[hawkmoon77]

Hello everyone, and thanks in advance for your help.

About 6 months ago, I bought an Acoustic Elegance AV-15H speaker to use in my home theater. I ran it in a sealed 4 foot enclosure, thinking that it would never hit xmax at my power levels, but I was wrong. I also thought that I'd be happy with the ouput, and I was not. I wondered if the speaker was deffective, but that's a whole different issue.

My point is that I'm looking everywhere for a good replacement. One of the things important to me that led me to the AV15-h was it was good for smaller enclosures. I've looked at the list of all of the subs used in projects here, and visited the manufacturers websites, but simply cannot find a good replacement.

So here's where I stand today.

• I have a Behringer ep4000 amplifer to power the sub.
• I'm willing to make another enclosure to fit the new driver.
• I am limited to an "end table" size (as defined by my wife). I estimate I'll have 5 to 7 cubic feet to play with.
• I want to vent it to get as low as possible (my left and right speakers each have built in 8" subs that give me a great response down to 40hz and taper off into the 30's)
• I'd prefer a 15 inch driver
• If I can find something that would work well and didn't break the bank, my wife might let me make a second subwoofer "end table!"

Price is a concern - I wouldn't mind 250 to 350. If it were truly justified, I suppose I could put in more.

So I was leaning toward the Dayton Titanic, but couldn't get it to perform in anything less than 9 to 12 cubic feet. The AE sub that I have models pretty good in a 6ish cubic foot box tuned to 20hz, but it doesn't work in practice. I was impressed by the SoundSplinter drivers, but vented box sizes are just too big, although the RLS15 says it could work from 5 to 9.5, I don't want to spend that much on a driver and put it in a sub-par enclosure (it also seems a bit overpowered for my amp).

Lastly, after my experience with the AE speaker, I'd like to get something that is "tried and true" for home theater sub use.

Thanks for reading this, and I appreciate any feedback.

 

[hawkmoon77]

Thanks for the thought. I'll look into it, but If I can stick with the size and budget requirements, I'll be able to make a second one. This sub seems too big and pricey to add a second one later on.

 

[hawkmoon77]

It works fine when I pump less than 300 watts in it (which is enough to get some things in the house buzzing). Anything more and it makes a metallic rattle or clicking like sound when there are quick bursts of heavy bass. I checked the dustcap, and it seems like it's on tight, no other noticible issues. I originally had an oaudio 500watt plate amp that powered it. I bought the amp thinking that I was never going to dump too much power into the sub, but after talking to John at AE, I figured there was a possibility of amp clipping. The problem was that I'd get rattling with the gain up only about 25 percent. I borrowed a friends sub and ran it off the oaudio amp at nearly full gain with no clipping.

I thought perhaps that the AE speakers were just a bit more power hungry, so I got the Behringer ep4000 amp, wired it up in mono, thinking that I wouldn't have any clipping problems. Rattling/clicking still appeared.

Now I did try running it in a vented enclosure, just to see what would happen. I basically removed the plate amp and put in a temporary piece of wood to cover the hole, and added an external vent to it tuned to 20hz (the box was 4 cubic feet). I had the same metallic clicking sound during moments of heavy bass with modest volume levels. (It did have slightly more sound ouput though).

So I'm more than a little dissaspointed in this driver (especially after waiting so long to get it), and I think I'm just going to cut my losses on it and the o-audio amp i had gotten for it, and just try again. I don't want to pay more for passive radiators to try to salavage this driver.

 

[hawkmoon77]

Funny you should mention that! What a frustrating experience I had with it. The short answer is that I tried all of them!

The O-audio amp apparently has some db gain at the lower filter settings - which meant that the 12 and 16hz options were not usable (I'd get a lot of rattle during movies). The 20hz filter protected it more often during movies, but I'd run sine waves through it from 20 to 60 and still have the problems when I'd turn the amp knob around the halfway mark. Nothing ruins the movie experience quite like, at the moment of some peak action sequence, hereing a rattle come out of your sub... so, gain was set back down to about 25%.

