds from the subs.

If interested I posted mine at the below location.
http://www.hometheatershack.com/forums/diy-subwoofers-sealed-ported/20273-duel-av15-hs.html

James

 

[Mike P.]

Let's not forget the application here. The AV-15H will not produce the low end output that the Tempest-X or SDX15 can if that is what he's after. As good as the AV-15H is, there are better choices.

 

[exojam]

Mike,

Has he stated what he is looking for out of the sub? I went through the thread again and do not see what he is really looking for in terms of how low and loud, what size room he has it in, etc.

I am not saying there may not be better driver out there but it really sounds like something is wrong with his driver if things go wrong with 300 watts.

There is also a small amount of information (modeling) at the below link on the AV15-H if interested.
http://www.avsforum.com/avs-vb/showthread.php?t=1149270&highlight=av15

Out of curiosity why do you feel the Tempest is better? I just took a quick look at the Tempest-X2 15" and it only has 3mm more xmax, lower sensitivity, lower le and same power rating compared to the AV15-H. And yes this is an honest question since I have never had one of these or modeled one. Thanks.

James

 

[Mike P.]

I obviously messed up when I previously modeled the sub. :rubeyes:I'm glad you questioned it. Since he's looking for a 6 - 7 cu.ft box here's all threes subs modeled with 1000 watts input and all have a hi - pass filter at 17 hz. There's not much difference between them.

 

[DrWho]

The AV-15 drivers have a real tight gap to keep Bl high without the extra inductance. I could see over-driving the sub quickly resulting in scraping sounds from an expanded former.

Can you push on the cone with your fingers without it scraping?

Try adding about 100 deg C temp rise to that last set of models and notice how the AV-15 is gonna be flatter than the other two. It's gonna sound cleaner too since it's gonna have way less inductance modulation.

 

[Mike P.]

It's gonna sound cleaner too since it's gonna have way less inductance modulation.

What it be enough to sound noticeable in a double blind test?

 

[hawkmoon77]

And you know, Looking at the charts that Mike posted, the AV does model well. Throw in an 80hz lowpass filter, and you are nearly flat to about 22 to 23hz, and only down 2db at 20. Room gain should compensate there.

As for what I'm looking for, well, I just want a really good home theater experience. My room is about 700 square feet, but with 12 foot ceilings, and is open to the rest of the house on three sides - with big entrances and cutouts, so it is not ideal at all.

Left and right speakers were fitted with an 8" sub with 240 watt amps in each, and are leveled to match the speakers pretty well. It really fills in the low end nice - for left and right speakers that is, and is perfect for music, no other subs are required for music.

What I want is to turn on these extra subs for movies only. I wouldn't use them for music. Because of that, I want to be able to put in a movie, feel the explosions a bit, and not have to worry about coils getting too hot, or drivers bottoming out. That's why I'm thinking running two at modest levels would be better than running one to the max. I've always been the sort to double up on hardware, rather than run what I got to its limits.

So as I looked at the charts, and saw things in the 110 to 115 range for 20hz and up, I'm thinking that would be pretty good for the movie experience. Doubling up on it would be the extra impact I want, without the extra worry about exceeding the limits of the equipment. Like I said before, I don't want some intense explosion in the movie at some critical plot point disrupted by my amps clipping or my subs making funny noises.

I'm also not keen on reproducing some 5hz sounds that the Ironman movie may or may not contain. Everyone who watches a movie over my house are your regular run-of-the-mill movie goers. Put them in front of a 72" screen, and shake them a bit with the audio, and they are easily impressed and have a good home experience. So in a nutshell, that's my goal.

I'm not sure if I'm asking too much in this regard. Hopefully I'm on track.

 

[hawkmoon77]

UPDATE:

So I had a chance to run some sine waves through it with the ep4000... but this time, I sealed up the hole in the back of the enclosure that the Oaduio plate amp was in. I also ran it unbridged. Both were a stupid oversight on my part. Wow, what a difference.

First of all, I had to double check the software I was using because the sine wave sounded completely different than what I was hearing previously. It had a much more distinct oscillating quality to it, if that makes sense. I'm not saying it was cleaner or better, just different.

After slowly creaping the levels upward, I eventually maxed out all of the gain knobs. The woofer was clean and handled it all fine. I then gradually lowered the fequency from 200hz down to 16hz, watching the excursion carefully. It had no problem with any of it. Even at 16hz, it didn't bottom. I was not running any type of high or low pass filters.

Needless to say I am pleased with this development, and owe it all to the encouragement I got from you guys to give the driver a second chance. After all of this, it looks like the driver had more of an appetite than the Oaudio 500watt amp could reliably deliver. Thanks to the build quality of the AE driver, and the soft bottoming feature (and me leaping out of my chair to unplug everything the moment I heard a "clink") it looks like the driver is undamaged.

If all of you don't mind providing additional guidance, I could really use some direction designing the 7 to 8 foot enclosure. I'm thinking slot port, but have no experience with that type of port. I'll do some more research on this point before I solicit any specific advice from you guys.

Thanks again.

 

[exojam]

Hawk,

Glad to hear about your driver. Just wondering, why are you wanting to move from the cabinet you have to another one? It also sounds like you are wanting to go from sealed to ported (in some fashion). From the description you used about your room and listening habits I would just place it back the original cabinets, no HPF, single channel of the EP and be done.

James

 

[hawkmoon77]

I'm going to have to remake the enclosure anyway. I had built a 4 cu. ft. cube, which it turns out, fits very poorly into our room. I really need something less deep and taller. Oh, and the 1.25 inch thick walls were overkill, so it is ridiculously heavy.

Because I thought that I'd also us it for music, I chose to go sealed. I completely underestimated the abilities of my towers though, and can now dedicate the sub(s) to home theater exclusively. As such, I'd like the response flatter toward 20hz. I don't care about anything lower than that, so that should keep the box size in check.

 

[hawkmoon77]

I'm going to do a few more tests. Apparently the "low-cut" filter as Behringer calls it, was on, and set to 30hz. This would explain why I was able to max it down to 16 hz. I still got some decent results, but need to test it unfiltered. Apperently to turn the filter off, you have to set the switch to on.

By the way, I wasn't able to find what order the filter is. Does anyone happen to know? I can't imagine it is too steep because there was a lot happening in the 16 to 20 range.

 

[exojam]

Hawk,

Sounds like good reasons to me

What mains are you using? I am not sure I have ever seen what filter style is used in those amps.

James

 

[Mike P.]

Apparentlyto turn the filter off, you have to set the switch to on.

Facing the back of the amp switch #3 and #8 need to be moved to the right hand side for the filter to be off.

 

[Ryan Anderson]

I also took Blaser's advice, which was great - discuss the enclosure size with my wife. I showed her winisd, explained what the lines meant. I showed her what -3db sounded like on our 8 inch sub, and let her play with the box sizes in winisd to compare the results. It wasn't long before she was taking the tape measure and playing with the dimensions in our TV room. After seeing the compromises to be made in winisd, she thought that 8 cubic feet would produce a good effect while still being workable space-wise.

youre my hero

Because of that, I want to be able to put in a movie, feel the explosions a bit, and not have to worry about coils getting too hot, or drivers bottoming out. That's why I'm thinking running two at modest levels would be better than running one to the max. I've always been the sort to double up on hardware, rather than run what I got to its limits.

Doubling up on it would be the extra impact I want, without the extra worry about exceeding the limits of the equipment. Like I said before, I don't want some intense explosion in the movie at some critical plot point disrupted by my amps clipping or my subs making funny noises.

well said!

UPDATE:

So I had a chance to run some sine waves through it with the ep4000... but this time, I sealed up the hole in the back of the enclosure that the Oaduio plate amp was in. I also ran it unbridged. Both were a stupid oversight on my part. Wow, what a difference.

First of all, I had to double check the software I was using because the sine wave sounded completely different than what I was hearing previously. It had a much more distinct oscillating quality to it, if that makes sense. I'm not saying it was cleaner or better, just different.

After slowly creaping the levels upward, I eventually maxed out all of the gain knobs. The woofer was clean and handled it all fine. I then gradually lowered the fequency from 200hz down to 16hz, watching the excursion carefully. It had no problem with any of it. Even at 16hz, it didn't bottom. I was not running any type of high or low pass filters.

Needless to say I am pleased with this development, and owe it all to the encouragement I got from you guys to give the driver a second chance. After all of this, it looks like the driver had more of an appetite than the Oaudio 500watt amp could reliably deliver. Thanks to the build quality of the AE driver, and the soft bottoming feature (and me leaping out of my chair to unplug everything the moment I heard a "clink") it looks like the driver is undamaged.

If all of you don't mind providing additional guidance, I could really use some direction designing the 7 to 8 foot enclosure. I'm thinking slot port, but have no experience with that type of port. I'll do some more research on this point before I solicit any specific advice from you guys.

Thanks again.

great news!

I'm going to have to remake the enclosure anyway. I had built a 4 cu. ft. cube, which it turns out, fits very poorly into our room. I really need something less deep and taller. Oh, and the 1.25 inch thick walls were overkill, so it is ridiculously heavy.

Because I thought that I'd also us it for music, I chose to go sealed. I completely underestimated the abilities of my towers though, and can now dedicate the sub(s) to home theater exclusively. As such, I'd like the response flatter toward 20hz. I don't care about anything lower than that, so that should keep the box size in check.

why not tune lower?

 

[hawkmoon77]

why not tune lower?

Well, there seem to be a lot of compromises going too low in terms of space and power usage. I'm not putting a hard stop at 20hz of course, I'm okay if the rolloff starts off about there if it means a smaller enclosure and a cooler amp.

That being said, I'll tune as low as I can within my design constraints. I'm still researching round ports vs slot port design and trying to come up with some ideas on the enclosure size/shape.

As popular as the Behringer ep2500/ep4000 amps are, I'm surprised that I couldn't find the filter specs posted anywhere. Does anyone have that amp and a SPL meter to take some rough measurements?

 

[hawkmoon77]

Facing the back of the amp switch #3 and #8 need to be moved to the right hand side for the filter to be off.

Yeah, so according to the instructions, you have to turn on "filter-off mode." Not exactly intuitive.