Anyway, and disapointingly enough, I'd leave the highpass filter at 25hz. But then, the output was so low because I also kept the lowpass filter at around 60hz, that I'd want to turn the gain up on the amp - which then caused it to clip, which caused me to unplug everything and put the speaker back in the box out of frustration!

No matter what I did, I just couldn't get the db's out of it reliably. I also came across some recent criticism of this driver, so I'm really questioning its long term relaibility anway. I really do not want to make another enclosure for it, and then have it fail.

 

[hawkmoon77]

Thanks for the advice. I'll try that. Since I've gone into more detail about the AE driver than I had intended to, let me add this...

I am not suggesting that all of them have this problem, and I still really don't know if it is me, my setup, or the driver. I still contend that it looks like they are made well. From what I know of the AE company, they would probably be very helpful in a troubleshooting/warranty scenario - and I will follow up with John about this.

It's just that I've spent about 900 bucks between the sub, amp, second amp, and enclosure supplies (not to mention the many weekends building the thing), only to have less than steller auditions of it with the wife while trying to watch some movies. I think I have a better chance of keeping this project funded if I can just get a proven subwoofer/box combo built. It's what I did for the left,right, and center speakers (I went with a slight modification of Zaph's ZDT3.5 design). My wife was so impressed with the quality, sound-levels, and size that she instantly gave me the go ahead to bring in as many as two end table size subs. 900 bucks into it, and I have three failed attempts at watching movies.

 

[hawkmoon77]

So is there any modestly price 15" sub that will fit well in a 6 to 7 cubic foot vented box and can be powered by a Behringer ep4000? If not, I need to figure out how to build an end table that is 9 cubic feet big.

 

[hawkmoon77]

I'm looking into the Tempest-X2 15"

The power requirements make me think that my amp could power two of them, which would really cut the price of the total project if I only need one amp between the two subs. I'm eager to see how it will model in a smaller enclosure. The price is right. Does anyone know the RMS power on this?

 

[hawkmoon77]

This looks great. I noticed on the DIYcable website that they say the Tempest would work well setup as: "180L (6.35 cubic feet) Ported and tuned to 19Hz with 15% poly-fill." So this is right in line with my limitations. Do you think that my amp could power two of these subs, or would I need one amp per sub?

I also like the pricepoint. I'm thinking two of these, powered from one channel each of the ep4000, (or each having its own amp in bridged mode) would make two great end tables sized boxes. I'd spend about 450 for the drivers, and perhaps another 350 for another amp (if needed) and I'd think I'd get the right HT experience without taking up too much space.

 

[hawkmoon77]

I was originally thinking of using an "f-mod" RCA inline high pass filter. Unfortunately, it looks like the lowest they go is 20hz.

 

[hawkmoon77]

Thanks!

 

[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.

 

[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.

 

[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.

 

[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.

 

[hawkmoon77]

***Moved to my build thread***

 

[hawkmoon77]

I'd like to put the enclosure design into another thread to keep this one on point. So with that in mind, I'll sum up the thread here, and move on to designing a better enclosure. Regarding the problems I was having with the AE speaker, and my request for other subwoofer recomendations:

It looks like the SDX15 and Tempest-X are good recplacements. They seem to have similar performace and pricepoints. When modeled in ported 9 to 11 cu. ft. enclosures, they all seem to model well and perform similarly, although the AE did not have the flattest response. When modeled in ported enclosures from the 6 to 9 range, the the AE seemed to do better on the low end.

As far as the original problems with the AE driver, it looks like the OAudio 500 amp is NOT a good choice to power it. The amp was fine on another sub of that size, but caused clipping early on for the AE driver. My guess is that the lower resistance of the AE speaker was the culprit. Running the same driver on a single channel of the Behringer ep4000 produced great results.

Thanks again to everyone for their support an encouragement to give the speaker another chance.

Now, onto creating a build thread for it...